annual activity report - INCT

Edital N º 15/2008 – MCT/CNPq/FNDCT/CAPES/
FAPEMIG/ FAPERJ/FAPESP
INSTITUTOS NACIONAIS DE CIÊNCIA E TECNOLOGIA
(Tema: Tecnologias da Informação e Comunicação)
ANNUAL ACTIVITY REPORT
NATIONAL INSTITUTE OF WIRELESS COMMUNICATIONS
INCT-CSF
APPLIED RESEARCH IN WIRELESS WIDEBAND
COMMUNICATION SYSTEMS
2010
INCT de Comunicações Sem Fio (INCT-CSF)
Caixa Postal 1655, Campus da UFRN
59078-380 Natal, RN, Brazil
Homepage: www. inct.ct.ufrn.br / www.inctcsf.ct.ufrn.br
Tel.: +55-84-3215-3907 / 3215-3912; Fax: +55-84-3215-3703
e-mail: [email protected] / [email protected]
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Contents
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Institute Universities
Main Researchers
Administration Committee
CNPq / Institute Research Groups
Our Mission
Our Goals
Main Research Topics
Summary of Results to Date
Main Publications
Developed Research Activities (2009-2010)
CETUC-PUC/Rio
GAPTEM/UFMG
LEA / LCT–UFPA
GMA/UFRN
Events
Conclusion
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Institute Universities
• Federal University of Rio Grande do Norte (UFRN)
• Catholic University of Rio de Janeiro (PUC/Rio)
• Federal University of Minas Gerais (UFMG)
• Federal University of Pará (UFPA)
Main Researchers
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Adaildo Gomes D’Assunção, UFRN (Coordinator)
José Ricardo Bergmann, PUC-RJ (Vice-Coordinator)
Luiz Alencar Reis da Silva Mello, PUC-RJ
Flávio José Vieira Hasselmann, PUC-RJ
Marlene Sabino Pontes, PUC-RJ
Gláucio Lima Siqueira, PUC-RJ
Laércio Martins de Mendonça, UFRN
Humberto César Chaves Fernandes, UFRN
Sandro Gonçalves da Silva, UFRN
Gervásio Protásio dos Santos Cavalcante, UFPA
João Crisóstomo Weyl Albuquerque Costa, UFPA
Carlos Leônidas da Silva Souza Sobrinho, UFPA
Evaldo Gonçalves Pelaes, UFPA
Fernando José da Silva Moreira, UFMG
Cássio Gonçalves do Rego, UFMG
Administration Committee
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Adaildo Gomes d’Assunção (Coordinator)
José Ricardo Bergmann (Vice-Coordinator)
Gervásio Protásio dos Santos Cavalcante
Fernando José da Silva Moreira
Flávio José Vieira Hasselmann
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CNPq / Institute Research Groups
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Microwaves and Antennas Group
Adaildo Gomes d’Assunção (Coordinator), UFRN.
•
Antennas
Flávio José Vieira Hasselmann and José Ricardo Bergmann (Coordinators), PUC/RJ.
Radio Propagation and Wireless Communication Systems
Luiz Alencar Reis da Silva Mello and Marlene Sabino Pontes (Coordinators), PUC/RJ.
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Applied Electromagnetism
Gervásio Protásio dos Santos Cavalcante (Coordinator), UFPA.
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Antennas, Propagation and Electromagnetic Theory
Fernando José da Silva Moreira (Coordinator), UFMG.
Our Mission
To consolidate the cooperation between the research groups from PUC, UFMG, UFRN
and UFPA, with the end result of creating a structure (based on measurement and
modeling) to implement access technology, which targets the viability of strategic
applications in the country. Another objective is the training of human resources, at the
undergraduate and graduate levels, as well as in the dissemination of production, services,
and public services of new technology involved in the use of Digital TV and Radio.
Our Goals
- To experimentally and theoretically determine the characteristics of the propagation
channel in the VHF and UHF ranges in tropical and equatorial regions.
- To develop mathematical models for the forecasting of VHF and UHF range coverage,
for use in digital TV systems.
- To carry out measurements of the electrical characteristics of the ground by means of
field intensity in the medium wave rage.
- To propose a propagation model which allows the consideration of the irregular profile
of the terrain, and which optimizes the planning of the digital radio systems.
- To propose a new ground conductivity map for Brazil.
- Development of propagation models, project techniques and computational tools for the
WiMAX networks in urban, suburban and rural areas.
- To plan, coordinate and optimize the WiMAX networks in urban, suburban and rural
areas.
- To develop project techniques and antenna analysis for signal reception of fixed and
mobile users and for 3G broadband services and WiMAX.
- To develop formulas in the time and frequency domains for scattering by antennas
(reflector and microstrip) and selected frequency surfaces to be used in digital
broadcasting and UWB systems.
- To develop adaptive algorithms for signal processing in antenna arrays.
- To develop techniques using artificial intelligence for television and broadcasting use.
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Main Research Topics
• Measurements and propagation models at MW, VHF and UHF for application in the
deployment of digital TV and radio systems in Brazil.
• WiMax network planning – Measurements and propagation models.
• Antennas for the reception of signals by fixed and mobile users and broadband
services.
Summary of Results to Date
To date, four workshops were promoted by INCT-CS, with the participation of
researchers and students in the cities of Belem, Natal, and Belo Horizonte. Furthermore,
RF measurement campaigns were carried out in Rio de Janeiro, Sao Paulo, Belo
Horizonte, Belem, and Natal. Since 2009, several Doctoral dissertations were supervised:
3 at UFRN, 2 at PUC-RJ, and 1 at UFMG. Regarding Masters theses: 11 at UFRN, 3 at
PUC-RJ, and 2 at UFMG have been supervised. Results of these studies were published
in major conferences (IMOC 2009, COMPUMAG 2009, IWATA 2010, EuCAP 2010,
Antem 2010, CEFC 2010, EuMC) and technical journals. Publications in technical
journals are listed in a following section.
There were four measurement campaigns, two in Sao Paulo (medium wave) and two
in Belo Horizonte (VHF), to determine the propagation characteristics in urban and
suburban areas. We performed a measurement campaign in Rio de Janeiro in the UHF
band to characterize the channel systems in SFN Digital TV. In Rio de Janeiro and Natal,
measurement campaigns were conducted to characterize the propagation channel systems
WiMAX. The results were used in the development and optimization of prediction
models to 3.5 GHz. In Belem, measurements were performed at 5.8 GHz.
We developed new configurations of microstrip antennas and frequency selective
surfaces (FSS) for applications in wireless communications systems. Aspects related to
the miniaturization of such antennas are being investigated through the use of fractal
structures and substrates with high permittivity. Antennas for broadband and multiband
services are being investigated. The increased bandwidth of FSS is being investigated by
the use of fractal geometries and coupled structures. Techniques were developed for
modeling omnidirectional dual-reflectors based on Geometrical Optics (GO). The
objective is to develop design techniques where there is a need to model only one of the
reflector surfaces, keeping the other classical (ie, generated by conic sections). The
desired radiation profile for the omnidirectional coverage is the cosecant-square elevation
in the plane of the antenna. Furthermore, formulations were developed for asymptotic
integral operators that allow the determination of complete response of parabolic reflector
antennas excited by feeders with arbitrary temporal behavior. The objective is to obtain
tools for the analysis and design of UWB antennas.
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Main Publications
• Oliveira, E. E. C., Silva, P. H. da F., Campos, A. L. P. S., and D'Assunção, A. G., “Smallsize quasi-fractal patch antenna using the Minkowski curve”, Microw Opt Technol Lett, v.
52, p. 805-809, 2010.
• Carneiro Filho, R., Araújo, J. H., Ginani, M. F., D’Assunção Jr, A. G., Martins, R. A.;
D'Assunção, A. G., and Mendonça, L. M., “Simulation and measurement of inset-fed
microstrip patch antennas on BiNbO substrates”, Microw Opt Technol Lett, v. 52, p. 10341036, 2010.
• Araújo, L. M., Maniçoba, R. H. C., Campos, A. L. P. S., and D'Assunção, A. G., “A simple
dual-band frequency selective surface”, Microw Opt Technol Lett, v. 51, p. 942-944, 2009.
• Cruz, R. M. S., da F. Silva, P. H., and D'Assunção, A. G., “Neuromodeling stop band
properties of Koch Island patch elements for FSS filter design”, Microw Opt Technol Lett,
v. 51, p. 3014-3019, 2009.
• Silva, P. H. F., Cruz, R. M. S., and D'Assunção, A. G., “Blending PSO and ANN for
Optimal Design of FSS Filters with Koch Island Patch Elements”, accepted for publication,
IEEE Trans. on Magnetics, 2010.
• Campos, A. L. P. S., Maniçoba, R. H. C., Araújo, L. M., and D'Assunção, A. G., “Analysis
of Simple FSS Cascading with Dual Band Response”, accepted for publication, IEEE
Trans. on Magnetics, 2010.
• Bergmann, J. R., and Moreira, F. J. S., “Shaping Axis-Symmetric Dual-Reflector Antennas
by Combining Conic Sections,” accepted for publication, IEEE Transactions on Antennas
and Propagation, 2010.
• Nicomedes, W. L., Mesquita, R. C., and Moreira, F. J. S., “An integral meshless-based
approach in electromagnetic scattering,” The International Journal for Computation and
Mathematics in Electrical and Electronic Engineering (COMPEL), accepted for
publication, 2010.
• Nicomedes, W. L., Mesquita, R. C., and Moreira, F. J. S., “2-D scattering integral field
equation solution through an IMLS meshless-based approach,” IEEE Transactions on
Magnetics, accepted for publication, 2010.
• Rego, C. G., Gonçalves, S. T. M., and Moreira, F. J. S., “High-frequency • asymptotic
formulation for prompt response of parabolic reflector antennas,” AEÜ - International
Journal of Electronics and Communications, vol. 64, no. 1, pp. 36-46, Jan. 2010.
• Bergmann, J. R., and Moreira, F. J. S.,, “Omnidirectional ADE antenna with GO shaped
main reflector for arbitrary far-field pattern in the elevation plane,” IET Microwaves,
Antennas & Propagation, vol. 3, no. 5, pp. 1028-1035, Oct. 2009.
• Bergmann, J. R., and Moreira, F. J. S., “Bandwidth behavior of omnidirectional dualreflector antennas synthesized for uniform coverage,” Journal of Microwaves,
Optoelectronics, and Electromagnetic Applications, vol. 8, no. 1, pp. S1-S8, June 2009.
• Gonzalez Castellanos, P.V., Pérez García N.A., Paredes J.L., Uzcátegui J.R., Peña J.B.,
Duque L., Silva Mello L.A.R., and Souza R.S.L., “Measurements of terrestrial digital TV
signals at two cities in South America”, 4th European Conference on Antennas and
Propagation, EuCAP 2010, Barcelona, Spain, April 2010. • Ramirez, A.R., Silva Mello, L.A.R., and Hasselmann, F.J.V., “Application of FDTD to the
Analysis of Indoor Coverage”, 3rd European Conference on Antennas and Propagation,
Berlim, 2009. • Ramirez, A.R., Silva Mello, L.A.R., and Hasselmann, F.J.V., “On the Implementation of
FDTD Codes in the Coverage Analysis of Indoor Scenarios”, SBMO/IEEE International
Microwave and Optoelectronics Conference, Belém, 2009. • Couto de Miranda, E., Quesnel, M. C., and Silva Mello, L.A.R., “Empirical Model for the
Statistical Characterization of Rain Fade Slope in Tropical Climates”, Journal of
Microwaves and Optoelectronics, v.8, p.143S - 153S, 2009.
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• Silva Mello, L.A.R., Pontes, M.S., and Couto de Miranda, E., CASTELLANOS,
P.V.G."Outage Intensity Due to Multipath Fading in Terrestrial Links", Electronics Letters,
Londres, v. 45, p.491-492, 2009.
• Silva Mello, L.A.R., Pontes, M.S., and Couto de Miranda, E., Measurements and Prediction
of Outage Intensity Due to Multipath in Terrestrial Line-of-Sight Links, 3rd European
Conference on Antennas and Propagation, Berlim, 2009, v. 1, pp. 1-4.
• Ramirez, L.A.R., Carvalho, A.D., Trintinalia, L.C., Hasselmann, F.G.V., and Silva Mello,
L.A.R. “Indoor Channel Characterization: FDTD Simulations and Measurement”, 4th
European Conference on Antennas and Propagation, EuCAP 2010, Barcelona, Spain, 2010.
• Rodríguez Ron, C. V., and Silva Mello, L. A. R., “Propagation Measurements at 3.5 GHz
in a Dense Urban Area”, 4th European Conference on Antennas and Propagation,
EuCAP’2010, Barcelona, Spain, 2010.
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Developed Research Activities (2009-2010)
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CETUC-PUC/Rio
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GAPTEM/UFMG
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LEA / LCT – UFPA
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GMA/UFRN
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1. A Brief Description of CETUC-PUC/Rio
The Center for Telecommunication Studies at the Catholic University of Rio de Janeiro is a
complementary unit of the Technical-Scientific Center at the Pontifical Catholic University of Rio
de Janeiro, created in 1965 to conduct research, coordinate and carry out teaching activities at
the graduate and postgraduate levels (Masters and Doctorate) and develop projects in the
telecommunications area. The teaching activities are performed by the Department of Electrical
Engineering at PUC-Rio. Postgraduate activities take place within the Postgraduate Program in
Electrical Engineering, which received a grade of 6 in the most recent CAPES assessment. The
professors are involved in the areas of applied electromagnetism and communications systems.
CETUC has 9 laboratories and one mechanical shop. It also has a library specialized in
telecommunications. Additional information on this project can be found on the CETUC website
(www.cetuc.puc-rio.br).
Research activities in antennas and propagation began with the very creation of CETUC in 1965.
Initially, VHF and UHF antenna prototypes were developed for radio transmission and rural
telephones, whose design and manufacturing technology was passed on to the then incipient
national industry. Accompanying the implementation of the microwave-based ground
communication system was the development of parabolic reflectors and conventional feeders, as
well as passive repeaters. During the 1970s, with the perspective of launching a domestic
communication satellite, research efforts were directed toward the study of feeders and reflector
systems that would integrate future ground stations. In this phase, diagonal and corrugated
multimode horn prototypes were developed. A double-reflector system was also designed for the
C-band, transferred to industry through the Center for Research and Development (CPqD) of
TELEBRAS. To accompany the growing capacity of telecommunication companies along with the
consolidation of CPqD laboratories in the 1980s, antenna synthesis and analysis methods were
developed for communications in the microwave band to meet the demands of the National
Communications System. Starting in 1990, in addition to the important support of
CPqD/TELEBRAS, the team professors also took part in international agreements entered into by
INTELSAT for the exploratory development of satellite interlacing in equatorial regions and of
loaded antennas for satellite communications. Additional support for the research was provided
by specific projects financed by the Study and Project Financer (FINEP) and by the Program for
Centers of Excellence (PRONEX) of the Ministry of Science and Technology (MCT) within the
project “Applied Research in Telecommunications”. CETUC was the recipient of the first
university project (Engineering of Broadband Networks and Services) financed by FUNTTEL.
2.
Research Activities Developed by CETUC-PUC/RIO
During the period 2009-2010, CETUC-PUC/Rio developed the following research activities.
2.1 – Measurements and propagation models in VHF and UHF medium waves for use in
the implementation of digital TV and radio systems in Brazil
2.1.1 Field intensity measurements, delay profiles and analysis of the results in the
medium wave, VHF and UHF bands
A medium wave propagation measurements campaign carried out in São Paulo, BR. The hybrid
signal composed of an analog signal (AM) and a digital signal was transmitted during a short
period of time, broadcasting the same content, in diurnal and nocturnal transmission.
Measurements were carried out in 1210 kHz and 790 kHz.
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2.1.1.1 Measurements setup
Measurements were carried out in 1210 kHz and 790 kHz in the city of São Paulo, Brazil. Figure
1 presents a schematic configuration of the transmission modules.
Figure 1 - Diagram of transmitter setup
Reception was carried out with a mobile station of Inmetro (Instituto Nacional de Metrologia,
Normalização e Qualidade).
Figure 2 – Mobile reception unit
A diagram of the reception system is shown in Figure 3.
Figure 3 - Diagram of receiver setup
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The AOR7030 receiver measures the intensity of received signal (eletrical field) and the signal-tonoise ratio of DRM digital signal. Signal-to-noise measurement is based on the modulation error
ratio (MER) [3], which measures the quality of the received signal. This parameter includes the
contribution of all failures that the received signal has suffered, not only the noise contribution. In
this way, this measurement provides an indication of the receiver ability to correctly decode the
signal. The AOR7030 receiver calculates MER each 400 ms (or at each transmitted frame of
DRM signal). For subjective analysis of audio quality, the receiving setup contained also two
analog AM radios and one UNIWAVE radio. 2.1.1.2 Measurements campaings
The assesment of DRM system is divided in two analysis, as follows:
-performance evaluation: it verifies the robustness of DRM digital signal the coverage area and
digital audio quality;
-compatibility with existing AM analog systems: it analyses the mutual interference between the
digital signal and existing AM systems, including the hybrid simulcast signal;
The coverage area of a broadcast digital signal is defined as the area within a contour of field
intensity, where the signal loss is almost imperceptible. The extension of this area depends on
the effective radiated power, and, in the case of terrestrial medium waves, it depends on the
ground eletrical conductivity. Another issue is the ability of the signal to resist deterioration until it
reaches the receiver. Man made noise, atmospheric noise and inter-system interference are the
main causes of the signal deterioration.
The DRM coverage evaluation was done with measurements of the received signal along radial
and circular routes. The radial routes allowed the knowledge of the extension of DRM coverage
area. The circular routes were directed to the study of special environments in São Paulo city,
where the received signal could be exposed to degrading conditions like tunnels, power lines and
noise.
Measurements were registered during the displacement of the mobile unit. DRM frames have the
length of 400ms and their specification is defined in document ETSI TS 102 349 [3]. The
parameters to be registered are defined in the software of the receiver. The sets of both
campaigns have information about hour, signal intensity, doppler shift, delay spread,
syncronization flags, signal-to-noise ratio of logic channels, geographical coordinates and mobile
velocity. The routes of the mobile station in each campaign are shown in Figure 4 and Figure 5.
Figure 4 – Measurement routes – Campaign 1
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Figure 5 – Measurement routes – Campaign 2
2.1.1.3 Measurements results
As a sample of the measured results, Figure 6 and Figure 7 show a comparison between
measured values of received field intensity in campaign 1 and those predicted by
Recommendation ITU-R P-368 and a similar prediction method, used by Anatel, the Brazilian
Telecommunications Regulatory Agency.
Figure 6 – Measurements at fixed points - 16QAM, campaign 1
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Figure 7– Measurements at fixed points - 64QAM, Campanha 1
The signal to noise ratio required for good reception was evaluated based on the average value
of field intensity at fixed points, the corresponding signal to noise ratio and the measured audio
quality (AQ). Figure 8 and Figure 7 show the results.
Figure 8 – Field intensity vs. SNR - 16QAM, Campanha 1
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Figure 9 – Field Intensity vs. SNR - 64QAM, campaign 1
Data collect in campaign 2 are still under analysis.
2.1.2
Published papers and thesis
The following papers were published as a result of the work in this research area:
a) R.S.Souza, M.Almeida, P.Castellanos, A.Soledade, F.F.Lima, J.Carvalho Neto e L.A.R
da Silva Mello, “Preliminary Results of Medium Wave Propagation Measurements in
Metropolitan São Paulo”, MOMAG 2010, Vila Velha, ES, Agosto 2010.
b) Gonzalez Castellanos, P.V., Pérez García N.A., Paredes J.L., Uzcátegui J.R., Peña
J.B., Duque L., Silva Mello L.A.R., and Souza R.S.L., “Measurements of terrestrial
digital TV signals at two cities in South America”, EuCAP’2010, Barcelona.
The following Masters thesis is under development:
a) Maurício Vilela Guerra. Efeitos de Propagação em redes de TV Digital de Frequência
Única (SFN). Dissertation (MSc in Electrical Engineering) - Pontifícia Universidade
Católica do Rio de Janeiro.
2.2 – WiMAX network planning – Propagation measurements, models and computer
tools
2.3 Propagation measurements at SHF
Wideband propagation channel measurements at 3.5 GHz were performedin an urban area in
Rio de Janeiro, Brazil. Results include multipath delay profile characterization and comparison
of measured path loss and predictions using ITU-R and SUI models.
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2.3.1
Measurements setup
The OFDM channel sounder [1] used in this campaign permits measurements on all frequencies
simultaneously, similarly to a chirp sounder.
The equipment was configured to obtain one sample per second, each sample including six
OFDM symbols. To facilitate the recovery of OFDM symbols, guard intervals of half a symbol
duration were introduced. For practical reasons, each measurement run was recorded over a 15
minutes of collected data, producing data files of 200 MB per run.
The transmitter was set-up on the top of a building at the Catholic University of Rio de Janeiro.
The region has a relative flat terrain with moderately high residential buildings surrounded by hills.
Fig. 1 shows the distribution of buildings in the measurements area. Fig. 2 shows the
measurements routes.
A 15 dBi sector antenna with 120° HBW was mounted at 42 meters of height above ground level
with no vertical tilt. A MS2781B Anritsu signal generator and a class A power amplifier were
configured to provide 1 watt EIRP.
The receiver set up includes a 5 dBi antenna, a low noise amplifier with 30 dB gain, a GPS
receiver and a signal vector analyser Anritsu MG3700A. The receiver system was mounted in a
vehicle and data were collected while travelling in the urban neighbourhood with an average
speed of 40 km/h. The bandwidths of 20 MHz, 7 MHz, 3.5 MHz and 1.75 MHz. used in
measurements provide multipath resolutions of 15 m, 42.9 m, 85.7 m and 171 m, respectively.
Figure 10 ‐ Measurement routes.
2.3.2
Propagation loss measurements
The propagation loss was obtained from temporal measurements of in-phase (I) and quadrature
(Q) components. Considering the GPS error, the measured power values of all points within a 8
meters radius was averaged to provide the received power for a specific geographical coordinate.
Figure 2 shows the measurements routes.
The measured propagation loss was compared with two ITU-R propagation models, ITU-R
P.1546-3 for distances over 1 km and ITU-R P. 1411-3 for distances below 1 km.
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Figure 11 ‐ Measured path loss and Rec. ITU-R P.1546 predictions (d>1km)
Figure 12 ‐ Measured path loss and Rec. ITU-R P.1411 predictions (d<1km)
It can be observed that the model in Rec. ITU-R P. 1546 significantly overestimates the
attenuation whereas the model in Rec. ITU-R P. 1411 significantly underestimates it.
Additionally, comparison was made against the SUI point-to-area prediction models. The SUI
models provide the best prediction results but still tend to underestimate for short distances and
overestimating for longer paths.
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Figure 13 ‐ Comparison between measured path loss and SUI prediction models
2.3.3
Delay spread measurements
Data processing to obtain the channel impulse response consists of multiplying the received
signal (Y) on the frequency domain by the inverse of a replica of the transmitted signal (X).
Additional correction is made in order to compensate the effects of hardware components
(antennas, connectors, cables and amplifiers). To allow this correction an impulse response
(CAL) was obtained on an open area with no obstructions.
The Inverse Fourier Transform of the resulting vector in equation (1) provides the power delay
profile of a specific measurement.
relative amplitude (dB)
relative delay
µsec
()
distance )(m
Figure 14 - Comparison between measured path loss and SUI prediction models
The CFAR (Constant False Alarm) cleaning procedure was applied received signal to identify the
actual multipath components. A total of 2440 power delay profiles were obtained along 13
different routes in the measurements region. The average value and the standard deviation of the
RMS delay spreads obtained from the measured power delay profiles in each route are shown in
Table 2. For the whole set of measured data the average value of the RMS delay was 0.196 ms
with standard deviation of 0.161 ms.
The probability density function (PDF) and the cumulative distribution function (CDF) of the RMS
delay spread were obtained for LOS and NLOS conditions.
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Figure 15 ‐ PDF (∗) and CDF (—) of RMS delay spread in NLOS conditions
Figure 16 - PDF (∗) and CDF (—) of RMS delay spread in LOS conditions
2.4 Indoor propagation measurements and modeling
Considering typical indoor environments with different morphologies, as furnished offices, the
FDTD technique was adapted for the prediction of indoor coverage of SIMO systems (Simple
Input Multiple Output), Results were validated through comparison with predictions with analytical
methods (ray tracing) and measured data.
The method was used to predict the coverage in a complex environment, consisting of several
rooms with a variety of door, walls and furniture varied geometry and materials.
The investigation of coverage patterns at different time instants allowed verification of the
expected pulse evolution through the environment. This was confirmed by the analisys of the
received signal received in different points, either in line-of-sight and non line-of-sight aituations.
In the same enveironment, a measurements campaign of Digital TV signals at UHF and
simulation results were confirmed by the experimental data, further validating the methodology.
The program was also tested, with very good results, against simulations and experimental
results (made available by IMST GmbH, Germany) of UWB (Ultra Wide Band) signal
characterization.
2.5 Point-to-area propagation modeling
Using the measurements results given in section 2.2.1, a first study of two models were
developed. As a first study, to predict propagation loss in urbanized areas.
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The first model considers two distinct situation, line-of-sight (LOS) and non line-of-sight
conditions. Starting with the SUI model, for the NLOS conditions a dependency with distance was
introduced in the path attenuation factor in the form γ = a + b * d + c / d . Multiple nonlinear
regression provided a=3,83, b=-0,0002 e c=1600.
LLOS = 82.5 + 10 * (3,83 − 0,0002d + 1600 / d)log(d / 100)
For the any loss case an expression based on the free sapece loss with a correction constant
provided good results:
LLOS = 112,8 + 20log(d / 100)
With this hybrid model the average error obtained against the measured data is -0,036 dB with a
standard deviation of 8,37 dB. The following figure shows a comparison between measured
propagation loss and values predicted with this model, as a function of the distance to the
transmitter.
Figure 17 – Predicted (model 1) and measured values of the propagation loss
The second model uses a single expression for both cases with the inclusion of an additional
term, proportional to the single knife edge diffraction loss of the main obstacle in the path profile
between transmitter and receiver.
LLOS = 84.5 + 10 * log(2,97 + 1430 / d) * log(d / 100) + 0,27 * Diff
With this model the average error obtained against the measured data is 0.0044 dB with a
standard deviation of 8,0 dB. The following figures show a comparison between measured
propagation loss and values predicted with this model, as a function of the distance to the
transmitter, and the histogram of residues.
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Figure 18 – Predicted (model 2) and measured values of the propagation loss
Model 1 is recommended for a simplified evaluation, without the knowledge of the terrain profile.
Model 2 can be used for a more accurate calculation.
2.5.1
Published papers and thesis
The following papers were published as a result of the work in this research area:
a) Miranda, E. C. B., Quesnel, M. C., Silva Mello, L. A. R., “Empirical Model for the
Statistical Characterization of Rain Fade Slope in Tropical Climates”. Journal of
Microwaves and Optoelectronics. , v.8, p.143S - 153S, 2009.
b) Silva Mello, L. A. R., Pontes, M. S., Miranda, E. C. B., Gonzalez Castelanos, P. V., “Outage Intensity Due to Multipath Fading in Terrestrial Links. Electronics Letters. , v.45,
p.491 - 492, 2009.
c) Ramirez, L. A. R., Silva Mello, L. A. R., Hasselmann, F. J. V., “Application of FDTD to the
Analysis of Indoor Coverage” In: 3rd European Conference on Antennas and
Propagation, 2009, Berlin. Proceedings of the 3rd European Conference on Antennas
and Propagation. Berlim: VDE VERLAG GMBH, 2009. v.1. p.2248 - 2251
d) Capsoni, C., Luini, L., Pontes, M. S., Silva Mello, L. A. R., “Global Prediction of
Cumulative Rainfall Statistics from the Simple Knowledge of the Yearly Rain Amount” In:
3rd European Conference on Antennas and Propagation, Berlin. Proceedings of the 3rd
European Conference on Antennas and Propagation. Berlim: VDE VERLAG GMBH,
2009. v.1. p.666 - 670 3.
e) Silva Mello, L. A. R., Pontes, M. S., Miranda, E. C. B., “Measurements and Prediction of
Outage Intensity Due to Multipath in Terrestrial Line-of-Sight Links”. Proceedings of the
3rd European Conference on Antennas and Propagation. Berlim: VDE VERLAG GMBH,
2009. v.1.
f)
Miranda, E. C. B., Pontes, M. S., Silva Mello, L. A. R., “Outage Intensity Due to Rain in
Terrestrial Line-of-Sight Links”. Proceedings of the 3rd European Conference on
Antennas and Propagation. Berlim: VDE VERLAG GMBH, 2009. v.1. p.662 - 665
g) Ramirez, L. A. R., Hasselmann, F. J. V., Zhang, Y. P., “Channel Charactristics in
Tunnels: FDTD Smulations and Measurements”, In: 14o. Simpósio Brasileiro de
Microondas e Optoeletrônica, 2010, Vila Velha. Anais do MOMAG 2010. SBMO, 2010.
21
h) Ramirez, L. A. R., Carvalho, A. D., Trintinalia, L. C., Hasselmann, F. J. V., Silva Mello, L.
A. R. S., “Indoor Channel Characterization: FDTD Simulations and Measurement”, In: 4th
European Conference on Antennas and Propagation, 2010, Barcelona. Proceedings of
EUCAP 2010. , 2010.
i)
Couto de Miranda E., Almeida M., Souza R. S. L., Pontes M.S., Silva Mello L.A.R.,
Rodrigues M., “Extremes of Attenuation and Rainfall in Satellite Links in Brazil”, 4th
European Conference on Antennas and Propagation, EuCAP’2010, Barcelona, Spain,
April 2010.
j)
Rodríguez Ron C. V., Silva Mello, L. A. R., “Propagation Measurements at 3.5 GHz in a
Dense Urban Area”, 4th European Conference on Antennas and Propagation,
EuCAP’2010, Barcelona, Spain, April 2010.
k) Miranda E.C., Almeida M.P., Souza R. S. L., Pontes M.S., Silva Mello L.A.R., Rodrigues
M. Pina T., “Duration and Number of Rainfall Events in Brazil”, 4th European Conferene
on Antennas and Propagation, EuCAP’2010, Barcelona, Spain, April 2010.
l)
Rodrigues M.E.C., Silva Mello L.A.R. , Pontes M.S., Carrie G., Castanet L. : “Slant Path
Rain Attenuation Synthesizers for Tropical and Equatorial Regions”, 14th International
Symposium on Antenna Technology and Applied Electromagnetics, ANTEM’2010,
Ottawa, Canada, July 2010.
The following thesis have been concluded or are under development:
a) Diego dos Santos. Planejamento de Cobertura e Capacidade de Redes de Acesso em
Banda Larga com Tecnologia LTE. 2010. Dissertação (Mestrado em Engenharia Elétrica)
- Pontifícia Universidade Católica do Rio de Janeiro. Concluída.
b) Marcio Eduardo da Costa Rodrigues. Synthesis of rain attenuation time series for Earthspace paths in tropical and equatorial areas. 2010. Tese (Doutorado em Engenharia
Elétrica) – Pontifícia Universidade Católica do Rio de Janeiro. Concluída.
c) Carlos Vinicio Rodríguez Ron. Caracterização do Canal Rádio em Banda Larga na Faixa
de 3.5 GHz em Ambiente Urbano. 2009. Tese (Doutorado em Engenharia Elétrica) Pontifícia Universidade Católica do Rio de Janeiro. Concluída.
d) Leonardo Henrique Gonsioroski Furtado da Silva. Caracterização do Canal de
Propagação Banda Larga em Regiões Urbanas. Tese (Doutorado em Engenharia
Elétrica) - Pontifícia Universidade Católica do Rio de Janeiro. Em andamento. e) Ângelo Antônio Caldeira Canavitsas. Efeitos de propagação em Sistemas Rádio
Cognitivos. Tese (Doutorado em Engenharia Elétrica) - Pontifícia Universidade Católica
do Rio de Janeiro. Em andamento.
f)
Fernando José de Almeida Andrade. Simulação de Eventos de Atenuação por Chuvas
em Enlaces Terrestres. Tese (Doutorado em Engenharia Elétrica) - Pontifícia
Universidade Católica do Rio de Janeiro. Em andamento.
22
1. A brief description of GAPTEM/UFMG
The Group of Studies in Antennas, Propagation, and Electromagnetic Theory (GAPTEM) of the
Federal University of Minas Gerais (UFMG) is composed by professors from the Department of
Electronics Engineering of UFMG and by undergraduate and graduate students in Electrical
Engineering of UFMG. The group’s activities are geared to teaching and researching in the areas
of telecommunications and applied electromagnetism, aimed at solving engineering problems
involving analysis and synthesis of antennas and microwave devices, numerical simulation of
radio wave propagation for the characterization of radio channels, and the development of
theoretical and numerical tools dedicated to solve such problems.
The research activities undertaken by GAPTEM/UFMG led to the establishment of several
partnerships and projects with other research groups in Brazil, including CETUC/PUC-Rio, UFPA,
and UFRN. The group is presently formed by two professors and 11 graduate students (six of
them doctoral candidates). During the years 2009 and 2010, 2 Doctoral and 4 Master’s
Dissertations were concluded, 8 articles were published or accepted for publication in technical
journals and 19 papers were presented in national and international conferences. One of the
group’s graduate students (Mr. Williams Lara de Nicomedes) won the Emerald Compel to a
young researcher award for the best Paper presented at IGTE 2010.
2. Research Activities Conducted at GAPTEM/UFMG
During the years 2009 and 2010, the following activities were conducted at GAPTEM/UFMG:
2.1 – Measurements in medium waves, VHF and UHF for the implementation of digital
radio broadcast in Brazil
Measurement campaigns to evaluate the DRM+ system were performed in the metropolitan area
of Belo Horizonte, Minas Gerais, involving two FM broadcasting stations: UFMG Educativa Radio
and Itatiaia FM Ltda. Radio. UFMG Educativa is a station of educational nature of UFMG, with its
transmitter located in the city of Contagem. The station operates on low power, working with 1.5
kW at 104.5 MHz. Radio Itatiaia has its transmitter located in Belo Horizonte and constitutes one
of the most traditional broadcasters in the city. The transmission power is 30 kW at 95.7 MHz.
The tests occurred in distinct phases for each station according to the schedule below:
•
Phase 1: UFMG Radio
DRM+ Equipment installation and initial testing: 29/01 to 05/02/2010
Start of measurements: 07/02/2010
End of measurements: 05/03/2010
•
Phase 2: Itatiaia Radio
DRM+ Equipment installation and initial testing: 09/04 to 14/04/2010
Start of measurements: 17/04/2010
End of measurements: 12/05/2010
For combined digital DRM+ and analog FM transmission, a specific transmitter-antenna group for
digital signal was installed at the transmitting stations. The model and the position of the antenna
were chosen in an attempt to match the digital coverage with existing analog. The parameters
used for the combined irradiation were Frequency Separation ∆F = 200 kHz and Protection Ratio
∆P = 13.7 dB for UFMG Radio and ∆P = 19.8 dB for Itatiaia Radio. The characteristics of the
stations are summarized in Table 1.
23
Table 1: Transmitting station parameters
Location
Carrier frequency [MHz]
EIRP [W]
Antenna Height [m]
Location
Carrier frequency [MHz]
EIRP [W]
Antenna Height [m]
UFMG Educativa Radio
Latitude:19o 55'11’’S
Analog system
104.5
793
25
Itatiaia FM Radio
Latitude:19o 58'14'' S
Analog system
95.7
22,165.0
19
Longitude:44o 0' 48 W
Digital system
104.3
34
19
Longitude: 43o 55' 41'' W
Digital system
95.5
228.5
9.6
Figure 1 displays the equipment diagram of the broadcasting stations. The audio signal
generated by the studio is sent to both analog and digital transmitters and the antennas have
height Ha (analog) and Hd (digital). Thus, through this setup it is possible to compare the
performances of both radiated signals and also the interference between them. Table 2 details
the equipments used.
Figure 1: Scheme used in FM broadcasting transmitting stations
24
Table 2: Transmission stations main equipment description.
Item
FM antenna
(analog)
FM antenna
(digital)
FM analog
transmitter
FM digital
transmitter
UFMG Educativa Radio
Description
Manufacturer: Trans-Tel, Model: TTFM3A (2 elements),
type: FM ring, gain: 0 dBi
Manufacturer: Ideal, Model: FA1RS (1 element), type: FM ring,
gain: -1,3 dBi
Manufacturer: Lys Electronic, Model: LT-2,5kW-FMV,
Power: 1,5 kW
Nautel RF amplifier, Power: 70 W
DRM+ modulator
Item
FM antenna
(analog)
FM antenna
(digital)
FM analog
transmitter
FM digital
transmitter
Itatiaia FM Radio
Description
Manufacturer: Electronics Research (ERI), Model: SHPX-2AC
(2 elements), type: bent dipole , gain: 2,13 dBi
Manufacturer: Mectrônica , Model: MT-FMC2 (2 elements),
type: FM cycloid , gain: 1,24 dBi
Manufacturer: Broadcast Electronics , Model: FM-30,
Power: 19,9 kW
Nautel transmitter model NV-10, Power: 500 W
DRM+ modulator
The measurements were collected using the measurement mobile unit from EBC (Empresa Brasil
de Comunicação) whose were equipped by the various entities involved in the measurement
campaign. The car, a Mercedes Benz Sprinter van, was adapted for the allocation of various
devices, prepared for the measurement of RF parameters (electric field amplitude, bandwidth,
modulation) and recording of audio content. Figure 2 shows the equipment diagram used in
measurement mobile unit.
The system consists of two antennas for RF measuring: a Kathrein monopole antenna and a
Kathrein Rohde & Schwarz biconical antenna. Both can be connected to the spectrum analyzer to
record the waveform of the signal or connected to the DRM receiver for demodulation and
storage of digital content. The digital audio is recorded into Notebook 01 with GPS interface and
analyzed by the software provided by the DRM consortium. The reception of analog audio is
performed by an analog FM receiver and stored on the notebook 02. All data collected is stored
on a portable hard disk (HD). Table 3 displays the description of the equipment involved.
Figure 2: Equipment diagram used in measurement mobile unit.
25
Table 3: Measurement mobile unit equipment description
Item
Kathrein Antenna
Description
Manufacturer: Kathrein, Model: K51164, type: monopole,
frequency range: 58 to 300 MHz, gain: 1,85 dBi
Biconical Antenna Manufacturer: Rohde & Schwarz, Model: HK116, type: biconical,
frequency range: 20 to 300 MHz, gain: 1,2 dBi
FM antenna
Standard FM automotive antenna
GPS system
Manufacturer: Navilock, Model: NL302U
Spectrum
Manufacturer: Anritsu Company, Model: Spectrum
analyzer
Master MS2711D, frequency range:100 KHz A 3 GHz
DRM+ receiver
Manufacturer: DRM+ consortium
Notebook 01
Manufacturer: MSI, Processor: Intel Atom N270 1,6 GHz,
(DRM+ software) Windows XP
Notebook 2
Manufacturer: Lenovo, Processor: Intel Core 2 Duo 2.20GHz
(Audio Recording) Linux Ubuntu
FM Analog receiver Manufacturer: Rolls Corporation, Model: RS79
Portable HD
Manufacturer: Western digital, Model: WD1600XMS 160 Gbytes
To evaluate DRM+ coverage the received signal was measured along radial and closed (circular)
routes. The radial routes allow the knowledge of the extension of DRM coverage area. The
closed routes provide information for the study of particular environments. Fixed measurement
reference points were defined on each route and also signal recording were carried out along the
path between these points. The routes for each station are listed below with their respective
extensions.
UFMG Radio
Radial 1 (R1): Southwest Route = 20.5 km
Radial 2 (R2): South Route = 19 km
Radial 3 (R3): Northeast Route = 24 km
Radial 4 (R4): Northwest Route = 27.3 km
Circular 1 (C1): Urban Route 1 = 14.1 km
Circular 2 (C2): UFMG Route = 7.9 km
Circular 3 (C3): Industrial Route = 6.8 km
Circular 4 (C4): Urban Route 2 = 9 km
Itatiaia Radio
Radial 1 (R1): Northeast Route = 68 km
Radial 2 (R2): South Route = 50.5 km
Radial 3 (R3): Southeast Route = 31.2
km
Radial 4 (R4): North Route = 59.9 km
Radial 5 (R5): West Route = 56.8 km
Circular 1 (C1): Urban Route 1 = 14.1 km
Circular 2 (C2): UFMG Route = 7.9 km
Circular 3 (C3): Industrial Route = 6.8 km
Circular 4 (C4): Urban Route 2 = 9 km
Circular 5 (C5): Urban Route 3 = 7 km
Figures 3 and 4 exhibit, respectively, the routes to the UFMG Radio and Itatiaia Radio phases.
The Radio UFMG phase gathered 31 fixed points with distances ranging from 2 to 22 km from the
transmitter. In the case of Itatiaia Radio was collected 41 fixed measurements points with
distances to the transmitter ranging from 2 to 51 km. It is noteworthy that the moving
measurements during the displacement between fixed points must be processed to eliminate the
fast fading and obtain the average received power.
The established routes cover different terrains and environments, providing different propagation
scenarios. Measurements were collected in dense urban environment, sub-urban, countryside,
open countryside with vegetation, irregular terrains and areas with many obstacles (tunnels,
bridges. buildings. transmission lines for electricity. etc). For further details of the routes, relevant
events and obstacles are written in a occurrence spreadsheet throughout the entire campaign.
The verification of the equipment functionality was performed every day by measures carried out
in a fixed reference point.
26
To evaluate the DRM+ system, two different available modulation schemes for the MSC channel
was used: QAM-4 and QAM-16. At all considered points the RF parameters and audio content
was recorded for the two modulations. The radio frequency signal is sampled for five minutes at
each fixed point and the time average is stored on the spectrum analyzer. Furthermore, during
this interval, it was recorded the analog and digital audio and DRM+ software analyzed quality
parameters of digital audio. During the moving measurements, the RF waveform storage was
performed in an interval of 200 ms and audio content recorded on the entire journey.
Finally, after the processing of the measures of all trades, one can extract information such as
field strength, bandwidth, analog/digital amplitude ratio, analog and digital audio signal to noise
ratio and the behavior of the broadcasting systems mobile reception situation.
Figure 3: Measurement routes during UFMG Radio transmission
27
Figure 4: Measurement routes during Itatiaia FM Radio transmission
2.2 - Development of models for the prediction of path loss and delay spread in VHF e UHF
Computational models based on asymptotic techniques (ray tracing in conjunction with the
Uniform Theory of Diffraction) and integral equations are being developed for the simulation of
radio wave propagation in urban and rural areas. The objective is the creation of theoretical and
numerical tools for application in the characterization of radio systems, including time domain
characterization of broadband radio channels.
Developing of ray-tracing tools for the characterization of urban radio channels: (a) plane view of a typical urban scenario
and (b) comparison between simulations and measurements. Ref.: D. Schettino, F. Moreira, and C. Rego, “Heuristic UTD
coefficients for electromagnetic scattering by lossy conducting wedges,” Microwave and Optical Technology Letters, vol
52, no. 12, pp. 2657—2662, Dec. 2010.
As consequences of the research, the following articles were published:
a) Daniela N. Schettino, Fernando J. S. Moreira, and Cássio G. Rego, “Heuristic UTD coefficients
for electromagnetic scattering by lossy conducting wedges,” Microwave and Optical Technology
Letters, vol. 52, no. 12, pp. 2657—2662, Dec. 2010.
Abstract: In this study, heuristic uniform theory of diffraction coefficients are suited to account for
scattering by lossy conducting wedges. The novel heuristic solution is determined from other
previously developed heuristic coefficients, combining their characteristics to improve the
28
estimation of radiowave propagation in urban scenarios. Slope diffraction is also considered to
account for double-diffracted fields in consecutive wedges. Maliuzhinets’ coefficients provide
base solutions to validate the novel formulation. The novel solution is then applied to the wave
propagation in a typical urban scenario, and results are compared against measurements
provided in the literature.
b) Cláudio G. Batista, Danielle M. Okamoto e Cássio G. Rego, “SPrad - Sistema de Predição de
Cobertura Radioelétrica,” MOMAG 2010 (14o. Simpósio Brasileiro de Microondas e
Optoeletrônica & 9o. Congresso Brasileiro de Eletromagnetismo), Vila Velha, ES, pp. 260—265,
Agosto 2010.
Also, the following Doctoral and Master’s Thesis were concluded or are in progress:
a) Daniela Naufel Schettino, “Métodos assintóticos para predição banda larga da cobertura
radioelétrica em ambientes urbanos,” Doctoral Thesis, PPGEE/UFMG, 2009.
b) Danielle Mendonça Okamoto, “Solução numérica e assintótica de propagadores para a faixa
de HF,” Master’s Thesis, PPGEE/UFMG, 2010.
c) João Renato Aguiar Soares, “Modelo e predição de cobertura radioelétrica na faixa de VHF
para ambientes de propagação em regiões cobertas por densa vegetação,” Doctoral Thesis,
PPGEE/UFMG. In progress.
d) Cláudio Garcia Batista, “Métodos de previsão de cobertura e propagadores temporais para
terrenos mistos,” Doctoral Thesis, PPGEE/UFMG. In progress.
e) Marcos Pacheco, “Estudo de funções de base características para a solução do problema do
espalhamento eletromagnético sobre terrenos rugosos,” Master’s Thesis, PPGEE/UFMG. In
progress.
f) William Eustáquio da Silva, “Métodos para aceleração da solução numérica de equações
integrais aplicadas à solução do problema do espalhamento eletromagnético sobre terrenos
mistos,” Master’s Thesis, PPGEE/UFMG. In progress.
2.3 - Development of techniques based on the method of moments for the analysis of
cylindrical microstrip antennas
At GAPTEM/UFMG, in partnership with Prof. Odilon Maroja C. Pereira Filho (UFPE), techniques
were developed for the analysis of cylindrical microstrip antennas using the method of moments.
These antennas consist of a cylindrical conductor which is constructed within a cylindrical-sector
cavity filled with dielectric. A cylindrical antenna is printed on the interface between dielectrics,
and is fed by a coaxial cable inside the conductor. This geometry has the potential to minimize
the mutual coupling between elements in arrays of cylindrical microstrip antennas, and thus make
possible a precise synthesis of these antennas. Microstrip antennas stand out for their ability to
conform to curved surfaces.
As consequences of the research, the following articles were published:
a) Odilon Maroja C. Pereira Filho, Tiago Braga Ventura, Cássio Gonçalves do Rego, Alexis
Tinoco e José Carlos Lacava, "Cavity-backed cilindrical wraparound antennas", Book chapter
accepted for publication, IntechWrap.
b) Odilon M. C. Pereira-Filho, Leonardo A. Costa e Fernando J. S. Moreira, “Conjuntos de
Antenas de Microfita Esférico-Trapezoidais,” MOMAG 2010 (14o. Simpósio Brasileiro de
Microondas e Optoeletrônica & 9o. Congresso Brasileiro de Eletromagnetismo), Vila Velha, ES,
pp. 392—395, Agosto 2010.
c) Tiago B. Ventura, Odilon M. C. Pereira Filho, and Cássio G. Rego, “Cavity-backed Cylindrical
Wraparound Antennas,” 2009 International Microwave and Optoelectronics Conference (IMOC
09), Belém, PA, Brazil, pp. 57—60, November 2009.
29
The following Master’s Thesis was concluded:
a) Tiago Braga Ventura, “Antenas de microfita anulares cilíndricas embutidas. Master’s Thesis,
PPGEE/UFMG, 2009.
2.4 - Synthesis and analysis of omnidirectional antennas providing uniform coverage
At GAPTEM/UFMG, in partnership with CETUC/PUC-Rio, numerical and asymptotic techniques
are being developed for the synthesis and analysis of omnidirectional reflector antennas. These
antennas have wideband features and may be used in WiMAX and LMDS systems. One of the
objectives is to control the antenna radiation pattern in the vertical plane, in order to provide
uniform coverage. This is accomplished by modeling the reflector surfaces. Several analysis
techniques are being used, in particular the physical optics (PO) and the method of moments
(MoM). Meshless (Mesh Free) techniques are also being investigated for future application in the
analysis of reflector antennas.
Omnidirecional ADE antenna shaped to provide a uniform coverage: (a) reflector generatrices and (b) radiation pattern in
the elevation plane. Ref.: J. Bergmann and F. Moreira, “Omnidirectional ADE antenna with GO shaped main reflector for
arbitrary far-field pattern in the elevation plane,” IET Microwaves, Antennas & Propagation, vol. 3, no. 5, pp. 1028—1035
Oct. 2009.
As consequences of the research, the following articles were published or accepted for
publication:
a) Fernando J. S. Moreira and José R. Bergmann, “Shaping Axis-Symmetric Dual-Reflector
Antennas by Combining Conic Sections,” IEEE Transactions on Antennas and Propagation,
accepted for publication.
Abstract: A simple procedure for the shaping of axissymmetric dual-reflector antennas is
described. The shaping procedure is based on the consecutive concatenation of local conic
sections suited to provide, under geometrical optics (GO) principles, an aperture field with uniform
phase, together with a prescribed amplitude distribution. The procedure has fast numerical
convergence and is valid for any circularly symmetric dual-reflector configuration. To illustrate the
procedure two representative configurations are investigated. The GO shaping results are
validated using accurate method-of-moments analysis.
b) Úrsula C. Resende, Fernando J. S. Moreira, and Odilon M. C. Pereira Filho, “EMFIE and
MEFIE Formulations for the Analysis of Scattering from Dielectric and Composite Bodies of
Revolution,” Microwave and Optical Technology Letters, accepted for publication.
Abstract: In this paper the electromagnetic scattering from dielectric and composite bodies of
revolution are analyzed by the electric-magnetic field integral equation (EMFIE) and the
30
magnetic-electric field integral equation (MEFIE), which are customarily overlooked in the
literature. A standard method-of-moments (MoM) technique is applied for the numerical solution
of the surface integral equations. Several dielectric and composite geometries are analyzed
through the bandwidth and results are compared to those of well-established Müller and
PMCWHT integral equation formulations. Investigated case studies indicate that the MoM Z
matrices yielded by the EMFIE and MEFIE are as well-conditioned as those provided by the
Müller and PMCWHT formulations.
c) Williams L. Nicomedes, Renato C. Mesquita, and Fernando J. S. Moreira, “An integral
meshless-based approach in electromagnetic scattering,” The International Journal for
Computation and Mathematics in Electrical and Electronic Engineering (COMPEL), accepted for
publication.
d) Williams L. Nicomedes, Renato C. Mesquita, and Fernando J. S. Moreira, “2-D scattering
integral field equation solution through an IMLS meshless-based approach,” IEEE Transactions
on Magnetics, vol. 46, no. 8, pp. 2783—2786, Aug. 2010.
Abstract: In this work, we apply a meshless-based method to a set of integral equations arising
in electromagnetic wave propagation and scattering. The objective is not only to solve these
equations through a meshless-based method, but also to find a way to build shape functions that
could work for any cross-sectional geometry. We have found that the Moving Least Squares
(MLS) approximation is not able to provide useful shape functions in every situation. This
technique relies on matrix inversions and, according to the geometry, singular matrices can
occur. In order to avoid this problem, we have taken the ImprovedMoving Least Squares (IMLS)
approximation, that does not depend upon matrix inversions and then applied it to a number of
cross-sectional geometries.
e) José R. Bergmann and Fernando J. S. Moreira, “Omnidirectional ADE antenna with GO
shaped main reflector for arbitrary far-field pattern in the elevation plane,” IET Microwaves,
Antennas & Propagation, vol. 3, no. 5, pp. 1028—1035, Oct. 2009.
Abstract: This work presents a formulation for shaping the main reflector of a dual-reflector
antenna designed to offer an omnidirectional coverage with an arbitrary radiation pattern in the
vertical plane. The subreflector is generated by an axis-displaced ellipse and the main reflector is
shaped to achieve a prescribed far-field radiation pattern. The shaping procedure is based on
geometrical optics (GO) principles. Two distinct far-field ray structures are investigated. The GOshaping results are validated by an analysis using the accurate method of moments technique.
f) José R. Bergmann and Fernando J. S. Moreira, “Bandwidth behavior of omnidirectional dualreflector antennas synthesized for uniform coverage,” Journal of Microwaves, Optoelectronics,
and Electromagnetic Applications, vol. 8, no. 1, pp. S1—S8, June 2009.
g) Fernando J. S. Moreira and José R. Bergmann, “Omnidirectional Dual-Reflector Shaping by
Concatenating Conic Sections,” 4th European Conference on Antennas and Propagation (EuCAP
2010), Barcelona, Spain, April 2010.
h) Williams L. Nicomedes, Renato C. Mesquita, and Fernando J. S. Moreira, “Meshless Local
Petrov Galerkin (MLPG) Methods in Quantum Mechanics,” 14th International IGTE Symposium
on Numerical Field Calculation in Electrical Engineering (IGTE’10), Graz, Austria, Sept. 2010.
Emerald COMPEL award to a young researcher for the best paper presented at IGTE'10.
i) Williams L. Nicomedes, Renato C. Mesquita, and Fernando J. S. Moreira, “A Meshless Local
Boundary Integral Equation Method for Three Dimensional Scalar Problems,” 14th Biennial IEEE
Conference on Electromagnetic Field Computation (CEFC 2010), Chicago, USA, May 2010.
j) Úrsula C. Resende and Fernando J. S. Moreira, “Numerical Convergence of Method of
Moments in the Analysis of Bodies of Revolution” 17th International Conference on the
Computation of Electromagnetic Fields (COMPUMAG 2009), Florianópolis, SC, Brazil, pp. 817—
818, November 2009.
k) Williams L. Nicomedes, Renato C. Mesquita, and Fernando J. S. Moreira, “2D Scattering
Integral Field Equation Solution through a IMLS Meshless-Based Approach” 17th International
31
Conference on the Computation of Electromagnetic Fields (COMPUMAG 2009), Florianópolis,
SC, Brazil, pp. 350—351, November 2009.
l) Fernando J. S. Moreira and José R. Bergmann, “Shaping Axis-Symmetric Dual-Reflector
Antennas by Consecutively Concatenating Conic Sections,” 2009 International Microwave and
Optoelectronics Conference (IMOC 09), Belém, PA, Brazil, pp. 359—362, November 2009.
m) Úrsula C. Resende, Fernando J. S. Moreira, and José R. Bergmann, “Analysis of
Omnidirectional Antennas with Radome Operating in LMDS Band for Signals of Digital TV,” 2009
International Microwave and Optoelectronics Conference (IMOC 09), Belém, PA, Brazil, pp. 83—
86, November 2009.
n) Williams L. Nicomedes, Renato C. Mesquita, and Fernando J. S. Moreira, “The Unimoment
Method and a Meshless Local Boundary Integral Equation (LBIE) Approach in 2D
Electromagnetic Wave Scattering,” 2009 International Microwave and Optoelectronics
Conference (IMOC 09), Belém, PA, Brazil, pp. 514—518, November 2009.
o) Williams L. Nicomedes, Renato C. Mesquita, and Fernando J. S. Moreira, “2D Scattering
Analysis through Meshless Methods: A Comparison Between Two Different Shape Function
Schemes,” 2009 International Microwave and Optoelectronics Conference (IMOC 09), Belém,
PA, Brazil, pp. 368—372, November 2009.
p) Williams L. Nicomedes, Renato C. Mesquita, and Fernando J. S. Moreira, “A Local Boundary
Integral Equation (LBIE) Method in 2D Electromagnetic Wave Scattering, and a Meshless
Discretization Approach,” 2009 International Microwave and Optoelectronics Conference (IMOC
09), Belém, PA, Brazil, pp. 133—137, November 2009.
q) Williams L. Nicomedes, Renato C. Mesquita, and Fernando J. S. Moreira, “Electromagnetic
Scattering Problem Solving by an Integral Meshless-Based Approach,” 8th International
Symposium on Electric and Magnetic Fields (EMF 2009), Mondovi, Italy, 2009.
r) Sandro R. Zang, José R. Bergmann, and Fernando J. S. Moreira, “Omnidirectional Dualreflector Antenna with a GO Shaped Main Reflector for an Arbitrary Far-Field Pattern in the
Elevation Plane,” 3rd European Conference on Antennas and Propagation (EuCAP 2009), Berlin,
Germany, pp. 3047—3050, March 2009.
Also, the following Doctoral and Master’s Thesis were concluded or are in progress:
a) Rafael Abrantes Penchel, “Modelagen Geométrica de Antenas Duplo-Refletoras para
Cobertura Omnidirecional,” Master’s Thesis, PPGEE/UFMG, 2009.
b) Williams Lara de Nicomedes, “Técnicas Sem Malha na Análise de Espalhamento
Eletromagnético,” Master’s Thesis, PPGEE/UFMG. In progress.
c) Ramon Dornelas Soares, “Aplicação de Técnicas Sem Malha em Espalhamento
Eletromagnético. Doctoral Thesis, PPGEE/UFMG. In progress.
d) Arnaldo Avidago Geraldo, “Aplicação de Técnicas Sem Malha a Antenas Refletoras
Omnidirecionais. Doctoral Thesis, PPGEE/UFMG. In progress.
2.5 – Development of numerical and asymptotic techniques for the analysis of
electromagnetic transients in antennas
Numerical and asymptotic techniques are being developed for the analysis of UWB (Ultra Wide
Band) antennas directly in the time domain. The interest in the analysis of transient wave
phenomena has increased with recent advances in the development of narrow-pulse radars and
antennas for the transmission of signals with high data rates. Possible applications are: remote
sensing, target identification, UWB wireless communication systems, and digital broadcasting.
As consequences of the research, the following articles were published:
a) Cássio G. Rego, Sandro T. M. Gonçalves, and Fernando J. S. Moreira, “High-frequency
asymptotic formulation for prompt response of parabolic reflector antennas,” AEÜ - International
Journal of Electronics and Communications, vol. 64, no. 1, pp. 36—46, Jan. 2010.
32
Abstract: This work presents some important concepts for the temporal characterization of
reflector antennas based on the determination of the transient antenna response together with a
useful definition of the early-time antenna radiation pattern. The concepts are useful in the
analysis and design of reflector antennas intended for high resolution radars and for high capacity
digital, and UWB communication systems.
b) Cássio G. Rego, “Operadores integrais para a determinação da resposta completa de antenas
refletoras parabólicas,” MOMAG 2010 (14º Simpósio Brasileiro de Microondas e Optoeletrônica e
9º Congresso Brasileiro de Eletromagnetismo), Vila Velha, ES, pp. 534—539, Agosto 2010.
c) Cássio G. Rego, “Closed-form solution for integral operators applied to the calculation of
radiated fields from parabolic reflector antennas,” 2009 International Microwave and
Optoelectronics Conference (IMOC 09), Belém, PA, Brazil, pp. 441—446, November 2009.
The following Doctoral and Master’s Thesis were concluded or are in progress:
a) Sandro Trindade Mordente Gonçalves, “Caracterização Unificada de Antenas nos Domínios
do Tempo e Freqüência,” Doctoral Thesis, PPGEE/UFMG, 2010.
b) Virgílio Ribeiro Mota, “Técnicas de caracterização de antenas em microfita via FDTD e
extração de ressonâncias naturais,” Master’s Thesis, PPGEE/UFMG, 2010.
c) Weber Costa Pinto dos Anjos, “Aplicação do Método de Expansão de Singularidades para a
caracterização de antenas filamentares banda-larga,” Master’s Thesis, PPGEE/UFMG. In
progress.
d) Gláucio Lopes Ramos, “Antenas impressas para aplicações MIMO e UWB,” Doctoral Thesis,
PPGEE/UFMG. In progress.
e) Emanuel Fonseca dos Santos, “Análise de Transientes em Antenas Duplo-Refletoras
Omnidirecionais,” Master’s Thesis, PPGEE/UFMG. In progress.
33
1 A brief description of LEA/ITECC/UFPA
The Laboratory of Electromagnetism Applied (LEA) was created in 1984 by teachers Gervásio Cavalcante and Joao Tavares Pinho, researchers of Eletrical Post‐Graduate Program (PPGE). With the creation of PPGE was structured area of Applied Electromagnetics, which in its first phase emphasized the training of human resources. Along with the LEA Group was created in Electromagnetism Applied Research, which has been directing its activities towards the real needs of the area, considering, where possible, the regional aspect. The arrival of new researchers to Group with operations in telecommunications and computer science led to the creation of new research groups, including the Group of Information Technology, Communication and Automation ‐ TICA, the Group of Numerical Analysis in Applied Electromagnetics ‐ LANE, coordinated by Professor Carlos Leonidas, and Signal Processing Group, with which the researchers of the LEA develop a series of projects in R & D. Finally, the NESC was created ‐ Center for Energy Systems and Communications, which integrates research groups of PPGE, the areas of Power Systems, Applied Computing and Telecommunications. These last two areas, plus the LEA are part Laboratories Numerical Analysis and Electromagnetics (LANE), the Laboratory of Signal Processing (LAPS) Laboratory of Network Planning for High Performance (LPRAD). Currently in LEA and LANE, whose teachers participate in this project, working about 50 students, including doctoral, masters and undergraduates. Most of these students is a fellow in research projects financed by funding agencies (CNPq, CAPES, FAPESP) or in partnership with businesses, primarily associated with resources of the computer (CTINFO), telecommunications (FUNTTEL) and energy (CTEnerg). Laboratório de
Eletromagnetismo Aplicado
UFPA - Universidade Federal do Pará
ITEC- Instituto de Tecnologia
34
2
Research Activities Carried out by the LEA / LCT ‐ UFPA During the years 2009 and 2010, LEA / LCT - UFPA conducted the following research activities:
2.1 – Studies of Propagation Loss in Semi-Confined Environments Using Parabolic
Equations for Large Angels of Propagation.
The model was developed for the study of the propagation of electromagnetic waves in semiconfined environment, taking into account the buildings and the trunks of trees. The chosen
environment for test was Av. Brás of Aguiar, in the central area of Belém of Pará, where the
measurements were made; with characteristics similar to those used in the model proposed,
where the cups of the trees form a tunnel of foliages, confining the electromagnetic wave. This
model calculates the behavior of the field in the vertical direction (in the sense of the elevation of
the receiver) and in the horizontal direction (longitudinal displacement of the receiver).
Fig. 1 shows the Avenue Brás of Aguiar and the location of the transmitter antenna.
Fig. 1 - Illustration of the Av. Brás of Aguiar
Fig. 2 shows the pictorial illustration of the Avenida Brás of Aguiar and Fig. 3 illustrates the partial
view of the urban environment with an area of dense vegetation characterizing a semi-confined
environment.
Fig. 2 - Pictorial figure of the Av. Brás of Aguiar
35
Fig. 3 – partial view of the semi-confined environment
As a consequence of the research, was published the following work:
SOUZA, João Furtado de ; Magno, F. N. B. ; CAVALCANTE, G. P. S. ; Cozzolino, K. ; COSTA, Jessé Carvalho . “Studies of Propagation Loss in Semi-Confined Environments Using Parabolic
Equations for Large Angels of Propagation”. In 4th European Conference on Antennas and
Propagation, EuCAP 2010, 2010, Barcelona.
Abstract: In this article the propagation loss in mobile cellular systems in semi-confined
environment using parabolic equations is studied. The proposed model uses approximations for
small and large angles of propagation, with the paraxial direction and its results are validated
through a campaign of measurement and the ray tracing model. The semi-confined environment
is represented by a street with large trees and shaped by a set of rectangles (representing the
buildings) and a set of dielectric cylinders (representing the trunks of trees). In the campaign of
measurements was used the frequency of 890 MHz The results compared with the experimental
results and by ray tracing model showed good agreement, with a less computational effort.
2.2
- COST231-Hata and SUI Models Performance Using a LMS Tuning Algorithm on
5.8 GHz in Amazon Region Cities
The collected data have been acquired in cities on Para State at Amazon Region, Brazil. These
cities are known by their woodland environments. The vegetation normally appears mixed with
the residential and commercial constructions resulting in a single medium. An example of
Amazon region city is shown in the following figure.
Fig. 4 – Part of Santarém, city in Para State, Brazil
Different of the traditional measuring campaigns [1]-[2] that are made with continuous data
collection in a mobile unit, this data acquisition has been performed by taking the punctual RSSI
(Received Signal Strength Indicator) in 211 fixed clients installed in eight cities that have been
contemplated with the Digital Inclusion Para State Government Project named NavegaPara [3].
The project consists of WLL (Wireless Local Loop) networks installed in the cities, bringing
36
broadband access and multimedia services. It is interesting to analyse this collected data
because fixed clients have different distances with respect to their Base Stations and different
installation heights. From the collected RSSI it can be found the path loss for each client.
The process for obtaining the distances between the clients and base stations is based on the
coordinates that was collected during the implantation stage.
[1]
M. Yang, W. Shi, “Linear Least Square Method of Propagation Model Tuning for 3G Radio Network Planning”, Fourth
International Conference on Natural Computation ICNC, Jinan, 18-20 October 2008, pp. 150-154.
[2]
G. R. Pallardó, “On DVB-H Radio Frequency Planning: Adjustment of a Propagation Model Through Measurement Campaign
Results”, Master’s Thesis, Department of technology and Built Enviroment, University of Gävle, Sweden, 2008.
[3]
NavegaPara Project. Available in: http://www.navegapara.pa.gov.br/
As a consequence of the research, was published the following work:
LYRA, B. C. ; CAVALCANTE, G. P. S. ; GOMES, I. R. . COST231-HATA and SUI Models
Performance Using a LMS Tuning Algorithm on 5.8 GHZ in Amazon Region Cities. In: EuCAP
2010 - 4th European Conference on Antennas and Propagation, 2010, 2010, Barcelona.
Abstract — This paper presents a performance comparison between COST231-Hata and SUI
Models through LMS tuning Algorithm for 5.8 GHz frequency band. The studied environment is
based on the cities located in Amazon Region. After the adjustments and the simulations, SUI
Model has shown a smaller RMS error when compared with COST231-Hata Model. 2.3 Other related publications
1.SOUZA, J. F., Magno, F. N. B., Valente, Z. , COSTA, Jesse Carvalho; CAVALCANTE, G. P. S.
. Mobile Radio Propagation along Mixed Paths in Forest Environment using Parabolic Equation,.
Microwave and Optical Technology Letters, v. 51, p. 1133-1136, 2009
2.RIBEIRO JR, F. C., GOMES, I. R.; LYRA, B. C., Cavalcante, G. P. S.. Comparison Between
Known Adaptive Algorithms for Pre-FFT Beamforming in OFDMA Systems. In: 4th European
Conference on Antennas and Propagation, EuCAP 2010, 2010, Barcelona. 4th European
Conference on Antennas and Propagation, EuCAP 2010. Barcelona, 2010
3.Rodrigues, J., Fraiha, S., Araujo, J., Gomes, H., French, C. and Cavalcante, G. , "Strategy for
Performance Evaluation Based WLANs in Extended Measurement Data for Indoor Environments,
MOMAG2010, Vila Velha (ES), August 2010.
4.Castro, B., Gomes, I. R., Ram, O., Pike, M. and Cavalcante, GPS, "Comparison Between
Known Propagation Models Using Least Squares Algorithm Tuning on 5.8 GHz in Amazon
Region Cities," MOMAG2010, Vila Velha (ES), August 2010.
5.Castro, B., Gomes Cavalcante, G.P.S, Gomes, I. R., Ram, O., "Propagation Model Tuning SUI
from Collected Data in Fixed Wireless Systems at 5.8 GHz on Arboreous Environments Band,
ITS 2010 - International Telecommunications Symposium, Manaus, Amazonas, Brazil, 2010.
6.Fernanda Smith, Marcio Monteiro (Lund University, Sweden), Francisco Muller, Aldebaro
Klautau, Federal University of Pará, Brazil Evaldo Gonçalves By Boris Dortschy (Broadband
Technologies Ericsson Research, Sweden), "On the Effectiveness of Dynamic Spectrum
Management Algorithms in xDSL Networks ", ITS 2010 - International Telecommunications
Symposium, Manaus, Amazonas, Brazil, 2010.
7.RODRIGUES, J. C.; frah, S. of G. C. , ARAÚJO, J. P. L., FRENCH, C. R. L; CAVALCANTE, G.
P. S.. Empirical Study of the Behavior of the QoS Parameters VoIP Application in Wi-Fi Networks.
In: International Microwave and Optoelectronics IMOC2009 Conference, 2009, Belem. 2009
SBMO / IEEE MTT-S International Microwave & Optoelectronics Conference (IMOC 2009).
Bethlehem, 2009.
8.Magno, F. N. B; SOUZA, J. F., Cozzolino, K. , COSTA, Jesse Carvalho; CAVALCANTE, G. P.
S. . A Model for Radio Propagation Loss Prediction in Buildings using Parabolic Equations wide-
37
angle. In: 2009 SBMO / IEEE MTT-S International Microwave & Optoelectronics Conference
(IMOC 2009), 2009, Belem. 2009 SBMO / IEEE MTT-S International Microwave &
Optoelectronics Conference (IMOC 2009). Belem, 2009
9.R. Igor; Fraiha, S. OF G. OF C. , RODRIGUES, J. C. , GOMES, Herminio S. ; LYRA, B. C. ;
PINHEIRO, M. R. , Ribeiro, F. ; CAVALCANTE, G. P. S. . A Methodology to Minimize the
Measured Points Project is an Indoor WLAN. In: International Microwave & Optoelectronics
Conference (IMOC 2009), 2009, Bethlehem 2009 SBMO / IEEE MTT-S International Microwave
& Optoelectronics Conference (IMOC 2009). Belem, 2009.
10.PINHEIRO, M. R., GOMES, I. R; LYRA, B. C NETO, M. C. A; CAVALCANTE, G. P. S.. Matlab
Tool for Point-to-point links in 5.8 GHz Band Simulation Using The Stanford University Interin
(SUI) Model. In: 8th International Information and Telecommunication Technologies Symposium I2TS 2009, 2009, 2009, Florianópolis. 8th International Information and Telecommunication
Technologies Symposium - I2TS 2009, 2009 .. Florianópolis, 2009.
11.CARDOSO Diego Lisbon; FRENCH, Carlos Renato Lisboa, COSTA, João CrisóstomoWeyl
Albuquerque; SERUFFO, Marcos Cesar da Rocha, Silva, Marcelino Silva's. Wi-MAX as Channel
Interactive SBTVD to the Amazon. In: 1st International Symposium on Digital Television, 2009.
THESES COMPLETED – 2009 – Adviser - Gervasio Protásio dos Santos Cavalcante
1. Fatima Nazareth Baraúna
Title: CELLULAR MOBILE SYSTEMS MODELING IN INDOOR ENVIRONMENTS USING
PARABOLIC EQUATIONS
2. João Furtado de Souza
Title: MODELING SYSTEMS RADIOPRAPAGATION IN CELLULAR MOBILE ENVIRONMENTS
USING PARBOLIC EQUATIONS
3. Simone das Graças Castro Frahai
Title: LOCATION OF BEST ACCESS POINTS IN INDOOR ENVIRONMENTS IN WIRELESS
SYSTEMS DESIGN
THESES IN PROGRESS
1.Josiane Couto Rodrigues. Characterization and Measurement of Propagation Loss in Indoor
Environment and determination of a propagation model .. Home: 2002. Thesis (Ph.D. in Electrical
Engineering) - University of Pará.
2.Rômulo Oliveira, Evaluation of models using Radiopropagação Computational Intelligence
techniques for radio systems and TVDigitais, beginning in 2010 (Doctorate in Electrical
Engineering) - University of Pará.
DISSERTATIONS COMPLETED – 2010
1.Igor Ruiz Gomez. Indoor Propagation Model for Multi-Storey at 2.4 GHz with estimation of QoS
in VoIP calls. Dissertation (Masters in Electrical Engineering) - University of Pará, the National
Council for Scientific and Technological Development.
2.Bruno Souza Castro Lyra. Propagation Model for Fixed Wireless Networks in the Band 5.8 GHz
in Typical Cities of the Amazon region.. Dissertation (Masters in Electrical Engineering) University of Pará, Coordination for the Improvement of Higher Education.
38
GUIDELINES FOR MASTERS IN PROGRESS
1.Josiane Siqueira Cabral. Research and Teaching of antennas and radio wave propagation
systems applied to digital TV. Home: 2009. Dissertation (Masters in the Graduate Program in
Electrical Engineering) - University of Pará, Coordination for the Improvement of Higher
Education. (Supervisor).
2.Carlos Alberto Nunes Junior. Analysis and Improvements of 3G/4G networks in the Amazon
region. Home: 2009. Dissertation (Masters in the Graduate Program in Electrical Engineering) University of Pará
3.Juliana Santiago Montero. Study of the Digital TV signal in metropolitan Belém Start: 2009.
Dissertation (Masters in the Graduate Program in Electrical Engineering) - University of Pará,
Coordination for the Improvement of Higher Education.
4.Alan Teixeira da Silva. Empirical Performance Analysis of Microwave Propagation (5.2GHz) in
the Amazon Environment (River Forest Suburban) .. Home: 2008. Dissertation (Masters in the
Graduate Program in Electrical Engineering) - University of Pará, Coordination for the
Improvement of Higher Education.
5.Márcio Rodrigues Pinheiro. Using A New Tool in Planning Links Radio Operating in the 5.8
GHz band in Regions Amazon. Home: 2007. Dissertation (Masters in the Graduate Program in
Electrical Engineering) - University of Pará.
39
1. A Brief Description of GMA/UFRN
The microwave and antenna group (GMA) of the Department of Electrical Engineering at UFRN
was created in 1982. The repercussions of studies conducted in the areas of antennas,
propagation and mobile communications may be associated to the excellent quality of approved
dissertations/theses. As a consequence, its researchers and students have regularly taken part in
the main national (SBMO, CBMag and SBrT) and international (IEEE-AP-S, ICAP, EuCOM and
IEEE MTT-S) symposiums and conferences. An international technical cooperation was
established with INPT-Toulouse, through the CAPES-COFECUB program in the 1990s. The
formation of doctors, as a result of collaboration with UFCG researchers since 1988 deserves to
be mentioned, as well as the intense interaction with CEFET-PB researchers. GMA researchers
have also taken part in the organization of 3 national symposiums (SBMO 1988, SBT 1993 and
CBMag 2000) and 2 international conferences, IMOC 1997 (SBMO/IEEE MTT-S) and ITS 2002
(SBrT/IEEE COMSOC). Currently, GMA researchers are developing international technical
cooperation activities with ENST-Paris, through the CAPES-COFECUB program, and with INPTToulouse, through the BRAFITEC program. Moreover, GMA researchers are also developing
activities directed to the organization of IMOC 2011 (SBMO/IEEE MTT-S), which will take place in
Natal, RN.
The GMA Group is formed by 4 professors and more than 20 graduate students (9 of them are
PhD students). In the last two years 3 PhD Dissertations were approved, as well as 6 Master
Theses. Presently several students are working to conclude their graduate courses at UFRN,
advised by GMA researchers. It should be emphasized that one of our PhD students is presently
at Telecom ParisTech in Paris, in a cotutelle doctoral research program.
The works developed in our Group mainly those that were done by our graduate students have
been published in technical journals and conference proceedings. In the last two years 7 papers
were published in technical journals and 16 were presented in international conferences and
symposiums and published in their proceedings. In the conferences organized by Brazilian
Scientific Societies, more than 10 papers were presented and published in the conference
proceedings. Lately 2 other papers were accepted for publication in technical journals.
In the last two years our researchers had a very good cooperation with professors from the
Telecom ParisTech, in Paris, due to a CAPES-COFECUB Project, and from the INPT, in
Toulouse, due to a Brafitec Project, both supported by CAPES. In Brazil, our researchers had an
excellent cooperation with the professors from PUC-Rio, UFPA, and UFMG, due to the scheduled
INCT-CSF activities that were started in the end of 2008. This cooperation included the
organization of workshops as well as the participation in PhD Juries.
40
2. Research Activities Developed by GMA/UFRN
In 2009 and 2010, in the INCT-CSF Project, our main research activities were focused in two
areas:
• Antennas for the reception of signals by fixed and mobile users and broadband services
• WiMax network planning – Measurements and propagation models.
We developed new configurations of microstrip antennas and frequency selective surfaces (FSS)
for applications in wireless communications systems. Aspects related to the miniaturization of
such antennas are being investigated through the use of fractal structures and substrates with
high permittivity. Antennas for broadband and multiband services are being investigated. The
increased bandwidth of FSS is being investigated by the use of fractal geometries and coupled
structures.
The results of these works were published in the most important newspapers and symposiums
and conferences. In particular our papers were presented in IEEE AP-S 2009, IMOC 2009,
COMPUMAG 2009, iWAT 2010, EuCAP 2010, CEFC 2010 and EuMW 2010 as well as in
MOMAG 2010.
As mentioned before, in the last two years 3 PhD Dissertations were approved, as well as 6
Master Theses. In the next sections these works are presented as well as some of the related
papers that were published in conference proceedings and technical journals.
2.1 Antennas for the reception of signals by fixed and mobile users and broadband
services
2.1.1 Development of antennas for UWB system applications
In the last years a special attention has been devoted to the development of UWB antennas. The
UWB technology is a short range wireless technology for transmitting large amounts of data at
very high-speed with very low power. Generally the effective isotropic radiated power (EIRP)
must be smaller than -41.3 dBm/MHz between 3.1 to 10.6 GHz. The use of UWB systems needs
efficient antennas to provide acceptable bandwidth requirements, and radiation pattern
characteristics throughout the designated UWB spectrum. It is generally accepted that for
antennas to be classified as ultra-wideband, the requirement will be to satisfy minimum fractional
bandwidths of at least 20 % or 500 MHz or more.
The following conference paper was published:
• Brito, D. B., Begaud, X., d’Assunção, A. G., Fernandes, H. C. C., “Ultra Wideband Monopole
Antenna with Split Ring Resonator for Notching Frequencies”, 4th European Conference on
Antennas and Propagation, Barcelona, Espanha, Proc. EuCAP 2010, vol. 1. p. 1-5.
Abstract—In this paper a new configuration of an Ultra Wideband (UWB) antenna is proposed.
The antenna is an optimization of the circular monopole patch antenna with a slot type Split
Ring Resonator (SRR) that is inserted in the radiating part. The SRR structure will work as a
band stop filter for notching a frequency band between 5 to 6 GHz. A good agreement was
observed between the simulated and measured results.
41
Figure 1. Return loss curves for the circular monopole antenna with a slot-type SRR.
Measured (red) and simulated (blue) results.
Presently D. B. Brito is preparing the final version of his PhD report, including metamaterial
inspired antennas and FSS geometries. He also developed Fabry-Perot antennas. The advisers
are Adaildo Gomes d’Assunção (UFRN) and Xavier Bégaud (Telecom ParisTech).
Figure 2. Fabry-Pérot antenna.
Also, the following Master’s Theses were approved:
• Bruna Alice Lima da Silva, “Antena Monopolo Planar com Patch em Anel Circular para
Sistemas UWB”. Master’s Thesis, Universidade Federal do Rio Grande do Norte, Natal, RN,
2010. Adviser: Adaildo Gomes d’Assunção.
• Antonio Salvio de Abreu, “Desenvolvimento de Monopolos Quase-Espirais para Aplicações em
Sistemas UWB”. Master’s Thesis, Universidade Federal do Rio Grande do Norte, Natal, RN,
2009. Adviser: Adaildo Gomes d’Assunção.
2.1.2 Development of printed antennas with fractals, EBG structures, or metamaterial substrate.
The advance of wireless communications and the growth of its applications in recent years have
made use of compact antennas multiband/broadband a great attraction of fundamental
importance in commercial and military applications. The most common examples are found in a
variety of portable wireless devices, such as cellular phones, handsets, palmtops, laptops, among
others. The emergence of different wireless technologies, such as the GSM (Global System for
Mobile Communications), RFID (radio frequency identification), Bluetooth, Wi-Fi and WiMAX, has
served as a motivation to boost research in the search for lighter, compact and lower cost
devices, as it is the case of microstrip patch antennas.
The ever increasing demand for compact radiators for application in modern communication
systems, have improved the use of artificial materials properly engineered to achieve some
antenna features. For instance, it has been proven that metamaterials can be applied to reducing
the antenna size.
42
The following papers were published:
• Oliveira, E. E. C., Silva, P. H. da F., Campos, A. L. P. S., d'Assunção, A. G., “Small size quasifractal patch antenna using the Minkowski curve”, Microw Opt Technol Lett, v. 52, pp. 805-809,
2010.
Abstract—This article shows a new quasi-fractal microstrip patch antenna using the Minkowski
curve at the radiant and nonradiant margin of this device. The structures analyzed were initially
designed using the Ansoft Designer™ software that implements the method of moments. Some
antenna prototypes were built and measured. The use of the inset-fed technique enables a
good impedance matching, as can be confirmed by the low return loss obtained (<−25 dB) at
the resonance frequencies. Antennas designed using the Minkowski curve presented a
reduction of up to 42% when compared with a conventional inset-fed rectangular patch. © 2010
Wiley Periodicals, Inc. Microwave Opt Technol Lett 52:805–809, 2010.
• Carneiro Filho, R., Araújo, J. H., Ginani, M. F., D'Assunção Jr., A. G., Martins, R. A.,
d’Assunção, A. G., Mendonça, L. M., Simulation and measurement of inset-fed microstrip patch
antennas on BiNbO4 substrates, Microwave and Optical Technology Letters, v. 52, p.10341036, 2010.
• Oliveira, E. E. C., Silva, P. H. F., Campos, A. L. P. S., Silva, S. G., “Overall Size Antenna
Reduction Using Fractal Elements”, Microwave and Optical Technology Letters, v. 51, p. 671675, 2009.
• Carneiro Filho, R., Araújo, J. H., Ginani, M. F., d’Assunção, A. G., and Mendonça, L. M.,
“Experimental and simulation analysis of microstrip patch antennas on BiNbO4 Ceramic
Substrates”, Proc. IEEE AP-S, Charleston, SC, USA, 2009, p.1-4.
Figure 3. X-ray diffraction results for the BiNbO4 samples obtained using a brand Shimazdu XRD-6000.
43
• Vasconcelos, C. F. L., Albuquerque, M. R. M. L., Silva, S. G., Oliveira, J. R. S., d’Assunção, A.
G., “Full Wave Analysis of Annular Ring Microstrip Antenna on Metamaterial”, IEEE
Transactions on Magnetics, accepted for publication.
⎡ε r
⎢
ε =⎢0
⎢0
⎣
=
0
εr
0
0 ⎤
⎥
0 ⎥
ε eff ⎥⎦
⎡1 0 0 ⎤
⎢
⎥
µ = ⎢0 1 0 ⎥
⎢0 0 µ eff ⎥
⎣
⎦
=
Figure 4. Resonant frequency as a function of the antenna outer radius.
Also, the following doctoral dissertations were approved:
• Cristhianne de Fátima Linhares de Vasconcelos, “Desenvolvimento de Antenas de Microfita
com Patch em Anel Utilizando Materiais Ferrimagnéticos e Metamateriais”. PhD dissertation,
Universidade Federal do Rio Grande do Norte, Natal, RN, 2010. Adviser: Sandro Gonçalves da
Silva.
• Ranilson Carneiro Filho, “Desenvolvimento de Substrato Cerâmico BiNbO4 para Antenas de
Comunicações sem Fio”. PhD dissertation, Universidade Federal do Rio Grande do Norte,
Natal, RN, 2010. Adviser: Laércio Martins de Mendonça.
2.1.3 Development of single and coupled frequency selective surfaces (FSS)
Recently, we can observe an increasing demand on the multifunctional antennas for
communication that requires the development of FSS with multi-band characteristics. The use of
frequency selective surfaces (FSS) has been successfully proven as a mean to increase the
communication capabilities of satellite platforms. In space missions such as Voyager, Galileo,
and Cassini, the use of dual-reflector antennas with FSS sub-reflectors has made it possible to
share the main reflector among different frequency bands. Therefore frequency selective surfaces
with dual-band and multi-band responses have been studied by several researchers.
The following papers were published:
• Araújo, L. M., Maniçoba, R. H. C., Campos, A. L. P. S., d'Assunção, A. G., “A simple dual-band
frequency selective surface”, Microw Opt Technol Lett, v. 51, p. 942-944, 2009.
Abstract⎯Design and experimental investigations are presented for a dual-band frequency
selective surface (FSS) with perfectly conducting rectangular patch elements. The work was
developed in two steps. In the first step, two single-band FSS screens were designed to obtain
resonant frequencies at 9.5 GHz and 10.5 GHz, each one with about 1.5 GHz bandwidth. In the
second step, these single FSS screens were cascaded and separated by an air gap layer to
achieve a dual-band response. The proposed dual-band FSS screen is easy to analyze and to
fabricate with low cost materials and exhibits a low weight and easy to handle structure. © 2009
Wiley Periodicals, Inc. Microwave Opt Technol Lett 51: 942–944, 2009.
44
• Cruz, R. M. S., da F. Silva, P. H., d'Assunção, A. G., “Neuromodeling stop band properties of
Koch Island patch elements for FSS filter design”, Microw Opt Technol Lett, v. 51, pp. 30143019, 2009.
Abstract—This work investigates the use of Koch Island patch elements to design frequency
selective surface (FSS) band stop filters that reflect X- or Ku-band signals. To control the FSS
resonant frequency and -10 dB bandwidth, we modify the shape of Koch Island patch elements
adjusting the fractal parameters, iteration factor, and iteration number. The electromagnetic
(EM) behavior is described as a function of the element shapes and the permittivity of the
dielectric substrate. A FSS parametric analysis is accomplished through the use of the Ansoft
DesignerTM software. The obtained EM-data is utilized for training a multilayer perceptrons
(MLP) artificial neural network to achieve the FSS modeling task. Experimental and simulated
results are obtained to validate the developed MLP model. VC 2009 Wiley Periodicals, Inc.
Microwave Opt Technol Lett 51: 3014–3019, 2009.
• Silva, P. H. F., Cruz, R. M. S., and d'Assunção, A. G., “Blending PSO and ANN for Optimal
Design of FSS Filters with Koch Island Patch Elements”, IEEE Trans. on Magnetics, vol. 46, n.
8, pp. 3010-3013, 2010.
Abstract—This work presents a new fast and accurate electromagnetic (EM) optimization
technique blending the Particle Swarm Optimization (PSO) algorithm and a Multilayer
Perceptrons (MLP) Artificial Neural Network (ANN). The proposed technique was applied for
optimal design of Koch fractal Frequency Selective Surface (FSS) with desired stop-band filter
specification. Initially, a full-wave parametric analysis was carried out for accurate EMcharacterization of FSS filters. From obtained EM-dataset, a MLP network was trained with the
first-order Resilient Backpropagation (RPROP) algorithm. The developed MLP model for FSS
synthesis was used for efficient evaluation of cost function in PSO iterations. The advantages in
the optimal design of FSS through the PSO-ANN technique were discussed in terms of
convergence and computational cost. Two optimized FSS prototypes were built and measured.
The accuracy of the proposed optimization technique was verified through the excellent
agreement obtained by means of comparisons between theoretical and experimental results.
Figure 5. Measured and simulated results for the transmission coefficient of a Koch fractal FSS
with level 2 and iteration factor 5. Dielectric substrate: εr = 4.4 and h = 1.6 mm.
• Campos, A. L. P. S., Maniçoba, R. H. C., Araújo, L. M., D'Assunção, A. G., “Analysis of Simple
FSS Cascading with Dual Band Response”, IEEE Trans. on Magnetics, vol. 46, n. 8, pp. 33453348, 2010.
Abstract—Numerical and experimental investigations are presented for a dual-band frequency
selective surface (FSS) with perfectly conducting rectangular patch elements. In the first step
two single-band FSS screens were designed to obtain resonant frequencies at 9.5 GHz and
45
10.5 GHz, each one with about 1.5 GHz bandwidth at -3 dB. In the second step these single
FSS screens were cascaded and separated by an air gap layer to achieve a dual-band
response. The Moment Method is used to analyze the structures single band. After this, a
numerical cascading technique is used to analyze the effect of the air gap between the
cascading structures. Numerical and measured results were compared and a good agreement
was obtained.
Figure 6. Measured and simulated results for the transmission coefficient of coupled Koch fractal FSS.
Structure 1 has fractal level 1 and structure 2 has fractal level 2. The air gap spacing is 10 mm.
• A. Gomes Neto, A. N. Silva, J. C. Silva, P. H. da F. Silva, A. G. D’Assunção “Simulations and
Measurements of FSS with Fractal Elements”, 40th European Microwave Conference, Paris,
France, Proc. EuMC 2010, vol. 1. p. 1-4.
Figure 7. Measured and simulated results for the transmission coefficient of a Koch fractal FSS
with level 2 and iteration factor 5. Dielectric substrate: εr = 4.4 and h = 1.6 mm.
46
Also, the following doctoral dissertation and master’s theses were approved:
• Rossana Moreno Santa Cruz, “Análise e Otimização de Superfícies Seletivas de Frequência
Utilizando Redes Neurais Artificiais e Algoritmos de Otimização Natural”. PhD dissertation,
Universidade Federal do Rio Grande do Norte, Natal, RN, 2009. Adviser: Adaildo Gomes
d’Assunção.
Figure 8. Crossed loop FSS: (a) measured and simulated transmission coefficients
and (b) photograph. The square loop inner dimension, l, is 9 mm.
Table 1: Values of resonant frequency and bandwidth for the
fabricated crossed loop FSS.
Length l (mm)
9.00 (measured)
9.00 (simulated)
fr (GHz)
9.37
9.12
BW (GHz)
4.05
4.78
BW (%)
50.22
52.41
• Robson Hebraico Cipriano Maniçoba, “Estudo Comparativo de Técnicas de Cascateamento de
Superfícies Seletivas em Frequência”. Master’s Thesis, Universidade Federal do Rio Grande do
Norte, Natal, RN, 2009. Adviser: Adaildo Gomes d’Assunção.
• Iradilson Ferreira da Costa, “Antenas e Superfícies Seletivas de Frequência Reconfiguráveis
para Sistemas de Comunicação Sem Fio”. Master’s Thesis, Universidade Federal do Rio
Grande do Norte, Natal, RN, 2009. Adviser: Adaildo Gomes d’Assunção.
2.2 Planning of WiMax networks -- Propagation models and measurements.
2.2.1 Development of propagation models for WiMAX applications
The telecommunications industry has experienced recent changes, due to increasing quest for
access to digital services for data, video and multimedia, particularly using the mobile phone
networks. Recently in Brazil, mobile operators are upgrading their networks to third generations
systems (3G) providing to users broadband services such as video conferencing, Internet, digital
TV and more. These new networks that provide mobility and high data rates has allowed the
development of new market concepts. Currently the market is focused on the expansion of
WiMAX technology, which is gaining increasingly the market for mobile voice and data. In Brazil,
the commercial interest for this technology appears to the first award of licenses in the 3.5 GHz
band. As a consequence a lot of work has been done in the development techniques and
methods to predict the path loss.
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• Gustavo Araújo Cavalcante, “Otimização de Modelos de Predição da Perda de Propagação
Aplicáveis em 3,5 GHz Utilizando Algoritmos Genéticos”, Master’s Thesis, Universidade Federal
do Rio Grande do Norte, Natal, RN, 2010. Advisers: Adaildo Gomes d’Assunção e Ronaldo de
Andrade Martins.
In this work a genetic algorithm (GA's) was developed in order to optimize the prediction of the
propagation loss at 3.5 GHz, thus enabling an estimate of the signal closer to reality to avoid
significant errors in planning and implementing wireless communication system at this frequency.
Figura 9. Measurement routes in the UFRN campus.
Figure 10. Measured and simulated results for the propagation path loss.
2.2.2 Wireless communication
The following master’s theses were approved:
• Diego Fernandes Sales, “Análise de Handover inter e intra célula em um Sistema de Telefonia
Celular através de Método de Medição Simplificado”. Master’s Thesis, Universidade Federal do
Rio Grande do Norte, Natal, RN, 2009. Orientador: Sandro Gonçalves da Silva.
Abstract—This dissertation has the purpose to present a portable device named PlugData
MG100G, equipper with a cellular module, to analyze the radiofrequency coverage in a GSM
network situated in João Pessoa city, state of Paraíba, at four distinct regions. The equipment,
originally, was developed to be used in fixed environments, so it was adapted so that it could be
used in conditions of mobility. From the Mobile Measurement Reports (MMRs) RF coverage and
the handover process are analyzer. The MMRs enable the identification of the serving cell and
the list of the closest neighboring cell monitored by the mobile. This works analyses only data
referents to the serving cell and the two closest neighboring cells. Inter-cell and intra-cell
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handovers are identified. The frequency planning and quality of service offered by the network
related to the regions are discussed as well.
• Talles Rodrigues Ferreira, “Esquemas de Modulação para Sistemas com Codificação Wavelet
Sujeitos ao Desvanecimento Rayleigh”. Master’s Thesis, Universidade Federal do Rio Grande
do Norte, Natal, RN, 2009. Adviser: Sandro Gonçalves da Silva.
Abstract—Since its advent, wavelet coding has been recognized as a promising technique for
digital transmission over wireless communication environments, especially due to its low
decoding complexity and good performance over multipath fading. However, this technique
generates not-equiprobable symbols, and consequently the performance gains from these
systems are influenced significantly by their modulation schemes. In this work, it is proposed a
design methodology to obtain sub-optimum modulation schemes for wavelet systems over
Rayleigh fading channels. In this context, novels signal constellations and quantization schemes
are obtained via genetic algorithm and mathematical tools. Numerical results obtained from
simulations show that the wavelet-coded systems derived here have very good performance
characteristics over fading channels.
Events
•
I Workshop on Wireless Communication
Belém, PA, December 2008.
•
II Workshop on Wireless Communication
Natal, RN, May 2009.
•
III Workshop on Wireless Communication
Belo Horizonte, MG, June 2009.
•
IV Workshop on Wireless Communication
Natal, RN, April 2010.
•
V Workshop on Wireless Communication
Vila Velha, ES, August 2010.
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Conclusion
The main activities developed in the INCT-CSF in the biennial 2009-2010 were described.
Quantitative and qualitative features were presented, emphasizing the activities involving
graduate students, the development of research activities that will contribute to the national
development and the cooperation with the telecommunication industry, telecommunication
operators, as well as governmental agencies and institutions.
It should be mentioned that ,despite the fact that the developed activities have been described by
each one of the research groups and institutions, the whole work was developed with the
knowledge, approval and mostly in cooperation among researchers of different laboratories.
This is a consequence of a compromise of the INCT-CSF of planning the project activities in a
participative way, including the organization of meetings in a regular basis. In fact, we organized
five workshops, three of them including students and researchers, with oral presentations (Belem
and Natal), one in order to evaluate and plan the project activities (Belo Horizonte) and the last
one in Vila Velha, during the MOMAG Symposium, open to all the conference participants.
The excellent relationship among the INCT-CSF researchers could be verified by the joint
development of several research activities that resulted in the publication of several papers in
technical journals and conference proceedings, co-authored by members of different INCT-CSF
research groups. This cooperation was extended to the joint advisory activity for several students
of the INCT-CSF groups, as well as in the participation of several PhD committees.
Another important contribution for this excellent cooperation activity came from the measurement
campaigns. Five measurement campaigns were conducted in São Paulo, Rio de Janeiro, Belo
Horizonte, Belem and Natal. It should be mentioned that these campaigns were developed with
the participation of researchers of different universities. In the campaigns developed in São Paulo
and Belo Horizonte we had also the support of the National Institute of Metrology (INMETRO),
including the mobile reception unit and technical staff.
Several measurement equipments are being bought to prepare the INCT-CSF mobile reception
units that will be used in the future measurement campaigns. The opportunity of using the
INMETRO mobile reception unit was unique in improving knowledge and skills.
The main difficulty is related to the administration of INCT-CSF. It is really very hard to handle the
INCST-CSF budget without having a good infrastructure. Nevertheless, the experience in the last
two years was very important and now we are able to handle these issues in a better way.
Particularly, the UFRN administration has given positive signs with respect to use its
administrative units.
The continuity of the INCT-CSF Project is imperative. Since the beginning, it has been very
motivating for the students and researchers. In fact, we believe that its formation was a very
successful initiative.
For 2011 and beyond, we are expecting a faster development for this project with an increase of
the cooperation among the researchers, the graduation of our students, the development of
research works that will contribute to the national development and the cooperation with the
telecommunication industry, telecommunication operators, as well as governmental agencies and
institutions. Particularly we are planning to extend the INCT-CFS international activities.
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