Dissertações em Engenharia Elétrica (Mestrado) - PPGEE/ITEC

URI Permanente para esta coleçãohttps://repositorio.ufpa.br/handle/2011/2316

O Mestrado Acadêmico inicou-se em 1986 e pertence ao Programa de Pós-Graduação em Engenharia Elétrica (PPGEE) do Instituto de Tecnologia (ITEC) da Universidade Federal do Pará (UFPA).

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Agora exibindo 1 - 18 de 18

Acesso aberto (Open Access)
Avaliação da tecnologia femtocell como canal de retorno para TV digital
(Universidade Federal do Pará, 2013-08-26) COSTA, Allan Barbosa; CARDOSO, Diego Lisboa; http://lattes.cnpq.br/0507944343674734; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
Traffic measurement on Digital TV interactive applications for fourth generation networks, especially WiMAX and femtocell, has been a challenge to researchers around the world. The traffic pattern of an interactive application on the Brazillian System of Digital TV (SBTVD) was identified. Simulations on a wireless network were carried out using data obtained of traffic analysis. In this work a WiMAX and a femtocell network were chosen to simulate the return channel of a Digital TV application on a WMAN (Wireless Metropolitan Area Network). In order to reduce signal attenuation, femtocell arises as a promising solution, reducing macrocell usage, as femtocells cover indoor environments. The simulations is this work were executed using OPNET software. Through them it is possible to estimate the feasibility of femtocell and WiMAX technologies as return channel for Digital TV.
Acesso aberto (Open Access)
MAERNI - Módulo de avaliação da exposição à radiação não ionizante proveniente das antes de transmissão de TV digital e rádio FM para uma ferramenta com o ambiente virtual 3D
(Universidade Federal do Pará, 2018-10-09) GUERREIRO, Charllene de Sousa; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
In recent years given the technological advancement of the communication media, and the increasing of users demand who wants a high quality of these services offered to them, the companies have increased the number of Radio Base Stations in cities, where many of these are located in environments with high housing density. Considering that each antenna or set of antennas present in these stations have an electromagnetic field of radiofrequency and transmit radiation, the concern with the population living in the adjacency of the transmitting antenna is the studies object of systems than regulate the companies that offer radiofrequency services, as well as, is the object of studies that aim not only to discover the effects of the contact with the ionizing and non-ionizing radiation present in these fields, but also to find out if the standard established for the regulation of services is being fulfilled. In this work presents the stages of development of a module, which consists of an extension added to the simulator for planning mobile communication networks (SIMPLARCOM). The module proposed allows, through the Virtual Reality environment (VR), to build and configure different scenarios, as well as the parameters of the transmission antenna, to provide an environment for non-invasive tests to evaluate non-ionizing radiation exposure; and identify potential insecure areas for housing, providing information for aid in decision-making regarding the relocation of transmitter antennas and aiming to decrease the ERP (effectively radiated Power) radiated by these Antennas. The module considers the guidelines present in resolution Nº. 303, published by the National Telecommunications Agency (ANATEL). In the results obtained is possible, navigate through the constructed scenario and check the value of the received power, the field intensity, the operation frequency, the antenna being analyzed and whether a certain point in the scenario is or is not receiving radiation at according to the threshold permitted by ANATEL.
Acesso aberto (Open Access)
Metodologia de predição de perda de propagação e qualidade de vídeo em redes sem fio indoor por meio de redes neurais artificiais
(Universidade Federal do Pará, 2018-02-27) CRUZ, Hugo Alexandre Oliveira da; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
This dissertation presents a methodology that aims to assist the planning of indoor wireless network systems, which require prior knowledge of the environments in which they will be deployed. Thus, accurate signal analysis is necessary by means of a statistical empirical approach, which takes into account some factors that influence the propagation of the indoor signal: architecture of the buildings; arrangement of furniture inside the compartments; numbers of walls and floors of various materials, and the spread of radio waves. The methodology adopted is based on measurements with a cross-layer approach, which demonstrates the impact of the physical layer in relation to the application layer, in order to predict the behavior of the Quality of Experience (QoE) metric, called Peak signal- to-noise ratio (PSNR), in 4K video streams on 802.11ac wireless networks in the indoor environment. In order to do so, measurements were performed, which demonstrate how the signal / video degrades in the studied environment. It is possible to model this degradation by means of a computational intelligence technique, called Artificial Neural Networks (RNA), in which input parameters are inserted as, for example, the distance from the transmitter to the receiver and the number of walls crossed in order to predict loss of propagation and loss of PSNR. In order to evaluate the predictive capacity of the proposed methods, the values of the Root Mean Sqare (RMS) errors between the measured and predicted data were obtained by the prediction methods loss of propagation and loss of PSNR, with respective values of 2.17 dB and 2.81 dB.
Acesso aberto (Open Access)
Uma metodologia para predição do campo elétrico de radiodifusão sonora em ondas médias utilizando inferências bayesianas
(Universidade Federal do Pará, 2013-06-11) COSTA, Juliana Santiago Monteiro; ARAÚJO, Jasmine Priscyla Leite de; http://lattes.cnpq.br/4001747699670004; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
The adoption of digital sound broadcasting systems, which are under testing in the country, allows new studies aimed a better planning for the implementation of new stations, which means to reassess the major existing radio propagation models or propose new alternatives to meet demands inherent in digital systems. The current models, as Recommendations ITU-R P. 1546 and ITU-R P. 1812, do not match closely with the reality of some regions of Brazil, especially in the tropical regions, such as the Amazon Region, due to the high rainfall and the vast existing flora. Using models suited to the propagation channel, it becomes feasible to develop planning tools covering most accurate and efficient. The use of these tools is applicable both to ANATEL, for the elaboration of the basic plans, as distribution channels for broadcasters. This paper presents a methodology using a computational intelligence based in Bayesian Networks for prediction of electric field intensity, which can be applied to planning or expanding coverage areas in broadcasting systems for frequencies in the range of medium wave (300 kHz to 3 MHz). This methodology generates electric field values estimated from the values of terrain altitude (through analysis of conditional probability tables) and provides a comparison of these values with the measured electric field. The data used in this study were collected in Brazil’s central region, nearby the city of Brasilia. The transmitted signal was an AM radio signal transmitted at a frequency of 980 kHz. With the data collected during the measurement campaigns, simulations were performed using conditional probability tables generated by Bayesian Networks. Thus, it’s proposed a method for predicting values of electric field based on the correlation between the measured electric field and the altitude through the use of artificial intelligence. Compared to numerous studies in the literature that have the same goal, the results found in this study validate the use of the methodology to determine the electric field in medium wave radio broadcasting using Bayesian Networks.
Acesso aberto (Open Access)
Métricas de QoE/QoS de vídeo em redes sem fio para auxilio ao planejamento de ambientes indoor utilizando uma abordagem bayesiana
(Universidade Federal do Pará, 2015-03-30) CARVALHO, André Augusto Pacheco de; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
The evolution of applications on wireless networks has grown in recent years, due to the increased number of smartphone users, tablets and others. The availability of demanding services such as video transmission, affects Quality Experience (QoE) and Quality of Service (QoS) provided to domestic users and trade, this had stimulated the study of new resource management techniques networks, aiming to provide quality services to a customer each increasingly demanding. This thesis presents a methodology Intelligence Artificial using a Bayesian network with a hybrid evaluation strategy analyzing the behavior metrics QoE and QoS in the LAN network design wireless. The diversity of the place of Measurements chosen compound materials such as brick, glass, wood and concrete. It was necessary first to map all the points to be measured before and after deliberately placing each barrier outdated the signal. Metrics as level Receiver Signal Strength Intensity signal (RSSI) Jitter, delay end to end network for the video transmission, PeakSignal-to-NoiseRatio (PSNR) and Structural Similarity (SSIM) were collected during the Measurements. And using the Bayesian Network inferences were made for each metric and could not find satisfactory results for the proposed solution assist the wireless network planning in indoor environments. Enabling demonstrate that up to 10 meters away from the transmitter, the signal has its best power, and delay metrics in order to have more than 65% probability that the lower delay range and following this optimum performance the Jitter has more than 65% probability in this lower range. And the QE metrics, PSRN and SSIM have a similar behavior and has more than 80% probability of getting your greater value, and consequently the video has its best reception. These results show that does not preclude the use of this proposal in other situations.
Acesso aberto (Open Access)
Modelagem Neuro-Fuzzy de perdas de propagação para planejamento de redes LTE
(Universidade Federal do Pará, 2016-05-06) NASCIMENTO, Regina de Nasaré Almeida do; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
The development of mobile communication technologies is associated to the demand of services by users who are more and more using the data services than voice. And to keep up with those demands the telecommunication enterprises seek to meet with new technologies this user searching for speed and quality in the service used by mobile networks. The technology LTE (Long Term Evolution) has shown flexible features that stand out in relation to the technologies that preceded it as the GSM and UMTS and the operators to meet the goals of existing networks such as multimedia services, spectral efficiency and business for mobile broadband. The organization that developed the LTE specifications is the 3GPP (3rd Generation Partners Project) and standardized by the European Standards Institute in the area of Telecommunications ETSI (European Telecommunications Standard Institute). This dissertation was realized a study about propagation losses in outdoor environment, from models found in the literature and suitable for the propagation channel. Performance results are presented using the metrics of root mean square error and standard deviation and the graphical representation of data measured. And to helpful to understand this analysis is interesting to map the area and deploy or adapt planning tools of coverage with more accurate and efficient. The data used in this study was collected on some main roads in the Castanhal city, of Pará state, northern Brazil. The frequency of the transmitted signal used for LTE is 1.800 MHz and the method used to predict propagation loss was Neuro-Fuzzy. This system uses the techniques of Computational Intelligence that combines Artificial Neural Networks (ANN) and Fuzzy Logic (LF) and have demonstrated ability to solve different types of problems in various applications in different areas. And through this technique, the comparison between the results predicted by the proposed method and literature propagation models to provide an analysis by the signal characteristics in specific channels, observing the limitations and local features.
Acesso aberto (Open Access)
Modelagem paramétrica linear aplicada à faixa de sinal de televisão digital para cidades densamente arborizadas
(Universidade Federal do Pará, 2014-02-26) LOPES, Ramz Luiz Fraiha; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
This work proposes a linear parametric (auto-regressive) model applicable to digital television and mobile phone signals propagation studies on densely arborized cities. The proposed model has a strong statistic basis and depends only on measured data, in case, power signal and PSNR (Peak Signal-to-Noise Ratio) values data. A genetic algorithm was used to adjust the parameters of the model to a measured data set. This work was carried out on the digital television frequency and the signal power level and PSNR values were analyzed. Measurement campaigns were carried out in Belém city. Power signal data was collected as well as videos form the daily schedule of a television station. The results indicate that the model applicability is feasible on planning telecommunication services.
Acesso aberto (Open Access)
Modelo de propagação de campo elétrico para TV digital em percursos mistos do tipo cidade-rio na região Amazônica
(Universidade Federal do Pará, 2016-02-24) ERAS, Leslye Estefania Castro; PELAES, Evaldo Gonçalves; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
In this work the study of the electric field propagation is presented for two typical mixed paths in the Amazon region. A first scenario discussed is Belém-Bay Guajará located in the state of Pará. This path has 24% of land and 76% of water. A measurement campaign was carried out over land and over water; using the digital channel 22 of a TV station in the frequency of 521 MHz. Were measured a total of 239 points, including 19 over ground and 220 over water distributed in 3 Radials. Data were compared with various empirical and deterministic propagation models, found in the literature. The metric to test the performance of the models was the RMS error. Furthermore, it is proposed in this paper, the combination of two models: ITU-R P.1546 and Millington. This model had the lowest RMS error compared to the other models used in this work and follows the signal behavior in the transition area land-water, where the signal experiences an increment of the electric field strength, a phenomenon known as "Recovery Effect." Other models used were: Okumura-Hata, Free space, Dyadic Green's function, ITU-R P.1546-5 and Ray Tracing. Such models did not adapt to the signal behavior. In order to evaluate the proposed model a second scenario was used Belém-Mosqueiro, this has 25% of water and 75% of land. In this case, the data was measured only over land, the water data were obtained by simulation. In this situation, the data calculated with the proposed model has agreement with measured data. The simulated water data showed the characteristic of "Recovery Effect," phenomenon that is not described by the other models. It is concluded that the combination of the ITU-R P 1546-5 and Millington models has a better agreement with the data measured on mixed paths land-water than the other models.
Acesso aberto (Open Access)
Modelo de propagação indoor multi-andar em 2.4 GHz com estimativa de parâmetros de QoS em chamadas VoIP
(Universidade Federal do Pará, 2010-05-07) GOMES, Igor Ruiz; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
The advent of new multimedia forms has attracted many customers, concerns not only with the service, but also with the quality of service that can be offered. The WLAN have become the most common form of Internet routing, this is because of its low cost and ease implementation. To achieve a good routing planning it’s necessary to use propagation models. In the literature many propagation models make the prediction of signal strength but do not include the provision of quality of service metrics (parameters). In this sense this work proposes to develop an empirical propagation model indoor multi-floor that not only predicts the received power, but also makes a prediction for some metrics of QoS for VoIP (Voice over Internet Protocol). To develop the proposed model, measurement campaigns were performed on separate floors of a building while maintaining the position of the access point AP) fixed in one floor. Studies of analytical geometry were taken for counting and aggregation of losses on floors/walls. The results of the proposed model were compared with model of literature which has similar propagation behavior. To improve a comparison, a test with a simulated floor was introduced using the proposed model.
Acesso aberto (Open Access)
Modelo de propagação para redes sem fio fixas na banda de 5,8 GHZ em cidades típicas da região amazônica
(Universidade Federal do Pará, 2010-05-07) CASTRO, Bruno Souza Lyra; GOMES, Hermínio Simões; http://lattes.cnpq.br/0696136066497209; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
The study of propagation loss in the Amazon region cities involves an environment characterized by tropical climate and suburban environments densely arborous. Based in the importance of ISM band 5.8 GHz, this work presents a propagation model for this frequency band, combining the characteristics of attenuation experienced by a radio wave when it propagates in typical environments found in Amazon region cities. For such purpose, measurements of the received power were carried out in 335 fixed customers distributed in 12 towns in northern Brazil, which are served by digital inclusion program in the state of Pará, Navega Pará. Measurements with mobility were also carried out on the Federal University of Pará (UFPA) area. Still, it is presented the performance of the proposed model over other models (SUI model and COST231-Hata), described in the literature, when in fixed and mobile networks. Performance metrics such as RMS error and standard deviation were applied taking as reference the measured data. Tuning procedure of the model parameters is performed by the method of linear least squares, applied in two steps to reduce uncertainty about the parameters set. The proposed model achieved an RMS error of 3.8 dB and standard deviation of 2.3 dB, surpassing all other models that had RMS errors above 10 dB and standard deviations over 5 dB. The results show its efficiency on other models to predict losses in the range of 5.8 GHz in stationary and mobile systems.
Acesso aberto (Open Access)
Modelo estatístico para aplicações no planejamento de sistemas móveis celulares em ambiente indoor multifontes
(Universidade Federal do Pará, 2005-12-15) LIMA, Rosely dos Anjos; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
The project of systems of mobile communications requires the knowledge of the environment where it will be implemented. For so much, the accuracy is looked for in the prediction of propagation of the signal through the use of prediction models. The present work proposes an empirical model for estimating of the signal strength received in indoor environments that presents more than indoor transmitter source, using Distributed Antennas Systems (DAS). The method presents a generalization for the case of multiple sources, also called multisources and as particular case to only one source. The modeling is made through the use of radial go away of each transmitter, with aim to consider the variability of the signal in indoor environments. These some disturbances in the signal, that they cause fast fading; they are characterized through the statistical distributions of fading. The most used as of Rayleigh, Rice and Nakagami are presented for characterization of the channel; besides the distributions recently developed are calculated, so Kappa-mi and Eta-mi. For the validation of the model, campaigns of measurements in shopping center were made, where possesses one DAS, with the test in two distinct environments, a supermarket and a feeding square. The simulations are carried out through using the software MATLAB® and the performance of the results evaluated through the calculation of the absolute error, standard deviation and rms error.
Acesso aberto (Open Access)
Planejamento de rede LTE utilizando aproximação híbrida de modelo empírico outdoor: medição e técnica de algoritmo genético
(Universidade Federal do Pará, 2015-03-20) PINHEIRO, Márcio Rodrigues; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
Currently, it is visible the growing number of mobile communications networks in the telecommunications scenario. In order to supply the demands of the most demanding users of mobile services with data transmission rates increasing constantly are developed by companies linked to the telecommunications industry, new technologies to keep up with these demands. As 2G and 3G networks can no longer bear the demands of current users because they can not provide quality services to customers due to limitations of data transfer rate. It was then developed, the LTE system (Long Term Evolution), which has become one of the most promising solutions to meet the growing demand of the telecommunications sector. In the LTE system, also called 4G is implemented efficiently on the network, various simulation tools to cover prediction has been developed. Great efforts have been invested in the development of these tools, in order that the predicted values are the closest possible to reality, making it indispensable in planning the LTE network. In this context, this paper is intended to study and optimization of outdoor propagation loss models available in the literature, operating in the 2.6GHz frequency range, in order to provide a propagation loss prediction more accurate the study environment. Therefore, signal measurements campaigns were held in Bethlehem in order to compare how satisfactory are the adjustments of the models of propagation loss with the signal loss measured in realized routes. It was observed that in certain measurements, models of propagation loss, did not show similar curves to that measured on the routes taken, showing high prediction error. Thus, optimization technique was used for all prediction models based on a Genetic Algorithm (GA). Through this technique, it was possible to achieve a significant improvement of the models studied compared the losses encountered on the routes taken, thus contributing to more efficient planning for networks operating in the LTE 2.6GHz range.
Acesso aberto (Open Access)
Planejamento de redes de comunicação sem fio para ambientes indoor considerando aplicações multimídia: abordagem híbrida - simulação e medição
(Universidade Federal do Pará, 2014-08-29) BRAGA, Allan dos Santos; FRAIHA, Simone da Graça de Castro; http://lattes.cnpq.br/6398509825377181; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
Wireless technologies have evolved rapidly in recent decades. It is an efficient alternative to transmit information, whether data, voice, video and other network services. Knowledge of the propagation process of this information in different environments is a factor of great importance for the planning and development of wireless communications systems. Because of the rapid progress and popularization of these networks, the services offered become more complex and therefore need requirements for qualities that are offered to the end user in a satisfactory manner. Because of this, it is necessary to designers of these systems, a methodology that provides a better assessment of the indoor environment. This assessment is made by analyzing the coverage area and the behavior of the metrics of multimedia services anywhere in the environment that is receiving the service. The work in this study intends to evaluate a methodology for the prediction of quality metrics experience. For this, measurements of video streaming campaigns were conducted in a wireless network and network parameters (packet/frames jitter and packet/frames loss) and some quality parameters of experience (PSNR, VQM and SSIM) were evaluated. The results showed good agreement with literature data and with measurements.
Acesso aberto (Open Access)
Predição de campo elétrico para TV digital usando Funções de Green diádicas
(Universidade Federal do Pará, 2014-07-01) SILVA, Diego Kasuo Nakata da; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
This work provides a method for the prediction of electric field intensity to Digital TV using the Dyadic Green's function. The Dyadic is a powerful mathematical tool which has symbolic simplicity and robustness, thus enabling some characteristics of the medium (such as permittivity, conductivity and permeability, for example) are considered in developing the electric field model, as well as take into account the anisotropy of the medium. In most related works using the dyadic Green's functions are related in the VHF band. This work will present from basic concepts of dyadic, developing it for the calculation of a model which can predict the electric field to the UHF band, in which systems are Digital TV. A theoretical explanation and mathematical development will be made such that a clear understanding and objective are achieved in the study of dyadic Green's functions, in a part of the theory of electromagnetism Tests were performed to confirm the applicability of the suggested formulation, making simulations that perform a comparison between measured data, from two TV stations located in the city of Belém, and the Okumura-Hata model modified, showing satisfactory results for both frequencies in VHF and UHF.
Acesso aberto (Open Access)
Predição dos campos elétricos na faixa de ondas médias em ambiente rural utilizando equações parabólicas
(Universidade Federal do Pará, 2011-12-19) SILVA, Alan Teixeira da; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
Brazil is carrying out trials to select the digital broadcasting standard to be adopted. Systems Digital Radio Mondiale (DRM) and High Definition Radio (HD Radio) developed only for frequencies below 30 MHz allow operation with bandwidth compatible with that used in Brazil, opening the possibility of coexistence of analog and digital radio broadcasting. Especially in the range of medium wave, the prediction of field strength of the surface wave is essential for planning of broadcasting systems considering the effects of terrain in order to determine the coverage area of the seasons. To contribute to the planning and adjustment of the Basic Plan in Medium Wave Broadcasting - PMWB the inclusion of new stations operating primarily in on-channel simulcast, it becomes necessary to develop tools that enable the evaluation of soil characteristics where no provides accurate data, allowing a review of theoretical models to predict adoption, contributing to the deployment of digital radio in our country. This work presents the results of the Brazilian field trial carried out carried by ANATEL (Agência Nacional de Telecomunicações) and Radiobrás to analyze a DRM (Digital Radio Mondiale) system in the medium-wave band. A 50-kW ERP power omnidirectional ground-wave experimental DRM transmission at a frequency of 980 kHz was surveyed by means of a measurement vehicle for fixed and mobile reception. Several radial routes starting from the transmitter site suburban area around the capital of Brazil, Brasilia provided behavior features of the system. Field strength threshold values were determined for the tested transmission configurations and compared with a Parabolic Equation model prediction.
Acesso aberto (Open Access)
Projeto de antenas multibandas integradas para terminais 4G
(Universidade Federal do Pará, 2014-02-26) FERREIRA, Hélio Renato Oeiras; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
This paper presents a design and analysis of a planar monopole antenna operating in multiband frequencies of 2000 MHz, 2500 MHz and 3500 MHz for use in 3G and 4G mobile devices. Among these bands are contained 3G (1895-2165 MHz), 4G (2500-2690 MHz) and 4G (3400-3600 MHz) spectra used by LTE and WIMAX 3.5. For the development of this study was taken as reference Hua-Ming Chen’s dual-band antenna designed to operate at ISM systems (1800 MHz), wireless networks and Bluetooth (2400 MHz). The project proposed in this work is a modification in the structure of the dual-band antenna adapted for simultaneous triple resonance frequencies used in 4G mobile networks. To achieve the proposed objective was used to simulate the CST® MICROWAVE STUDIO software based on the Finite Integration method in Domain; the simulations were done in the time domain. After obtaining satisfactory simulated results, a prototype antenna was built to test and measurement; the presented results are consistent with those obtained in the simulation, which validates the proposed method.
Acesso aberto (Open Access)
Projeto de um monopolo Hi para aplicações no sistema brasileiro de TV digital
(Universidade Federal do Pará, 2013-01-04) ALCÂNTARA NETO, Miércio Cardoso de; BARROS, Fabrício José Brito; http://lattes.cnpq.br/9758585938727609; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
This research deals with the design and analysis of a planar monopole antenna with modified geometry aiming its use for signal reception of digital TV in Brazil working in the of 470 MHz to 806 MHz. Track this contained in the spectrum of UHF-Ultra High Frequency (300 MHz to 3 GHz). To develop this work was taken as reference the antenna called "The Hi Monopole". What originally was presented to operate in UWB (Ultra Wide Band) at 3.1 to 10.6 GHz. For the development of the proposed work, different techniques of adjustment of the antenna can be used for broadband operation, such as: changes in the structure of antenna, resistive loading, switching, using of parasitic elements and matching structures. The design of broadband antennas can be made from three different approaches: time domain, frequency domain and expansion for singularities method. The frequency domain method was employed in this work to the antenna design proposed, some of the techniques mentioned above were analyzed aiming to increase bandwidth, and made a prototype of the antenna to validate the concepts employed. The antenna was designed for the range of 470 MHz to 890 MHz. the prototype built for this same range presented good results, which validates the technique employed. Positive and negative aspects of use of this technique are discussed throughout the work. The commercial computer program CST® MICROWAVE STUDIO, based on the Finite Integration Technique (FIT) was used for simulations in frequency domain.
Acesso aberto (Open Access)
Projeto e construção de um monopolo para aplicações de banda ultralarga (UWB) com elementos fractais
(Universidade Federal do Pará, 2015-05-08) SANTOS, Nelson Mateus Ferreira; CAVALCANTE, Gervásio Protásio dos Santos; http://lattes.cnpq.br/2265948982068382
This work describes the design and analysis of antenna monopole printed type. The initial geometry in the printed monopole antenna is of a regular hexagon, with 9 mm segments in length. The initial proposal is an antenna to serve the UWB range (3.1 to 10.6 GHz). To achieve a bandwidth satisfying the proposed problem, fractal curves (Peano curve and the Koch curve) were implemented in the geometry composition of the monopole and the ground plane, respectively, the introduction of these curves generate additional resonances, optimizing bandwidth and serving the specifications of UWB systems. To perform the analyzes, CST Microwave Studio ® software was used, which is based on finite integration method in the time domain, having the computing environment to simulate the antenna properties and the electromagnetic behavior of the same as the results of these simulations, a new frequency range going from 2.74 to 11.5 GHz is presented, satisfying the range of UWB systems. As a last stage, a prototype was made and the measurements with the proper equipment to compare the measured results with the simulated were realized, covering a frequency range from 3.2 to 13.5 GHz, where the range of results shows concordance with the simulated, validating the model.

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