Banca de DEFESA: FRANCISCO DAS CHAGAS BARBOSA DE SENA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
DISCENTE : FRANCISCO DAS CHAGAS BARBOSA DE SENA
DATA : 13/04/2018
HORA: 09:00
LOCAL: Auditório do PPGEEC
TÍTULO:

Optimization of DGS and PBG Structures in Rectangular Microfine Antennas Using Genetic Algorithm

PALAVRAS-CHAVES:

Microstrip Antenna, Optimization, Genetic Algorithm, PBG and DGS.

PÁGINAS: 116
GRANDE ÁREA: Engenharias
ÁREA: Engenharia Elétrica
SUBÁREA: Telecomunicações
ESPECIALIDADE: Teoria Eletromagnetica, Microondas, Propagação de Ondas, Antenas
RESUMO:

Microstrip antennas have attracted the attention of researchers worldwide because of their interesting features for various applications. However, disadvantages such as low gain, narrow bandwidth and low radiation efficiency can limit their use in a given system. Besides, this type of antenna can excite higher order modes in addition to the fundamental. This feature is particularly important for systems with multiple operating frequencies, in other cases, it is necessary to use filters to eliminate the unwanted modes. Alternatively, arrangement of defects can be added to the ground plane or substrate antenna to achieve the same aim, such structures are named Defected Ground Structure (DGS) and Photonic Band Gap (PBG), respectively. However, the development of really efficient projects involving these types of structures presents great dependence on the correct specification of the physical parameters of the used arrangements. In this context, aiming at eliminating and/or attenuating the higher order modes, without significantly affecting the performance of the antenna to the fundamental mode, the present work studied the application of a Genetic Algorithm (GA) in the development of new models with DGS and PBG. The proposed models are composed of circular holes, filled with air, in the hexagonal and rectangular patterns for the periodic configuration and with micro structured pattern for the quase periodic configuration. The proposed GA was responsible for specifying the following parameters of the analyzed arrangements: diameters of the holes, distance among them and the location of the arrangement along the length of the antenna. Based on the obtained results, it was verified that the proposed GA was able to optimize the analyzed structures in order to preserve the fundamental mode of the analyzed antennas, whereas the higher order modes were eliminated and/or considerably attenuated. It was also verified that for the same type of arrangement, the antennas with DGS presented better performance regarding to those with PBG, considering the reflection coefficient to the fundamental mode. In addition, the optimized structures did not show significant variations in the gain or radiation pattern and they exhibited important characteristics to miniaturization projects. The obtained results are particularly important, assuming that optimized structures can be used to eliminate higher order modes in application with passive or active microstrip antennas which also operate as resonators.

 

MEMBROS DA BANCA:
Presidente - 1422265 - JOSE PATROCINIO DA SILVA
Interno - 2524053 - ANTONIO LUIZ PEREIRA DE SIQUEIRA CAMPOS
Interno - 1412682 - VICENTE ANGELO DE SOUSA JUNIOR
Externo à Instituição - HUMBERTO DIONISIO DE ANDRADE - UFERSA
Externo à Instituição - ÁDLLER DE OLIVEIRA GUIMARÃES - UFERSA