Banca de DEFESA: THAYUAN ROLIM DE SOUSA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : THAYUAN ROLIM DE SOUSA
DATE: 29/11/2024
TIME: 09:00
LOCAL: Google Meet
TITLE:

Application of Frequency Selective Surface as a Reconfigurable Reflector for Optimizing Microstrip Antenna Performance for 5G Applications

KEY WORDS:

frequency-selective surface, reconfiguration, microstrip antenna, PIN diode.

PAGES: 80
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUBÁREA: Telecomunicações
SPECIALTY: Teoria Eletromagnetica, Microondas, Propagação de Ondas, Antenas
SUMMARY:

This work presents the development of reconfigurable frequency-selective surface (RFSS) structures for 5G applications. Frequency-selective surfaces (FSS) are widely used in communication systems, with applications in the microwave to terahertz range. Initial analysis is performed by characterizing the FSS in its ideal form to predict the behavior of the reconfigurable structure. Then, the proposed RFSS is designed and evaluated. The proposed structure consists of a single dielectric substrate with a metallization layer. The RFSS unit cell is based on a V-shaped element and a single PIN diode is used as the active device per unit cell. The PIN diode in each line of the RFSS is connected in parallel by the biasing network. These structures were fabricated and experimentally characterized to validate the numerical results, and good agreement between them was observed. Three polarization state configurations are analyzed: off-state, on-state and intermediate state. Depending on the polarization state, the RFSS can exhibit single or multiple band response. The proposed RFSS exhibits independently switchable characteristics that make it suitable for a variety of applications, in its single- or multi-band configuration. Following this analysis, the RFSS were applied in a system with a dual-band rectangular microstrip antenna. The system consists of placing the RFSS in front of the microstrip antenna, acting as a reflector. The antenna used is a rectangular patch type, modified by the insertion of two T-shaped slots to provide dual-band response at 1.7 GHz and 3.7 GHz. The numerical results were obtained through simulations using the commercial software ANSYS HFSS. By changing the state of the PIN diode, the system increases the antenna gain and reconfigures its radiation pattern, reaching values of 5.6 dB and 5.5 dB of gain enhancement for the first and second resonance frequencies, respectively.

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