Banca de QUALIFICAÇÃO: MYCHAEL JALES DUARTE

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
STUDENT : MYCHAEL JALES DUARTE
DATE: 13/12/2021
TIME: 09:00
LOCAL: Google Meet
TITLE:

Analysis and Design of Ultraminiaturized and Reconfigurable Frequency Selective Surface for Applications in Wireless Communication Systems

KEY WORDS:

Frequency Selective Surfaces; Ultraminiaturization, Equivalent Circuit; Reconfiguration.

PAGES: 50
BIG AREA: Engenharias
AREA: Engenharia Elétrica
SUBÁREA: Telecomunicações
SPECIALTY: Teoria Eletromagnetica, Microondas, Propagação de Ondas, Antenas
SUMMARY:

This work presents a study on ultraminiaturized and reconfigurable Frequency Selective Surfaces (FSS) for applications in modern wireless communication systems. Initially, a 2.5D FSS is proposed with an element inspired by convoluted metallic lines printed on a FR-4 dielectric substrate, the inserted vias contribute to the capacitive and inductive effects on the structure, providing the ultraminiaturization of the dimensions of the unit cell. The size of the unit cell is equal to 4.68% of the wavelength in free space for the 2.34 GHz frequency (first resonant frequency). The surface has dual-band responses centered on the frequencies of 2.34 GHz and 8.45 GHz. An equivalent circuit model is proposed to better understand the operating principle of FSS. The second structure analyzed is based on the first, being planar and with its size increased. Four PIN diodes were inserted symmetrically for switching, providing three operating states (all OFF diodes, all ON diodes and two ON diodes and two OFF diodes). The reconfiguration allows the frequency response to vary between frequencies from 0.9 GHz to 2.5 GHz. All FSS were shown to be stable with respect to the angle of incidence of the plane wave on the surface of the circuit. The simulated numerical results for the projected prototypes were obtained by the ANSYS HFSS software and by the equivalent circuit model. The prototypes were built and the experimental characterization of the transmission coefficients, bandwidth and resonance frequency was carried out, values obtained were compared and discussed with the simulation results, which showed good agreement.

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