Deisy Formiga Mamedes

Topic

Design of Frequency-Selective Surfaces for Advanced Applications

Department of Electrical and Computer Engineering

Date & location

• Wednesday, April 10, 2024

• 10:00 A.M.

• Virtual Defence

Reviewers

Supervisory Committee

• Dr. Jens Bornemann, Department of Electrical and Computer Engineering, University of Victoria (Supervisor)

• Dr. Thomas Darcie, Department of Electrical and Computer Engineering, UVic (Member)

• Dr. Afzal Suleman, Department of Mechanical Engineering, UVic (Outside Member) 

External Examiner

• Dr. Custódio Peixeiro, Instituto de Telecomunicações, Instituto Superior Técnico 

Chair of Oral Examination

• Dr. Richard T. Marcy, School of Public Administration, UVic

   

Abstract

The advancement of mobile technology is driven by the requirements for wider bandwidth, higher data rates, a large number of users, and reliable connectivity. The fifth generation (5G) mobile network is currently in its early stages of commercialization with two frequency bands allocated for its technology. Frequency-selective surfaces (FSS) form a promising technology to help meet these requirements. Extensive research has been conducted on the use of FSSs as spatial filters in the sub-6GHz and millimeter-wave (mm-wave) spectra, as they are able to impart screening properties in the spatial domain. Therefore, this dissertation presents works focused on FSS technology to demonstrate and verify its advantages.

First, a new polarization converter system using only a single-layer FSS is proposed. Design equations are introduced for the four-arms star geometry which is used as polarizing element. Polarization converters have become popular in different communication systems due to their characteristics of mitigating the effects of polarization mismatching, thus improving signal strength.

Second, an ultra-wide band-stop FSS operating at K- and Ka-bands for mm-wave applications is presented. This structure comprises of double-layer FSS with simple modeling, where a series of basic equations are implemented and described. When the proposed resonators are cascaded, they offer wide bandwidth, eliminating the need for extra layers.

Third, a new beam-tilting and gain enhancement system operating at 28 GHz is proposed. The system is composed of a bio-inspired bow-tie antenna as excitation source and a single-layer FSS positioned at the bottom of the antenna. The effect of FSS panel size is investigated to achieve the better antenna performance.

Fourth, a system of closely coupled-complementary passive FSSs that achieves dual- and triple-band operations is presented. Four configurations of the elements are investigated, which can present two and three transmission bands in one or both polarizations by inducing an electromagnetically induced transparency effect.

Fifth, a novel reconfigurable complementary-inspired FSS with reconfigurable frequency response is described. The proposed structure consists of two resonators with immersed biasing network, and only a single PIN diode per unit cell as active device. Single- and dual-passband performance is achieved by switching the diode’s state from off to on. When the threshold voltage is applied, no passband appears. Sixth, two high-gain beam-switching antenna systems are presented. Both systems comprise of a dipole antenna as excitation source and single-layer PIN-diode-switched FSS panels as mechanism of reconfiguring the radiation pattern. The first system is configured as a reconfigurable corner antenna with large beam-switching range. The second system can steer the beam in the azimuth and elevation planes.