STUDY OF MICROWAVE METASURFACE ANTENNAS USING CHARACTERISTIC MODE ANALYSIS

Abstract

Metasurfaces (MTS) are the two-dimensional equivalents of metamaterials capable of manipulating electromagnetic waves. Most of previous studies focus on infinite-sized and electrically-large MTSs under far-field excitation, offering limited physical insights into the resonant behavior of finite-sized MTSs under near-field excitation. The lack of a systematic approach hinders further developments in this field.

In this thesis, finite-sized MTSs are studied in detail using the theory of characteristic modes (TCM), with the primary aims of improving the performance of low-profile antennas, arrays, and multi-antenna systems. The multi-mode resonant nature of finite-sized MTSs are clearly revealed, based on which a systematic analysis and design framework for MTS structures is formulated. With the novel physical insights gained on the MTS modes, innovative methods of mode excitation, mode manipulation and mode synthesis are proposed for low-profile antennas to achieve significantly better performance over existing designs.