Investigation of a Generalized Frequency Domain Method for Modeling Time-Varying Loads on Antennas

Abstract

Within traditional antenna design, the behavior of the antenna can be dictated by its physical dimensions and their proportions to a wavelength. Traditional electrically small antennas in particular face many limitations on factors such as their gain, quality factor, or bandwidth. The limitations on traditional antennas are based on the assumption that the antenna in question is a Linear Time-Invariant (LTI) component. This project proposes the introduction of time-varying loads to antennas in order to fundamentally alter the limitations assumed by electrical size. Non-LTI antennas however cannot be modeled and characterized by many traditional electromagnetic solvers used commonly. In this thesis, an expanded and generalized frequency domain method for analyzing time-varying loads on antennas is introduced. It combines traditional method of moments techniques with conversion matrices commonly used for time-varying circuit analysis. The Conversion Matrices Method (CMM) has shown to be promising, providing agreement with results found using a known time-domain method. This thesis provides the fundamental first step toward non-LTI antennas with an accurate method of modeling antennas with time-varying components.