Minimization of Antenna Quality Factor

TL;DR

This paper introduces a new, efficient method for minimizing the antenna quality factor Q on arbitrarily shaped radiators, extending the class of solvable problems through dual problem formulation and modal analysis.

Contribution

It presents a novel dual problem approach combined with modal decomposition and group theory to efficiently minimize antenna quality factor Q, applicable to complex geometries and specific radiation patterns.

Findings

Method achieves minimal Q efficiently for arbitrary shapes.

Numerical results align with previous methods, validating the approach.

Extends solvable problem class beyond existing techniques.

Abstract

The optimal currents on arbitrarily shaped radiators with respect to the minimum quality factor Q are found using a simple and efficient procedure. The solution starts with a reformulation of the problem of minimizing quality factor Q as an alternative, so-called dual, problem. Taking advantage of modal decomposition and group theory, it is shown that the dual problem can easily be solved and always results in minimal quality factor Q. Moreover, the optimization procedure is generalized to minimize quality factor Q for embedded antennas, with respect to the arbitrarily weighted radiation patterns, or with prescribed magnitude of the electric and magnetic near-fields. The obtained numerical results are compatible with previous results based on composition of modal currents, convex optimization, and quasi-static approximations; however, using the methodology in this paper, the class of solvable problems is significantly extended.