Computer-aided antenna feed design using Characteristic Modes

A new design technique that provides practical feed designs for arbitrary PEC structures is introduced. The technique requires minimal guidance from a human operator Using the information provided by a modal analysis, known as Characteristic Modes, allows us to construct a feed arrangements solution(s). From this solution(s), we can obtain the number, locations, and excitation voltages of one or more feed ports to excite a set of modes over some specified frequency range. The technique was applied to antennas and shows to provide highly realistic feed arrangements.

I. Introduction

Antenna design is typically composed of three distinct, but related tasks: geometry and materials definition, feed design, and impedance matching (when necessary). By feed design, we mean the determination of the number and location of feed ports. Usually, the first two tasks are lumped together, as optimum feed design for classical antennas such as spiral antennas or others is part of the overall geometrical design. The last task is sometimes considered independent of the antenna design and is well treated by a variety of techniques mostly for the single-port case [1].