Understanding Single-Element Beamforming using Characteristic Modes and a Change of Basis

An insightful approach to single-element beamforming is presented. In order to enhance the understanding of single-element beamforming, a change of basis is used to connect the characteristic modes of a single element to array theory. For the analyzed patch antenna, this allows not only the derivation of new explicit relationships for the excitation, but also enables the use of the array factor and other valuable tools from array theory.