Using Evanescent Plane Waves as Free Parameters in Array Design

Abstract

A generalized Poisson summation formula produces an explicit expression for the surface current on a plane that radiates a set of preselected plane waves. When only a finite number of plane waves are specified, the surface current is a continuous function. If an infinite number of plane waves are specified, the surface current can degenerate into a discrete set of line sources. In such situations, the expression for the surface current determines both the location and strength of the line sources that radiate the infinite set of plane waves. One can specify both propagating and evanescent plane waves. The evanescent plane waves can be used as free parameters to reduce the imaginary power.