Synthesis of Plane Stratified Dielectric Slab Spatial Filters Using Numerical Optimization Techniques.

Abstract

Abstract : The synthesis of plane stratified dielectric slab spatial filters using numerical optimization techniques is presented. The stratified dielectric slab spatial filter is a unique concept for element pattern control on large planar arrays in that it gives protection for the array in the fashion of a radome. However, because of the relatively limited number of low loss microwave dielectrics, the synthesis of practical spatial filters must proceed in a manner which guarantees that the final configuration consists of materials which are readily available and reproducible. A numerical optimization technique of stratified dielectric filter synthesis has been developed which provides this guarantee while simultaneously attaining the required spatial and frequency bandwidth response. Using the optimization technique, an eleven layer filter design for use with a large mechanically scanned array has been obtained which has greater than 10 dB rejection in an angular stopband of 36 deg and less than 0.3 dB transmission loss in an angular passband of 10 deg around broadside. An up to date tabulation of available low loss microwave dielectrics and complete computer program listings are given in the Appendices. (Author)