Wide Angle Impedance Matching techniques for volumetrically scanned phased arrays

The scan and frequency dependent aperture surface impedance is a useful way to study the effects of the active phased array. The surface impedance of an ideal current sheet diverges for orthogonal E- and H-plane polarizations at large scan angles, based on fundamentals. This phenomenon can be reproduced in the phased array unit cell using modern Finite Element Modeling techniques. It can also be corrected within a limited frequency range using complex conjugate matching schemes, which are also termed Wide Angle Impedance Matching (WAIM) techniques. While these latter techniques often introduce surface wave resonance effects, a parasitic element approach satisfies the complex conjugate condition with minimal surface wave effects. This last approach includes the geometry found in a stacked patch radiator.