A Planar 4.0 GHz Reactively Steered Adaptive Array

A planar reactively steered adaptive array comprised of a single active microstrip element and eight closely coupled parasitic microstrip elements is described. Null steering is accomplished by adaptive control of reactive terminations on the parasitic elements using both a steepest descent algorithm and a guided random search algorithm. The planar array can steer nulls in elevation and azimuth with a depth of about 35 dB.