Some Properties and Limitations of Electronically Steerable Phased Array Antennas

The class of antennas widely known as phased arrays includes essentially two types of radiators: stationary and steerable ones. The first operates at fixed amplitude and fixed relative phase between the array elements. Consequently, the antenna characteristics, such as radiation pattern, input impedance, and mutual coupling between elements, remain unchanged during the entire operational lifetime of the antenna. The steerable antenna is characterized by time varying ex* This work was supported bv the U. S. Army under contract DA-30-069AMC-333CY). 1561 1568 T H E BELL SYSTEM T E C H N I C A L J O U R N A L , SEPTEMBER 19