Range Improvement in Single-Beam Phased Array Radars by Amplifier Impedance Tuning

Significant radar range degradation can be incurred due to variations in antenna impedance from changing array scan angle. Element-wise reconfigurable impedance tuners can be used to optimally match the power amplifier device; however, the impedance matching can also affect the array pattern. In this paper, the effects of element-wise impedance tuning on the transmitted power and on the array pattern are studied, and an approach is recommended for the element-wise implementation of impedance tuners. Examples of impact on array pattern and transmitted power are given using simulation of a designed switched-stub impedance tuner. As a result of these experiments, guidelines are developed for the creation of real-time circuit optimization techniques in the array elements.