A Retrodirective Array with Interference Rejection Capability

A retrodirective array with interference rejection capability is presented. Signals from two sources (one desired and one interfering) are first detected and then a null is formed in sub-arrays at each element in the retrodirective array and directed toward the unwanted signal. The null-forming subarray pattern can be multiplied to the retrodirective pattern through application of the principle of pattern multiplication. The system continues to track the desired signal through its purely analog retrodirective function, requiring no digital signal processing and maintaining almost instantaneous self-tracking. Demonstration of interference suppression shows promise in furthering the functionality of retrodirective arrays in addition to the already high-speed self tracking benefits.