A retrodirective null-scanning array

A full-duplex self-steering array using power detection and phase shifting is presented. The system utilizes two sub-arrays to autonomously steer its beam toward an interrogating signal. A two-element null-scanning array is used for power detection where the interrogator direction is determined by the location where minimum power is detected. Retrodirectivity is reported for angles of 0°, -30°, and +10° at a receive frequency of 7.31 GHz and a transmit frequency of 7.33 GHz.