A full-duplex dual-frequency self-steering array using phase detection and phase shifting

A full-duplex dual-frequency self-steering array using phase detection and phase shifting is presented. By RF decoupling the transmitter and receiver arrays, the proposed system promises greater system efficiency by ensuring a constant transmit power. This also allows for a separate low-frequency interrogating signal capable of various modulation schemes. A two-element prototype is demonstrated with interrogating and retrodirective frequencies of 1.425 and 2.85 GHz, respectively. Retrodirectivity is reported for angles of 0/spl deg/, -15/spl deg/, and +25/spl deg/. The power of the received signal is improved by up to 12 dB for -60/spl deg//spl les//spl theta//spl les/60/spl deg/ when compared to a conventional two-element array.