A dual-gate phase conjugating antenna with ASK modulation capability for retrodirective communication links

In this paper, a phase conjugating antenna with amplitude shift keying (ASK) modulation capability is presented for its use in retrodirective arrays. A dual-gate FET resistive mixer is integrated with a slot coupled square patch, and a data signal is applied to the second gate terminal in order to amplitude modulate the device time-varying output conductance. Measurements of the response signal in a backscatter test set-up validate the proposed solution for carrying information back to the interrogator position in an ASK format.