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A High Efficiency Circularly-polarised Van Atta Analog Adaptive Array for Full Duplex Communications

A new kind of information carrying technology is proposed on the platform of a circularly-polarised Van Atta retrodirective (analog adaptive) array. Similar to the phase conjugated array but with lower design complexity, the proposed array exhibits retrodirectivity and can transmit information from the base station to the interrogator. In this paper, a dual-circularly-polarised antenna array that can isolate the incoming and outgoing signals is designed for both receiving and transmitting purposes. The radar-cross-section (RCS) patterns confirm the retrodirective ability with a wide scanning range of over 120°. High-efficiency class-F power amplifiers (PAs) with low-noise driver amplifiers are employed to increase the link gain. A DC-DC converter provides not only a stable active bias for the class-F PAs but also information carrier for the outputs of class-F PAs with magnitude modulation. Without the need of a LO, the proposed array can modulate information source such that signal at the output of the amplifier can carry information.