A wideband circularly-polarized active Van Atta retrodirective transponder with information carrying ability

A new kind of information carrying technology is proposed on the platform of a circularly-polarized Van Atta retrodirective 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-polarized 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 120deg. Low-noise ET amplifiers with low power consumption and noise figure are employed to increase the link gain. Without the need of an LO, the proposed array can modulate a digital source such that signal at the output of the amplifier carry information.