Double-differential-fed, dual-polarized patch antenna with 90 dB interport RF isolation for a 2.4 GHz in-band full-duplex transceiver

Official URL: http://dx.doi.org/10.1109/LAWP.2017.2786942

This letter presents a 2.4 GHz, dual-polarized microstrip patch antenna with extremely high interport isolation for a shared antenna architecture-based in-band full-duplex transceiver. The presented antenna configuration is based on four-ports linearly polarized single radiating element with differential feeding for both transmit (Tx) and receive (Rx) operation. The double-differential feeding using two identical 3 dB/180° ring hybrid couplers with nice amplitude and phase balance effectively suppresses the interport RF leakage to achieve very high isolation. The prototype of the proposed antenna architecture is implemented using a 1.6 mm thick general-purpose FR-4 substrate. The implemented antenna provides more than 90 and 80dB interport RF isolation for 20 and 40 MHz bandwidths, respectively, in addition to more than 98 dB port-to-port peak isolation when measured inside an anechoic chamber. To the best of our knowledge, this is the highest amount of RF isolation reported for a single dual-polarized patch antenna.