Broadband antenna for passive self-interference suppression in full-duplex communications

This paper presents the design, implementation and isolation performance of coaxially fed orthogonally polarized broadband rectangular spiral antenna for in-band full duplex communications. Two antennas one with RHCP and other with LHCP are designed and implemented close together on one substrate system. Measured isolation performance and radiation patterns of implemented antennas are presented. Within -10 dB impedance bandwidth of 2.2 GHz (2.5-4.7 GHz), the isolation between ports varies from -33.5 dB to -21.5 dB