Full-Duplex Radio Frontend Architecture with Enhanced Transmitter-Receiver Isolation

To overcome the main bottleneck of a circulator-based full-duplex radio frontend, i.e., limited transmitter-receiver isolation, we propose a radio frontend architecture in which the circulator is omitted and two separate orthogonally polarized printed antennas on a common substrate are employed. The transmitter-receiver isolation is further enhanced by patterning the antenna ground plane. The measured isolation for the fabricated frontend amounts to 47 dB for a 2.4 GHz full-duplex system. This can substantially reduce self-interference in a full-duplex communication system.