A Simple Self-Decoupling Method for Co-Polarized In-Band Full Duplex Antennas

This paper presents a simple self-decoupling method and a corresponding radiation pattern improvement technology for co-polarized in-band full duplex (IBFD) antennas. The selfdecoupling method is implemented based on a widened planar rectangular dipole antenna. By exciting a superposed mode produced by the second- and third-order modes of the widened dipole, a specific superposed electric field can be constructed between two arms of the dipole. The transmitter port and receiver port can be located at a strong and a weak field region, respectively. As a result, a self-decoupling between TX and RX ports is realized without any extra decoupling structures or designs. Simulation shows that the antenna achieves a maximum in-band isolation of 31.5 dB at 3.5 GHz.