Antenna Reflections in Shared-Antenna In-Band Full-Duplex Systems : (Invited Paper)

As opposed to multiple-antenna solutions, in-band full-duplex (IBFD) systems can utilize a shared antenna for signal transmission and reception to reduce the device form factor. These single-antenna designs, however, must additionally consider the self-interference (SI) that is generated by antenna impedance-mismatch reflections. This paper investigates the effect of different antenna loads and transmission line lengths for commercially-available magnetic circulator and omnidirectional antenna components operating between 2 and 6 GHz. The results indicate that both the load impedance and the distance between the antenna and interface device can drastically impact the composite SI frequency-selectivity, which influences the overall IBFD system bandwidth.