A Simultaneously Transmit and Receive Antenna Terminal for In-Band Full-Duplex Applications

In this paper, a low-profile co-linearly polarized simultaneously transmit-receive antenna (STRA) terminal is presented for 5G and upcoming technologies. The proposed STRA terminal comprises of an identical pair of spatially rotated half-circular microstrip antennas for transmission (Tx) and reception (Rx). The challenge of self-interference (SI) is addressed by employing passive SI cancellation techniques such as spatial diversity, field confinement, and surface perturbations. This has been accomplished by using fence-strip structure and V-shaped slots in the ground plane. The STRA was designed, fabricated, and tested for full-duplex operation in a sub-6 GHz band lying from 5.73 to 5.88 GHz, providing high interport isolation ranging from 35.5 dB to a maximum of 46.5 dB. The proposed STRA was implemented using Rogers 3003™ substrate. The measurements yield radiation characteristics with high gain of 5.45-6.0 dBi and 5-6.5 dBi for Tx and Rx antennas, respectively. The measured results are in good conformance with the simulated design. This antenna finds its potential usage in V2X and private 5G networks and can be extended for full-duplex MIMO implementations.