A duplexing hybrid antenna design for full-duplex applications

In this paper, a hybrid antenna is proposed for full-duplex system. The antenna design utilizes a single slot for resonance, and the length is 3/4 λ0 for a short circuit at the other port. Therefore, two parallel transmission lines can be extended across the specified slot design and individually connected with two equal length open stubs for impedance matching. After the design optimization, the RF bandwidth is from 24 to 25 GHz, and an isolation 58 dB at the center frequency of the system is achieved by using liquid-crystal polymer (LCP) material for low loss. The front-end module with wire bonding assembly is also considered in 3D simulation. The simulation is performed using transient-solver of CST EM simulation tool, and the meshes of critical structures included the wire bonding, substrate, and slot that will be set to 1/50 step width.