Wideband Co-Polarized Stacked Patch Antenna for In-Band Full-Duplex Applications

Here, a wideband two-port co-linearly polarized stacked patch antenna is investigated for in-band full-duplex (IBFD) applications. The initial antenna structure is composed of a single patch element and a pair of metallic probes. A mutual coupling dip is visibly observed in the band of interest without an extra decoupling structure. To further broaden the working and decoupling bandwidths, a stacked patch is introduced to obtain wideband characteristics of the antenna. Two transmission nulls occur in the passband at the same time. Characteristic mode analysis (CMA) is used to elucidate the detailed decoupling mechanism. A proof-of-concept prototype is fabricated and measured. The measured results show that the proposed antenna operates from 3.23 to 4.26 GHz, and the isolation between the two ports is higher than 20 dB over the working band.