Commonly Differentially Hybrid-Fed Method for Isolation Enhancement in Two-Port Co-Polarized Co-Radiator Applications

Abstract

This study introduces a decoupling method for isolation enhancement in two-port co-polarized co-radiator applications, called the commonly differentially hybrid-fed (CDHF) decoupling method. Unlike conventional feed architectures, the proposed feed architecture allocates two ports to feed the antenna with a power divider and an anti-phase power divider. Theoretical analysis indicates that this feed architecture offers particularly high isolation. Generally, for two-port antennas (with one port supporting Wi-Fi 6 applications and another supporting Wi-Fi 6E applications), suppressing mutual coupling effects using traditional filters is challenging owing to the extremely narrow guard band of 0.09 GHz. The CDHF decoupling method offers a filter-free solution to this problem. To validate its effectiveness, a two-por co-polarized co-radiator patch antenna using this method is designed, fabricated, and tested. Results reveal that the two ports of the antenna, respectively, cover the Wi-Fi 6 U-NII-3 (5.725–05.835 GHz) and Wi-Fi 6E U-NII-5 bands (5.925–6.425 GHz). Furthermore, the antenna achieves an isolation exceeding 35 dB across the 5.5–6.5-GHz frequency range. Moreover, the antenna exhibits both conical and broadside radiation patterns, making it suitable for indoor scenarios requiring radiation pattern diversity, such as offices and supermarkets.