Hybrid Modes Based Wideband Dual-Polarized Empty Substrate Integrated Waveguide Antenna for 5 G Applications

In this letter, a hybrid high-order-mode (HOM) cavity fed dual-polarized empty substrate integrated waveguide (ESIW) antenna is proposed for fifth-generation mobile communication (5G) n257 (26.5- 29.5GHz) band and n258 (24.25- 27.5GHz) band. ESIW hybrid HOM cavity is utilized in the dual-polarized 2×2 slot subarray, which reduces the loss and complexity of the antenna structure and plays a key role in increasing the impedance bandwidth. An ESIW 4×4 slot array is designed and fabricated using low-cost FR4 material. The measured results show that the overlapped -10-dB impedance bandwidth is 22.5\% and the peak gains are over 20 dBi for both polarizations. Besides, the isolation between two polarization ports is over 40dB by introducing an orthogonal feeding network.