Dual‐Band Dual‐Circularly Polarized Aperture‐Shared Antenna Based on SIW for Millimeter‐Wave/Sub‐6 GHz Communication Applications

ABSTRACT In this paper, a dual‐band dual‐circularly polarized antenna based on substrate integrated waveguide (SIW) is proposed. The proposed antenna adopts a fusion structure to reuse the whole millimeter‐wave antenna as the upper structure of the microwave antenna, which leads to the aperture reuse ratio is 1. The whole antenna size is 0.98λ 0 × 0.98λ 0 × 0.045λ 0 , where λ 0 is the free‐space wavelength at the low‐band center frequency. Meanwhile, the frequency ratio can be adjusted by modifying the position of the vias and the distance of the vias on the diagonal of the microwave antenna. Furthermore, the polarization modes right‐handed circular polarization/left‐handed circular polarization (RHCP/LHCP) in both bands can be adjusted flexibly by turning the phase sequence of the feed network. The measured results show that the design achieves the impedance bandwidths of 2.3% and 17.9%, AR bandwidths of 1.3% and 10.7%, with gains of 7.8 and 13.8 dB at 5.3 and 25 GHz, respectively. The proposed microwave and mm‐Wave dual‐band dual circularly polarized shared‐aperture antenna provides a promising candidate for 5G communication applications.