Aperture-shared Multi-port Waveguide Antenna with Rectangular Metallic Block for 5G applications

An aperture-shared multi-port rectangular horn antenna is presented in this paper. The antenna consists of four traditional WR-2S waveguides for 28 GHz. This structure can be compact but the coupling between the opposite ports and the cross-polarization is higher than the acceptable level. In this paper, the effect of a metallic block (MB) on decoupling the feeding port is discussed. The antenna consists of sequentially rotated four traditional WR-2S waveguides for the 28 GHz band, which are positioned with sequential rotation to create a multi-polarized function with low mutual coupling. In addition, a metallic block is mounted at the center of the aperture rotation for decoupling over a broad band and suppressing the cross-polarization. The proposed antenna obtains a high gain of 16 dBi, a low mutual coupling of ≤ −20dB at the maximum ≤ −23dB on average, and a sufficient cross-polarization discrimination level at $\simeq$ 20 dB in 27-29 GHz frequency band.