A 60 GHz High Cross-Polarization Discrimination 45° Linearly Polarized Cavity-Backed 2 × 2-Slot Subarray Based on Gap Waveguide Technology

This paper presents a V-band 45° linearly polarized 2 × 2-slot subarray antenna based on gap waveguide (GW) technology. It can be a good candidate subarray for larger planar array antennas. The proposed subarray is composed of two unconnected metal plates: radiating layer and cavity layer. The radiating layer contains 45° tilted radiating slots, upper exciting slots, 45° twist slots and lower exciting slots. The cavity layer contains cavities (formed by pins) and a coupling slot. With the benefit of GW technology, the electromagnetic (EM) leakage among the metallic blocks can be cancelled. Besides, by introducing the novel 45° twist slots to the radiating layer, the grating lobe suppression and XPD improvement over a wide band are achieved without increasing additional metal structures. The simulated results of the proposed antenna over the operating frequency range from 57 GHz to 66 GHz are as follows: The input reflection coefficient is better than -18.47 dB. The minimum XPD can reach a considerable level of 39.8 dB.