A 45° Polarized Wideband and Wide-Coverage Patch Antenna Array for Millimeter-Wave Communication

A 45 degrees polarized millimeter-wave (mmWave) patch antenna and arrays with wide impedance and gain bandwidth are proposed in this article. The compact antenna consists of stacked patches, one substrate integrated waveguide (SIW) back cavity, one SIW square cavity, and a feeding line. The patches and the SIW back cavity rotate 45 degrees with respect to the SIW square cavity. For the antenna, the -10 dB impedance bandwidth is from 22.31 to 29.65 GHz, and the peak gain is greater than 5 dBi in the bandwidth from 22 to 30.5 GHz. Based on the proposed antenna, a 1 x 16 linear array is designed, fabricated, and measured. According to the experimental results, all antenna elements can realize the -10 dB impedance bandwidth from 21.7 to 27 GHz. Within 3 dB gain fluctuation, the scanning coverage of the linear array can achieve 116 degrees in the frequency band from 22 to 26 GHz and 110 degrees at 27 GHz. Then, an 8 x 8 planar array with wide bandwidth and wide scanning coverage is proposed. The reflection coefficient can achieve less than -10 dB from 21.82 to 27.22 GHz. The main beam of the radiation pattern can be widely spatially scanned. In the bandwidth from 22 to 26 GHz, the scanning coverage within 3 dB gain fluctuation can achieve 107 degrees. Also, at 27 GHz, the coverage can achieve 90 degrees. Due to the outstanding performance, reliable multilayer printed circuit board (PCB) fabrication technology, and easy integration with circuits, the proposed antenna and arrays are good candidates for the fifth-generation (5G) mmWave communication systems, satellite communication systems, and so on.