Low-Profile, Broadband, Dual-Linearly Polarized, and Wide-Angle Millimeter-Wave Antenna Arrays for Ka-Band 5G Applications

A low-profile, broadband, dual-linearly polarized (dual-LP), and wide-angle millimeter-wave antenna array with beam-steerable capabilities operating in the Ka-band is proposed for 5G applications. By jointly exploiting miniaturized vertically stacked elliptical patches, orthogonal aperture-coupled stripline feeding structures, and groups of shorting pins loaded close to the coupling apertures, the proposed dual-LP element has a small footprint of 4.5 x 4.5 mm with a total thickness of 1.57 mm, which exhibits a measured -10 dB impedance bandwidth of 21.8% and a mutual coupling below -41 dB. Wideband stripline-based Butler matrix circuits are designed and integrated with the 1 x 4 element array for verifying its broadband dual-LP multibeam radiation performance. Experimentally, the integrated array generates four beams with an angular coverage of about +/- 61 degrees and +/- 75 degrees for x- and y-polarizations, revealing that the proposed array is a promising candidate for 5G applications.