Series-Fed Beam-Steerable Millimeter-Wave Antenna Design With Wide Spatial Coverage for 5G Mobile Terminals

A low-cost beam-steerable antenna operating at 28 GHz is presented for 5G mobile terminal applications. The proposed array has a sandwich-like stack structure, including ten patch elements, a ground plane with two rows of slots, and a long microstrip transmission feed line. The radiators and the transmission line are placed at the two sides of the ground plane, which provides great flexibility in designing the radiating pattern and the feed network. Switches are added on the transmission line to construct periodic distributed phase shifters for beam steering. The 2 bit phase shifter with phases of 0 degrees, 90 degrees, 180 degrees, and 270 degrees is formed without using phase delay lines. Continuous beam steering is achieved, and the steerable angle is 121 degrees in the upper hemisphere. Two location configurations of the proposed array in 5G mobile terminals are analyzed and the angular coverage range is evaluated. The array can cover 38.8% of the hemispherical space with a gain threshold of 10 dBi.