A 28 GHz Switchable 3-D Coverage Millimeter-wave Phased Array Antenna for 5G Handset Terminals

This paper presents a new design of millimeter-wave handset array for 28 GHz mobile communications. The required three-dimensional beam steering coverage with high-gain beams can be realized by locating three identical subarrays of microstrip patch antennas (MPAs) along the upper edge of the mobile phone printed circuit board (PCB). Each subarray works as a phased array and roughly covers a broad sector in one plane and can perform RF beam steering in the other plane. In this way the whole sphere can be covered with high array gain. The isolation between neighboring elements of each subarray is improved by optimizing the shape of the patch and introducing notches in the ground plane. The mutual coupling values among the nearby elements of the proposed handset array are less than -30 dB. This significant improvement in the isolation performance can help in achieving better active reflection coefficient values at higher scanning angles, which improves the coverage efficiency of the proposed handset array.