A Compact Hemispherical Beam-Coverage Phased Array Antenna Unit for 5G mm-Wave Applications

A compact low-profile phased array antenna unit with unidirectional hemispherical beam-coverage for 5G mm-wave applications is proposed in this paper. A four-subarray configuration is used for the proposed structure to achieve unidirectional hemispherical coverage in the boresight direction normal to the substrate. An artificial magnetic conductor (AMC)-backed slot antenna array with an optimal separation distance of 1.9 mm (= 0.31 lambda at 28 GHz) is proposed as a subarray. The proposed antenna has increased H-plane beamwidth with the measured peak gain of 11.62 dBi and provides the desired wide inclined beam pattern in the elevation plane. The proposed antenna also offers steered beams over the range within +/- 45 degrees in the azimuth plane. The hemispherical-coverage, phased array antenna unit composed of the four designed subarrays has overall dimensions of 80.8 mmx80.8 mmx2.4 mm. The coverage efficiencies of the proposed phased array antenna unit are 0.82, 0.71, and 0.61 for threshold gains of 5 dBi, 8 dBi, and 10 dBi, respectively, where the maximum solid angle is 2 pi steradians.