A 28 GHz 480 elements digital AAS using GaN HEMT amplifiers with 68 dBm EIRP for 5G long-range base station applications

This paper reports the design, development and performance of a 28 GHz 480 elements digital Active Antenna System (AAS) prototype for 5G long-range applications. AAS accommodates 32 channels of 0.15 um GaN HEMT power amplifier chains. The antenna array prototype consists of full digitally controlled 32 streams of 15 elements sub-arrays. They can deliver a total conductive power of 41 dBm and Average Effective Isotropically Radiated Power (EIRP) of 68 dBm for the macro-cell coverage at 28 GHz. The prototype also features newly proposed high density heat spreading structure dissipating around 450 W in an 11 liter compact enclosure. The paper proposes and demonstrates one of direction of the high power GaN HEMT application to the millimeter-wave 5G long-range base stations.