A 24-29.5 GHz 256-Element 5G Phased-Array with 65.5 dBm Peak EIRP and 256-QAM Modulation

This paper presents a 24-29.5 GHz 256-element phased-array for 5G applications, which is based on commercial 2x2 TRX beamformer chips, with 6-bit phase and 8-bit gain control. The phased-array can achieve -20 dB sidelobe levels after calibration, and can scan up to ±60◦ in azimuth- and ±50◦ in elevation-plane. The measured EIRP is 63.5 and 65.5 dBm at P1dB and Psat respectively, with a 3-dB bandwidth of 5.5 GHz (24-29.5 GHz). Complex modulation measurements on the 16x16 array with 64-QAM and 256-QAM 100 Mbaud waveforms (α=0.35, PAPR=7.7 to 8.2 dB) show low EVM values (2-3%) up to 58 dBm EIRP. An ISI (inter-symbol interference) study shows that the time delay between antennas at edges of the array contributes insignificant ISI error and can be removed by a equalizer. This is the first 256-element array for 5G applications with very high EIRP, which can support 64 and 256-QAM modulation formats.