A Ka-band 4-ch bi-directional CMOS T/R chipset for 5G beamforming system

This paper presents a Ka-band 4-channel bi-directional T/R chipset in 65 nm CMOS technology for 5G beamforming system. The proposed T/R chipset can provide bi-directional operation with moderate gain and dual polarization. Each channel consists of bi-directional gain blocks, a 5-bit step attenuator and a 5-bit phase shifter including tuning bits. The phase and attenuation coverage are 348° with the LSB of 11.25° and 31 dB with the LSB of 1 dB, respectively. The gain of 13 dB (Tx mode) and 6 dB (Rx mode) are achieved at 28 GHz including the 4-way power divider/combiner.