A 33.5-37.5 GHz 4-Element Phased-Array Transceiver Front-End with High-Accuracy Low-Variation 6-bit Resolution 360° Phase Shift and 0~31.5 dB Gain Control in 65 nm CMOS

Abstract

Millimeter-wave (mm-wave) phased-arrays for 5G communication, radar, and satellite communication systems have obtained ever-increasing attention. Power amplifiers (PAs) are one of the most critical components in phased-array front-ends (FEs). High output power is desired to support long-range communications and radar detection. Another critical component is the phase and gain controller that enables electric beam scanning. High accuracy, fine resolution, and orthogonality of phase and gain control are vital to support precise beamforming and improve usability. In this paper, we present a 33.5-37.5 GHz 4-element phased-array transceiver (TRX) FE with power combining PAs and hybrid architecture phase/gain controllers in 65 nm CMOS, which achieves (1) $P_{\text {sat }}$ of $19.8 dBm$ and $P_{1 dB}$ of $17.2 dBm$ per element, (2) 6-bit 360° phase shift range with RMS phase error less than 2° and gain variation less than $\pm 2 dB,(3)$ and 6 -bit 0-31.5 dB gain control range with RMS gain error less than $0.16 dB$ and phase variation less than ±3°.