A 33.5–37.5-GHz Four-Element Phased-Array Transceiver Front-End With Hybrid Architecture Phase Shifters and Gain Controllers

Abstract

To satisfy the requirements for a high output power of the transmitter (TX) and high-quality beamforming with a wide range, fine resolution, high accuracy, and good orthogonality, in this work, we present a 33.5–37.5-GHz four-element phased-array transceiver front-end with two-way power combining power amplifiers (PAs), high-linearity low-loss stacked T/R switches, hybrid architecture phase shifters, and hybrid architecture gain controllers in a 65 nm CMOS process. The hybrid architecture phase shifter combines a reflection-type phase shifter (RTPS) with a 0°/180° phase switch. The RTPS provides a 180° phase shift (PS) range, and the 0°/180° phase switch expands the 0°–180° PS states into a full 360°. The hybrid architecture gain controller combines a 4-bit digital-step single-pole-double-throw (SPDT)-only attenuator with a two-stage 3-bit cascode variable gain amplifier (VGA). The attenuator generates large attenuation states for coarse-tuning, and the VGA generates small gain states for fine-tuning. The proposed phased-array transceiver front-end achieves a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$P_{\mathrm {sat}}$ </tex-math></inline-formula> of 19.8 dBm and an OP <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$_{\mathrm {1\,dB}}$ </tex-math></inline-formula> of 17.2 dBm per element, a 6-bit full 360° PS range with an rms phase error lower than 2° and a gain variation lower than ±2 dB, and a 6-bit 0–31.5 dB gain control range with an rms gain error lower than 0.16 dB and a phase variation lower than ±3°.