A 60-GHz Variable Gain Phase Shifter With 14.8-dB Gain Tuning Range and 6-Bit Phase Resolution Across −25 °C–110 °C

Abstract

This article presents a 60-GHz variable gain phase shifter (VGPS) with orthogonal phase and gain control technique and linear phase control technique in 65-nm CMOS. Using the orthogonal phase and gain control technique, the proposed VGPS has the ability of gain tuning without extra variable gain block, significantly reducing the size of conventional phased arrays. The linear phase control technique is proposed to greatly improve the accuracy and robustness of phase control against temperature variation. As results, the VGPS achieves 6-bit phase resolution across -25 °C to 110 °C and continuous gain tuning range of 14.8 dB. The measured 3-dB bandwidth is 52-64 GHz. As the gain of VGPS is -22.4 to -dB, the measured root-mean-square (rms) phase errors are 1.3°-3.3°, while the measured rms gain errors are 0.2-0.5 dB in 3-dB bandwidth. Across -25 °C to 110 °C, the variations of rms phase and gain errors are below 1.2° and 0.1 dB, respectively. With supply voltage varying from 1.0 to 1.2 V, the variations of rms phase and gain errors are below 1.1° and 0.2 dB, respectively. During the measurement with different combinations of temperature and supply voltage, no gain and phase calibrations are conducted. The measured input-referred P <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1 dB</sub> at the maximum gain state (-7.6 dB) is about -3.8 dBm. The chip consumes 16.4 mA from a 1.1-V voltage supply and the core area of the VGPS is 720 μm ×560 μm.