A 1 V 2.4‐6 GHz 6‐bit vector‐sum phase shifter with very low rms phase error and gain error

Abstract

AbstractWe present a 2.4‐6 GHz 6‐bit vector‐sum phase shifter with a full 360° phase‐shift range based on 65‐nm CMOS technology. This paper exploits an improved reconfigurable quadrature all‐pass filter with a cross‐coupled buffer as the quadrature generator circuit, and a common‐gate programmable gain stage with optimal transistor size ratio and in‐phase/quadrature (I/Q) gain ratio as the I/Q variable gain amplifiers (VGAs). Through the optimization of circuit topologies, a superior overall performance has been achieved with extremely low root mean square (RMS) phase error and gain error, capable of low voltage, wide bandwidth, and high‐accuracy operations. The measured RMS phase error is less than 2°, 1.4°, and 1°, between 2.4‐6 GHz, 2.5‐5.6 GHz, and 3‐4.7 GHz & 4.9‐5.5 GHz, respectively, with a RMS gain error of less than 0.75 dB. The circuit draws 14.6 mW from a 1 V supply, with a chip size of 0.45 × 0.47 mm2.