A Wideband Millimeter-wave Vector-Sum Phase shifter in 28-nm bulk CMOS

This paper presents a wideband vector-sum phase shifter (VSPS) operating within 21-43.9 GHz, implemented in TSMC 28-nm bulk CMOS. The VSPS comprises a quadrature all-pass filter (QAF) with a compensation network, a vector modulator with a compensation amplifier, and input and output wideband matching networks. Simulated phase and gain imbalances of the QAF are below 1.6° and 1 dB, respectively. Measured results of the proposed VSPS exhibit a peak gain of 1.8 dB (inclusive of input and output baluns), with a 3-dB bandwidth of 21-43.9 GHz and a DC power consumption of 38.7 mW. The measured RMS phase error and gain error are 0.75° to 1.25° and 0.57 dB to 1.35 dB, respectively. The core chip area is 0.34 mm<sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup>. The circuit can cover mainstream communication frequency bands with a good performance, making it a promising candidate for practical applications.