A 71–76 GHz Four-Element Phased-Array Receiver With Compact Footprint in 65-nm CMOS

Abstract—This paper presents a 71–76 GHz 4-element phased-array receiver in 65-nm CMOS for compact and high-performance phased-array applications. A novel magnetic coupling based Wilkinson combiner is proposed to reduce the size, improve power combining efficiency and balance the signals. The receiver also features an active phase shifter with a phase-adjustable I/Q signal generator to improve phase resolution under various process, voltage, and temperature (PVT) conditions. Each receiver channel occupies 0.76 mm² with 57 mW power consumption, achieving a 360° phase-shifting range with 6-bit resolution and 12 dB attenuation range with 1 dB steps. Measured RMS phase and gain errors at 0 dB attenuation are 0.95°~1.05° and 0.14~0.23 dB, respectively. With the small Wilkinson combiner, the receiver offers a compact and low power consumption solution for multi-channel phased-array systems.