A four-path 60GHz phased-array receiver with injection-locked LO, hybrid beamforming and analog baseband section in 90nm CMOS

We present a 60 GHz four-antenna phased-array direct conversion receiver in 90 nm RF CMOS with an LO based on subharmonic injection locking, beamforming that is partially in the LO path and partially at analog baseband, and an analog baseband section. The LO system features a set of four 60 GHz oscillators, locked to the fifth harmonic of a central oscillator, improving the phase noise performance and robustness. Phase shifting is realized in two steps and two domains, which reduces the complexity of phase shifters and signal degradation at analog baseband. Signal combination is performed at analog baseband, followed by a variable-gain amplifier and a baseband filter, which together allow for 6-th order filtering with 880 MHz bandwidth and 20 dB of gain adjustment with 1 dB steps. The system provides a maximum conversion gain of 42 dB with a total power consumption of 450 mW and chip area of 3.15 × 1.9 mm.