UCLA

The 5G New-Radio standard includes bands in the millimeter-wave spectrum that provide channel bandwidth of up to 400 MHz. When compared to the maximum bandwidth of lower frequency (sub-7-GHz) bands of the same standard, millimeter-wave bands can provide four times the bandwidth, yielding faster data rates. Within the millimeter-wave spectrum, many transceiver implementations targeting the 26.5 GHz - 29.5 GHz band have been reported recently. The use of millimeter wave communications in 5G radios becomes viable if (1) extensive beamforming is employed to overcome the high path loss and (2) the power consumption is sufficiently low to afford frequent high-throughput connections for mobile devices.

Recent beamforming receivers in the vicinity of 28 GHz draw, per element, 27.5 mW to 50 mW. A key observation in the design of beamforming receivers (RXs) is that the phase shift network typically consumes high power whether it appears in the receive path or the local oscillator (LO) path. This work introduces a new phase shifting technique that avoids the loss, power consumption, and phase shift resolution trade-offs of conventional topologies. In addition, several other new concepts are presented that reduce the power with no noise figure penalty. To demonstrate the efficacy of the proposed concepts, an eight-element directconversion RX with on-chip LO generation has been realized in 28-nm CMOS technology. The RX draws 156 mW, achieving a minimum noise figure of 3.7 dB, a phase resolution of 10 degrees, and an LO rms jitter of 155 fs.