A 10-GHz Localized-LO-Phase-Shifting Phased-Array Transmitter

This work presents a phased-array transmitter architecture based on the localized LO phase-shifting technique. Each LO element consists of a DTC-based digital PLL with direct phase control. The latter allows inherently-linear high-resolution phase shifting characteristic, even in presence of analog components nonlinearities. A 10-GHz quad-element phased array is implemented in a 28-nm CMOS process and drive an on-board patch antenna. The measured radiation pattern demonstrates beam-steering capabilities, and the measured phase noise of the combined beam shows a phase-noise scaling down with the number of LO elements.