A 151-to-173 GHz FMCW Transmitter Achieving 14 dBm Psat with synchronized Injection-Locked Power Amplifiers and Five in-Phase Power Combining Doublers in 65nm CMOS

This paper presents a novel frequency-modulated-continuous wave (FMCW) transmitter with 22 GHz frequency sweeping bandwidth and 14 dBm Psat for FMCW imaging radar. The proposed transmitter consists of a high linearity and ultra-wideband VCO which utilizes an inductor with two second coils coupled with varactor. With a novel zero-phase coupler (ZPC), four injection-locking power amplifiers (ILPA) are synchronized with in-phase outputs. The ILPAs can realize high power efficiency. Moreover, the five-channel doubler with in-phase power combing realize maximum power efficiency. The transmitter can realize multi-rate FMCW sweeping with period from 1 μs to 20 s and the phase noise is -90 dBc/Hz @1MHz. The total power consumption is around 141mW while operating at a 1.2 V single supply. The chip was fabricated in a 65 nm LP CMOS technology.