Low-power injection-locked zero-IF self-oscillating mixer for self-powered millimeter-wave identification (MMID) active tag in 65-nm CMOS

In this paper, a 40 GHz zero-IF self-oscillating mixer (SOM) with low-power consumption, is proposed and demonstrated for the next generation of battery-free yet active mm-wave identification (MMID) tag. It exploits the mixing property of LC cross-coupled VCO, and by injection-locking the SOM to the reader´s carrier frequency, it enables a direct-conversion to the baseband. It, therefore, does not require any external LO source (self-mixing) nor RF frequency conversion into IF frequency. A chip was designed using 65-nm CMOS process, and experimental results exhibit a conversion loss of about 29 dB, with a power consumption of only 280 µW.