This paper presents a CMOS full-wave switching rectifier capable of mixer operation. The proposed CMOS switching rectifier allows DC power generation and frequency conversion without a power supply. The proposed CMOS switching rectifier using a center-tapped balun produces DC power with 25% efficiency, while at the same time providing frequency up-conversion with -18.9 dB and down-conversion with -11.9 dB. The size of the chip is 0.286 mm 2 , and four chips are mounted on the phased-array antenna board. The board can be used as a wirelessly powered relay module, and the module can be driven without an external power supply. The measured EVM values are -27.4dB for Tx mode and -27.5dB for Rx mode with a 400-MHz 64QAM OFDMA-mode signal (5G NR, MCS 17).