A 28-GHz Phased-Array Relay Transceiver for 5G Network Using Vector-Summing Backscatter With 24-GHz Wireless Power and LO Transfer

This article introduces a wirelessly powered phased-array transceiver for fifth-generation (5G) relay systems. To realize the battery-less relay operation, 24-GHz wireless power transfer (WPT) is employed. This relay transceiver consists of the proposed vector-summing backscatter for Transmitter (Tx) and a passive phase-shifting self-heterodyne Receiver (Rx) with a rectifier for Rx and WPT. The receiver generates dc power from the 24-GHz WPT signal, which is also used as a local oscillator (LO) signal to down-convert the 28-GHz 5G modulated data to a 4-GHz IF. The vector-summing backscatter up-converts the 4-GHz IF signal to 28-GHz using a 24-GHz LO signal while working as a 360° phase shifter with a 7-bit resolution. Both transmitter and receiver operate only using the generated power from the 24-GHz WPT. The chip area of the eight-path transceiver is 1.8 mm 2 and the transceiver is mounted on a 32-element phased-array antenna board. This module generates 3.1-mW dc power from 6.7-mW/cm 2 received power density at 24 GHz. The transmitter achieves a −2.2-dBm measured saturated equivalent isotropically radiated power (EIRP) and supports a −30° to +30° beam range. The measured error vector magnitude (EVM) values are −27.5 dB for Tx mode and −31.3 dB for Rx mode with a 400-MHz 64-QAM orthogonal frequency division multiple access (OFDMA)-mode signal (5G new radio (NR), MCS 19). The power consumption for each path is 0.03 mW in both Tx and Rx modes.