A W-Band Single-Antenna FMCW Radar Transceiver With Adaptive Leakage Cancellation

This article presents a leakage cancellation architecture for single-antenna frequency-modulated continuous-wave (FMCW) radars at W-band. A shared antenna for transmitter (TX) and receiver (RX) can substantially reduce the form factor, cost, and complexity of radar modules. Due to the simultaneous operation of the TX and RX in FMCW radars, employing a shared antenna will, however, significantly increase TX-to-RX leakage, resulting in RX saturation and desensitization. Our proposed cancellation scheme employs analog feedback to confine the TX leakage right at the RX input port, and thus, relieves the ongoing RX chain from saturation. The proposed single-antenna transceiver (TRX) prototype was fabricated in 65-nm CMOS technology with a die area of 1 mm(2). The output power of 2 dBm was achieved for the TX in a frequency range of 80-84 GHz. In addition, a conversion gain and noise figure of 45 and 15 dB was measured for the RX in the presence of the TX signal via a shared antenna port. TX-to-RX isolation of more than 45 dB was achieved in the operating W-band. The chip consumes 108 mW (80.5 mW for the TX and 27.5 mW for the RX) from a 1.2-V supply voltage. Moreover, the functionality of the single-antenna radar operation was verified by connecting the chip to an on-printed circuit board (PCB) 4 x 8 patch antenna array with a simulated gain of 15 dBi, implemented on RO3003 Rogers material. Using the single-antenna radar module as a demo system, a 40 x 50 cm(2) rectangular metallic plate was detected at a distance up to 19 m.