A W-Band FMCW Radar Transceiver with Self-Calibrated Type-III ADPLL Achieving 1.27-cm Range Resolution for Imaging Applications

This paper presents a W-band frequency-modulated continuous wave (FMCW) radar transceiver designed for centimeter-level imaging applications. The transceiver features a self-calibrated Type-III all-digital phase-locked loop (ADPLL) that generates highly linear wideband chirps by correcting both band-transition discontinuities and slope errors through LMS-based adaptive overlap compensation and Type-III ramp-tracking control. To enable precise beam steering without extra path loss, a 19-bit equivalent phase shifting capability is embedded directly within the fractional-N division path. The transmitter (TX) delivers 11 dBm saturated output power, and the receiver (RX) provides 30 dB gain with a minimum noise figure (NF) of 8.66 dB. Measurements demonstrate a 12-GHz chirp bandwidth with an RMS frequency error of only 48.7 kHz. Over-the-air (OTA) experiments with a corner reflector validate a range resolution of 1.27 cm. Implemented in a 40-nm CMOS process, the chip occupies 1.35 mm × 2.43 mm and consumes 270 mW.