A 140-GHz FMCW Radar Transceiver With Dual-Lens Packaging for Improved Beam Alignment in 65-nm CMOS Technology

An frequency-modulated continuous-wave (FMCW) radar transceiver (TRX) chip operating near 140 GHz has been developed based on a 65-nm CMOS technology, subsequently packaged with a pair of silicon lenses for optimal beam alignment. The TRX consists of a wideband local oscillator (LO) chain, a high-power transmitter (TX), and a low-noise receiver (RX). The design procedures for sub-block circuits as well as integrated TX and RX are described in detail along with their measured performances. With the integrated single-chip TRX, a TX output power of 9.5 mW with a corresponding effective isotropic radiated power (EIRP) of 14 dBm was achieved along with a noise figure (NF) of 9.9 dB near 140 GHz. The chip with a size of 2930 × 830 µm² consumed 350 mW of dc power. A dual-lens packaging technique has been proposed and successfully applied to the fabricated TRX chip, in which an individual dedicated lens is assigned for each of the TX and RX ON-chip antennas, leading to significantly improved beam alignment as well as TX-RX isolation. A ranging experiment has been performed with the packaged radar TRX module with a chirp bandwidth of 32 GHz (128–160 GHz), which exhibited a range resolution of around 10 mm. For the chirp generation, a very short modulation period of 6.0 µs was adopted, which would help suppress the effect of the low-frequency noise especially for CMOS-based systems.