A W-Band Transmitter for Automotive Radar Sensors in 28-nm FD-SOI CMOS

This article presents a 77-GHz transmitter (TX) in a 28-nm fully depleted silicon-on-insulator CMOS technology for automotive radar applications. The circuit has been designed to simultaneously fulfill both short-/medium-range (S/MR) and long-range (LR) operations. It exploits an LO frequency doubling architecture, which allows preventing voltage-controlled oscillator (VCO) pulling effects for improved phase noise (PN) performance. The proposed TX comprises a 38-GHz VCO driving a frequency doubler and then a current-combining two-path power amplifier. The VCO takes advantage of a novel tank architecture to cope S/MR and LR requirements with an effective and silicon area-saving solution. The proposed TX also features a feedback loop that allows properly setting the power delivered to the output load. It exhibits a 5-GHz bandwidth, ranging from 76 to 81 GHz, with a PN performance as low as −93 dBc/Hz at a 1-MHz offset frequency from a 77-GHz carrier. It is also able to deliver a maximum output power as high as 17.5 dBm with a dynamic control range of around 13 dB. The overall power consumption is 351 mW.