A Direct-Sampling Pulsed Time-of-Flight Radar With Frequency-Defined V ernier Digital-to-Time Converter in 65 nm CMOS Y u-Hsien Kao

Abstract

This paper presents a direct-sampling pulsed radar with a high-resolution digital-to-time converter ( DTC) for esti- mating the time of flight (TOF), which is to identify the distance between a target and radar. The implemented direct-sampling radar can reconstruct the scanning waveforms in di gital domain. The link budget of the radar transceivers is analyzed for the overall scanning range. The scanning range of the radar is de- pendent on the TOF between radar transmitter an d receiver. The range resolution of the pulsed TOF radar is determined by DTC. With the help of exquisite DTC, a high resolution radar can be achieved. The vernier concept has been a dopted to achieve an accurate timing resolution desi gn in the DTC. The vernier time steps are defined by the oscillating frequency of the phase-locked loops (PLL), and therefore the DTC wit h a high resolution in the order of picosecond and with high immunity to PVT variation was developed and demonstrated. The proposed radar was fabricated using 65 nm CMOS technology and oc cupies a chip area of 2 mm , consumes 88.4 mW of DC power. The receiver has a 10 GHz instantaneous front-end bandwidth for capturing all scattering reflected waveforms and a 666 GS /s equivalent sampling rate for recording all received signals for subsequent digital signal processing (DSP) analysis.