A 1.5GHz-modulation-range 10ms-modulation-period 180kHzrms-frequency-error 26MHz-reference mixed-mode FMCW synthesizer for mm-wave radar application

A frequency modulated continuous-wave (FMCW) radar using triangular modulation is one of the promising candidates for realizing a CMOS radar IC. Range and velocity resolutions of the FMCW radar are determined by the band width and period of triangular modulation (Pourvoyeur et al., 2008). A short-range measurement requires wide (several GHz) bandwidth, while a long-range measurement with high-velocity resolution requires moderate (hundreds of MHz) bandwidth and long (several ms) period. Furthermore, since frequency error in the FMCW signal deteriorates range and velocity accuracy, a highly linear frequency chirp signal is required. However FMCW radars reported so far exhibit a period up to 1.5ms because a long period degrades the chirp linearity in a conventional analog PLL. In this work, an analog/digital mixed-mode 82GHz FMCW synthesizer with 1.5GHz bandwidth, a period from 1ms to 10ms and less than 180kHz_rms frequency error is described. The achieved performance corresponds to range and velocity resolutions of 10cm and 1.4km/h, respectively.