Time-domain algorithm for FMCW based short distance ranging system

Frequency modulated continuous wave (FMCW) based ranging system have been widely used in many on-chip system applications. The conventional signal processing methods for this kind of ranging system were mainly focused on the frequency-domain, analyzing the spectrum of the beat frequency. In that case, the increasing of frequency deviation for the modulated signal was usually used to improve the accuracy of ranging systems. However, this parameter is severely restricted by the hardware design of the system, especially microwave components in the front-end, which will reversely limit the further improvement of the measurement accuracy. In this paper, a time-domain (TD) algorithm for FMCW based ranging system was proposed to facilitate high accuracy, which avoids the method of widening the frequency deviation to improve the accuracy. The performance of the proposed algorithm is verified with measurements using low-cost radar components and miniature size circuits, operating in the 3.0 GHz ISM band.