An efficient method for decreasing the problems of transmitter leakages on low-cost homodyne FMCW radar with a signal-antenna configuration

In this paper, we analyze the effects of IF noise due to transmitter-signal leakage for homodyne frequency-modulated continuous-wave (FMCW) radar with a single-antenna configuration. We find that the magnitude of the IF noise from the front end can be reduced by matching the LO-signal delay time with that of the antenna leakage. As the IF noise has periodic singularities, the spectrum of the IF noise can be modeled by a VCO modulation signal (except low-frequency elements near DC). Based on an analysis of IF noise, we implement a W-band homodyne FMCW radar sensor and the performances are verified outdoors. The presented concept can be applicable to the design of low-cost homodyne FMCW radars with a single-antenna configuration.