Nonlinear Calibration Algorithm of THZ FMCW Radar

This article proposes a linearity calibration algorithm for ultra-wideband FMCW (Frequency-Modulated Continuous Wave) radar. This algorithm acquires non-linear phase terms by using auxiliary targets and subsequently subtracts the corresponding phase from the intermediate-frequency signal to achieve higher measurement accuracy. When applying this algorithm to our self-developed terahertz non-destructive testing system, it can extract the morphological features of the target from the chaotic raw signals. This method is straightforward and treats the non-linear terms as a whole, making it suitable for various forms of FMCW systems, effectively reducing the impact of non-linearity on imaging results.