Nowadays, Frequency-Modulated Continuous Wave (FMCW) radar systems are widely used in many domains, such as automotive and ADAS, industrial sensing, smart home applications and so on. However, these radar systems do suffer from undesired patterns such like interference from transmitter or LO, multiple reflections of static objects in the environments. Conventional systems employ high-pass filters (HPF) to remove the interference, those filters eliminate the interference and close objects blockage well, but they do attenuate all low frequency objects simultaneously no matter it is blocker signals or not. Also, such implementations tend to have smaller gain at the front end of the HPF, that cause bad noise and linearity balance. In this paper, a novel pattern cancel DAC system technique is proposed to mitigate the undesired pattern and enhance the signal processing capability of the FMCW systems greatly.