A novel DDS based 94 GHz high linearity FMCW RE front end

FMCW millimeter wave sensors are very useful for both military and civilian applications, due to their low cost, simplicity and low transmitted power. In this paper we present a novel approach to the realization of linear FMCW chirp at a frequency of 94 GHz based on a DDS (Direct Digital Synthesizer). This is a much superior method compared to the common approach using a VCO with a linearization loop, the linearity of which is limited. Our approach enables realization of a relatively low cost, small size sensor with an extremely good linearity. We demonstrated an excellent range resolution of better than 0.5 meter at a range of 1 kilometer.