Analysis and optimization of accumulation-mode varactor for RF ICs

This paper presents a novel RF IC varactor implemented in a standard CMOS process. This device has shown a remarkable tuning range of 150%, sensitivity of 300%/V, and quality factor of 23 at 1 GHz. A physical model of the varactor is presented and confirmed with measured data. Using the model derived, optimization has shown that a Q as high as 200 can be achieved.