A wide tuning range gated varactor

A wide tuning range gated varactor for radio frequency (RF) applications is described in this paper. The gated varactor is a three-terminal device. The third terminal helps achieve an improved tuning range. The measured tuning range of the varactor exceeds /spl plusmn/50%. The new device can be implemented with a standard CMOS process without any post-processing. A 2 GHz prototype voltage-controlled oscillator (VCO) is implemented using the new varactor in a 0.35-/spl mu/m CMOS process. The VCO achieved a sensitivity of 220 MHz/V.