Re: MOS varactors
Try these papers from IEEE and others, I don't have them however here.
1.) P. Andreani and S. Mattisson, “On the Use of MOS Varactors in RF VCO’s,” IEEE J. of Solid-State Circuits, vol. 35, no. 6, June 2000, pp. 905-910.
2.) A-S Porret, T. Melly, C. Enz, and E. Vittoz, “Design of High-Q Varactors for Low-Power Wireless Applications Using a Standard CMOS Process,” IEEE J. of Solid-State Circuits, vol. 35, no. 3, March 2000, pp. 337-345.
3.) E. Pedersen, “RF CMOS Varactors for 2GHz Applications,” Analog Integrated Circuits and Signal Processing, vol. 26, pp. 27-36, Jan. 2001