Finding the Lumped Element Varactor Diode Model

Download Whitepaper
  • Author: George H. Stauffer
An accurate model for the varactor diode is necessary when designing a voltage controlled oscillator (VCO) using CAD simula-tion. In order to predict tuning range, start up gain, and phase noise, the resonator must be accu-rately modeled over the frequency range of the oscillations. The varactor diode used for tun-ing has a predominant effect on the Q, phase noise and tuning range of the resonator. If the varactor model is inaccurate, the results of the most elaborate computer simulation will be misleading and the oscillator, when built, may have disappointing performance.