One well known implementation of the variable capacitor is the varactor, typically realized as a p-n junction diode. A varactor is a nonlinear device that provides a capacitance that varies responsive to an applied control voltage. The capacitance of a varactor, when within its operating parameters, decreases as a voltage applied to the device increases. A diode-type of device is often used as a varactor. Varactor diodes are operated in a reverse-bias operating mode. When the diode is reverse-biased, the capacitance