According to one exemplary embodiment, a differential varactor circuit for a voltage controlled oscillator having two differential outputs includes a first varactor having first and second terminals and a second varactor having first and second terminals. In the differential varactor circuit, each of the first and second terminals of the first varactor and each of the first and second terminals of the second varactor are coupled to one of the two differential outputs of the voltage controlled oscillator, thereby allowing a size of each of the first and second varactors to be reduced so as to increase varactor quality factor. Each of the first and second terminals of the first varactor can be coupled to one of the two differential outputs by a capacitor, and each of the first and second terminals of the second varactor can be coupled to one of the two differential outputs by a capacitor.