An example voltage controlled oscillator includes an inductor, a capacitor coupled to the inductor, and a signal source coupled to the inductor and the capacitor to sustain an oscillating signal. The voltage controlled oscillator includes a first varactor coupled to the inductor and the capacitor, wherein the first varactor is biased by a first bias voltage and is configured to change a frequency of the oscillating signal based on a first control voltage signal. The voltage controlled oscillator includes a second varactor coupled to the inductor, the capacitor, and the first varactor, wherein the second varactor is biased by a second bias voltage and is configured to compensate temperature variation of the frequency of the oscillating signal over a plurality of frequency bands based on second control voltage signal.