Abstract: A low noise wide tuning bandwidth voltage controlled oscillator employs a resonator circuit formed from at least two microstrip lines which are electromagnetically coupled to one another. Each of the microstrip lines has one end electrically coupled to circuit ground to provide a substantially inductive resonator circuit which is substantially immune to parasitic end effects and radiation loses. The frequency of the voltage controlled oscillator circuit is controlled by a variable capacitance varactor circuit coupled to at least one of the microstrip transmission lines. The resonator circuit is well suited for use with a bipolar transistor configured as a negative resistance oscillator.