Variable frequency JFET microwave oscillator with variable impedance bias

A variable frequency microwave oscillator comprising a first function field effect transistor (JFET) having a gate, source and a drain, an impedance block connected to the source of said first JFET to determine a source impedance appearing on the source of said first JFET, and a variable bias block having a control terminal for receiving a control voltage and connected to the drain of said first JFET to determine a drain impedance appearing on the drain of said first JFET at a value based on said control voltage, whereby the gate of said first JFET exhibits in a certain frequency range a negative impedance for oscillation determined by said source impedance and drain impedance,

• wherein said variable bias block comprises an inductance having a first electrode connected to the drain of said first JFET and a second electrode, and a second JFET having a drain connected to the second electrode of said inductance.