Power oscillator

A high power solid state power RF oscillator, comprising:

• a power FET having a gate, a drain, and a source, wherein the source is RF grounded and suitable voltages are respectively applied to the drain and gate to place the transistor in a conducting condition;
• a drain circuit connected to the drain of the power FET;
• and
• a feedback circuit connected between the drain circuit and the gate, wherein the feedback circuit is adapted to provide suitable positive feedback to initiate and sustain an oscillating condition with a fundamental frequency being greater than 300 MHz and with an RF power output in excess of 50 watts;
• characterized in that the drain circuit comprises a first transmission line connected at a first end to the drain and at a second end to an output matching circuit, and a second transmission line which is an open stub connected to the second end of the first transmission line, wherein the first transmission line and second transmission lines each have a width which provides a conjugate match for the drain at a fundamental frequency and an effective electrical length of about one twelfth of a wavelength of the fundamental frequency.