Abstract: A bulk semiconductor oscillator subassembly is carried on a support pin. The oscillator assembly includes a semiconductor diode mounted on the pin with one terminal connected thereto. The other terminal is connected to one end of an input coupling loop which has its other end connected to the pin through a by-pass capacitor. Biasing voltages are applied to the diode via a lead connected to the loop. The loop is coupled to a Yttrium Iron Garnet (YIG) sphere which serves as a resonator. The resonant frequency of the resonator is tuned by adjusting a DC magnetic field applied thereto. The output is obtained by an output loop which is located orthogonally with respect to the input loop and coupled to the YIG whereby the input and output loops are coupled through the YIG resonator.