70 GHz Planar Integrated Oscillator on Semiinsulating GaAs

Planar oscillators with λ/4 rectangular microstrip-line resonators have been developed for operation with cw Impatt diodes at V-band frequencies. The impedance matching of the capacitive output coupling gap has been investigated for gap widths from 10 to 50 μm. Using GaAs Impatt diodes a maximum output power of 25 mW has been achieved at frequencies of about 70 GHz. The oscillation frequency remained stable over the whole bias current range and no frequency jumps have been recognized. The maximum efficiency was between 3.5 % and 5.2 %.