Partially Integrated Electronically Tuned Millimeter-Wave (33-75 GHz) Gunn Oscillators

Experimental results are presented for varactor tuned GaAs Gunn-effect oscillators at millimeter-wave (33-75 GHz) frequencies for both microstrip and suspended substrate configuration. An electronic tuning range of almost 2 GHz with an output power of +20 dBm ±0.65 dB has been achieved at 41 GHz using a novel radial disc geometry for the microstrip oscillator. The tuning element was an IMPATT diode. A hyperabrupt tuning varactor, in this circuit, increased the tuning range to 2.5 GHz at 42 GHz with modest decrease in power to +18 dBm ±0.8 dB. Corresponding results for a suspended substrate oscillator configuration were +23.5 dBm ±0.75 dB power output with approximately 1 GHz electronic tuning. Preliminary results at V-Band (50-75 GHz) yielded an electronic tuning bandwidth of 2 GHz with a minimum output power, across the band, of +13 dBm.