Millimeter-wave dual band bowtie oscillator array

A dual band 36 element bowtie grid oscillator has been demonstrated. The bowtie structure provides the design flexibility to achieve the dual frequency band operation and may allow the optimum load impedance to be presented to the transistor for maximum DC-to-RF conversion efficiency. When the grid drain-source bias voltage is 2 V and the total drain current for the grid is 110 mA, the oscillator operated at 21.3 GHz and 29.7 GHz. The output power at 21.3 GHz is 45 mW and the directivity is 13.8 dB. The DC-to-RF conversion efficiency is 20.5% at 21 GHz. The output power at 29.7 GHz is 2 mW and the directivity is 21.8 dB. DC-to-RF conversion efficiency is less than 1%.