A W-band self-oscillating subharmonic MMIC mixer

A novel 77-GHz subharmonically pumped self-oscillating mixer has been imple mented using monolithic-microwave integrated-circuit (MMIC) technology. The microstrip mixer achieves mixing and doubling simultaneously using a singl e 4 mu m x 15 mu m x 0.15 mu m gate-length pseudomorphic high electron-mobi lity transistor, eliminating the need for an external local oscillator. The total circuit size is 1 mm x 2 mm, including coplanar probing pads, The mi xer exhibits a measured double-sideband (DSB) conversion loss of 11.0 dB at 77.6 GI-Iz and an average measured DSB conversion loss of 15 dB from 70 to 85 GHz, which compares well with simulated results, To the authors' knowle dge, this is the first demonstration of a subharmonically pumped MMIC self- oscillating mixer operating with state-of-the-art performance at W-band fre quencies.