A 12 GHZ OSCILLATOR BASED ON A GAAS HEMT INTEGRATED TO A HTS RESONATOR

A hybrid oscillator operating at 12 GHz and 77 K was designed and char acterised. The design incorporated on a single substrate a passive sup erconductive circuit and a III-V active device. YBaCuO films (300nm), grown on MgO, had a surface resistance at 77 K of 0.3 mOMEGA scaled to 12 GHz. The DC and RF characteristics of the pseudomorphic HEMT showe d minor differences before and after hybridation. The characterisation of a preliminary prototype oscillator including a superconducting res onator patterned on a MgO substrate, a gold matching network fabricate d on Al2O3 and a transistor wire bonded gave a phase noise as low as - 75 dBc/Hz at 10 KHz.