A compact GaAs MESFET-based push-push oscillator MMIC using differential topology with low phase-noise performance

We present a fully integrated 6.7 GHz push-push oscillator MMIC using a cross-coupled differential topology with a capacitive coupling feedback in a commercial GaAs MESFET process. The push-push oscillator shows phase noise of -118.83 dBc/Hz at an offset frequency of 600 kHz with a 3.3 V supply voltage. This low phase-noise performance is comparable to, or better than, the best reported results of 5/spl sim/6 GHz-band oscillators implemented in CMOS and SiGe HBT processes. A 6.4 GHz fundamental oscillator MMIC using the cross-coupled differential topology was also fabricated. The measured phase-noise of the fundamental oscillator is -108 dBc/Hz at an offset frequency of 600 kHz. In addition to the low phase-noise, the push-push oscillator in this paper occupies a compact area of 480/spl times/500 /spl mu/m/sup 2/. To our knowledge, it is the first implementation of a GaAs MESFET-based push-push oscillator MMIC using the cross-coupled differential topology with capacitive coupling feedback. This work is also the first report that shows the low phase-noise performance of the push-push oscillator using the differential topology as compared with that of the fundamental oscillator.