A PLL-stabilized W-band MHEMT push-push VCO with integrated frequency divider circuit

In this paper, a PLL-based stabilization technique for monolithic integrated W-band voltage controlled oscillators (VCOs) is presented. A 92 GHz push-push oscillator in coplanar waveguide technology and a frequency divider by eight were developed and integrated on a single MMIC using our established 100 nm metamorphic HEMT technology. The oscillator achieves a tuning range of 3.4 GHz around the center frequency of 92 GHz and an output power of more than 5.5 dBm. By applying this concept, the VCO was synchronized to a low frequency reference signal at 180 MHz using a commercially available PLL circuit. Compared to the free running oscillator, the phase-noise was improved by 24 dB to 77 dBc/Hz at 100 kHz offset from the carrier.