Phase noise enhancement of the GaAs high electron mobility transistors using micromachined cavity resonators at Ka-band

We introduce a new structure of the micromachined cavity resonator coupled GaAs-based oscillator to enhance the phase noise and the frequency stabilit y. The oscillator and the cavity are designed for Ka-band applications. Com pared to the free running oscillator, the cavity resonator coupled oscillat or showed the phase noise enhancement of about 20 dB. The phase noises of a bout -110 and -85 dBc/Hz are obtained at 1 MHz and 100 kHz offset frequency , respectively. The frequency pushing for the gate bias of the cavity coupl ed oscillator is about two order of magnitude less than that of the free ru nning oscillator.