An innovative, ultra low noise, single chip cavity oscillator is proposed. The oscillator is fully integrated on standard MMIC process. It operates in the frequency range of 50 ? 100 GHz with phase noise of -112 at 100 KHz offset. At the core of the oscillator is a rectangular cavity based resonator. To our knowledge, this is the first ever implementation of a waveguide cavity on standard MMIC process. This new technique, will allow the realization of ultra small high performance integrated oscillators for future market demands. In the future, a phase locked oscillator can be implemented on a single chip. The PLO will consist of a cavity oscillator, phase frequency detector, prescaler and a loop filter. All components can be integrated on a standard GaAs HBT process.