A Dielectric Resonator Oscillator with 5 PPM Long Term Frequency Stability at 4 GHz

High Q, temperature stable dielectric resonators are excellent stabilizing elements for microwave transistor oscillators. A 4 GHz Ba/sub 2/Ti/sub 9/O/sub 20/ resonator integrated with a Si bipolar transistor in a compact oven has a frequency stability of 5 ppm/yr., 4/spl deg/ to 60/spl deg/C (40 to 140/spl deg/F). It is significantly simpler than alternative generators and has 10 to 20 dB lower FM noise. An 18 GHz generator is also described which uses a 4.5 GHz oscillator and a varactor quadrupler.