Design and Fabrication of Low Noise Oscillator Using Active Dielectric Resonator

In this paper, the design theory of an 8 GHz oscillator based on a new structure of active dielectric resonators is presented. The new structure emphasizes on phase noise reduction by employing only one active device. The proposed structure uses additional feedback from transistor to resonator in order to increase the quality factor. Measurement results report that phase noise is reduced to -145.19 dBc/Hz at 100 kHz offset frequency which represents 12 dB improvement compared to oscillators with passive dielectric resonators. Also, compared to oscillators with conventional active resonators, noise source of the second amplifier which makes spurious oscillation is removed. The size and power consumption are reduced since one transistor is used in the presented structure. This structure performs the lowest phase noise compared to oscillators with other dielectric resonators.