A Low Phase Noise Microwave Oscillator Using Split Ring Resonators

The split ring resonators (SRRs) are utilized to implement a microwave oscillator in this paper. Since the SRRs provide a sharp band reject characteristic, a high Q-factor is realizable for microwave oscillators. Several identical SRRs are simultaneously employed to obtain as large as high reflection coefficient as possible which generates the oscillation condition incorporated with a microwave transistor. The output power is obtained as 10.6 dBm at 5.2 GHz with 2.0 V DC supply and 18 mA current consumption. Due to the sharp performance of the resonators, the phase noise is observed excellently around -115 dBc/Hz at 1 MHz offset. DC-RF conversion efficiency is measured 30.7 % and the figure of merit is 178.72 dB. Since further miniaturization of the resonators is possible adjusting the proposed configuration, this kind of oscillator can easily be adapted to the MMIC fabrication