Low phase noise anti-interference differential oscillator based on balanced bandpass filter with common-mode reflectionless characteristic

Abstract

In this paper, a low phase noise anti-interference differential oscillator is proposed. The balanced bandpass filter with common-mode reflectionless characteristic is proposed and adopted in the differential oscillator to simultaneously achieve high group delay peak and common-mode interference noise absorption. For demonstration, the proposed differential oscillator is designed, simulated, manufactured and measured. It demonstrates that the proposed differential oscillator has a high output power of 6.67 dBm at the center oscillating frequency of 2.48 GHz, excellent second harmonic suppression of 46.01 dB, low phase noise of − 119.96 dBc/Hz at 100 kHz offset. The verification of the anti-interference function is performed with a differential mixer and the results show that the proposed differential oscillator can absorb external common-mode interference and effectively ensure the stable output of intermediate frequency signals.