A Differential Oscillator Based on Filtering Power Divider With Low Phase Noise and Output Ports' Common-Mode Reflectionless Characteristics

In this paper, a differential oscillator with low phase noise and output ports' common-mode reflectionless characteristics is presented. The proposed oscillator adopts a narrowband bandpass filtering power divider as the frequency selection network, simplifying the oscillator's design and improving the phase noise performance of the oscillator. A microstrip-slotline balun with common-mode reflectionless characteristics is utilized to accomplish the differential output and output ports' common-mode reflectionless performance. To validate the design method, the proposed oscillator's circuit is designed and simulated using the Advanced Design System software. The results show that the proposed differential oscillator has an output power of 6.987 dB, phase noise of -133.4 dBc/Hz @ 100 kHz and -155.3 dBc/Hz @ 1 MHz, second harmonic suppression of 65.289 dBc. Meanwhile, the common-mode reflectionless characteristic is achieved at the differential output ports, which verifies the proposed concept.