Low phase noise microwave oscillator based on gain driven polariton

Low phase noise oscillators are key building blocks of many high-end microwave systems. This work introduces a phase noise reduction mechanism through a gain driven polariton platform, where coherent coupling is used to suppress frequency distribution around the carrier, effectively reducing the phase noise. The design process for achieving low phase noise performance is outlined, and three prototypes are constructed, all of which feature key components, such as gain-embedded planar microwave cavity, yttrium iron garnet, and magnets. In particular, the first prototype is used to showcase the phase noise reduction mechanism, while the second prototype, a fixed-frequency oscillator working at 3.544 GHz, exhibits phase noise levels of −117 and −132 dBc/Hz at 10 and 100 kHz offset frequencies, respectively. The third prototype offers a tuning range from 2.1 to 2.7 GHz, while maintaining phase noise levels comparable to the second prototype.