Filter-based low phase-noise microwave oscillators

In this paper, two filter-based microwave oscillators are developed using two types of filters, namely the stub filter and trisection filter. The filter is treated as a stabilization element in the oscillator feedback network to improve the phase noise performance. For the oscillator using the stub filter, the oscillating frequency is designed at 1.99 GHz, and the measured phase noise is -105 dBc/Hz at 100 KHz offset frequency. On the other hand, the oscillator using the trisection filter operated at 2.47 GHz and gives -125.7 dBc/Hz at 100 KHz offset frequency.