Designing a Low Phase Noise Oscillator Based on Elliptical Filter and Active Resonator in X- Band

Oscillators play a significant role as telecommunication signals sources in today s world of microwave telecommunications, so that designing an oscillator with appropriate parameters have a major impact on the telecommunication system final performance. In many radar systems, coupled with low cost and mass production, improved signal generation performance requires low phase noise oscillators.In this study, we developed a voltage-controlled X-band oscillator, which uses an active resonator, for microwave and radio frequency applications over the elliptical filter concept. The high frequency selection of an active filter used as a resonator is a key factor in phase noise reduction. It is also that affects the oscillator. A design process is proposed to optimize the resonator performance in low phase noise applications. In particular, the additional noise effect on the active filter is investigated and its effect on the oscillator phase noise is minimized. The designed oscillator phase noise passive filter equals 145 dBc/Hz at 1 MHz offset frequency. However, an active resonator technique has been used in order to improve the critical phase noise parameter in the oscillator. When this method is applied in the oscillator design, the phase noise is obtained equal to -154 dBc / Hz at offset frequency of 1 MHz.

کلیدواژه ها:

Oscillator ، Phase Noise ، Active Resonator ، Elliptical Filter.