X-band Dro Frequency Source

With the development of the wave electronic equipment, seeking the oscillators with lower phase noise, better spectrum purity and higher frequency stability has become to the trend of development. DRVCO is abroad applied to frequency synthesizers and microwave oscillators because of their excellent phase noise performance, spectrum purity and stability.This thesis studies how to enhance performance of DRVCO in the condition of identical hardware. The ingredients that are related with phase noise are analyzed base on the formula of oscillator phase noise and the theory of oscillator. The method to improve oscillator phase noise has been presented,which is that the loaded quality factor of dielectric resonator is increased by the factor of oscillator performance improvement by any possibility in these ingredients. this thesis compares two kinds of DRO and chooses the feedback type DRO connection in parallel, it's width of electric tuning is better than one the other. The coupling degree of DR with micro strip line should be decreased and coupling energy should be also decreased for the increasing of the factor of loaded quality factor of dielectric resonator, which couldn't accord with the amplitude condition of oscillator. This thesis solves the question by make use of two-level amplifier feedback type, and calculates the value of phase noise improvement of two-level amplifier feedback type relative to single-stage amplifier reflecting type.This thesis realize the two-level amplifier feedback type DRO connection in parallel and single-stage amplifier reflecting type DRO at 10.4GHz in the X-band, and make comparison with its by the result of analyzed above. Testing result indicates that the phase noise and quadratic harmonic of two-level amplifier feedback type DRO connection is better than the phase noise of single -level amplifier feedback type DRO connection in parallel, and the power of the former is greater than power of the later. Phase noise is improved by a factor of 5dB, quadratic harmonic is improved by a factor of 10dB. It achieves the research aim basically. Simultaneously, this thesis realizes the PLL+DRVCO of the two-level amplifier feedback type DRO connection in parallel.