نوع مقاله : مقاله پژوهشی
عنوان مقاله English
نویسندگان English
In microwave oscillators, the quality factor of the resonators decreases with an increasing frequency. There exist some methods for compensating the losses in the resonators. The push-push configuration is able to improve the oscillator phase noise. In this work, a push-push voltage-controlled oscillator utilizing a parallel coupled resonator has been designed for the frequency range of 1200-1400 MHz. The push-push oscillator consists of two similar Collpits oscillators, which are designed for the frequency range of 600-700 MHz. These sub-oscillators are coupled by a phase coupling network and with 180 degrees phase difference. The in-phase combiner combines the even harmonics of each sub-oscillator and cancels the fundamental and odd harmonics. The overall oscillation of the push-push oscillator consists of the second and even harmonics of the sub oscillators. By this technique, the phase noise is improved 9 dB compared to the case of the stand-alone oscillation of each sub circuit at the output frequency.
کلیدواژهها English