X-band Low Phase Noise Sampling Phase-locked Dro

Frequency source is referred as"a heart"of electronic systems, such as modern communication systems, radars, instruments, and so on, and its performance will play an important role in the performance of the whole system. The technique of frequency synthesizer has a history of nearly 80 years, and the development can be generally divided into several parts: direct frequency synthesizer, analog phase-locked loop frequency synthesizer, digital phase-locked loop frequency synthesizer, decimal frequency synthesizer and hybrid frequency synthesizer.Sampling phase-locked loop has the merits of high performance, compact structure, low power consumption and low cost. When compared with the digital phase locked loop, the phase noise of sampling phase-locked loop performs better.Based on the theory of oscillator, I firstly designed the active circuit of dielectric resonator oscillator (DRO). Then, through the simulation by HFSS and ADS software, I find out that the frequency of a DRO is mainly decided by the resonate frequency of dielectric resonator (DR) itself, and also prove it by several experiments. Thirdly, this article describes the function of three components within the sampling phase detector (SPD), and analyzes how sampling phase locked loop works. Finally, oriented from the Wien-Bridge Oscillator, I design the acquisition sweeping circuit and loop filter.This article completed an 11.5GHz voltage-controlled dielectric resonator oscillator (VCDRO), with a mechanical tuning range of 285MHz and voltage tuning range of 11.6MHz. When the reference input is provided by a 100MHz crystal oscillator, the final output signal of 11.5GHz performs well. The output power is 13.05dBm, phase noise is -110.34dBc/Hz at 10 kHz offset carrier, and the spurs level is better than -80dBc within the span of 1 GHz.