Study On Frequency Stabilization Of MEMS Oscillator

Oscillator is the most important and fundamental part in electronic equipment,the performance affects the overall performance of the system.Oscillator is generally used to produce a standard signal source as a reference clock signal.With the development of science and technology in modern society,the eager for the superior performance of electronic equipment is increasing.We have to pursue miniaturization,low cost and low power consumption.But the traditional quartz crystal oscillator which is big volume,uneasily integrated and high cost has been unable meet the requirements.So we want to use MEMS oscillator to replace quartz crystal oscillator.This work mainly introduces the design principle of MEMS resonators,and analyzes the advantages and disadvantages of capacitor resonator and piezoelectric resonator.A Piezoelectric resonator based on AlN Piezoelectric materials and TPoS(Thin-Film Piezoelectric-on-Substrate)structure is designed.The design frequency is 100 MHz.And the physical processing has completed which is based on MEMS CAPs PiezoMUMPs processing technology.After processing,the bare chip on the probe platform is tested and analyzed.The equivalent RLC resonance circuit is established based on the test results and the oscillation circuit is studied to complete the design of the oscillator.The output frequency,power and phase noise of the oscillator respectively are 101.438 MHz,8.63 dBm,and-110.49dBc/Hz@1kHz,-125.78dBc/Hz@100kHz,-148.07dBc/Hz@1MHz.The stability of the MEMS oscillator is tested and analyzed,and the results showed that the stability of the oscillator is poor and the frequency deviation is up to 3958.3ppm at-30?~85?.Final temperature compensation scheme of oscillator is studied,the constant temperature compensation system and the temperature compensation system of temperature control phase locked frequency synthetic are designed.The experiment results show that the constant temperature compensation system frequency stability is up to ?40 ppm at-30?~85?,and the temperature compensation system of temperature control phase locked frequency synthetic frequency stability is up to ?50 ppm at-30?~45?.