基于高性能MEMS可调谐振器的压控振荡器研究

According to future wireless communication RF front-end’s requirement for large dynamic range, high stability, integration, low-power voltage-controlled oscillator, the new voltage-controlled oscillator is a potential solution. Utilizing the high-performance tunable MEMS resonators which replace traditional capacitor array and tunable circuits to build high-performance MEMS voltage-controlled oscillators which has advantages of high precision, large tuning range, low noise, and low power consumption. A high-performance voltage-controlled oscillator can simplif the structure of the frequency synthesizer, eliminating the reference quartz oscillator and phase-locked loop circuits.This project will study the energy loss mechanism, high-order modal excitation extraction method and tuning principle of the novel tunable resonator under the micro-nano scale, and realize a high-frequency, high-Q tunable resonator with a multi-electrode structure. The Study is based on the design method of adjustable drive circuit of MEMS tunable resonator, realizing the method of composite frequency modulation of resonator digital tuning and circuit analog tuning and building a high-performance MEMS voltage controlled oscillator withan output frequency covering 1 GHz and an adjustable frequency range is 20%. The development of nano-precision resonator processing techniques and device construction techniques and high-precision voltage-controlled oscillator test methods will lay the foundation for the large-scale application of new MEMS voltage-controlled oscillators. We develop nano-precision resonator processing technology and device construction technology and high-precision voltage controlled oscillator test method, laying the foundation for large-scale application of the new MEMS voltage controlled oscillator.

未来无线通信射频前端对大动态范围、高稳定性、可集化、低功耗的压控振荡器有迫切需求，MEMS压控振荡器是极具潜力的解决方案。利用高性能可调MEMS谐振器可取代传统电容阵列，和可调谐电路构建高性能MEMS压控振荡器，具有高精度、大调谐范围、低噪声、低功耗等优势。高性能压控振荡器可简化频率综合器的结构，取消参考石英振荡器和锁相环电路。本项目将研究微纳尺度下新型可调谐振器的能量损耗机制、高阶模态激发提取方法和调谐原理，实现具有多电极结构的高频、高Q值可调谐振器；研究基于MEMS可调谐振器的可调驱动电路设计方法，实现谐振器数字调谐和电路模拟调谐的复合调频方法，构建高性能MEMS压控振荡器，输出频率达1 GHz，可调频率范围达20%。开发具有纳米级精度的谐振器加工工艺及器件的构筑技和高精度测试方法，为新型MEMS压控振荡器的大规模应用奠定基础。

未来无线通信射频前端对大动态范围、高稳定性、可集化、低功耗的压控振荡器有迫切需求，MEMS压控振荡器是极具潜力的解决方案。本项目研究基于MEMS谐振器的压控MEMS振荡器，提出多种核心的高性能可调MEMS谐振器件和高性能振荡驱动电路结构，实现了高性能MEMS压控振荡器。首先对MEMS谐振器的谐振模态和能量损失机理，重点研究了支撑损耗、热弹性损耗、空气阻尼等损耗的影响，优化了器件结构，开发了多种谐振模态、多谐振频点的电容式、压电式谐振器，研制了阵列化多频点器件集成和单器件多频输出的谐振器件，开发了新型谐振器的高阶谐振模态激发和提取方法，实现高Q值谐振器，输出频率最高达到1GHz，部分器件Q值大于10000，作为高性能MEMS压控振荡器的调频基础。开发了多种跨微纳尺度结构的制备工艺，包括电容式硅基制备工艺和基于SOI技术氮化铝制备工艺，开发了谐振结构和电极的一次成型技术、多层结构自对准填充、纳米间隙的牺牲层实现方法，实现了多种谐振器件的高可靠性制备。研究了适用于高性能MEMS压控谐振器的振荡器驱动电路，针对电容式谐振器动态阻抗较大等问题，对电路各模块进行了性能优化，开发了大带宽、大增益、低噪声放大电路、阻抗匹配电路、相移电路等，实现了在GHz的宽频范围MEMS谐振信号的低噪声放大电路，电路增益达到40dB，通过阻抗匹配，进一步提高信号增益达60 dB，提高了振荡驱动电路的可靠性。通过电压调节MEMS谐振器的频率，可实现压控振荡器的频率输出调节，最大压控振荡器的频率偏移达到-600 ppm。针对微纳压控振荡器的动态小信号高精度测试需求，实现低噪声的射频信号检测方法。