基于机械耦合谐振器的MEMS超窄带滤波器研究

The project focuses on the demand of integrated and low-power ultra-narrow band filter applied in future wireless communications. High frequency and high Q micro- mechanical resonators with coupling structure were utilized to achieve ultra- narrowband MEMS filter. Micro and nano scaled resonator model was established s to explore modal mechanism and principle of high resonant frequency with higher-order modes. By revealing the mechanism of energy loss and noise characteristics of the resonator with micro-and nano-scale variation , high frequency , high- Q micro- nanoelectromechanical resonator structure with low energy loss was achieved. Based on the principle of mechanical wave propagation, the coupling mechanism was analyzed and the micro-and nano mechanical resonant filter theory was established. Designing of low-velocity coupling point and weak coupling beam structure, ultra- narrow-band filter was achieved. Micro- nanofabrication technology with nanoscale precision was developed. Technology with independent intellectual property rights for micro /nano structures and devices fabrication was developed as well. With optimization of circuit and signal detection methods, feedthrough signal and noise were reduced. Then the detection method for MEMS weak signal was developed with high sensitivity. This project was a foundation for the integrated, high-performance RF MEMS resonant filter devices .

本项目针对未来无线通信领域对集成化、低功耗的超窄带滤波器的需求，基于高频、高Q值的微机械式谐振器和耦合结构实现具有低插入损耗，超窄带特性的MEMS超窄带滤波器。建立微纳尺度下谐振器模型，探明微纳谐振的模态敏感机理，发展高阶模态提取等提高谐振频率的新原理，通过揭示微纳谐振器的能量损失机理和噪声特性随尺度变化规律，实现低能量损耗的高频、高Q微纳机电谐振结构；从机械波传播原理出发，分析耦合机理，建立微纳机械谐振式滤波器理论基础。设计低速点耦合和弱耦合梁结构，实现超窄带滤波特性。开发具有纳米级精度的微纳加工工艺，开拓拥有自主知识产权的微米/纳米结构及器件的构筑技术。通过电路设计和检测方法改进，减小馈通信号和噪声干扰，开发高灵敏度的MEMS微弱信号检测方法。本项目的研究为实现集成化、高性能的MEMS射频谐振滤波器奠定了基础。

针对未来无线通信对高性能MEMS超窄带滤波器的需求，研究了射频MEMS谐振器和滤波器等核心射频器件，以实现具有超窄带、陡峭边带的集成化硅基MEMS滤波器..1、为了构建MEMS超窄带滤波器，研制了多种高频、高Q值MEMS谐振器。实现了多种谐振模态的高频、高Q值圆盘谐振器，包括圆盘径向谐振器和回音壁高阶模态谐振器等，频率覆盖数百MHz到GHz范围，其Q值大于10000，三阶模态频率高达728 MHz。通过设计新型电极结构，实现了高达十阶回音壁谐振模态的提取。.2、实现了多种高性能耦合MEMS超窄带滤波器。在高频、高Q值谐振器的基础上，利用耦合结构，构建多种超窄带滤波器。研究了耦合梁对超窄带特性的影响，实现了多圆盘耦合滤波器，这种高阶滤波器的中心频率149 MHz，百分比带宽小于1 %。通过设计多电极控制结构，实现了新型带宽和中心频点可调的滤波器。开发了新型单圆盘耦合超窄带滤波器，基于模态自耦合原理，实现滤波器中心频率79.4 MHz，百分比带宽0.4 %。.3、发了批量化微纳加工工艺和低噪声真空气密性射频封装方法。开发了的高成品率、批量化MEMS滤波器微纳加工技术，实现了与CMOS兼容。实现了低噪声真空气密性射频封装方法，极大提高了封装器件性能。.4、实现了多种高精度射频测试方法。针对射频MEMS滤波器的小信号测试难点，开发了混频、差分等多种高精度测试方法，抑制寄生噪声，实现真实信号的提取。