硅基MEMS射频前端模块技术研究

Multi-frequency, multi-mode, high-frequency, low-power integrated RF front end system is highly desired for future wireless communication. The Si-based MEMS RF front end is attractive candidate due to the promising performance of MEMS resonators, such as high frequency, high Q factor, and tunability. This project aims at developing new function moduli in RF front end with MEMS resonance devices: filter frequency selection module, frequency synthesizer module, and mixing filter module. The concrete work include:.1. Studying on the working principle of multi-channel narrowband filter selection and the method for low noise filtering based on self-switched MEMS filter array, the theory of frequency synthesizer module based on integrated high-stable MEMS oscillators with multi-frequencies output, the working principle of mixer-filter with large linearity based on MEMS mechanical mixer structure..2. Studying on the integration techniques and signal matching routines for MEMS devices and CMOS circuit, co-designing methods for different RF front end moduli..3. Exploring new resonating structures with high frequency and high Q, investigating the coupling mechanisms between the resonators..4. Developing the fabrication techniques for MEMS devices and moduli, producing the new MEMS RF front end moduli: the MEMS frequency selection array with resonant frequency up to 4 GHz, the high-stability MEMS frequency synthesis module with frequency stability < ± 1ppm, and the mixer-filter module with large linear range > 10 dBm..5. Proposing the novel theory of MEMS based RF front-end architecture for achieving the high-performance MEMS RF front-end. 25-30 SCI/EI papers will be published, and more than 10 patents will be applied.

多频、多模、高频率、低功耗和集成化是未来无线通信射频前端系统的发展趋势。本项目针对未来无线通信系统对新型硅基射频前端模块的应用需求，利用高频、高Q微纳谐振单元，构建新型MEMS射频前端模块：MEMS信道选择模块、频率综合器模块和混频滤波模块。研究基于MEMS滤波器阵列的多信道选通原理和低噪声滤波方法、基于高稳定性MEMS振荡器的频率综合器模块和多频率输出方法、基于MEMS谐振混频原理的高线性度混频滤波方法。研究谐振器件和CMOS电路的集成和信号匹配方法、不同功能模块的协同设计方法；发展提高谐振频率的新原理，澄清谐振单元集成和耦合谐振原理、电路控制方法等。开拓拥有自主知识产权的微纳器件和模块的构筑技术，研制高性能射频前端模块：频率达4GHz的滤波选频阵列，稳定性<±1ppm的频率综合模块和线性范围>10dBm的混频滤波模块；探讨新型射频前端系统架构理论，为新型射频前端系统奠定基础。

项目针对未来无线通信对新型硅基射频前端模块的应用需求，突破了提高谐振频率同时保持高Q值的瓶颈问题，开发了微纳谐振器的高精度制作技术和高气密性真空封装方法。发展了机械谐振结构和CMOS电路的协同设计方法，研究了阵列化窄带滤波、高精度频率调控、高线性度混频等频谱变换机制，探索了新型MEMS射频前端模块的构建方法。取得了如下成果：.1.系统研究了高性能MEMS谐振器件基础理论，发展了十余种高频、高Q值的体模态MEMS谐振器，揭示了谐振器的机电转换效率提升方法和能量损耗机制，频率覆盖MHz-GHz，真空中大于10e5，多种谐振器的f × Q接近理论上限。.2.开发了谐振器的高精度规模化制备方法，发展了基于低阻硅垂直引线和Au-Sn低温键合的晶圆级三维真空封装方法，封装气密性和长期稳定性满足国军标要求。开发了基于阳极键合和薄膜封装的晶圆级真空封装方法，封装后Q值可达6×10e4。开发了基于金硅共晶的晶圆级真空封装技术，实现了高深宽比TSV技术，结合非蒸散型吸气新技术，降低封装腔体压强。实现了基于集成微蒸发器的频率修调技术，频率修调范围8-1442 ppm。高成品率制备了不同谐振器及其阵列，并为产业界提供加工服务。.3.针对不同器件和模块需求，设计了高增益、大带宽的驱动电路、频率综合电路、滤波电路等CMOS芯片，突破了增益和带宽的限制，可满足高频器件的性能需求。.4.构建了基于MEMS谐振结构的新型频率综合模块、滤波器及阵列模块、高性能MEMS混频模块。研制了新型高稳定性硅基振荡器，性能比肩商业产品，正在和产业界合作，开发全硅振荡器产品；实现了磷重掺杂恒温控制振荡器，在-40 ℃ ~85 ℃，频率稳定性小于±500 ppb，已完成成果转化。 .在执行项目期间，发表SCI/EI论文30篇，其中SCI收录17篇，EI收录23篇；培养博士生6人，硕士生6人；申请发明专利27项，其中5项获得授权；相关研究成果转化获得合同金额210万元。