【作者】 蔡描；

【导师】 赖宗声；

【作者基本信息】 华东师范大学 ， 微电子学与固体电子学， 2007， 硕士

【摘要】 微波滤波器是微波无线通信系统中的重要元件之一,在多频段、宽带无线通信系统前端装置和无线收发器中实现信道选择,镜像消除寄生滤波、双工等重要的功能。射频/微波微机械系统滤波器具有低损耗、高隔离、高线性度、体积小、易于和IC、MMIC电路集成等特点,可使传统的射频、微波、毫米波器件电路的结构和特性发生根本性的变化。可重构调滤波器可以减小多波段的模拟接收前端子系统的尺寸、抑制大的信号干扰及完成多个波段转换,具有很好的高频性能。本论文在RF/MW MEMS滤波器工作原理的基础上,重点研究由MEMS元件构成的微波频段可重构低通滤波器的设计、建模和制造工艺。首先从微波传输线理论,分形自相似理论上分析MEMS滤波器的设计原理,并在多触点MEMS开关、可调电容、电感及CPW传输线基础上进行微波MEMS可重构滤波技术的研究。并采用ADS、HFSS,ANSYS等软件对电路和结构进行仿真,优化MEMS滤波器的设计结构。然后设计了MEMS滤波器的版图,采用适当的工艺,在石英和高阻硅衬底上进行实现单片低通可调滤波器芯片设计与制备试验。最后搭建试验平台,对试验制备的样片进行测试分析。本文研究取得的成果如下:1.研究了石英和高阻硅衬底上的共平面波导传输线等效电感及低通滤波单元的性能,从理论上分析了低通滤波器单元的慢波传输因子对滤波性能的影响。2.研究低通滤波单元结构,提取低通滤波单元等效电路模型。对滤波单元等效电路模型进行了拟合及优化。优化设计后的滤波器单元的纹波为1.0dB,带外衰减可达到50dB。3.研究了分形自相似理论及其在可重构滤波器设计中的应用,对两种结构的滤波器原型运用了分形自相似理论进行重构。引入射频微机械开关及可变电容来重构两个滤波单元,设计的可切换的滤波器截止频率分别为8GHz和18GHz。4.研究了开关线型MEMS滤波器中的接触式开关进行,设计制备的接触式MEMS开关获得了良好的隔离度和传输特性,为下一步进行MEMS带通滤波器的设计和研制打下了基础。初步测试结果证明,本文对硅基微波MEMS器件的设计是合理的,所选择的材料和制备工艺是比较切实可行的。更多还原

【Abstract】 Filter is one of the most critical devices in the microwave wireless communication system, which complete channel selection, image rejecting parasitic filtering and duplex in the multi-frequency, broadband wireless communication system. RF/MW MEMS filter has low insertion loss, high isolation and linearity, miniature size, and easy for integration with IC and MMIC circuits, which can fundamentality change alter the structure and characteristics of traditional RF, MW and millimeter wave devices. In the multi-standard transceiver, tunable filter can remarkably decrease the dimension of the analog front-end, choke back big signal interference and complete multi-frequency transverse.This paper is based on the theory of the RF/MW MEMS filter, and research on the design, modeling and process of the reconfigurable low pass filter. The design principle of the MEMS filter is introduced first, such as microwave transmission line and fractal self similar theory; and the MW MEMS tunable technology is researched based on the multi-contact MEMS switch, MEMS varactor, tunable inductor and the CPW transmission line. Agilent ADS, HFSS, ANSYS are used for the simulation and optimization of the circuit as well as the structure. The layout is design by L-edit, and the low pass tunable filter is fabricated on the quartz and HR silicon substrate. The state of art chip is tested and the results have been analysed. These works are presented in this thesis:1. Research on the characteristics of the CPW filtering prototype on both quartz and high resistance silicon substrate. Analyse the effect of the slow-wave transmission factor to the low pass filter unit, and the slow wave CPW transmission factor is design as 0.54.2. Analyse and research on structure model of the CPW filtering prototype, the distributed filtering unit is optimized based on the simulation of the related lumped circuit model. The ripple of the optimized filter prototype is 1 .0dB, and the out of band attenuation is about 50dB.3. Research on the appliance of the quasi fractal self similar theory on the reconfigurable filtering design. Introducing the RF/MW MEMS switches and capacitor to reconfigure the low pass filter units base on the research of CPW filtering prototype, in order to tune the cut-off frequency.4. Reach on the multi-contact switches, in order to get better isolation and insertion loss, ground the design of the MEMS band pass filter in the next step.As for the test result, the design of silicon based MW MEMS devices are reasonable, the material and process are feasible.更多还原