【作者】 蒋菱；

【导师】 石艳玲；

【作者基本信息】 华东师范大学 ， 微电子学与固体电子学， 2005， 硕士

【摘要】 射频/微波移相器做为调控电磁波相位的器件,是雷达探测、卫星通信、移动通信系统中的核心组件。与传统的移相器相比,RF MEMS移相器具有频带宽、损耗低、微型化、易于集成等特点,在射频电路,尤其是收发模块的应用中具有广泛前景。本文在分类介绍了加载线型RF MEMS相移器、开关线型RF MEMS相移器及反射型RF MEMS相移器的基础上,重点研究了一“位”数字式开关线型MEMS相移器及其重要组件--并联接触式MEMS开关。由于开关线型MEMS移相器的工作电压决定于并联接触式MEMS开关的下拉电压,本文利用双端固定、双端驱动的力电模型代替以往双端固定、单端驱动的力电模型对并联接触式MEMS开关的下拉电压模型进行了较为精确的理论修正。与实验结果比对表明:经修正的模型误差小于1%,较之传统模型10%的误差有很大提高。这是本文的创新工作之一。在双驱动模型的基础上,提出优化并联接触式MEMS开关的下拉电压可通过减小电极间距、降低初始桥高、减薄桥厚、缩短桥长及加宽电极宽度等方法。在多次流片的基础上,通过合理选材和设计优化工艺结构制备了一“位”数字式开关线型MEMS移相器。该移相器在10GHz的中心频率下,相移量为45. 27°(相误差为7. 9%),这是本论文的另一个创新工作。在50M-40GHz的全频段范围内,移相器相误差≤10%,插入损耗小于-1. 7dB。最后,本文对加载线型MEMS相移器进行了研究,设计制备的相移器在50M-40GHz的全频段范围内,插入损耗小于-3dB,相移范围在0°-250°之间。本文设计理论合理,选材、工艺安排及测试方案切实可行。理论分析方法、分析结论、工艺设计及实验结果、对并联接触式MEMS开关、数字式开关线型MEMS移相器及加载线型MEMS移相器器件下一步深入研究提出了建设性意见。更多还原

【Abstract】 The radio frequency and microwave phase shifter, which can change the phase of the electromagnetic waves, is the kernel components of radar detection, satellite communication, and mobile communication systems. Compared to FET and diode-based phase shifters, the radio frequency micromechanical (RF MEMS) phase shifter has many outstanding performances, such as broadband, low loss, miniaturization. Therefore, the MEMS phase shifter has a brilliant perspective in RF circuit application, especially in receive and transmit module.This thesis mainly presents a one-bit digital switched-line MEMS phase shifterand its component------the contact shunt MEMS switch. As the basis of the researchwork, a brief introduction has been firstly given to the structure and principle of the distributed MEMS phase shifter, the switched-line MEMS phase shifter and the reflection type MEMS phase shifter.Since the operating voltage of the switched-line MEMS phase shifter depends on the pull-in voltage of its contact shunt MEMS switch. Instead of the double clamped and single-actuated model, the double-clamped and double-actuated model is used to precisely predict the pull-in voltage of the contact shunt MEMS switch, which is one of the innovative works of this thesis. The comparison to the measured data demonstrates that the double-actuated model improves the voltage error less than 1%, while the single-actuated model provides the voltage error only less than 10%. Based on the double-actuated model, the pull-in voltage of the contact shunt MEMS switch can be optimized by many structural improvements, such as the reducing the gap between two electrodes, decreasing the initial air gap, thinning the thickness of suspended bridge, lessen the length of the bridge and widening the width of two electrodes.A one-bit digital switched-line MEMS phase shifter has been fabricated, with the phase shifter of 45.27° at 10GHz, which is the another innovative work of this thesis. The phase error of the phase shifter is less than 10%, and the insertion loss isbetter than — 1.7dB in the frequency range of 50M—40GHz.At the last, an analog distributed MEMS phase shifter has been fabricated. The distributed MEMS phase shifter provides the continuously changed phase shifter in the range of 0° ~ 250°, and insertion loss better than -1.7dB.The experiment results suggest a reasonable design, an appropriate materical choice and a feasible process arrangement. The conclusion is constructive to deeper research in the MEMS device fields.更多还原