【作者】 巫正中；

【导师】 钟先信；

【作者基本信息】 重庆大学 ， 仪器科学与技术， 2002， 博士

【摘要】 近年来，微机电系统(MEMS)研究得到了迅猛的发展。用于射频通信领域中的MEMS技术，即 RF-MEMS (Radio Frequency Micro-electro-mechanical System)技术，蕴藏着巨大的市场潜力，已经成为研究的热点，受到学术界和政府部门的高度重视。采用微机械技术研制的RF-MEMS天线是RF-MEMS系统的关键器件之一，它不但具有体积小、重量轻、性能稳定等优点外，还能和其他电路元件集成在一起。本文在分析了国内外RF-MEMS天线研究现状的基础上，对微尺度下微机械天线的电磁辐射与耦合理论、数学建模与数值仿真、参数优化、加工、测试及应用等方面进行了深入系统的理论分析和实验研究，成功地研制出了多种结构的微机械天线，在微机械天线的理论、数值模拟、参数优化和制造上取得了突破和创新。本文研究的主要内容包括：从麦克斯韦方程和波动方程出发，分析了RF-MEMS天线的电磁辐射和耦合机理、准静态特征参数，讨论了色散和表面波效应及相关的电磁特性；对微机械天线进行了数学建模，着重优化了时域有限差分法（FDTD），用优化的FDTD法对微机械天线进行了数值计算和仿真，并通过傅里叶变换将时域计算所得结果转换到频域中，然后进行有关参数计算；采用理论分析和实验研究相结合的方法，对微机械天线进行参数优化，提出用新颖的结构和复合基片介质材料来实现微机械天线的小型化和宽带化，解决了多层混合基片介质相对介电常数、输入阻抗等参数的计算，采用短路结构实现四分之一波长贴片天线，并推导了其长度计算公式；结合微机械天线的特点对材料选取、制作工艺进行了研究，提出了材料的选用标准，在硅基片介质加工工艺上，提出用双面刻蚀法进行狭缝刻蚀以提高腐蚀因子；介绍了微机械天线测试场，对天线参数进行了误差分析；在微机械天线的应用方面，首先设计了蓝牙计算机无线通信演示装置，并在该系统上使用了微机械天线试验样品，该系统可以成功地进行无线互连，然后在Motorola G18无线通信平台上使用了微机械天线，可以成功地收发短信息；最后提出了微机械天线阵列、多芯片组装等下一步的研究计划。本论文的创新点主要体现在：(1) 将传输线法、空腔模型法及FDTD法用于微尺度下微机械天线的建模和仿真。重点对FDTD法进行了合理的优化，用以进行微机械天线的数值仿真，并用实验对其结果进行验证，表明这种优化方法是合理的，可以用以指导微机械天线的设计。通过贴片和接地板间添加短接柱的理论分析和实验研究表明，短路针可降低微带天线的频率，根据微机械天线的工艺特性，首次提出了用短路壁结构代替短路针的结构，将天线变为四分之一波长结构，其长度减小了一半，并提出了四分之<WP=5>(2) 一波长天线长度的计算公式。还采用C型折叠贴片等结构将天线尺寸进一步缩小，最小尺寸只有自由空间波长的。(3) 针对高介电常数基片介质对天线性能的负面影响，提出将贴片下方的高介电常数介质腐蚀掉一部分，或在硅片和接地板间添加一层介电常数较低的媒质，可有效抑制表面波激励，提高天线效率、增加带宽。(4) 采用添加寄生贴片、附加微带振子方案，通过电磁耦合作用有效地增加了天线带宽。本论文对微尺度下微机械天线的电磁辐射和耦合理论、微型化和宽带化等方面做了有益的探索，为微尺度下电磁场理论的完善、天线的集成化制造奠定了理论和技术基础。更多还原

【Abstract】 In recent years, Micro-electro-mechanical System (MEMS) has been developed drastically. MEMS technology applied in radio frequency communication field, which is known as RF-MEMS (Radio Frequency Micro-electro-mechanical System), has great potentials. RF-MEMS research has become very important in application of radio frequency, and drawn attention of academe and governments greatly. Micromachined RF-MEMS antenna, one of the key devices in RF-MEMS, has small size, light weight, stable quality and other merits; it can be integrated with other circuit element.Rest on present research status of RF-MEMS antenna, systematically theoretical analysis and profoundly experimental research on electromagnetic radiation and coupling, mathematical modeling and numerical simulation, parameter optimization, machining and measuring of micromachined antenna in micro-scale have been presented in this thesis. Several types of micromachined antennas have been fabricated successfully. Innovation and breakthrough have been obtained in theory, numerical simulation, parameter optimization and fabrication.The main contents of the thesis are shown as follow: analysis on electromagnetic radiation and coupling mechanics, quasi-static characteristic parameter of RF-MEMS antenna, discuss on the related electromagnetic character of dispersion and surfacewave effect; optimization of Finite-Difference-Time-Domain (FDTD), numerical simulation of micromachined antenna using optimized FDTD, and related parameter calculation; parameter optimization by theoretical analysis associated with experimental research, realization downsize and broadband by novel structure and hybrid substrate, resolution of calculations on relative dielectric constant and input impedance, realization of a quarter wavelength antenna by shorted wall. Material selection standard and fabrication process of micromachined antenna are presented. The antenna measurement fields are introduced, then error analysis of parameters developed. We applied the micromachined antennas in Bluetooth computer Demo devices and Motorola G18 wireless communication system, both can communicate with other devices. In the end some research plan such as micromachined array and multi-chip module are put forward.Following are the important achievement and innovation:To model and simulate micromachined antenna in micro-scale using TLM, cavity model and FDTD. To simulate micromachined antenna by optimized FDTD, and<WP=7>(1) verify it by experiment. It indicates that the optimized method is rational, and the optimized FDTD can be used to design micromachined antenna.(2) By theoretical analysis and experimental research of shorting stubs between patch and ground, it indicates that the shorting stub could lower frequency of microstrip antenna. Shorting wall in place of shorting stub, which can turn the antenna to a quarter wavelength antenna, has been put forward. The antenna dimensions will be downsized further if C folded structure is used; the length of the antenna is only 1/12 wavelength in free space.(3) According to deficiency of high index substrate to antenna, some of the substrate beneath the patch should be partially removed, or some low index substrate should be sandwiched between the ground and the high index substrate, so the surfacewave would be suppressed greatly, then the efficiency and bandwidth would be increased.(4) By using parasitic patch and additive microstrip vibrator, the coupling effect with drive patch could enlarge bandwidth of the antenna.The research of electromagnetic radiation, miniaturization and broadband of micromachined antenna in micro-scale has benefits, and found theoretical and technical base for improvement of electromagnetic field theory in micro-scale and antenna integrated fabrication.更多还原