固体电介质薄膜、薄片复介电常数的测量研究

【作者】 吴静静；

【导师】 延波；

【作者基本信息】 电子科技大学 ， 电磁场与微波技术， 2007， 硕士

【摘要】 随着微波电路的工作频率不断提高,体积越来越小,对于薄片状介质基片的需求日益增长,在这些应用中都必须准确地知道介质材料的微波特性。因此,固体电介质薄膜、薄片复介电常数的测量有着很重要的实际意义。本文主要对低损耗薄膜电介质材料复介电常数的测试进行系统的研究。在前人研究的基础上,改进了传统的高Q圆柱谐振腔测量方法,用抬高样品的高Q谐振腔法测量薄膜电介质材料的复介电常数。在此基础上建立了一套X波段自动化测量系统,由矢量网络分析仪内部计算机控制矢网对圆柱谐振腔进行变频测量,根据测量到的加载介质前后圆柱谐振腔的谐振频率和品质因数,自动计算出被测材料的相对介电常数εr’和损耗角正切tanδ。本课题的主要工作包括:1.通过对国内外相关测量技术的分析,根据实际情况,采用谐振腔法进行测量;分析了谐振腔的基本理论;利用合适的垫片材料抬高样品,把样品置于腔中电场较强处,建立了抬高样品的高Q谐振腔法测试的理论模型;推导出电介质薄膜复介电常数的计算公式。2.分析系统的可行性,对系统的各个部件进行分析;组建X波段测试系统;用VC++编写了测试软件,实现自动控制。3.用软件控制测试系统对样品在X波段进行测试,并且对测试结果进行误差分析。结果表明,本研究的理论分析正确,测量系统准确。因此,本文提出的用抬高样品的高Q谐振腔测量薄膜电介质材料复介电常数的技术可对多种薄膜电介质材料的复介电常数进行快速、可靠、自动化的测量,具有肯定的实用性。更多还原

【Abstract】 Microwave dielectric materials have been widely used in information and communication domain, which are used in the systems of microwave communication, electronic countermeasure and so on. Therefore it is highly significant to measure the electromagnetic parameters of medium materials, as knowing the dielectric materials’microwave characteristics is the most important factor in applications. As improvement of modern scientific technology, it is further and more and more accurately to measure electromagnetic parameters of dielectric materials.In this paper, the complex permittivity measurement of low-loss thin materials using a cylindrical cavity is researched. Based on the technique, a set of automatic system at X band is built. According to the frequency and the quality factor of the cylindrical cavity unloaded and loaded, the system can calculate the permittivityεr’ and the loss angle tangent tanδof the thin materials being tested.The main research work includes:1. Through analyses of the correlative measurement technology and consideration of the characteristic of the measured materials, the method by cylindrical cavity is selected; Theory of resonant cavity is analyzed; Physical model is settled; The formulas are deduced.2. Feasibility of test model is discussed. Measurement is done to all of department of the system. Finally the whole measurement system is built. It realizes auto control by software designed with VC++.3. The thin samples are measured by the system at X band. And the analysis of uncertain is summarized.The result indicates that the method is correct, and the test system is reliable. Therefore, the test technique can be used for the rapid, credible, automate measurement of material parameters of dielectric medium, and it is also extraordinary practical.更多还原