大尺寸样品介电常数测试系统研究与应用

【作者】 胡鹏；

【导师】 曾葆青；

【作者基本信息】 电子科技大学 ， 物理电子学， 2010， 硕士

【摘要】 本论文的主要研究目的是对大尺寸样品进行介电常数测量,从而更准确地表征沥青混合料在不同温度下的介电特性,从而为沥青路面微波加热修复选择合适的加热时间提供依据。通过对现有的多种介电常数测量方法的研究和分析,因谐振腔微扰和自由空间法在测量方面的简便性适合大量样品进行快速的测量,最终选择这两种方法作为测量手段。根据一般材料介电常数的色散特性,决定用0.915GHz频率附近的介电常数测量值表征其在2.45GHz频率的介电特性,前人对大量材料介电常数的测量结果支持了这种做法的可行性,本文也通过测量实验进行了初步的验证。对介电常数的自由空间法点频测量系统进行了设计,并对关键部件——金属板透镜和三探针阻抗测试仪进行了计算和设计。通过软件仿真找到了样品对谐振腔微扰介电常数测量测试精度的影响,对样品的选择提出了建议。在谐振腔微扰法实验测量过程中,找到了合适的耦合孔尺寸;找到了一种基于数据插值的数据处理算法来测量谐振腔的Q值;通过对有机玻璃样品的测量验证了测试系统的准确性;通过对大尺寸沥青混合料介电常数的测量,找到了其介电特性随温度变化的特性。找到了一种结合软件仿真的数据修正手法来提高不符合测量条件的样品测量结果的准确性。更多还原

【Abstract】 The main purpose of this dissertation is to measure the permittivity of big size samples. The material used for road constructing is the mixture of asphalt and rocks, so the big scale sample can represent the material’s dielectric property accurately.After the research and analysis of several present permittivity measuring method, as the cavity perturbation method and free-space method can measure large-quantity sample more easily, we choose the two methods in this dissertation. Based on the dispersion characteristics of normal materials, we use the measuring result on 0.915GHz to represent normal material’s dielectric on 2.45GHz, forerunner’s measuring result of many normal materials can support this practice, the experiment in this dissertation can also prove this method practicable.In this dissertation I design the free-space dot-frequency permittivity measuring system, the calculating and designing work of the metal-lens and three-probe impedance measuring apparatus has been done. After software simulating, the sample’s influence on permittivity measurement error has been researched, and the advice of choosing measure-sample has been given. In the process of permittivity cavity perturbation measurement, I found the suitable size of coupling-hole used in resonant cavity; a data processing method based on interpolation used in measuring Q-quantity has been given, after the measurement of plexiglass sample has been done, the measurement system has been proved to be accurate; after the permittivity measurement of big size asphalt mixture, the dielectric property varying caused by temperature change has been found. A data-correcting technique based on software simulating has been given to enhance the accuracy of measurement of samples which don’t conform to measuring condition.更多还原