【作者】 李恩；

【导师】 聂在平；

【作者基本信息】 电子科技大学 ， 电磁场与微波技术， 2009， 博士

【摘要】 透波材料广泛应用于天线罩、天线窗等构件中,为适应飞行器在大气层高速飞行时产生的高温环境中微波应用,必须确保天线罩(窗)在高温环境中具有优良的微波性能。天线罩(窗)等构件的微波性能和透波材料的介电性能直接相关,而透波材料在不同温度不同频率下具有不同的介电性能。在透波材料的研制、生产和使用过程中,需要掌握其在高温宽频下的微波介电性能。因此,研究透波材料高温宽频测试技术具有重要意义。本文根据透波材料介电性能测试方法及技术指标要求,选用圆柱谐振腔法进行高温宽频介电性能测试技术研究。研究了高温宽频测试物理模型和测试误差分析原理,设计并制作了宽频高温测试谐振腔和变温传输系统,研制了高温加热保护系统,集成并调试了测试系统。攻克了透波材料高温宽频测试难题,填补了国内在该领域的空白。在测试原理研究上,提出了在腔体纵向方向上采用分段计算的方法,建立了非等直径谐振腔体的高温测试物理模型,完善了高温测试状态下的测试物理模型,减小了腔体纵向分布上直径和长度的变化对测试结果的影响。在校准和测试过程中,提出了实时采集腔体不同位置工作温度和温度线性插值的方法,并根据腔体实际工作温度分布对关键尺寸和微波参数进行修正,降低了腔体热不稳定性对测试结果的影响,提高了高温测试结果稳定性。在微波介电性能高温宽频测试中,提出了采用超音频感应加热方式,提高了高温宽频谐振系统中的可操作性和可维护性。在提出的分段计算和实时修正方法的基础上,研制了透波材料高温宽频测试系统。根据圆柱腔的组成,结合高温使用环境,设计了一腔多模谐振腔、耦合装置和测试样品台活塞,利用高温金属材料研制了高温宽带谐振系统。根据测试系统需要,利用标准波导的设计方法和性能参数,设计了变温环境中使用的非标双脊矩形波导,研制了非标波导到同轴的微波转换接头,组建了宽带微波变温传输系统。研制了真空保护系统,采用感应加热方式研制了加热系统,为谐振系统提供了高温真空保护环境。调试了感应加热圈和隔热保温装置,获得了符合测试需要的谐振系统温度分布。制定了合理的测试流程,分析并减少了影响测试精度的因素。编写了自动测试软件,集成了测试系统。测试了谐振系统宽带高温微波参数及其稳定性,制作了石英、蓝宝石等高温材料样品,对测试样品在7～18GHz内进行了室温～1500℃的复介电常数变温测试和重复性测试。本文最后从测试原理出发进行了测试误差分析研究。分析了测试误差源,结合温度特性分析了误差源的不确定度,讨论了由测试物理模型的理想状态与实际测试中偏差引入的误差,利用Matlab编制了测试误差估算软件。为测试结果的准确性提供了评价依据。测试结果和误差分析结果表明:本文基于分段计算方法和感应加热方式,在国内首次建立的测试系统,可对透波材料进行7～18GHz、室温～1500℃的宽带高温介电性能测试,并具有较好的测试重复性,达到了论文要求的测试功能和测试精度的要求。更多还原

【Abstract】 Microwave transparent materials are widely applied in radome, antenna windows, and other components. While aerospace crafts are flying at a very high speed in atmosphere, high temperature and high speed air flow will occur. In order to work properly in these situations, the microwave properties of radome and antenna windows must be guaranteed first. The microwave properties of these components are directly related to the dielectric properties of microwave transparent materials. Moreover, the transparent materials have different microwave dielectric properties at different temperatures and different frequencies. Therefore, it is very important that we study the dielectric properties of microwave transparent materials at high temperatures over broad frequency band in the researches, productions, and applications of these materials.According to the dielectric property test method of microwave transparent material and specification requirements, cylindrical cavity was chosen in the study of high temperature broadband dielectric property test techniques. The physical test model at high temperatures over broad band and the analysis theory of measurement error were researched. High temperature broadband resonant cavity and transmission system working at variable temperatures were designed and fabricated. High temperature heating protecting system was developed, and finally the test system was built and debugged. We solved the difficult technical problem of high temperature broadband measurement of microwave transparent material and filled the gap of this field in domestic.Subsection calculation method along the longitudinal direction of cavity was brought forward in the study of measurement theory. High temperature physical test model of the resonant cavity with unequal diameters was built and improved so as to reduce the effects on measurement results caused by the changes of diameter and length along the longitudinal direction of cavity.During the process of calibration and measurement, real-time temperature acquisition at different position and linear interpolation method were proposed and used to correct the key dimension and microwave parameters of the cavity. The heat instability of the cavity was reduced and the stability of the measurement results at high temperatures was improved.Supersonic induction heating method was first used in the microwave high temperature broadband dielectric property measurements. Operability and maintainability of the system were improved.Based on the theory of subsection calculation theory and the method of real-time correction, the high temperature broadband test system for microwave transparent material was built. Multimode resonant cavity, coupling device, and piston for holding the test sample were designed according to the composition of cavity and high temperature environment. The high temperature broadband resonant system was fabricated with high temperature metal. Due to the system needs, nonstandard double ridge waveguide used in variable temperature environment and adapter from double ridge waveguide to coaxial were designed and fabricated. They composed the variable temperature broadband microwave transmission system. Induction heating method was applied in the system for heating the resonant cavity and sample, and vacuum protecting system was developed. The induction ring and thermal insulation equipment were debugged, and temperature distribution of the resonant system satisfying the test requirement was obtained. Finally the test system was built. The microwave parameters at high temperatures and stability of the resonant system were tested. Samples made of quartz, sapphire are designed and fabricated. The complex permittivity of the samples was measured at 7-18GHz over the temperature range from room temperature to 1500℃.Finally, the measurement errors were analyzed based on the measurement theory. Error sources were analyzed and uncertainties were obtained combining with temperature properties. The errors caused by the deviation between the ideal physical test model and real test were discussed. The measurement errors were calculated with the program complied by using Matlab software. Error analysis provided evaluation approach for the accuracy of the measurement results.The measurement results and error analysis results show that the test system bases on subsection calculation method and induction heating method and built for the first time in domestic can be applied to the measurement of high temperature broadband dielectric properties at 7～18GHz over the temperature range from room temperature to 1500℃. The test system features good test repeatability and reaches the requirements of test function and measurement accuracy.更多还原