圆柱腔复介电常数高温测试系统

Cylindrical cavity high-temperature measurement system for complex permittivity

围绕微波介质材料复介电常数高温测试关键技术进行系统设计,利用圆柱腔精确场解法实现材料介电性能变温特性测试。设计了TM_(010)模圆柱谐振腔,采用快速移动平台和感应加热技术,搭建了变温测试系统,实现了915 MHz,最高1 400℃的复介电常数快速自动化测试。针对测试系统受热后对测试结果的影响,提出了实时变温校准技术,减小了夹具介电波动引入的误差。以熔融石英为例进行重复性测试并与已有文献作对比,结果表明介电常数和损耗角正切高温下测试偏差分别在2%和6%以内。

The systematic design around the key technology of high-temperature complex permittivity measurement of microwave medium is presented.Dielectric property test at variable temperature is realized by the exact field theory solution.A TM010 mode cylindrical resonant cavity is designed and variable-temperature test system is constructed by using rapid specimen movement platform and induction heating technology.The system can realize the complex permittivity test automatically at 915 MHz and up to 1 400 ℃.For the influence caused by the heating of the test system, the real-time calibration technology is presented to reduce the error from the fluctuation of dielectric property of the fixture.The repeated variable-temperature measurements of the complex permittivity of fused quartz sample are done, and the test data is compared with published data.The results indicate that the test deviations of permittivity and loss tangent at high temperature is less than 2% and 6% respectively.