Research Of Variable-temperature Measurement Technique For Complex Permittivity Based On Cylindrical Cavity Perturbation Method

Microwave dielectric materials which are often used in aerospace equipment, medical devices and those fields on the frontier broadly, especially do well in military technology, which are more promote the progress and development of the microwave dielectric materials technology research base on the huge demand in the field of electronic countermeasure technology. As the crucial basis of characterization for dielectric properties, acquiring the information of electromagnetic parameter accurately is particularly important.In this article, we analyzed the development of dielectric material test methods in the domestic and overseas at present and recited the various test principle for dielectric parameters. Considering the advantages and weakness for different test method and test requirement of system, we choose cylindrical cavity perturbation theory serve for the test of dielectric constant finally and designed a 0n0 TM mode cylindrical cavity which are function in 1~6GHz. In addition, a variable temperature test system for complex dielectric constant has been built, which can realize range of measurement from room temperature to 800℃ for wave-transmitting materials(PCWs). In the progress of testing, we found that measured complex permittivity accuracy would be affected at the middle of air gap which caused by sample insertion hole, dielectric rod sample and guide bar. Therefore, the characteristic equation for loading multilayer dielectric was deduced with the purpose of revising those air gaps and programed by using MATLAB. Utilized USB data acquisition card to realize the automation of system. Accomplished fast real-time test for sample by adding single trigger program into the command part of vector network.The complex permittivity of PCWs was measured by using the test system. And the measured results and error source have been analyzed by test error theory. Finally an error formula has been presented for re and tand.The testing index:Temperature: 20~800℃Frequency: 1~6GHzTesting range: tan ErrorIndoor temperature:High temperature(800℃):...