Method Of Dielectric Properties Of High Temperature Medium Terminal Short Circuit Testing System Research

The performance of microwave devices and equipment has a direct relationship with the properties of dielectric materials been in use. Especially in the field of military equipment, the development and application of new materials has never stopped. So the measurement of characteristics of the dielectric materials has a important practical significance. In many applications, the dielectric material does not just work at a room temperature environment, especially in the areas of aerospace, military equipment, such as aircraft radome used in high-temperature wave-transparent materials, the temperature range from several hundred degrees below zero to several thousand degrees Celsius. Changes in dielectric properties of dielectric materials used in microwave devices or equipment caused by temperature variation have very serious implications on the entire microwave systems, so establishing a high temperature dielectric properties test system, to measure the dielectric properties of different media vary different temperatures accurately, has a very important practical value for the development of microwave devices and equipment.In this paper, we used the classic waveguide terminal short-circuit dielectric test method on the basis of previous studies by the group, made a innovational improvement on the test system’s critical test waveguide components, and designed high-performance test waveguide components including a back launcher and side launcher coaxial-waveguide converter and high-temperature microwave test choke flanges, then build a set of high-temperature microwave dielectric materials testing system around the testing waveguide with other subsystems. Variable temperature tests using automated testing software on the dielectric material to achieve room temperature-1300℃temperature range testing of microwave low-loss dielectric material. In addition, support vector machines were used to verify the feasibility and accuracy on estimating the dielectric constant and loss tangent of low loss dielectric material with the method of waveguide terminal short circuit, then simulated and analyzed the impact of high-temperature waveguide thermal deformation by comparison. This system can achieve the measurement of dielectric material in high-temperature stable conditions.Technical indicators are as follows:Test temperature:Room temperature～1300℃Test frequency:X-band(dot frequency)Test range: Room temperature: ε’r=2.0～10,tanδz=0.001～0.051300℃:ε’r:=2.0～10,tanδz=0.01～0.05Test errors: Room temperature:...