Research On Variable Temperature Testing Technology Of Microwave Material Permittivity

The rapid development of microwave technology, the requirements of antennas, microwave components increase as in high-tech fields of aviation, aerospace, communications technology and information technology, which also spawned a microwave material widely used in these areas, there Microwave Materials growing importance and practical value; Also the electromagnetic wave propagation requires medium, propagating in the medium and its interaction with the medium is completely determined by the dielectric constant of the medium, it is necessary to understand the various microwave dielectric constant of the materials by testing, and in a lot of areas such as stealth, various aircraft airframe, microwave components and quasi-optical components, microwave and millimeter-wave integrated circuits plate, which a large number of microwave materials are applied, accurate dielectric constant and wide-band characteristics data of the material plays a crucial role in design objects study.Currently on the market most of the microwave materials manufacturers unable to provide accurate permittivity of microwave material, and the operating ambient temperature will be rising with work power increases of microwave devices, so you need to get microwave dielectric constant that changing with temperature, it makes a microwave material dielectric constant variable temperature testing technology.In this paper, a coaxial transmission line as the measuring device and based on the theory of transmission and reflection parameters method. Firstly, extracting the CST simulation data, using MATLAB verified the known dielectric constant material at room temperature, secondly according to the temperature contours of ANSYS thermal analysis simulation, developing the coaxial insulation means, so that heat transfer to a vector network analyzer port the temperature dropped to the rang of port temperature operation(-20℃~50℃), the lastly measured microwave materials S parameter in the frequency range of 1~18GHz, temperature range of room temperature ~200℃ by a vector network analyzer, using MATLAB verified to calculate the value of the dielectric constant at different temperatures, resulting in different materials dielectric constant with temperature variation.This paper based on the traditional method of transmission and reflection parameters, developed a set of variable temperature test system to achieve variable temperature measurements, especially to complete the measurement of powder materials, which relate to the temperature control, calibration and thermal insulating. According to theoretical calculation, simulation measurements, data validation, ultimately complete the design of coaxial variable temperature test equipment, using of this device for measuring microwave materials, achieving accurate microwave material dielectric constant changes with temperature and frequency, it plays an important role in the design of a variety of microwave components and optics.