Wave-transparent Materials, High-q Cavity Method Complex Dielectric Constant Change Of Temperature Test

Low loss dielectric material is widely used in spaceflight aerocraft wireless system. complex permittivity is the basic parameter for low loss dielectric material, different aerocraft works in different environment. The accurate measurement of low loss dielectric material in different temperatures is important for radome design .The paper analyzes the usual measurement methods in room temperature, and applies high Q method to design automatic measurement system.The calibration kit,high Q cylindrical resonant cavity and transmission lines designed for different functions are fabricated and temperature control system is developed. Automatic test software is complied and low loss material samples are tested.The temperature response traces of electromagnetic parameters of low loss materials are obtained.The measurement error is analyzed in this paper.The error sources are defined according to measurement theory and the value of each error source is obtained through experiment or theory analysis.The error calculation formula is given and the measurement errors are computed.Frequency:7～18 GHzTemperature:room temperature～800℃Measurement range:ε_r = 1.1～10 tanδε= 1×10^-3～5×10^-2Measurement errors at room temperature: |Δε_r′/ε_r′|≤2.5 % |Δtanδε|≤15% tanδε+ 8×10^-4Measurement errors at 800℃: |Δε_r′/ε_r′|≤5.0 % |Δtanδε|≤17% tanδε+ 1×10^-3...