Abstract: Complex permittivity measurements at high temperature by short waveguide method were obtained, and the measurement and analysis results of some typical dielectric materials from room temperature to 1600 ℃ were given. The results show that, before 1000 ℃, the dielectric constant and the loss angle tangent of composite material will decrease with the increase of temperature, due to the presence of the surface water adsorbed and in vivo physical water. When the temperature is rising to 1000 ℃, dielectric constant and loss angle tangent decreases to minimum, which shows that composite materials in the absorbed water volatile completely. When the temperature is above 1000 ℃, the dielectric constant and loss angle tangent are greatly increased because of the trace impurities introduced in the preparation of composite materials, which will ionize and generate particle conductance with increasing temperature. The measurement methodology and considerations can be used in the study of hypersonic electromagnetic windows.

Key words: high temperature, complex permittivity, measurement, short waveguide method