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采用CVI法制备SiC f/PyC/SiC复合材料,在15~700℃内用矩形波导法测试了该材料在8.2~12.4 GHz(X波段)频率范围的复介电常数。该复合材料复介电常数的实部随温度的增加而增加,而虚部则随着温度的增加而显著降低。结果表明,材料内部电子极化导致弛豫时间的缩短是导致复介电常数产生变化的主要影响因素。
The SiC f / PyC / SiC composites were prepared by the CVI method and the complex permittivity of the material in the frequency range of 8.2 ~ 12.4 GHz (X band) was tested by rectangular waveguide method at 15 ~ 700 ℃. The real part of the complex dielectric permittivity increases with temperature, while the imaginary part decreases with increasing temperature. The results show that the shortening of the relaxation time caused by the electron polarization in the material is the main factor that leads to the change of the complex permittivity.