采用溶胶-凝胶法在多孔氮化硅表面制备了CaO-B2O3-SiO2(简称为CBS)微晶玻璃致密涂层.用高Q腔一腔多模扫频方法测量了样品从7.3GHz至18.4GHz频率范围内室温到1200℃的介电常数和介电损耗,研究了CBS涂层对多孔氮化硅高温高频介电性能的影响.结果表明:多孔氮化硅经表面处理后的介电常数略有增大,随着频率增大介电损耗的波动减小;9.2GHz典型频率下,样品介电常数的温度系数增大;室温下介电损耗降低了60%以上;表面处理改善了介电损耗的温度稳定性,满足高温宽频天线罩透波性能要求.%Compact moisture proof coating was fabricated with CaO-B2O3-SiO2 (CBS) glass ceramic on the porous silicon nitride substrate by sol-gel method. The dielectric constant and dielectric loss from 7.3GHz to 18.4GHz were tested from room temperature to 1200℃ by applying factor cylindrical cavity working in multimode before and after sealing. The result shows that, after coating, the dielectric constant is slightly higher and the fluctuation of dielectric loss decreases with frequency. At frequency of 9.2GHz the temperature coefficient of dielectric constant increases after coating. The dielectric loss is decreased by 60％ or more at room temperature after coating; the temperature stability of dielectric loss is improved by coating, and the demands of dielectric properties of radome are well satisfied.
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