Influence of space ultraviolet and proton irradiation on dielectric properties of BaO-TiO₂ microwave dielectric

Ultraviolet radiation and proton bombardment are two of the most important factors, which affect the properties of some BaO-TiO₂ series microwave dielectric materials in space environment. The space ultraviolet radiation and the proton bombardment were simulated in the laboratory. The dielectric properties of the materials which were exposed to vacuum-UV and proton bombardment were tested. The results show that the dielectric properties are related with the phase composition and the morphology of raw materials and the radiation conditions, i.e. the dielectric constants of composites increase about 10% after the proton bombardment. But when they are exposed to vacuum-UV, the dielectric constants of composites with rare-earth elements show the decrease tendency, while those of composites without rare-earth elements increase a little. Their dielectric loss is increased after these composites are exposed to ultraviolet radiation or proton bombardment. However, for BaTi₄O₉+5%Pr (in mole) samples, which are synthesized by fine powder, the dielectric properties are improved in space ultraviolet radiation and proton bombardment environment.