Sintered alumina with low dielectric loss

摘要: Low dielectric loss materials are required for applications in radio‐frequency and microwave communications. Aluminium is the second most abundant element Earth’s crust aluminium oxide (alumina) one of commonest ceramics. Single crystals oxide, i.e., sapphire, possess lowest losses any material. Polycrystalline alumina has a higher due to extrinsic factors. The sintered studied an attempt determine causes loss. Impurities shown play important role, but microstructure also key factor. High‐purity aluminas, near theoretical density, found display very low loss, tan δ=2.7×10−5 at 10 GHz. Doping with titanium dioxide was reduce tan δ=2×10−5.