Properties of Ba₂Ti₉O₂₀/PTFE dielectric composites

Ba₂Ti₉O₂₀ possesses the best dielectric properties of all the microwave dielectric ceramics. In order to improve the mechanical properties and dimensional thermal stability of microwave dielectric material PTFE but not to deteriorate its good dielectric properties, Ba₂Ti₉O₂₀/PTFE microwave substrate composites reinforced by different Ba₂Ti₉O₂₀ content have been prepared by the technique similar to powder metallurgy. The mechanical, physical and dielectric properties of Ba₂Ti₉O₂₀/PTFE microwave substrate composites were studied. It was found that 30vol% Ba₂Ti₉O₂₀/PTFE microwave substrate composites possess excellent combination of properties with flexural strength 16.4 MPa, elastic modulus 4.6 GPa, water absorption rate 0.12% at room temperature, and thermal expansion coefficient about 35×10^-6/°C at θ<200°C, while the dielectric constant and dielectric loss value also show excellent stability during a wide range of microwave frequency and temperature.