RF properties of BST–PPS composites

Ferroelectric ceramic–polymer composites provide flexible self-sustaining thin layers with unique electrical and mechanical properties, and thus a novel way to fabricate RF devices. In this work, a composite made of ferroelectric ceramic (barium strontium titanate, BST) and thermoplastic polymer (polyphenylene sulfide, PPS) was studied with various BST loadings up to 70 wt.%. The microstructures exhibited uniform distribution of ceramic particles in the polymer matrix. RF measurements showed that the relative permittivity and loss tangent of the composites gradually increase with increasing BST loading. At 1 GHz a composite with 70 wt.% BST loading had relative permittivity and a loss tangent of 13.5 and 0.0025, respectively.