Preparation and characterization of high permittivity and low loss PTFE/CaTiO3 microwave laminates

This article discusses the preparation and characterization of CaTiO3 filled PTFE flexible laminates for microwave substrate applications. Single phase CaTiO3 filler composition was prepared through solid‐state ceramic route. Phase formation was confirmed by powder X‐ray diffraction studies. Morphology and filler distribution of the composites were studied using scanning electron microscopic technique. Permittivity and loss tangent of the composite substrates were measured at X‐band frequency region (8.2–12.4 GHz) using waveguide cavity perturbation technique. Effective permittivity of the composites was compared with theoretically predicted values. Temperature coefficient of permittivity (τεr) of the composites was also measured in the 0–100°C temperature range. PTFE/CaTiO3 composite has an effective permittivity of 11.8 and a loss tangent of 0.0036 at optimum filler loading. POLYM. COMPOS., 2009.