The high dielectric constant of perovskite-type alkaline earth titanates makes them attractive for use in integrated thin film capacitors for microwave circuits. The application temperatures of those devices such as resonators, filters and phase shifters range from cryogenic temperatures for superconducting devices up to 250°C for semiconducting ICs. Significant material modifications have to be introduced to bring the pure components such as BaTiO3and SrTiO3into formulations which have a suitable temperature coefficient of the dielectric constant. For conventional powder based industrial processes, usually solid solution adaptations and heterogeneous mixtures are employed.