The growing demand for portable devices with more reduced size and weight has stimulated the search for materials with high dielectric constant and low losses in the microwave frequency range allowing circuit integration and miniaturization. In this work, a theoretical and experimental study of the use of high dielectric constant films in the fabrication of microwave passive devices with reduced sizes has been made. A frequency domain analysis of the influence of these films on the characteristics of different configurations of multilayer transmission lines has been done. From this analysis, a configuration, called here as QCPW (Quasi-Coplanar Waveguide), that allows a practical implementation of structures with several values of impedance using comfortable transversal dimensions was chosen. Composite thick films of calcium titanate and magnesium titanate deposited by screen-printing and thin films of strontium titanate deposited by RF Magnetron Sputtering have been elaborated and characterized. CPW linear resonator method and CPW transmission line have been used to determinate the value of the dielectric constant and loss tangent of these films in the microwave frequency range at room temperature. The CPW linear resonator method was adapted and improved in order to provide satisfactory results for the case of thin films. Finally, for the first time, impedance transmission line transformers (TLT) with reduced size and wide-band response, based on the QCPW configuration using high dielectric constant films have been designed, analyzed, and fabricated.