Thin films of CCVD Ba0.5Sr0.5TiO3 and SrTiO3 for electrically tunable coupled microstripline phase shifters

Epitaxial barium strontium titanate and strontium titanate thin films were deposited on (100) MgO single-crystal substrates, utilizing Combustion Chem ical Vapor Deposition. The as-deposited films were patterned with gold elec trodes to form interdigitated structure to function as electrically tunable devices, namely, coupled microstripline phase shifters (CMPS). Microwave d ielectric properties were characterized at 11-20 GHz with an applied electr ic field up to +/-35 V/mu m. A maximum figure of merit of 53 degrees/dB at 20 GHz and 23 degrees C was measured. The demonstrated high degree of tunab ility and relatively low loss showed great potential of these films for the targeted frequency agile device applications. Characterization, using SEM, EDS, and XRD, is presented in addition to microwave performance as a funct ion of do bias and frequency.