Novel ferroelectric materials for phased array antennas

Various composites of barium strontium titanium oxide (BSTO) combined with other nonelectrically active oxide ceramics have been formulated for application in phased array antennas. In general, the composites have adjustable electronic properties which can be tailored for use in phased array antennas and other phase shifting devices. The dielectric constant and the loss tangents have been reduced to enhance the overall impedance matching and thereby lowering the insertion loss of the device. In addition, the overall tunability, the change in the dielectric constant with applied voltage, is maintained at a sufficiently high level. In order to address a broad frequency range in the microwave region, the composites have been fabricated in bulk ceramic, thick film, and thin film form. This article discusses the processing, material characterization, and electronic properties of the composites in MHz and GHz frequencies.