Optical and electrical studies of novel ferroelectric composites for use in phased array antennas

Abstract

Ceramic composites of barium strontium titanate and other non-ferroelectric oxides have been fabricated for use in phased array antennas. These composites have shown superior electronic properties at low and microwave frequencies in that they have reduced dielectric constants, low loss tangents and high tunabilities. However, minimal work (other than X-ray powder diffraction) has been reported on the correlation of these electronic properties to the site substitutions and the sample topography. Raman and FTIR spectroscopy has been used to study the structural properties related to the additions of both strontium to the barium titanate crystal structure as well as the effect of the additions of oxide III on Ba/sub 1-x/Sr/sub x/TiO/sub 3/ (1-x=0.00, 0.15, 0.30, 0.40, 0.45, 0.50, 0.55, 0.6, 0.7, 0.80, and 1.0). The optical properties of the ceramic composites have been correlated to the electrical properties of the materials such as the Curie temperatures and these results are discussed in detail.