Layered perovskite structured La5−xSrxTi4+xSc1−xO17 microwave ceramics for dielectrically loaded antennas

The crystal structure, microstructure and dielectric properties of layered perovskite structured La5−xSrxTi4+xSc1−xO17 (x=0-0.8) ceramics prepared by a solid state reaction route were investigated. X-ray diffraction and Raman spectroscopy analysis revealed the formation of single phase orthorhombic (Pnnm) symmetry. The microwave dielectric properties (εr, Q×fo and τf) of samples have been investigated as a function of composition. εr and τf increased while Q×fo decreased with an increase in x. The sample x=0.6 exhibited εr=54.8, Q×fo= 12,260 GHz and τf=6.7 ppm/°C which may be a suitable candidate material for dielectrically loaded antenna applications. The complex impedance spectroscopy analysis of the sample x=0.6 revealed that the sample is highly insulative with two electro-active regions (bulk and grain boundary).