Microwave dielectric properties correlated to crystal structure: an analysis

Abstract

Microwave dielectric properties, quality factor, dielectric constant and temperature coefficient of resonant frequency, are discussed based on the crystal structure analysis of two systems. The tungstenbronze-type like Ba/sub 6-3x/R/sub 8+2x/Ti/sub 18/O/sub 54/ (R = rare earth) solid solutions and Y/sub 2/BaCuO/sub 5/ green phase are addressed as examples. The quality factor (Q/spl middot/f) is improved by ordering due to phase transformation, compositional ordering of cations and purifying the composition. Dielectric constant (/spl epsiv//sub r/) is affected by volume of cation polyhedron, tilting of TiO/sub 6/ octahedron and polarizability of cations. Temperature coefficients of resonant frequency is studied by crystal structural analysis with different temperature.