Low temperature properties of microwave dielectrics

Abstract

Temperature dependences of resonant frequency and dielectric loss tangent were measured at the temperature range from 20 to 300 K for three kinds of microwave dielectrics, (Zr, Sn)TiO4, Ba(Zr, Zn, Ta)O3, and Ba(Sn, Mg, Ta)O3. The deviations of resonant frequencies from 20 to 300 K for these materials were less than 1200 ppm, which is equivalent to 4.3 ppm/°C of the temperature coefficient. The dielectric loss tangents of (Zr, Sn)TiO4materials showed a remarkable difference when they were made of the raw materials of different purities. These low temperature characteristics are discussed in connection with the anharmonic terms in the crystal's Hamiltonian. © 1989 The Japan Society of Applied Physics.