Dielectric properties of La3Ga5SiO14 at microwave frequencies between 10 and 400 K

Abstract

We report measurements of dielectric permittivity and dielectric losses at microwave frequencies of lanthanum gallium silicate as a function of temperature. The dielectric rod resonator method was used to evaluate the two relative permittivity tensor components εt and εz of this uniaxial dielectric crystal. Between 10 and 400 K, εt varies from 18.92 to 19.65 whereas εz ranges from 60.81 to 46.66. Around 300 K, the temperature coefficients of εt and εz have opposite signs and are equal to 130 and −720 ppm/K, respectively. This characteristic enables one to design a self-compensated microwave resonator presenting a low frequency temperature sensitivity. For the measured dielectric sample the dielectric losses range from 1×10−4 to 5×10−6 between 300 and 20 K and are actually limited by the crystal quality.