Dielectric Characterization of Single-Crystal LiF,CaF2,MgF2, BaF2, and SrF2 at Microwave Frequencyies

Published

October 20, 2004

Author(s)

Richard G. Geyer, James R. Baker-Jarvis, Jerzy Krupka

Abstract

Lithium, calcium, magnesium, and barium fluorides have widespread use in ultraviolet, infrared, and scintillation applications. Although their optical properties have been well-studied, little data exist on their dielectric properties at microwave frequencies. Microwave dielectric properties of single-crystal LiF, CaF(d2), MgF(d2), BaF(d2), and SrF(d2), synthesized by Stockbarger melt-growth techniques, are measured using cylindrical specimens as Te(d01δ dielectric resonators enclosed in a cylindrical cavity. Single-crystal permittivity and dielectric loss tangent were evaluated at fixed frequencies between 7 and 9 GHz and over a temperature range from -75 to 150°C. The real permittivities of the measured fluorides increase quasi-linearly with temperature, permitting evaluation of the thermal coefficients of permittivity. The dielectric loss tangents increase approximately linearly with frequency, so that Qxf (GHz) products at room temperature for BaF2, SrF2, CaF2, LiF, and MgF2 (normal to c-axis) are 57600,7300,9200,192400, and 458600, respectively. Ion polarizabilities are determined from the dielectric data. When used together with molar volumes and molecular additivity rules, the permittivities of more complex fluorides, whose values have not been experimentally determined, may be estimated.

Proceedings Title

2004 IEEE Conference on Electrical Insulation and Dielectric Phenomena

Conference Dates

October 17-20, 2004

Conference Location

Boulder, CO, USA

Conference Title

IEEE Conference on Electrical Insulation and Dielectric Phenomena

Pub Type

Conferences

Keywords

complex permittivity, dielectric properties, ion polarizability, microwave, resonator, semiconductor buffer layer, single-crystal fluorides, substrates

Citation

Geyer, R. , Baker-Jarvis, J. and Krupka, J. (2004), Dielectric Characterization of Single-Crystal LiF,CaF2,MgF2, BaF2, and SrF2 at Microwave Frequencyies, 2004 IEEE Conference on Electrical Insulation and Dielectric Phenomena, Boulder, CO, USA (Accessed April 23, 2024)