Low temperature microwave characterisation of lithium fluoride

Abstract

Precise knowledge of dielectric properties of materials is required to implement the material in devices and circuits. At microwave frequencies complex permittivity (dielectric constant and loss tangent) are the two mandatory parameters prior to any design. We have identified Lithium Fluoride as a potential candidate, which can be used in conjunction with superconducting and non-superconducting parts of several microwave communication devices. Even though dielectric constant of LiF is known at room temperature there is no data presented at cryogenic temperatures. In this paper we have reported the dielectric constant and loss tangent of LiF as a function of temperature (19-295K) and at a frequency of 8 GHz.