Electrical characterisation of liquid crystals at millimetre wavelengths using frequency selective surfaces

Author

Dickie, R. ; Baine, P. ; Cahill, Ronan ; Doumanis, E. ; Goussetis, George ; Christie, Samuel ; Mitchell, Neil ; Fusco, Vincent ; Linton, D. ; Encinar, Jose Antonio ; Dudley, Richard ; Hindley, D. ; Naftaly, M. ; Arrebola, Manuel ; Toso, G.

Author_Institution

Inst. of Electron., Commun. & Inf. Technol. (ECIT), Queen´s Univ. Belfast, Belfast, UK

Volume

48

Issue

11

fYear

2012

Firstpage

611

Lastpage

612

Abstract

The accurate measurement of the permittivity, loss tangent and dielectric anisotropy DC bias dependence for two different liquid crystal (LC) materials in the frequency range 140-165 GHz is described. The electrical characteristics are obtained by curve fitting computed transmission coefficients to the experimental spectral response of a new class of electronically reconfigurable frequency selective surface. The periodic structure is designed to yield bandpass filter characteristics with and without an applied bias control voltage in order to measure the tunability of the LC material which is inserted in a 705 μm-thick cavity.

Keywords

band-pass filters; dielectric losses; liquid crystals; millimetre wave filters; millimetre wave materials; permittivity; DC bias dependence; LC materials; bandpass filter characteristics; bias control voltage; curve fitting computed transmission coefficients; dielectric anisotropy; electronically reconfigurable frequency selective surface; frequency 140 GHz to 165 GHz; frequency selective surfaces; liquid crystal; liquid crystal materials; loss tangent; millimetre wavelengths; permittivity measurement; size 705 mum;

fLanguage

English

Journal_Title

Electronics Letters

Publisher

iet

ISSN

0013-5194

Type

jour

DOI

10.1049/el.2012.1061

Filename

6204259