Title :
Broad-band microwave characterization of liquid crystals using a temperature-controlled coaxial transmission line
Author :
Mueller, Stefan ; Penirschke, Andreas ; Damm, Christian ; Scheele, Patrick ; Wittek, Michael ; Weil, Carsten ; Jakoby, Rolf
Author_Institution :
Lab. of Wireless Commun., Darmstadt Univ. of Technol., Germany
fDate :
6/1/2005 12:00:00 AM
Abstract :
Liquid crystals (LCs) promise to be suitable passive tunable material for microwave devices with excellent features concerning tunability and losses. In order to optimize the synthesis of LCs and the design of tunable microwave devices based on them, LCs have to be characterized at microwaves. For a microwave analysis between 360 MHz-23 GHz, use was made of a broad-band characterization method with a two-port coaxial line, temperature controlled within -7°C and 115°C. Two LCs are investigated: K15, as a quasi-standard, and MDA-03-2838, as a novel mixture with increased dielectric anisotropy and reduced microwave losses tanδ.
Keywords :
UHF measurement; anisotropic media; coaxial cables; liquid crystals; microwave materials; microwave measurement; -7 to 115 C; 0.36 to 23 GHz; K15; MDA-03-2838; anisotropic media; broad-band microwave characterization; dielectric anisotropy; liquid crystals; microwave analysis; microwave loss; microwave measurements; microwave phase shifters; passive tunable material; permittivity measurement; temperature control; temperature-controlled coaxial transmission line; tunable microwave devices; two-port coaxial line; Coaxial components; Crystalline materials; Design optimization; Dielectric losses; Liquid crystal devices; Liquid crystals; Microwave devices; Microwave theory and techniques; Temperature control; Transmission lines; Anisotropic media; coaxial transmission lines; liquid crystals (LCs); microwave measurements; microwave phase shifters; permittivity measurement; temperature control;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2005.848842
