Technological evolution and performances improvements of a tunable phase-shifter using liquid crystal.

The topic of this paper is the study of electrically tunable phase-shifters based on the use of liquid crystals. The dielectric characterization of the commercial liquid crystal involved in this study allows us to determine its dielectric permittivities (with and without DC voltage applied) and then its dielectric anisotropy. In this way, two phase-shifter configurations were studied. Every devices propose inverted microstrip line. The two circuits have been realized with coplanar accesses to be use in the millimeter-frequency range. With the aim to improve the phase shift parameter (in °/GHz/cm), our work aims to reduce the transmission line. Instead of a rectilinear transmission line, this one is based on a symmetric stub line. The phase shift obtained is enhanced from 0.87°/GHz/cm to 2.77°/GHz/cm. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 43: 338–341, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20463 [ABSTRACT FROM AUTHOR]