Experimental improvement of birefringence and response time in Liquid Crystals using surface preparation of polyimide at 20GHz

Author

Machado, M. ; Ebadi, Siamak ; Driscoll, Tom ; Smith, D.

Author_Institution

Metamaterials Commercialization Center (MCC), Intellectual Ventures, Bellevue, WA, USA

fYear

2014

fDate

1-6 June 2014

Firstpage

1

Lastpage

4

Abstract

This paper presents an experimental study analyzing the effects of surface treated Polyimide (PI) on dielectric anisotropy and response time of Liquid Crystal (LC) in an In-Plane Switching (IPS) cell design. A Co-Planar Waveguide (CPW) transmission line is used as an in-plane interrogation architecture, with a layer of LC enclosed on top of the CPW. By applying different surface preparations of PI, we are able to derive an optimum condition to maximize birefringence and minimize response times at 20 GHz. Measured phase change is increased from 28 deg to 72 deg for the same length of the CPW line. At the same time, measurement results show that fall time is decreased from 9.32 s down to 4.1 s. These improvements will facilitate realization of LC in microwave devices in need of fast and tunable materials.

Keywords

birefringence; coplanar waveguides; liquid crystal polymers; birefringence; co-planar waveguide transmission line; dielectric anisotropy; frequency 20 GHz; in-plane interrogation architecture; in-plane switching cell design; liquid crystals; microwave devices; polyimide; response time; surface preparation; time 4.1 s; time 9.32 s; Face; Frequency measurement; Gaskets; Integrated optics; Optical sensors; Liquid crystal; in-plane switching; polyimide; response time; switching speed;

fLanguage

English

Publisher

ieee

Conference_Titel

Microwave Symposium (IMS), 2014 IEEE MTT-S International

Conference_Location

Tampa, FL

Type

conf

DOI

10.1109/MWSYM.2014.6848609

Filename

6848609