Microwave properties of twisted and supertwisted nematic liquid crystals with weak anchoring

Abstract

The phase-shift per unit-length (PSL) of microwave radiation is calculated when it is passed through a cell containing a twisted nematic liquid crystal (NLC) with weak anchoring energy at the boundaries. It is shown that the PSL induced by a given applied voltage is strongly increased as the anchoring energy at the boundaries is decreased. The effect of weak anchoring is therefore important to consider when designing real devices, such as phase shifters. The calculation is then extended to treat supertwisted NLC cells with weak and strong anchoring energy. It is shown that the effective permittivity of such cells may have high sensitivity to the thickness of the cell, with potential application to new microwave filters.

Keywords:

• nematic
• microwave
• devices
• supertwist
• anchoring energy

Acknowledgements

The authors thank Profs. A. Glushchenko and R. Camley for useful discussions and N. Anderson for help in running the numerical routines.

Funding

CMK was supported by National Science Foundation [grant number 1102332].