Effective dielectric constant of top grounded coplanar waveguide on liquid crystal superstrate

<jats:title>Abstract</jats:title><jats:p>The effective dielectric constant of the top grounded coplanar waveguide with a liquid crystal (LC) superstrate for phase shifting applications is investigated in the frequency range of 30–60 GHz. Two nematic LC mixtures, namely E7 and MDA‐00‐3506, are used as the superstrate. The measurements show that MDA‐00‐3506 offers higher values of phase shift per millimeter than its E7 counterpart. In particular, the MDA‐00‐3506 provides 3.14°/mm, whereas E7 gives 2.79°/mm at 60 GHz. The results of the dielectric constants from measurement and computer modeling are found to agree to within 5%. For the modeling, a comprehensive finite element package predicting the local alignment of LC molecules and effective dielectric constant at different bias voltages and frequencies are used. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:1416–1418, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/mop.27564</jats:p>