Finite element analysis of a balanced microstrip line filled with nematic liquid crystal

Voltage-controlled formation of short pitch chiral liquid crystal structures based on high-resolution surface topography

“…Cholesteric fingers are no longer growing along the grating lines, but the whole area is immediately filled with a cholesteric structure. The grating lines induce an asymmetry in the surface anchoring and this induces some preferred orientation of the lying helix structure as demonstrated before [18,19,33]. In this work a more controlled growth of cholesteric structures with a decreased number of defects is demonstrated, by decreasing the voltage in small steps (~1 V p per step).…”

“…The finite element Q-tensor approach was used to find the director configuration in the bulk and the Jones Calculus was applied to simulate the transmission between crossed polarizers. The Q-tensor simulation tool has been developed at UCL and makes use of a minimization of the Landau-de Gennes free energy functional to find the spatial distribution of the LC director in the device [30][31][32][33]. The electrostatic field is determined from the variational form of Laplace's equation.…”

Accurate Modeling for Wideband Characterization of Nematic Liquid Crystals for Microwave Applications

“…Both methods used, the liquid crystal modeling programs [4], [5] and the electromagnetic modal solver [6] have been amply validated; however, potential errors could arise if there were other factors present in the test cell not accounted for in the models. One of these is uncertainty of the liquid crystal surface alignment, in particular in the vicinity of the electrodes.…”

“…We take a comprehensive approach in modeling both the liquid crystal orientation [4], [5] and the microwave fields [6]. The spatial distribution of the permittivity tensor resulting from the minimization of the free energy of the liquid crystal is used to calculate the microwave fields.…”

“…In [6] we presented modeling of a balanced microstrip line with a 1-mm-long liquid crystal section. The orientation of the liquid crystal was chosen along the transverse direction in order to have a simpler structure of the permittivity tensor.…”