Focusing properties of liquid crystal lens cells with stack-layered structure in the millimeter-wave region

Liquid crystal (LC) lens cells are fabricated using a nematic LC material with a positive dielectric anisotropy and semicircle-shaped metal substrates as quasioptical millimeter-wave devices. The millimeter-wave focusing properties of the LC lens are measured at 94 GHz and its convergent effects caused by the lens-shaped configuration are then observed. Changes in the focusing properties by applying an external electric field are confirmed.