The parasitic effects in high-frequency dielectric spectroscopy of liquid crystals – the review

Dielectric (impedance) spectroscopy of liquid crystals is a powerful experimental technique. It is especially essential because liquid crystals in many applications are still controlled by the electric field. In this paper, the problems with the high frequency (>1 MHz) measurements in classical (in the shape of the flat capacitor) measuring cells are discussed. The procedure for overcoming measurement difficulties was presented and applied to the dielectric response of antiferroelectric, binary mixture. Additionally, the paper presents the first example of extending the measuring range of dielectric spectroscopy from 1 MHz to ~50 MHz by overcoming the parasitic effect related to resonance in measuring setup.