Measurement of Dielectric Constants of Nematic Liquid Crystals at mm-Wave Frequencies Using Patch Resonator

Effect of test device thickness on liquid crystal characterisation

“…The accuracy of the extraction can be further improved by optimising the transition to get the minimum reflections at desired frequency band. Although they are good approximation to their actual values, to convert the effective dielectric constant and loss tangent obtained to the actual values a set of conversion curves is used [4].…”

Variable Temperature Broadband Microwave and Millimeter-Wave Characterization of Electrochromic (WO3/LiNbO3/NiO) Thin Films

“…The physical structure can be divided into four parts: (1) two conducting electrodes that permit the application of the bias voltage; (2) ion conductor or the electrolyte, which is the middle layer that acts as a tank of available ions and has a strong influence on the device performance; it must have a high ion conductivity (typically σi > 10 −7 S/cm) but low electron conductivity (σe < 10 −10 S/cm); (3) EC layer at the cathode end where ions and electrons are inserted into or extracted from in order to change the associated colouration of the layer. The EC layer should be capable of conducting electrons as well as ions; (4) ion storage layer at the anode end is sometime present and, ideally, displays electrochromic properties complimentary to that of the cathodic EC film. In this case, the EC device contrast is improved since two chromic layers are bleached and coloured together (one cathodically by losing electrons and the other anodically by gaining electrons).…”

Tunable liquid-crystal millimeter-wave bandpass filter using periodical structure

“…The application of the bias voltage to the LC substrate alters its effective dielectric constant and in this way filter tunability is accomplished. The LC used in this work is E7 and its dielectric parameters were previously characterized in [7].…”