A liquid crystal dielectric applicable to high-frequency electromagnetic wave modulation has a clearing point of the liquid crystal dielectric higher than 110° C., a low-temperature storage temperature lower than −20° C., and an optical anisotropy greater than 0.35. The liquid crystal dielectric includes: one or more compounds selected by general formula I, which occupy 30-80% of the total weight of the liquid crystal dielectric, and one or more compounds selected by general formula II and/or general formula III, which occupy 20-70% of the total weight of the liquid crystal dielectric. The liquid crystal dielectric has good low-temperature stability, high dielectric anisotropy, a high phase width, appropriate rotary viscosity, appropriate optical anisotropy, low dielectric loss, and a low loss tangent, exhibits strong high-frequency electromagnetic wave tuning capability, is specifically suitable for electromagnetic wave modulation in microwave or millimeter wave areas, and has a good application prospect in liquid crystal phase shifters. ##STR00001##

Liquid-crystalline media having one or more compounds of formula C ##STR00001##
and high-frequency components containing these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas (e.g. phased array antennas).

Provided are a liquid crystal composition containing a dibenzo derivative and a liquid crystal display device. The liquid crystal composition includes at least one compound of general formula I and at least one compound of general formula II. The liquid crystal compositions have the characteristics of high clearing point, large optical anisotropy, large dielectric anisotropy, large ε.sub.⊥, large ε.sub.⊥/|Δε|, and large K.sub.ave. The liquid crystal display devices containing these liquid crystal compositions have the effects of good transmittance and high contrast. The liquid crystal composition can meet the requirements of the liquid crystal display device on low power consumption and good display effect and has high application value in liquid crystal displays of in-plane switching (IPS) mode, fringe field switching (FFS) mode, and vertical alignment (VA) mode.

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Compounds of the formula I, liquid-crystalline media which contain at least one compound of the formula I and electro-optical displays which contain the LC mixtures, especially for the self-aligning VA, PSA, PS-VA, PVA, MVA, PM-VA, HT-VA or VA-IPS mode ##STR00001##
in which R.sub.1, R.sub.2, ring A.sub.1, Z.sub.1, Z.sub.2, Sp, P, L.sub.1, L.sub.2, r1, r2, r3, m, n, p1 and p2 have the meanings indicated above.

The present invention relates to an optical component comprising a liquid crystal (LC) medium, operable in the infrared region of the electromagnetic spectrum. The invention further relates to the use of said LC medium in the infrared (IR) region and to devices comprising said optical component. The present invention further relates to an LC medium comprising one or more compounds of the formulae I, II, and III

##STR00001##

##STR00002##

##STR00003##

in which the occurring groups and parameters have the meanings defined in claim 1, and preferably one or more compounds of the formula RO

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in which the occurring groups and parameters have the meanings defined in claim 2.

A steerable antenna having a plurality of radiating elements and a plurality of modifier elements configured for shifting phase and/or adjusting amplitude of a signal to be emitted by the radiating elements is disclosed. Each of the radiating elements is coupled to one of the modifier elements, wherein the modifier elements each comprise a liquid crystalline medium and wherein the modifier elements are configured such that the adjustment of the phase and/or amplitude is dependent on a state of the liquid crystalline medium. The steerable antenna further comprises a signal generator connected to the modifier elements and configured for generating a signal suited for dielectric heating of the liquid crystalline media of the modifier elements. Further aspects relate to a method for heating and/or controlling the temperature of the liquid crystalline medium of such a steerable antenna.

An object of the present invention is to provide a polymerizable liquid crystal composition used for formation of an optically anisotropic film having excellent moisture-heat resistance and an excellent surface condition, an optically anisotropic film, an optical film, a polarizing plate, and an image display device. The polymerizable liquid crystal composition of an embodiment of the present invention is a polymerizable liquid crystal composition containing a polymerizable liquid crystal compound and a compound represented by Formula (1): L.sup.1-SP.sup.1-(E.sup.3-A.sup.1).sub.m-E.sup.1-G.sup.1-C(═O)—O—C(═O)-G.sup.2-E.sup.2-(A.sup.2-E.sup.4).sub.n-SP.sup.2-L.sup.2, in which a content of the compound represented by Formula (1) is 0.01 to 5 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound.

A liquid crystal composition containing a dibenzo derivative comprising a compound of general formula I and a compound of general formula II, and a liquid crystal display device containing the same, are disclosed. The liquid crystal composition is characterized by its excellent physical properties with respect to a liquid crystal display. The liquid crystal display device containing the liquid crystal composition has a good transmittance and a high contrast. ##STR00001##

As a material used in an element used for phase control of an electromagnetic wave signal having a frequency of 1 GHz to 10 THz, a liquid crystal composition is required, which has a high upper limit temperature of a nematic phase, a low lower limit temperature of a nematic phase, large dielectric anisotropy and a small tan δ in a frequency region where the phase control of an electromagnetic wave signal is performed, and stability against heat, and which has an excellent balance of the characteristics. A liquid crystal composition which is used in an element for phase control of an electromagnetic wave signal having any frequency from 1 GHz to 10 THz, the liquid crystal composition containing at least one compound selected from compounds represented by Formula (1) as a first component.

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Aromatic isothiocyanates of formula C ##STR00001##
liquid-crystalline media comprising one or more compounds of formula C, and high-frequency components comprising these media, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, tunable filters, tunable metamaterial structures, and electronic beam steering antennas, e.g. phased array antennas.