The present invention relates to liquid-crystalline media comprising one or more pleochroic dyes and one or more compounds selected from the group of compounds of formulae I, II and III,

##STR00001##

in which the parameters have the meaning indicated in Claim 1, and to components comprising these media for high-frequency technology, in particular phase shifters and microwave array antennas.

The present invention relates to liquid-crystalline media comprising—one or more compounds of formulae CC and/or CP and—one or more compounds selected from the group of compounds of formulae (I), (II) and (III), in which the parameters have the meaning indicated in Claim 1, and to components comprising these media for high-frequency technology, in particular phase shifters and microwave array antennas.

##STR00001##

The present invention relates to liquid-crystalline media comprising one or more compounds of formula DFS ##STR00001##
in which the groups and parameters occurring have the meanings indicated in claim 1, to high-frequency components comprising same, especially microwave components for high-frequency devices, such as devices for shifting the phase of microwaves, in particular for microwave phased-array antennas. The present invention further relates to novel mesogenic compounds.

A polar compound having high chemical stability, high capability of aligning liquid crystal molecules, high solubility in a liquid crystal composition, and a large voltage holding ratio when the compound is used in a liquid crystal display device; and a composition containing the compound. The compound is represented by formula (1). In formula (1), for example, P.sup.1 is a group represented by any one of formulas (1b) to (1i), P.sup.2 is a group represented by formula (1d), Sp.sup.1 and Sp.sup.2 are a single bond, Z.sup.1, Z.sup.2, Z.sup.3, Z.sup.4 and Z.sup.5 are —COO—, and ring A.sup.1, ring A.sup.2, ring A.sup.3 and ring A.sup.4 are 1,4-phenylene: ##STR00001##

The present invention relates to components for high-frequency technology, 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) comprising a liquid-crystalline medium, and to the liquid-crystalline medium used therein, wherein the liquid crystal medium comprises one or more compounds of formula S

##STR00001##

as defined in claim 1.

Provided is a compound represented by formula (1) described below.

##STR00001##

In formula (1), a and b are independently 0, 1 or 2, and expressions: 0a+b3 hold, ring A.sup.1, ring A.sup.2, ring A.sup.3 and ring A.sup.4 are independently 1,4-cyclohexylene, for example, Z.sup.1, Z.sup.2, Z.sup.3, Z.sup.4 and Z.sup.3 are independently a single bond, alkylene having 1 to 10 carbons, or the like, Sp.sup.1 and Sp.sup.2 are independently a single bond, alkylene having 1 to 10 carbons, or the like, and P.sup.1 and P.sup.2 are independently a specific polymerizable group.

A polyamic acid composition is polymerized by dianhydride monomers and diamine monomers. A range of molar ratio of the dianhydride monomers to the diamine monomers is from 0.9 to 1.1. The diamine monomers have a combination of specific functional groups containing at least one nitrogen heterocycle structure, at least one liquid crystal structure, and at least one soft structure, wherein the diamine monomer containing nitrogen heterocycle structure has a molar weight percentage of 3% to 8% of a total molar weight of the diamine monomers, and the diamine monomers containing at least one liquid crystal structure and at least one soft structure have a molar weight percentage of 92% to 97% of the total molar weight of the diamine monomers. The disclosure further relates to a polyimide film, a copper clad laminate, and a printed circuit board.

A polar compound having high chemical stability, high capability of aligning liquid crystal molecules, high solubility in a liquid crystal composition, and a large voltage holding ratio when the compound is used in a liquid crystal display device; and a composition containing the compound. The compound is represented by formula (1). In formula (1), for example, P.sup.1 is a group represented by any one of formulas (1b) to (1i), P.sup.2 is a group represented by formula (1d), Sp.sup.1 and Sp.sup.2 are a single bond, Z.sup.1, Z.sup.2, Z.sup.3, Z.sup.4 and Z.sup.5 are COO, and ring A.sup.1, ring A.sup.2, ring A.sup.3 and ring A.sup.4 are 1,4-phenylene:

##STR00001##

Provide is a polar compound having high chemical stability, high capability of aligning liquid crystal molecules, high solubility in a liquid crystal composition, and a large voltage holding ratio when the compound is used in a liquid crystal display device. A compound represented by formula (1) is applied.

##STR00001##

For example, in formula (1), P.sup.1 is any one of formulas (1b) to (1i), Sp is a single bond, Z is COO, and A is 1,4-phenylene.

##STR00002##

A liquid-crystalline medium and the use thereof for an active-matrix display, in particular based on the VA, PSA, PS-VA, PM-VA, SS-VA, PALC, IPS, PS-IPS, FFS or PS-FFS effect.