Compounds for a liquid crystalline medium and their use for high frequency components

The present invention relates to compounds having at least one bicyclic or tricyclic ring system which is connected to acetylene or difluoroethylene bridges, their use for high-frequency components, liquid-crystalline media containing the compounds and high-frequency components containing these media, in particular antennas, especially for the gigahertz range. The liquid-crystalline media are used, for example, for phase shifting microwaves for tunable 'phased-array' antennas.