Abstract: The present disclosure discloses an earphone. The earphone may include a hook-shaped component, a connecting component, and a holding component. When the earphone is in a wearing state, the hook-shaped component may be configured to hang between a rear side of an ear of a user and a head of the user. The holding component may be configured to contact a front side of the ear. The connecting component may be configured to connect the hook-shaped component and the holding component and extend from the head to an outside of the head to cooperate with the hook-shaped component to provide the holding component with a pressing force on the front side of the ear.

Abstract: A metamaterial having a negative refractive index is presented, which has a dielectric carrier material (12; 48), first electrically conductive sections (14.1, 14.2, 14.3, 14.4) and second electrically conductive sections (16.1, 16.2). The metamaterial is distinguished by the fact that the dielectric carrier material (12; 48) is realized as a volume which consists of one piece and which has at least one inner area which is prestructured by positive or negative rib or mesa structures (52.1, 52.2) in the dielectric carrier material (48) and is covered with first sections (14.1, 14.2, 14.3, 14.4) and second sections (16.1, 16.2) in such a way that the first sections form capacitive series impedances upon illumination with an electromagnetic wave having a specific propagation direction and polarization, while the second sections are arranged in such a way that they form inductive shunt impedances upon the illumination.

Abstract: A metamaterial having a negative refractive index is presented, which has a dielectric carrier material (12; 48), first electrically conductive sections (14.1, 14.2, 14.3, 14.4) and second electrically conductive sections (16.1, 16.2). The metamaterial is distinguished by the fact that the dielectric carrier material (12; 48) is realized as a volume which consists of one piece and which has at least one inner area which is prestructured by positive or negative rib or mesa structures (52.1, 52.2) in the dielectric carrier material (48) and is covered with first sections (14.1, 14.2, 14.3, 14.4) and second sections (16.1, 16.2) in such a way that the first sections form capacitive series impedances upon illumination with an electromagnetic wave having a specific propagation direction and polarization, while the second sections are arranged in such a way that they form inductive shunt impedances upon the illumination.