Abstract: A frequency selective filter (18) for electromagnetic waves has a substrate (24) and a conductive structure (26) provided at the substrate (24), the conductive structure (26) having a plurality of filter elements (28) and a plurality of capacitive elements (30). The plurality of filter elements (28) forms an array of filter elements (28) forming a first resonance structure (32) for a first frequency band. The capacitive elements (30) of the plurality of capacitive elements (30) encircle one of or a group (44) of the plurality of filter elements (28) comprised in the array of filter elements (28), wherein the plurality of capacitive elements (30) forms a second resonance structure for a second frequency band, having a different filtering characteristic as the first resonance structure. The array of filter elements (28) spans a filter plane, at least one capacitive element extending in the filter plane. Further, an antenna (14; 16), a mobile communication base station (10) and a user device (12) are shown.

Abstract: A measurement device for ascertaining a pressure in a measurement volume which receives a fluid or through which fluid flows. The measurement volume is bounded at least sectionally by a side wall and a vibration transducer is arranged on the side wall. The vibration transducer is actuable by a control device of the measurement device to excite a wave that is guided through the side wall. The guided wave is able to be guided through the side wall along a propagation path back to the vibration transducer or to at least one further vibration transducer and it is captured there by the control device in order to ascertain measurement data. The pressure in the measurement volume is then ascertained by the control device in dependence on the measurement data.