Abstract: The invention relates to a method for maintaining and/or repairing the spout area (1) of a metallurgical vessel, wherein a substantially hollow-cylindrical sleeve (3) in a perforated brick (2) of the metallurgical vessel is removed. In order to allow the sleeve to be replaced quickly and simply in the event of wear, the method according to the invention has the following steps: a) introducing at least one radially extending slit (4) into the sleeve (3), whereby the sleeve (3) is interrupted at at least one circumferential point (5); b) reaching behind the sleeve (3) or segments (3?, 3?) thereof with a pulling tool (6); c) pulling the sleeve (3) or segments (3, 3?) thereof out of the perforated brick (2), and d) inserting a new sleeve (3) or a new brick material into the perforated brick (2).

Abstract: A directional coupler comprises, arranged on a substrate, two first ports connected by a first line and two second ports connected by a second line. The lines extend through a coupling zone in which they are separated by a conductor area not connected to the lines.

Abstract: A bandpass filter for a radio-frequency signal comprises an input section for a signal to be filtered, an output section for the filtered signal and at least one resonator electromagnetically or directly coupled to input and output sections. The shape of the resonator has binary rotation symmetry and/or mirror symmetry with respect to a signal propagation direction and is adapted to be excited into an oscillation having the same type of symmetry by applying the signal to be filtered to the input section.

Abstract: A directional coupler comprises, arranged on a substrate, two first ports connected by a first line and two second ports connected by a second line. The lines extend through a coupling zone in which they are separated by a conductor area not connected to the lines.

Abstract: A bandpass filter for a radio-frequency signal comprises an input section for a signal to be filtered, an output section for the filtered signal and at least one resonator electromagnetically or directly coupled to input and output sections. The shape of the resonator has binary rotation symmetry and/or mirror symmetry with respect to a signal propagation direction and is adapted to be excited into an oscillation having the same type of symmetry by applying the signal to be filtered to the input section.

Abstract: A radio apparatus is proposed which makes more flexible use of the antenna possible. The radio apparatus includes a case having a listening device on a first side and an antenna element in a second side opposite the first side. The antenna element is movably mounted on the second side of the case. The antenna element has a directional radiation characteristic in at least one first position and an omnidirectional radiation characteristic in at least one second position.