An arrangement (100, 400, 500, 600) comprising a first plate (110, 410, 510, 610) and a second plate (120, 420, 520, 620) at a first distance (di) from each other with an overlap between them. The arrangement also comprises a third (130, 430, 530, 630) and a fourth (140, 440, 540, 640) plate between the first and second plates in said overlap so that the third and fourth plates do not overlap each other. All plates are made of an electrically conducting material, are essentially flat and plane and are separated from each other by a dielectric material. The first plate comprises an input/output port (111, 411, 511, 611), the second plate comprises a ground port (112), and the third and fourth plates comprise an output/input port (131, 141, 431, 441, 531, 541, 551). The arrangement will serve as a power divider, a power combiner or as a balun.