Filter arrangement

A filter arrangement comprising:

• a first HF-inner conductor,
• a second HF-inner conductor spaced apart from the first HF inner conductor in a longitudinal direction,
• a transformation line extending between the first and second HF-inner conductors,
• a tubular outer conductor arrangement having a round or square cross-section in which the HF-inner conductors with the transformation line are arranged coaxially,
• at least first and second stub lines which are both connected electrically/galvanically with and held mechanically at a connection point at the transformation line;
• the at least first and second stub lines configured in the form of electrically conductive metal strips whereby each of the metal strips is provided with a longitudinal extension, a width and a thickness whereby the width in the transverse direction transverse to the longitudinal direction of the metal strips is bigger than the thickness of the metal strips;
• the transformation line as well as the at least first and second stub lines are arranged in the tubular outer conductor arrangement;
• and
• at least one of the at least first and second stub lines which branches off from the transformation line is configured as one of said metal strips comprising a leg portion which is more than 60% of the total length of the respective stub line whereby this leg portion runs parallel to the first HF-inner conductor or in an angle (a) of less than 10° with respect to the first HF-inner conductor,
• wherein the first stub line has an electrical length such that the frequency response of the first stub line would be overcompensated by the adjoining transformation line, the adjoining second stub line compensating the over-compensated frequency response caused by the transformation line to provide an overall desired frequency response.