Abstract: A microwave bandpass filter of the coupled bar type providing either an interdigital or combline structure. The filter consists of a plurality of resonator sections having two ground planes and a resonating bar integral with the structure and extending perpendicularly from one of the walls and parallel to the ground planes. The spacer sections match the dimensions of the resonator sections, but may have different widths thereby to control the spacing between adjacent resonator bars. Alternate resonator sections and spacer sections are mechanically interconnected to form a filter of the desired electrical properties.