Abstract: A distributed TEM resonator band pass filter has a set of rod-shaped resonators arranged in an interdigital line with alternate ones of the resonators being grounded to opposite walls of a housing. Each resonator has an ungrounded end which is capacitively coupled to a wall of the housing. Partitions, grounded to the housing, are located between successive ones of the resonators. Each partition closes off only a portion of the space between neighboring resonators to leave a coupling aperture. The interdigital arrangement provides for reduced loss and a higher Q. Input and output ports are provided at opposite ends of the interdigital line. The resonators may be constructed in the form of a suspended substrate, a stripline, or a microstrip configuration.