A multiple-section bandpass filter for broadcast communications includes
adjacent waveguide segments with a perpendicular connecting segment
between them to form a U-shaped signal path. The waveguide cavities of
the segments may be extruded and rectangular in cross section, and have a
groundplane spacing that allows signal propagation between filter
sections by evanescent coupling. Resonators in each of the adjacent
segments have a separation that establishes the coupling bandwidths
without the need for passive decoupling structures. A cross coupling
conductor between the adjacent segments provides a capacitive or
inductive coupling between them. A decoupling structure may be located in
the connecting segment.