Abstract: A microwave stripline signal distribution system utilizes a central conductor that is supported on a substrate, which is itself captured and supported between two foam layers. External ground plane shielding is provided on each side of the foam/central-conductor-substrate sandwich. The metallic central conductor is thin, as are the other structural elements, leading to a lightweight signal distribution system. The central conductor may be patterned to provide a large number of feeds. The approach allows: the inexpensive fabrication of lightweight signal distribution boards, whose inputs and outputs may be combined to provide single-channel or multi-channel combination or division of microwave signals. In a typical application, there is combination or division of microwave signals in an antenna involving hundreds of individual feed horns.