Abstract: A cylindrical multi-port combiner having a graceful degradation characteristic with a high degree of isolation (25 db) between ports and a high combining efficiency (>90.degree.) is disclosed. A radially-spaced inner and outer conductor forms a transmission line operating in a balanced mode. Circumferentially spaced plurality of like transmission lines have inner and outer RF absorbers at the outermost regions of the spaced adjacent inner and outer conductors, respectively. A corresponding end of each transmission line in adapted to be connected to one of a corresponding number of phase-matched RF sources. The other end of each transmission line has its inner and outer conductors connected in parallel, respectively, through stepped impedance-transforming transmission lines to form one connector for connection to an output RF load.