Abstract: A surface mount balun includes a first stripline segment having a first and second end, a first balanced port connected to the first end, and a second balanced port connected to the second end, a second stripline segment overlapping and coupled to the first stripline segment, and having a third end adjacent to the first end of the first stripline segment and a fourth end disposed approximately adjacent to the center of the first stripline segment, a third stripline segment overlapping and coupled to the first stripline segment, and having a fifth end adjacent to the second end of the first stripline segment and a sixth end disposed approximately adjacent to the center of the first stripline segment, and a third, unbalanced port connected to the sixth end of the third stripline segment.

Abstract: A balun includes first and second symmetrical couplers, preferably first and second backward wave couplers connected to form a balun having an unbalanced port and a balanced port. More specifically, a balun in accordance wit this invention includes first and second backward wave symmetrical couplers each having an input port, a direct port, coupled port, and an isolate port in which the input port of a first coupler is connected to an input port of the second coupler, and the isolated port of the first coupler and the direct port of the second coupler are connected to the balanced ports of the balun respectively.