A compact broadband balun (20). The balun (20) includes a waveguide transition (38) between one or more input ports (34, 54, 56) and one or more output ports (34, 54, 56) of the balun (20). A mechanism (36, 44), which depends on the tapered transition (38), provides a good match, while a resistor (44) provides isolation between input ports (34, 54, 56) and the output ports (34, 54, 56). In a specific embodiment, the balun (20) includes a first waveguide (34). One end of the first waveguide represents a first port of the balun (20). The balun (20) further includes a second wave guide (40, 42). Opposite ends (54, 56) of the second waveguide (40, 42) represent second (54) and third (56) ports. The waveguide transition (38) occurs between the first waveguide (34) and the second waveguide (40, 42). The waveguide transition (38, 44) is designed to provide a frequency-independent anti-phase response in response to an input signal provided at an input port (34). In alternative embodiment, microstrip waveguides are employed, and port inversion is achieved via a slotline inverter strategically positioned in the groundplane of the balun.