Ridged waveguide hybrid

Abstract

A waveguide hybrid includes a generally rectangular superstructure defined by first and second conductive broad walls and first and second conductive narrow walls, and an intermediate, conductive narrow wall bifurcating the superstructure into first and second generally rectangular waveguides, with each of the waveguides being provided with a central, longitudinally extending land or ridge, preferably having a generally rectangular, cross-sectional profile. A coupling window is provided in a central portion of the intermediate narrow wall, which is shared in common by the first and second waveguides. Further, a capacitive button, which preferably takes the form of a square peg, is provided on the floor of the superstructure between the lateral surfaces of the common narrow wall which define the coupling window. In operation, RF energy, such as a microwave excitation signal, is injected into the input port of the first or primary waveguide, thereby launching a TE.sub.10 mode which propagates through the primary waveguide towards its output port. A portion of the RF energy is coupled through the coupling window to thereby excite a TE.sub.10 mode to propagate through the second or auxiliary waveguide. The capacitive button functions to enhance the coupling efficiency. The RF energy is ultimately output via the output ports of both the primary and auxiliary waveguides, with the output power present at the output port of the auxiliary waveguide phase-lagging the output power present at the output of the primary waveguide by 90 degrees. The input port of the secondary waveguide functions as an isolation port since it receives minimum power due to phase cancellation.