Three bent waveguides are proposed and investigated, two for circular waveguide TM01 mode transmission and one for coaxial TEM mode transimission. For high power-handling capacity, all of them are over-mode waveguides. In the bend, circular or coaxial waveguides transmitting only sector waveguide TE11 modes are split into several same sector waveguides by metal plates and metal rod. Those sector waveguides are grouped by their lengths. Different lengths of sector waveguides mean there are phase differences of the TE11 modes after bending. Due to requirements of mode conversion, the phase difference regulated by radii of circular waveguide and metal rod must be 2nπ, n = 0, 1, 2…. Since the phase difference is independent of bend radius, the radius could be as small as possible. One of the prototypes is experimented, and the test result of the VSWR shows that simulation has good match with experiment. Insertion loss is 0.2 dB at 8.4 GHz, which proves the feasibility of the prototype.
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