Design of coaxial waveguide bend for high-power microwave applications

Based on mode coupling theory, coupling coefficients of TEM coaxial waveguide mode to TE11 mode have been derived theoretically, and the design of coaxial waveguide bend for transmitting TE11 mode is reported. The computer simulation via commercial software, based on finite-element method, shows that the TE11 mode transmission efficiency of the optimized coaxial waveguide bends have reached 99.5% at 0.680, 1.575 and 3.750 GHz. Moreover, the bandwidths in which the transmission efficiency exceeds 90% are 0.60 to 0.83 GHz, 1.10 to 2.42 GHz and 3.10 to 4.16 GHz, respectively. The power handling capacity has reached GW level.