Design of rectangular waveguide bend for high-power microwave applications

Coupling coefficients of TE01 rectangular waveguide mode to TE02, TE03 mode have been derived theoretically. Based on mode coupling theory, two kinds of transmission lines were reported. Firstly, a TE01 to TE02 mode converter at 9.5 GHz was designed. The conversion efficiency is 99.9% at center frequency. In the frequency range of 8.60～10.48 GHz, the conversion efficiency exceeds 90%. Secondly, dual- or tri-bend rectangular waveguide transmission line was designed to realize the transmission of TE01 mode, without stimulating higher order modes. The bandwidth and power capability can meet our requirements, which have been applied in high power microwave experiments.