Based on the coupled wave theory， this paper presents the design， numerical analysis， and simulation of two types of TE0n-TE0(n+1) ripple-wall waveguide mode converters: a uniform ripple-wall converter and a nonuniform ripple-wall waveguide converter. For the first type，17.17GHz，six-period TE02-TE03 mode converter and 34.30GHz，six-period TE01-TE02 mode converter were operative； and 34.30GHz，six-period TE01-TE02 for the nonuniform one was operative. The design study is focused on the maximization of the conversion efficiency and mode purity coupled with a broad bandwidth. The nonuniform one seems to have a significant advantage over the uniform one， its conversion efficiency reaches 99.5% at center frequency and has a conversion bandwidth of more than 1.5GHz. Simulation results agree well with the theoretical predictions.