Effect of serpentine and non uniform waveguide mode converters on TM01 and TE11 : A comparative study based on simulations

In the development of microwave systems with high power transmitting capability, the role of the antenna is very important. In general, any high power microwave source generates the microwaves in TM_0n modes, preferably the TM₀₁, the dominant in that scenario. It is a well evident fact that the radiation characteristics of the TM_0n modes produces a null in the axial direction of the antenna. It is inevitable to use a mode converter in order to convert the null producing mode, i.e., TM₀₁ to a mode producing a maximum in the axial direction, preferably, TE₁₁. A number of mode converter designs are available, namely, serpentine configuration[3] [4], non-uniform waveguide configuration[1][2] etc. The mode converters so designed should not only convert the TM₀₁ to TE₁₁ but also should retain the TE₁₁ as it is. A simulation study is carried out to assess the effect of these two type of mode converters on TM₀₁ and TE₁₁. The study also focused on the purity of the radiation patterns thus produced and the VSWR for both the configurations.