Investigation on single mode transmission of variable ferrite polarizer in circular waveguide

High order modes are a problem in the design of many ferrite devices. The conditions to guarantee single mode (TE11) operation are investigated. It is shown that when the ferrite thickness has been chosen as t = 0.0377lambda(0), the valid range of the dielectric thickness should be 0.01lambda(0) < d < 0.1046lambda(0) for single mode operation. It is shown that the dielectric ring filling can improve the figure of the merit and help to realize the single mode transmission in the device. Experimental results from a prototype polarizer are provided as verification of the analysis presented here.