Using finite element method

this paper investigates the influences of two deformed symmetrical double ridged

（elliptical and circular）

waveguides on their transmission characteristics.It calculates the cutoff wavelength and single-mode bandwidth at the change of the ridge dimensions

gives the dominant mode field pattern and the corresponding curve of the deformation vs.the effects on the cutoff wavelength and single mode bandwidth and analyzes the transmission characteristics with the changes of the waveguide dimensions.These studies provide valuable references for the applications and study of the deformed double-ridge waveguide.