Expansion of a continuous stop band of a corrugated waveguide by attenuation pole control

Attenuation characteristics are analyzed for a corrugated waveguide to achieve a wide continuous stop band. The image parameter analysis shows the waveguide has generally two stop bands with an attenuation pole in a two-octave frequency range. The attenuation pole frequency can be controlled by the length of the larger height section and can be adjusted into the passband between the stop bands. The adjustment eliminates the passband and gives a continuous wider stop band. The improved characteristics are verified by electromagnetic field simulation. This result for the one-dimensional periodic structure will be applicable to a two-dimensional waffle-iron structure of a PBG waveguide.