An investigation of periodic waveguides with axial and azimuthal corrugations

The existing studies about the dispersion characteristics of the sinusoidal rippled wall cylindrical waveguides mostly center on one-dimensionally (1-D) corrugated waveguides. Sometimes two-dimensional (2-D) corrugated waveguides are needed to provide better selective and resonance properties not achievable with 1-D periodic structures. The authors of this paper improve the method of calculating the waveguide axially periodic by expanding the slow-wave structure´s boundary function in Fourier series, so that it can be adopted in periodic waveguides with axial and azimuthal corrugations. In addition, the general dispersion equations for the investigation of 2-D periodic waveguide are presented in this paper. The advantage of the method lies in its universality, providing solution to the dispersion characteristics for most of the periodic waveguides with axial and azimuthal corrugations. By the method suggested here, the paper analyzes the dispersion characteristics and coupling impedance of a new rib-loaded disk-loaded waveguide and other periodic waveguides.