Electromagnetic Waves in an Open Circular Dielectric Waveguide with a Spirally Conducting Surface

An open circular dielectric waveguide with a spirally conducting surface is considered. The edge problem is posed, the procedure of the dispersion equation composing is described. The dispersion characteristics of the several azimuthally symmetrical and azimuthally asymmetrical modes propagating in the lossless structure are presented. It is shown, that the fundamental mode of the open circular dielectric waveguide with a spirally conducting surface is the azimuthally symmetrical mode HE01, which slowing coefficient on high frequencies is defined by geometrical slowing of the spiral. It is noted, that when the azimuthally asymmetrical mode with the plane polarization propagates in the lossless open circular dielectric waveguide with a spirally conducting surface the polarization plane of the mode rotates concerning the initial position. For the HE11 mode propagating in the structure frequency-dependent rotation angle of the polarization plane is calculated. The investigation of the radial distributions of the electromagnetic-field components shown that HE11 mode carries energy mainly near the directing structure axis, similarly to the mode HE11 propagating in the open circular dielectric waveguide