Low-Dispersive Transition from Circular Metallic to Circular Dielectric Waveguides at W-Band Frequencies

Abstract

At mm- and sub-mm-wave frequencies dielectric waveguides (DWGs) are an interesting alternative to commonly used metallic waveguides. DWGs have lower losses, lower weight and increased flexibility. In addition, dielectric waveguides can be designed for minimal waveguide dispersion over a wide frequency range. For instance, a short section of a metallic waveguide might be more dispersive than several meters of a dispersion-minimized dielectric waveguide. To replace metallic waveguides by DWGs a transition between both waveguide types is needed. In order to benefit from the low dispersion and low losses of DWGs, in this paper a low-dispersive, low-loss transition from circular metallic waveguide to circular dielectric waveguide is presented. The circular feeding waveguide allows dual or circular polarized wave propagation along the DWG.