Insufferably high conduction losses for metal-based guiding structures at millimeter/sub-millimeter wavelength range as well as the phenomenal success of dielectric-based optical waveguides and integrated optical circuits prompted us to take a new look at dielectric waveguides as viable guiding structures for mm/sub-mm waves. Our investigation shows that dielectric waveguides may yet be proven to be the best mm/sub-mm waveguiding struc-tures. There are two possible ways of realizing a low loss millimeter/sub-millimeter (mm/sub-mm) waveguide structure: Through the use of low loss material and/or through the use of specially configured structure. This paper will address the latter. New low loss configurations are presented. Detailed propagation characteristics of the dominant mode on these new structures are discussed. The finite element approach perfected for optical waveguide calculations was used to analyze these complex structures.
"Design Of New Millimeter Waveguides Using Optical Concepts", Proc. SPIE 0545, Optical Technology for Microwave Applications II, (28 October 1985); doi: 10.1117/12.948348; https://doi.org/10.1117/12.948348