Dominant-mode propagation characteristics for dielectric tape lines

Summary form only given, as follows. For some years the dielectric waveguide (and dielectric image line) have been studied at millimeter wavelengths, particularly for possible application in integrated circuits. Early analysis and measurements showed that low attenuation can be obtained, but that there may be a trade-off between reasonable field extent and low attenuation. This led to studies of various cross-sections for the dielectric, as well as choice of material (dielectric constant and loss tangent). It was found that the dielectric waveguide having the cross-section of a thin ellipse (i.e., like a tape) or a half ellipse mounted on an image plane provided lowest attenuation and certain other advantages, such as useful single mode bandwidth. This presentation will discuss quantitatively the comparisons for different dielectric constants, loss tangents, and ellipticities and compare attenuation factors, bandwidths, modal properties, and relative field extent. Measured results will be given for several millimeter wavelengths between 35 GHz and 140 GHz.