Propagation and radiation characteristics of the tape helix with a conducting core and dielectric substrate

An equation is presented to describe the dispersion characteristics of a tape helix separated from a concentric conducting core by a dielectric substrate. Numerical solutions of the complex-valued propagation constant can be used to obtain the complete k-β diagram of the helical geometry. The k-β diagram provides information regarding the real-valued solutions for β that represent true axial propagation, as well as the complex-valued solutions that represent surface waves and leaky waves. Several different helix geometries are considered. Under the assumption that these same solutions exist on a finite-length structure, the radiation pattern can be obtained for a given mode of propagation