Multimode propagation on radiating traveling-wave structures with glide-symmetric excitation

Abstract

Standing-wave measurements on a periodic traveling-wave array of dipoles driven with glide-symmetric excitation from a coaxial transmission line show the existence of multimode propagation in certain frequency bands. This phenomenon is explianed qualitatively in terms of coupling of symmetric and antisymmetric modes of the dipole array by the excitation from an unbalanced line. It has not been found when the dipoles are driven from a balanced two-conductor line. The avoidance of such multimode phenomena is crucial to the self-balancing property of successful log-periodic dipole arrays.