Transmission spectrum of coaxial localized-defected Bragg structures with uniform and inhomogeneous ripples

Transmission characteristics of coaxial localized-defect Bragg structures with uniform and inhomogeneous ripples are comparatively studied in the present paper. Results show that, higher-order mode operation in the coaxial localized-defect Bragg structure may cause the undesired hybrid-mode transmitting due to the side-lobes interactions between the operating mode and its neighboring modes; tailoring the ripples amplitude at both sides of the localized defect with Hamming-window-function distribution can achieve the requirement of the single-mode transmission, and further generate sharp transmission spikes to favor the applications of the coaxial localized-defect Bragg structure. These peculiarities provide potential applications of the coaxial localized-defect Bragg structure in constructing high-Q opened resonators, extremely narrow-band filters and pulse compressors at sub-terahertz and terahertz frequency range.