Influence of localized defect on transmission in a coaxial Bragg structure

Detailed simulations are presented for the effect of localized defect on the transmission of a coaxial Bragg structure. It is found that if localized defect is introduced to both the outer-wall and the inner-rod corrugations, two pass-bands will generate in the initial stop-band associated with the inter-coupling of the operating mode with spurious modes, which are quite narrow and thus may provide promising applications in high-Q resonators, tunable narrow-band filters, and pulse compressors.