Band Gap and Frequency Response in an Overmoded Coaxial Bragg Reflector

Based on the coupled mode theory of the 1D coaxial Bragg structure, numerical analysis is carried out to study the band-gap peculiarity of an overmoded coaxial Bragg reflector. Results indicate that, usually, the band-gap overlapping becomes very serious under the overmoded operation; however, it can be controlled by tuning the relative initial corrugation phase shift between the outer wall and the inner rod of the Bragg structure. Especially, the serious overlapping can be well improved by setting the phase shift to pi.