Degenerate band edge in periodically-loaded circular waveguides

We demonstrate the occurrence of degenerate band edge (DBE) condition in a periodically-loaded metallic waveguide at microwave frequencies. The unit cell of the periodic structure is composed of a circular waveguide loaded with two discs having elliptical irises with misaligned angle The demonstration of DBE in those Raregoides is understood relying to the concept of a simple multi- transmission line approach. The proposed structure has great potential for use in traveling wave tubes oscillators, resonators and pulse compression devices.