Gap opening around a given point of the spectrum of a cylindrical waveguide by means of a gentle periodic perturbation of walls (Q280876)

The paper deals with the problem of producing a specific gap at a prescribed place of the spectrum of a cylindrical waveguide by changing in a well-behaved manner the shape of the waveguide (actually, its periodic cell). All the necessary machinery to the performed investigation is shown along the paper in a quite complete basis. Also, the arguments are accurately exposed. In summary, the paper brings important results in band-gap engineering, reported in a rigorous, robust, and precise fashion.