Propagation in Waveguides With Transversal Twist-Symmetric Holey Metallic Plates

Here, we study the properties of a new type of twist-symmetric configuration inside a waveguide. The structure consists of a periodic repetition of transversal metallic sheets with perforated holes. This twist-symmetric configuration permits the propagation of TM modes inside the waveguide and prevents the propagation of the first TE mode at the conventional band employed on those waveguides. The TM modes exhibit a broader band of operation as the periodicity is reduced, i.e., the structure is more compact. In addition, we demonstrate that the twist-symmetric structure has a broader band than that of the aligned holes in which the twist symmetry is absent. Furthermore, the number of folds of the twist symmetry determines the propagation constant of the propagating mode. Therefore, a reconfigurable structure based on a different number of folds creates future opportunities to produce fully metallic reconfigurable waveguides with different phase delays.