Wave Propagation in Periodic Metallic Structures with Equilateral Triangular Holes Alex Amor, Antonio Valerio, Guido Ghasemifard, Fatemeh Mesa Aguado, Francisco Luis Padilla De La Torre, Pablo Fernández-González, José M. Quevedo Teruel, Óscar Periodic structures Equilateral triangular holes Mode-matching Dispersion analysis Glide symmetry Mirror symmetry This paper studies wave propagation in a periodic parallel-plate waveguide with equilateral triangular holes. A mode-matching method is implemented to analyze the dispersion diagram of the structure possessing glide and mirror symmetries. Both structures present an unexpected high degree of isotropy, despite the triangle not being symmetric with respect to rotations of 90º. We give some physical insight on the matter by carrying out a modal decomposition of the total field on the hole and identifying the most significant modes. Additionally, we demonstrate that the electrical size of the triangular hole plays a fundamental role in the physical mechanism that causes that isotropic behavior. Finally, we characterize the influence of the different geometrical parameters that conform the unit cell (period, triangle size, hole depth, separation between metallic plates). The glide-symmetric configuration offers higher equivalent refractive indexes and widens the stopband compared to the mirror-symmetric configuration. We show that the stopband is wider as the triangle size is bigger, unlike holey structures composed of circular and elliptical holes where an optimal hole size exists. 2020-05-06T12:04:14Z 2020-05-06T12:04:14Z 2020-02-28 info:eu-repo/semantics/article Alex-Amor, A., Valerio, G., Ghasemifard, F., Mesa, F., Padilla, P., Fernández-González, J. M., & Quevedo-Teruel, O. (2020). Wave Propagation in Periodic Metallic Structures with Equilateral Triangular Holes. Applied Sciences, 10(5), 1600. http://hdl.handle.net/10481/61853 10.3390/app10051600 eng http://creativecommons.org/licenses/by/3.0/es/ info:eu-repo/semantics/openAccess Atribución 3.0 España MDPI