Angela M. CovesHaroldo MaestreRaimon ArchilésMiguel V. AndrésBenito GimenoSurface-Impedance Formulation for Hollow-Core Waveguides Based on Subwavelength Gratings.18843-18854202210IEEE Accesshttps://doi.org/10.1109/ACCESS.2022.3151163db/journals/access/access10.html#CovesMAAG22