Modelling of a 3D Periodic Surface Based on a Folded Resonator Embedded into a Waveguide

This paper presents the analysis and modelling of a specific type of three-dimensional frequency-selective surface which unit cells are named as Waveguide Integrated Resonators. This unit cell is identified as a promising structure for broadband filtering applications. An original circuital approach is adopted in order to model this complex volume structure. An equivalent circuit is proposed which reproduces the structure's behaviour under normal incidence. Very good accuracy is obtained within the frequency band of interest, thus validating the proposal.