Theoretical seminar | 30 June 2021

The aim of this talk is to present research activities at the University of Zagreb related to the analysis and design of metasurface-based electromagnetic structures.
Metasurfaces that can manipulate electromagnetic waves have garnered significant attention in recent years. To date, the focus has been on planar devices, while many applications require curved surfaces. In this talk we will present a systematic approach to designing curved, multilayer metasurfaces consisting of multiple, patterned sheets. The proposed approach combines the concept of sheet impedance with a new transmission matrix formulation that is applicable to stratified, canonical curved geometries. The results are verified both numerically and experimentally through metsurface structure examples of cylindrical and spherical shape, as well as through structures with body of revolution type of symmetry.
In the presentation we will discuss the method for determining the value of surface sheet impedance by considering the metasurface response on impinging electromagnetic wave with different phase variation along the curved surface, i.e. by response on different spectral-domain components of incoming wave. The analysis approach is further extended to curved metasurfaces that are not homogeneous, i.e. to metasurfacses that have spatially-varying distribution of surface sheet impedance. The extended formulation also covers metasurfaces that are located only on a part of canonical curved surface. Finally, the problem of production of curved metasurfaces structures will be considered in the presentation.

Main paper/arXiv, related to the seminar, and other references

1. Z. Šipuš, M. Bosiljevac, A.Grbic, “Modelling Cascaded Cylindrical Metasurfaces Using Sheet Impedances and a Transmission Matrix Formulation,” IET Microwaves Antennas & Propagation, Vol. 12, No. 7, pp. 1041-1047, 2018.
2. G. Valerio, F. Ghasemifard, Z. Šipuš, O. Quevedo-Teruel, “Glide-Symmetric All-Metal Holey Metasurfaces for Low-Dispersive Artificial Materials: Modeling and Properties,” IEEE Transactions on Microwave Theory and Techniques, Vol. 66, pp. 3210-3223, July 2018.
3. M. Ebrahimpouri, E. Rajo-Iglesias, Z. Šipuš, O. Quevedo-Teruel, “Cost-Effective Gap Waveguide Technology Based on Glide-Symmetric Holey EBG Structures,” IEEE Transactions on Microwave Theory and Techniques, Vol. 66, pp. 927-934, Feb. 2018.
4. Z. Šipuš, Z. Ereš, D. Barbarić, “Modeling Cascaded Cylindrical Metasurfaces with Spatially-Varying Impedance Distribution,” Radioengineering, Vol. 28, No. 3, pp. 505-511, 2019.
5. D. Barbarić, Z. Šipuš, "Designing Metasurfaces with Canonical Unit Cells," Crystals, Vol. 10, Paper No. 938, 2020.