A Comprehensive Review of Multiband Electromagnetic Metasurface Structures for Absorption and Wave Manipulation Applications

Multiband metasurfaces have attracted significant attention as compact and multi-functional platforms for electromagnetic (EM) absorption and wave manipulation. This paper reviews recent advances in multiband absorbers, frequency selective surfaces (FSS), and polarization converters, emphasizing their operating principles, structural configurations, and performance trade-offs. Particular attention is given to the dimensional and resonator aspects of metasurfaces, highlighting how unit-cell geometry, periodicity, and resonant structures directly influence (1) absorption efficiency, angular stability, and operating frequency in absorbers, and (2) spectral selectivity, bandwidth control, and miniaturization in FSS, and (3) conversion efficiency, bandwidth, and polarization purity in polarization converters. These interdependent parameters provide key guidelines for designing compact yet high-performance metasurfaces across different functionalities. Multiband absorbers exploit impedance matching and multi-resonant unit-cell to achieve near-unity absorption across multiple frequency bands, with applications in stealth, electromagnetic interference (EMI) suppression, and RF energy harvesting. FSS structures integrate nested or hybrid resonators within subwavelength cells to deliver high selectivity, angular stability, and miniaturized filtering for communication and radar systems. Polarization converters extend metasurface functionality by enabling linear-to-linear and linear-to-circular transformations within ultra-thin platforms, addressing the growing demand for polarization-agile devices in modern wireless and sensing applications. By identifying limitations and opportunities, this review underscores the role of multiband metasurfaces as enabling technologies for next-generation EM systems.