Multipole Decomposition Method for Tailoring Multiband Microwave Frequency Selective Surfaces

This work demonstrates that the multipole expansion method can be effectively applied to the scattered fields of unit-cell elements in frequency selective surfaces to accurately reproduce their transmission properties. Additionally, our analytical approach reveals that multiband behavior can be achieved by combining different elements (with nearby resonances) within the unit cell. Importantly, the multipole expansion allows for identifying individual contributions from each multipole to the spectra, paving the way for future studies that could exploit interactions between these modes to design and fine-tune FSSs with desired features.