Widening of the large-angle half-wave wall through a pair of parameter-reversal Fano resonances

Widening the large-angle HWW through a pair of parameter-reversal Fano resonances and the designed Fano metasurface. θ i represents the incident angle, and q is the Fano parameter. • In this manuscript, we have first proposed to use the Fano resonance as an additional electromagnetic (EM) window, while other researches of Fano resonances are still focusing in sensing and switching. • With this idea, we have further proposed to widen the large-angle ( ≥ 60 ° ) half-wave wall (HWW) through a pair of parameter-reversal Fano resonances. • For a ceramic-matrix-composite (CMC) substrate, the method has well widened its 1st-order HWW within [60 ° , 85 ° ], where the effective bandwidth is expanded to 250 % of the origin at 80 ° . • Moreover, with Fano resonances’ characteristics, the HWW’s out-of-band suppression and angular stability are also improved here. • This work is not only the first study of Fano resonances for EM windows, but also solves the problem of the HWW’s narrow effective bandwidth at large angles, which is significant for radar systems, 5G/6G communication, and others. With the high quality (Q) factor, the Fano resonance has only been focused on sensing and switching, while its value in other fields ignored. In this manuscript, according to the Fano spectral characteristics, we have first proposed to use the Fano resonance as an additional electromagnetic (EM) window. With this idea, we have further proposed to widen the large-angle ( ≥ 60 ° ) half-wave wall (HWW) through a pair of parameter-reversal Fano resonances. To implement this method, we have designed the Fano metasurface based on the analysis. For a ceramic-matrix-composite (CMC) substrate, the metasurface has well widened its 1st-order HWW within [60 ° , 85 ° ], where the effective bandwidth is expanded to 250 % of the origin at 80 ° . Moreover, with Fano resonances’ characteristics, the HWW’s out-of-band suppression and angular stability are also improved. The method has been compared with other related studies, where the result has shown its superiority. This work is not only the first study of Fano resonances for EM windows, but also solves the problem of the HWW’s narrow effective bandwidth at large angles, which is significant for radar systems, 5G/6G communication, and others.