An absorbing material based on the non-reciprocity of magnetic surface plasmon state of ferrites

Under external biased magnetic field conditions, magnetic surface plasmon state (MSPs) can be excited on the surfaces of ferrites, endowing them with unidirectional propagation characteristics of surface waves within a certain frequency bandgap. This paper presents an absorbing material based on the non-reciprocity of MSPs of ferrites. Firstly, by utilizing the unidirectional properties of MSPs and the rational design of metal components on the surfaces of ferrites, a unidirectional transmission structure is realized, exhibiting forward transmission and backward cutoff in the non-reciprocal bandgap. Then, by adding a metal plane being added at the bottom of the structure, the entire material exhibits high-efficiency electromagnetic wave absorption within the unidirectional bandgap of the MSPs. Furthermore, by adjusting the bias magnetic field and utilizing ferrites with varying saturation magnetizations, absorptions in different frequency bands, including the P-band, can be realized. To demonstrate the presented design, a prototype is fabricated and tested. The experiment results agree well with the simulation, confirming excellent wave absorption performance. Our study offers a new approach for designing absorbing materials, with potential applications in radar stealth and electromagnetic interference reduction.