High-performance meta-absorber for the surface wave under the spoof surface plasmon polariton mode

Perfect absorbers are highly desired in many engineering and military applications, including radar cross section (RCS) reduction, cloaking devices, and sensor detectors. However, most types of present absorbers can only absorb space propagation waves, yet absorption for the surface wave (SW) has not been researched intensively. In reality, when the space wave illuminates on the metal under large oblique angles, surface waves can be excited on the interface between metal and dielectric and thus would increase the RCS and influence the stealth performance. Here, based on the wave vector and impedance matching theories, we propose a broadband absorber for the surface wave under spoof surface plasmon polariton (SSPP) mode. The former theory ensures that surface waves can enter the absorber efficiently, and the latter guarantees perfect absorption. The experimental results indicate that our absorber can achieve a broadband (9.4-18 GHz) performance with an absorption ratio better than 90%, which is in great agreement with the simulations. Therefore, our device can be applied in RCS reduction for the metal devices, antenna array decoupling and many other applications. Also, this work provides a unique methodology to design new types of broadband surface wave absorbers.