An optically transparent metamaterial structure with simultaneously broadband microwave absorptivity and low infrared (IR) emissivity is proposed. Two specifically designed optically transparent metasurfaces were combined to realize radar and IR bi-stealth. One was designed to control the microwave absorption though properly modifying the impedance and resonance peaks of the meta-atom. The other was designed to control the IR radiation. Within a wide incident angle of ±60°, the proposed structure displays high absorptivity greater than 90% in the region of 6.28-12.29 GHz for TE polarization. For TM polarization, the absorptivity in the region of 7.19-15.26 GHz is greater than 90%. The IR emissivity of the metamaterial structure is about 0.30 in the IR region from 3 µm to 14 µm. The perfect consistency between experimental results and simulation results demonstrates that the proposal has practical application of multispectral stealth technology.
The dispersion curves of spoof surface plasmon polaritons (SSPPs) are typically asymptotically nonlinear, with only one single intersection point with the dispersion curves of couplers. This means that wave-vector matching can be achieved only at a single frequency, leading to a narrow bandwidth of SSPP couplers. In this letter, we propose to achieve broadband SSPP couplers through dispersion engineering of metamaterials. To this end, we investigated the dispersion properties of a metallic patch array (MPA) that supports the propagation of TE-mode SSPPs at microwave frequencies. After this, we designed a planar metamaterial lens that can provide additional tangential wave-vectors to free space waves. By dispersion engineering, the dispersion curve of the coupled waves overlaps with that of SSPPs on the MPA in a broadband, resulting in high-efficiency broadband coupling of SSPPs. As an example, we demonstrated a broadband SSPP coupler with more than a bandwidth of 1 GHz in the X band. The method can be readily extended to millimeter-wave, terahertz, and other higher frequencies.
In this paper, a comprehensive scheme based on the dispersion engineering of spoof surface plasmon polariton (SSPP) is proposed which attempts to merge absorption bands of plasmonic structure into a continuous one. Theoretical investigation shows that multi-resonance can be tailored in a meandered wire structure, and thus, the closed interval of adjacent absorption is achieved. Then, the plasmonic absorbing structure (PAS) consisting of a meandered wire array with the gradient length are employed here to achieve spatial k-dispersion engineering of SSPP, and the original isolated absorption bands are demonstrated to be merged into a continuous one. On such a basis, a hybrid PAS consisting of a meandered wire array and a straight wire array is proposed. Simulation and experimental measurements show that the proposed hybrid PAS can achieve ultra-wideband absorption with an efficiency of more than 90% in the frequency range of 5.0–31.6 GHz, which is 107.7% broader with respect to the original PAS of the straight wire array at the same thickness. Our strategy overcomes the contradiction between broadening absorption bandwidth and keeping high absorption efficiency in PAS, enabling a wide range of applications, such as radar stealth technology, electromagnetic compatibility, and so on.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.