Camouflage is an emerging application of metamaterials owing to their exotic electromagnetic radiative properties. Based on the use of a selective emitter and an absorber as the metamaterials, most reported articles have suggested the use of single-band camouflage, however, multispectral camouflage is a challenging issue owing to a difference of several orders of magnitude in the unit cell structure. Herein, hierarchical metamaterials (HMMs) for multispectral signal control when dissipating the absorbed energy of microwaves through the selective emission of infrared (IR) waves from the unit cell structure of the HMM are demonstrated. Integrating an IR selective emitter (IRE) with a microwave selective absorber, multispectral signal control with the large-sized unit cell structures of up to 10 cm are realized. With an IRE, the emissive power from the HMM toward 5–8 µm is 1570% higher than the Au surface, which is preventing the occurrence of thermal instability. Furthermore, we determine that the signature levels of targeted IR waves (8–12 µm) and microwaves (2.5–3.8 cm) are reduced by up to 95% and 99%, respectively, when applying the HMM.
Bibliographical noteFunding Information:
This work was supported by the Human Resources Development program (No. 20174030201720) of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Trade, Industry and Energy and the Center for Advanced MetaMaterials (CAMM) funded by the Ministry of Science, ICT and Future Planning as Global Frontier Project (CAMM-No. NRF2014M3A6B3063716). H.H.C and T.K. envisioned and implemented the concept of research related to the simulations and experiments for multifunctional metamaterials. T.K. and N.L performed the parametric studies for ISE and microwave absorber by simulation and experiments. T.K. and J.-Y.B calculated the survivability of aircraft by simulation. T.K., J.-Y.B, N.L., and H.H.C. wrote manuscript. All authors discussed the results and commented the manuscript.
All Science Journal Classification (ASJC) codes
- Materials Science(all)
- Condensed Matter Physics