Metamaterial antenna design for thermal camouflage in defense industry applications

As a technology, camouflage involves achieving low visibility in the visible, mid-infrared and radar spectrums through color control, infrared signature modulation and absorption (reflection suppression). Natural (traditional) materials used in this direction have limitations in their optical efficiency. They are not as efficient as needed for optical application work or are too bulky to be used. Metamaterials, which also contain traditional materials in their structure but have various geometric designs, have enabled the emergence of structures that can perform much more efficiently than traditional materials. Perfect light absorbers require a semiconductor, metal or a layer with different absorption properties to trap light in their structures. In our study, a new Metal-Insulator-Metal-Insulator (MYMY) metamaterial design consisting of ring metal-insulator (Ag-ITO) arranged layers on a planar metal-insulator (Ag-Si) metasurface was designed. The proposed metamaterial design has been studied for the spectral region with infrared wavelength range from 800 to 12000 nm. Spectral features were analyzed using finite difference time domain (FDTD) software. With this design, low emissivity is maintained in atmospheric windows in the nontransparent infrared range (NTIR) for thermal camouflage applications compatible with shortwave infrared (SWIR) and radiative cooling. However, with the MYMY structure, excellent absorptions were obtained with two broad bands whose absorption peaks perfectly matched the atmospheric absorption windows (in SWIR and NTIR). Moreover, the proposed structure is polarization insensitive as it has an in-plane symmetrical design. The optical performance of the structure was optimized using numerical simulation techniques. The impedance values of the nanostructure and air were compared and it was shown that they provide excellent compatibility and that the average absorption values are very close to the desired value in the MWIR and LWIR regions. The designed structure offers an adjustable and highly efficient solution to manage thermal emissions in various applications and is an important innovation in the field of privacy technology.