Perforated lightweight microwave metamaterial broadband absorber with discontinuous ground plane

Abstract

In this study, we have demonstrated the fabrication of perforated absorbers on two substrates, i.e., ITO/PET and Twill weave cloth. Perforation is required to enable the use of absorbers in the application where air breathability, ventilation and thermal equilibrium are necessary. For perforations, holes were machined in all the layers of the absorber. To ascertain the effect of perforations on both the absorbers’ performance, simulation, using ANSYS HFSS software, was carried out. In the ITO/PET-based absorber, it was found that there were no significant effects of the variation of hole radius on the absorption. However, for textile-based absorber, the hole radius had a significant impact on the absorption. The proposed ITO/PET-based fabricated MMA can absorb radiation in the frequency band from 7.64 GHz to 16.6 GHz, whereas the textile-based absorber can absorb more than 90% of the frequency band corresponding to 6.61 GHz to 17.91 GHz. The measured absorptions are found to be in good agreement with the simulated results. Furthermore, perforation gives two mechanical advantages to the absorber: first, it reduces the absorber’s weight by 25% and 35%, respectively, in the case of ITO/PET- and textile-based absorber, and second, it increases the bendability of the absorber. Through experiments, we found that the perforated sample bends by an extra 22$^{\circ }$ and 24$^{\circ }$, respectively, for ITO/PET- and TWC-based absorber when placed as a cantilever. Theoretically, it was calculated that there would be a four-time increase in the absorber’s bendability due to perforations.