Study on broadband microwave absorbing performance of gradient porous structure

In this study, a gradient porous structure was designed for a novel microwave absorbing material, and the effects of various factors on its microwave absorbing characteristics were investigated. The computational and experimental results show that the bandwidth of this composite can reach up to 14.06 GHz with a microwave reflection loss below − 10 dB in the frequency of 1–18 GHz. The appreciable agreement between the simulation and the experiment verified the validity of this structure. The broadband microwave absorbing performance of designed gradient porous structure was significantly enhanced, which was ascribed to the synergistic effect of structural and material characteristics. The square aperture of this structure increased from the bottom to the top, which improved the impedance matching between the surface of gradient porous structure and the air and reduced the reflection of electromagnetic waves. In addition, the transmission path of electromagnetic wave inside the absorbing structure increased, thus facilitating the attenuation of electromagnetic wave. This study could provide a new design strategy for the research of antiradar detection technique and shielding the electromagnetic interference.Graphical abstract Summary: 1.The absorbing principle of the gradient porous structure. 2. The simulation and test results of the gradient porous structure.