Ultrathin moiré pattern interlayered metamaterials for broadband and wide-frequency range tunable microwave absorption

Abstract

The tunability of broadband absorption in metamaterial microwave absorbers (MMAs) becomes more focused when facing the application needs of switching to multiple frequency bands. In this paper, moiré patterned printed circuit boards (PCB) interlayers with various relative rotation angles were incorporated into the two carbonyl iron/epoxy resin mediums, defined as the moiré pattern interlayered metamaterials (MIMs), which had been synergistical realized tunable broadband absorption. Specifically, the structure parameters of the MIMs consisting of moiré patterns and magnetic mediums were optimized based on genetic algorithms. It can be recognized that the moiré pattern at different angles changes the surface current pattern, resulting in the modulation in power loss distribution of the magnetic medium. Thus, the optimized effective bandwidth of MIMs covers a broad frequency range of 5.09–18 GHz with a 3.9 mm thickness, and their tunable absorption performance was also verified experimentally. This work presents a novel design strategy to achieve tunable and broadband absorption in the microwave range.