Preparation, testing, and design of a radar-absorption polymethacrylimide foam

This article presents a new radar-absorbing polymethacrylimide (RAPMI) foam, measures the electromagnetic (EM) parameters of the foam, and establishes mechanical prediction models. The reflection loss (RL) curves of foams with different thicknesses and absorbent weight ratios (wt%) were analyzed along with the shear and compression behaviors of the RAPMI foam. Gibson models of the RAPMI foam were then established. The parametric effects of the absorption performance of multilayered RAPMI foams were analyzed using multimedia transmission-line theory. A numerically designed RAPMI foam exhibited excellent EM performance while retaining the outstanding mechanical properties of the original foam. The laminated foam can theoretically achieve a full-band effective absorption (RL <= -10 dB) of 2-18 GHz with a minimal thickness of 33.1 mm.