Knitted radar absorbing materials (RAM) based on nickel-cobalt magnetic materials

There has been a long-standing interest in the development of flexible, lightweight, thin, and re-configurable radar absorbing materials (RAM) for military applications such as camouflaging ground-based hardware against airborne radar observation. The use of polymeric Polyacrylonitrile (PAN) fabrics as a host matrix for magnetic metal nano-particles (either at the yarn-stage or after weaving the fabric) for shielding and absorbing applications has been described in the literature. In our experimental investigation, the relative concentrations of Nickel and Cobalt as well as the coating time are varied with a view to optimizing the microwave absorption characteristics of the resulting PAN-based composite material in the radar-frequency bands (X, K-u, and K). It is found that the PAN samples with the shortest coating time have the best return losses (under - 20 dB return loss over a moderate bandwidth). (C) 2016 Elsevier B.V. All rights reserved.