An active surface with dual smartness of controllable electromagnetic/radar reflectivity and adaptive structural dynamic characteristics

The authors demonstrate the feasibility of developing a composite material which can be used for realizing an active, smart target surface with controllable and adaptive radar reflectivity as well as controllable structural dynamic characteristics. Proof-of-concept studies were performed on a viscoelastic medium composed of hygroscopic polyacrylamide gel dispersed with a mixture of BaTiO/sub 3/ and ferrite (NiCo/sub 0.05/ Mn/sub 0.1/Fe/sub 2/O/sub 4/) powders (in the ratio 1:1:0.5 by weight). This heterogeneous material is a lossy, nonlinear electromagnetic medium with anisotropic ferroelectric and ferromagnetic properties. It is also a viscoelastic medium with electrostatic characteristics conducive to controllable structural dynamics. Measurements of electromagnetic reflectivity at X-band frequencies are discussed along with measurements on the smart structural behavior of the test material.<>