Microwave Scattering Characteristics of a Cylindrical Conductor Coated by Dispersive Metamaterials with an Intervening Air Gap

Abstract

Plane wave scattering characteristics of a conducting cylinder coated by a layer of metamaterial (MTM) having dispersive and lossy constitutive parameters – permittivity (ε) and permeability (μ) - with an intervening air gap is investigated by using the boundary-value technique. The backscattering cross section (BSCS) or the monostatic radar cross section (RCS) has been obtained for both the TM and the TE incident wave polarizations. Analysis based on a mathematical model, namely the Drude-Lorentz dispersion model, for the MTM coating shows that for a certain range of frequencies, the material may behave as either permeability- (or mu-) negative (MNG), permittivity- (or epsilon-) negative (ENG), both- (or double-) negative (DNG) or finally as both- (or double-) positive (DPS). The dispersive and lossy characteristics of these materials combined with the added features of an air gap (which can be practically realized by a layer of Styrofoam) seem to indicate that it is possible to achieve an extremely low radar echo width over a broad range of frequencies, particularly for the DNG type MTM. Further investigations on the total scattering cross section (TSCS) for the DNG type MTM, appear to demonstrate that near perfect broadband cloaking is possible with this geometry.

Keywords

• Cloaking
• Conductor
• Metamaterials
• Radar cross section
• Scattering