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A full-wave analytical method using the addition theorems and Hertzian potential functions are used to compute the radar cross section of a sphere coated by several layers composed of common materials and metamaterials. The minimization and maximization of radar cross section of a perfectly electric conductor sphere with such coatings are realized in a frequency band-width and in a wide interval of angles. One of the novelities of this contribution is, taking into dispersion relations of physically realizable metamaterials. So that the optimization procedure for RCS reduction is applied due to the coefficients describing dispersion characteristics. The method of least square is used for the design of a class of radar absorbing materials. The minimization of the error functions are performed by the combination of genetic algorithm and conjugate gradient method. It is shown that the proposed method of computation of radar cross section and its extremization effectively leads to the design of dispersive and isotropic metamaterials for the realization of radar absorbing materials. [ABSTRACT FROM AUTHOR]

Aerospace structures can be approximately modeled as a combination of canonical structures such as cylinder, cone and ellipsoid. Thus the RCS estimation of such canonical structures is of prime interest. Furthermore metamaterials possess peculiar electromagnetic properties which can be useful in modifying the RCS of structures. This paper is aimed at calculating the RCS of an infinitely long PEC circular cylinder coated with one or two layers of metamaterial. The incident and scattered fields of coated cylinder are expressed in terms of series summation of Bessel and Hankel functions. The unknown coefficients of summation are obtained by applying appropriate boundary conditions. The computations are carried out for both principal polarizations. The computed results are validated against the numericalbased method of moments. Further, the variation of RCS of the metamaterial coated PEC cylinder with material parameters, frequency, aspect angle and polarization is analyzed. [ABSTRACT FROM AUTHOR]

Abstract: The scattering of electromagnetic waves by a perfect electromagnetic conductor (PEMC) cylinder coated with a homogeneous plasma anisotropic material is studied in this paper. Both of the transverse electric and the transverse magnetic polarizations of the incident waves have been analyzed and formulated. The presented analysis and formulations are general for any perfect conductor cylinder (PEC, PMC, or PEMC) with general isotropic/anisotropic material coatings that include plasma and metamaterials. The co-polarized and the cross-polarized components of the scattered fields are computed for different cases of the anisotropic plasma coated PEMC cylinders and for an anisotropic plasma column. Bistatic echo widths for the cases of PEMC, PEC (perfect electric conductor) and PMC (perfect magnetic conductor) cores have been computed and compared. The behavior of the monostatic echo width with the variation of the admittance parameter for the co-polarized and the cross polarized fields is also investigated. The comparisons of the computed results of the presented formulations with the published results of some special cases confirm the accuracy of the presented analysis. [Copyright &y& Elsevier]

Abstract A full-wave analytical method using the addition theorems and Hertzian potential functions are used to compute the radar cross section of a sphere coated by several layers composed of common materials and metamaterials. The minimization and maximization of radar cross section of a perfectly electric conductor sphere with such coatings are realized in a frequency band-width and in a wide interval of angles. One of the novelities of this contribution is, taking into dispersion relations of physically realizable metamaterials. So that the optimization procedure for RCS reduction is applied due to the coefficients describing dispersion characteristics. The method of least square is used for the design of a class of radar absorbing materials. The minimization of the error functions are performed by the combination of genetic algorithm and conjugate gradient method. It is shown that the proposed method of computation of radar cross section and its extremization effectively leads to the design of dispersive and isotropic metamaterials for the realization of radar absorbing materials.