The first target to be simulated is a small thin metal (PEC) plate of dimensions 0.3λ<sub>0</sub> × 0.3λ<sub>0</sub>, where λ<sub>0</sub> is the free space wavelength. The backscatter RCS of this target is computed first using [[EM.Libera]]'s Surface MoM simulation engine and then using [[EM.Tempo]]'s FDTD engine. To calculate the backscatter RCS as a function of elevation angle θ, we ran an angular sweep of θ in both MoM3D and FDTD modules from θ = 180º (corresponding to a downward, normally incident, plane wave source) to θ = 90º (corresponding to a lateral, horizontally incident, plane wave source) with a step of 5 degrees. Figures 2 and 3 show the simulation results obtained from [[EM.Cube]]'s MoM3D and FDTD simulators and compare them to the results obtained using the finite element method (FEM) given by Ref. [1]. Both theta (TMz) and phi (TEz) polarizations are considered, and the RCS results are plotted in Figures 2 and 3, respectively. Two sets of FDTD data are presented in these figures, one for a planar PEC square of zero thickness and one for a thin metal plate of thickness 0.01λ<sub>0</sub>. It can be seen that the infinitesimally thin planar object in FDTD predicts slightly larger RCS than the actual values.
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[[Image:ART RCS1.png|thumb|left|360px|Figure 1: Geometry of a metal plate and its coordinate system..]]
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[[Image:ART RCS2.png|thumb|left|480px|Figure 2: Variation of normalized back-scatter RCS (σ/λ<sup>2</sup>) of a thin metal square plate of dimensions 0.3λ<sub>0</sub> × 0.3λ<sub>0</sub> as a function of elevation angle θ for the case of an incident TMz (Eθ) polarization, solid red line: [[EM.Libera]] results, solid blue line: [[EM.Tempo]] results with a zero-thickness plate, solid green line: [[EM.Tempo]] results with a 0.01λ0 thick plate, red symbols: simulated data using the finite element method (FEM) presented by Ref. [1].]]
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[[Image:ART RCS3.png|thumb|left|480px|Figure 3: Variation of normalized back-scatter RCS (σ/λ<sup>2</sup>) of a thin metal square plate of dimensions 0.3λ<sub>0</sub> × 0.3λ<sub>0</sub> as a function of elevation angle θ for the case of an incident TEz (Eφ) polarization, solid red line: [[EM.Libera]] results, solid blue line: [[EM.Tempo]] results with a zero-thickness plate, solid green line: [[EM.Tempo]] results with a 0.01λ0 thick plate, red symbols: simulated data using the finite element method (FEM) presented by Ref. [1].]]
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Figure 2: Variation of normalized back-scatter RCS (σ/λ<sup>2</sup>) of a thin metal square plate of dimensions 0.3λ<sub>0</sub> × 0.3λ<sub>0</sub> as a function of elevation angle θ for the case of an incident TMz (Eθ) polarization, solid red line: [[EM.Libera]] results, solid blue line: [[EM.Tempo]] results with a zero-thickness plate, solid green line: [[EM.Tempo]] results with a 0.01λ0 thick plate, red symbols: simulated data using the finite element method (FEM) presented by Ref. [1].
Figure 3: Variation of normalized back-scatter RCS (σ/λ<sup>2</sup>) of a thin metal square plate of dimensions 0.3λ<sub>0</sub> × 0.3λ<sub>0</sub> as a function of elevation angle θ for the case of an incident TEz (Eφ) polarization, solid red line: [[EM.Libera]] results, solid blue line: [[EM.Tempo]] results with a zero-thickness plate, solid green line: [[EM.Tempo]] results with a 0.01λ0 thick plate, red symbols: simulated data using the finite element method (FEM) presented by Ref. [1].
Figure 4: Variation of normalized back-scatter RCS (σ/λ<sup>2</sup>) of a thin metal square plate of dimensions a × a as a function of k<sub>0</sub>a (normalized plate length or normalized frequency) for the case of a normally incident plane wave source, solid red line: [[EM.Libera]] results, solid blue line: [[EM.Illumina]] (PO) results, red symbols: measured data referenced by Ref. [2].