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{{projectinfo|V&V|Computing Radar Cross Section Of Metallic Targets Using EM.Cube|ART RCS title.png|In this projectarticle, you will construct a center‐fed resonant dipole antennametallic target structures of different geometrical shapes are simulated using EM.Tempo, analyze it EM.Libera and visualize its near EM.Illumina, and far field characteristicsthe results are validated by the published data.|*PEC Objects[[EM.Tempo]]*Lumped Source[[EM.Libera]]*Port Definition[[EM.Illumina]]*Mesh DensityPerfect Electric Conductor*S/Z/Y ParametersPlane Wave Source*Radiation Pattern*Field Sensor Observable*EM.Grid *Cartesian and Polar GraphsRadar Cross Section|All versions|{{download|http://www.emagtech.com/downloads/ProjectRepo/EMTempo_Lesson1.zip EMTempo_Lesson1}} None }}

[[Image:ART RCS2.png|thumb|left|480px|Figure 2: Variation of normalized back-scatter RCS (σ/λ²) of a thin metal square plate of dimensions 0.3λ₀ × 0.3λ₀ 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 magenta symbols: simulated data using the finite element method (FEM) presented by Ref. [1].]]

[[Image:ART RCS3.png|thumb|left|480px|Figure 3: Variation of normalized back-scatter RCS (σ/λ²) of a thin metal square plate of dimensions 0.3λ₀ × 0.3λ₀ 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 magenta symbols: simulated data using the finite element method (FEM) presented by Ref. [1].]]

[[Image:ART RCS4.png|thumb|left|480px|Figure 4: Variation of normalized back-scatter RCS (σ/λ²) of a thin metal square plate of dimensions a × a as a function of k₀a (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 magenta symbols: measured data referenced by Ref. [2].]]

The next example involves a large square metal (PEC) plate of dimensions 5λ₀ × 5λ₀ illuminated by an obliquely incident, plane wave source with θ = 30° measured from the zenith. For this electrically large plate, the physical optics method yields very good results at the main laobe lobe and the first few side lobes. Figures 5 and 6 show the normalized bi-static RCS of the large plate as simulated by [[EM.Libera]] and [[EM.Illumina]]. The two figures correspond to the incident TMz and TEz polarizations, respectively. Note that the maximum RCS is observed at 30° as one would expect. At the grazing angles, one can see significant discrepancies between the asymptotic PO and full-wave Surface MoM results. For comparison, Figure 7 shows a reproduction of the physical optics results given by Ref. [3], which have been calculated analytically using a simple PO approximation of uniform surface currents on the metal plate.

[[Image:ART RCS6RCS7.png|thumb|left|480px|Figure 7: A reproduction of the results given by Ref. [3] for variation of normalized bistatic RCS (σ/λ²) of a large 5λ₀ × 5λ₀ metal square plate based on a simple physical optis optics approximation of uniform currents on the plate. The  TMx and TEx polarizations in this figure correspond to the TMz and TEz polarizations in Figure 5 and 6, respectively.]]

[[Image:ART RCS8.png|thumb|left|480px|Figure 8: Variation of normalized back-scatter RCS (σ/λ²) of a metal cube of dimensions a × a × a as a function of k₀a (normalized cube dimension or normalized frequency) for the case of a normally incident plane wave source, solid red line: [[EM.Libera]] results, solid blue line: [[EM.Tempo]] results, red magenta symbols: measured data given by Ref. [4].]]

Next, we examine scattering from a large metallic sphere. For this case, we consider a PEC sphere of radius 477.465 mm corresponding to k₀a = 10, at the frequency f = 1GHz. Figure 13 shows the triangular surface mesh of this sphere generated by the [[EM.Libera]] or [[EM.Illumina]] mesh generators. A mesh density of 100 samples/λ₀² has been used for this mesh. Figure Figures 14 and 15 show the bistatic RCS of the metallic sphere as a function of the elevation angle θ for the two cases of TMz and TEz polarizations, respectively. The two figures compare the results computed by [[EM.Libera]]'s surface MOM solver and [[EM.Illumina]]'s Physical Optics (PO) solverand compare them with the simulated results given by Ref. [6], which presents two sets of data, one based on the method of moments (MoM) and the other based on a hybrid PO/MoM/Fock technique. The two data sets in Ref. [6] are almost identical. Like in the previous example, physical optics predicts the RCS over the main beam (or maximum RCS angles) adequately; however, its accuracy degrades over the side lobes.[[EM.Libera]]'s results almost exactly match those of Ref. [6].

[[Image:ART RCS16.png|thumb|left|360px240px|Figure 16: Geometry of a metallic cylindrical rod with rounded ends.]]

[[Image:ART RCS17.png|thumb|left|360px240px|Figure 17: Surface triangular mesh of a metallic cylindrical rod with rounded ends.]]

[[Image:ART RCS18.png|thumb|left|360px240px|Figure 18: FDTD mesh of a metallic cylindrical rod with rounded ends.]]

Figures 20 19 and 21 20 show the computed bistatic RCS of the cylindrical rod as a function of the elevation angle when the target is illuminated from the bottom by a normally incident plane wave source. The two figures correspond to the bistatic RCS in the two principal planes YZ (φ = 90°) and ZX (φ = 0°), respectively. These figures compare the results simulated by [[EM.Libera]] and [[EM.Tempo]] with those reported in Ref. [7] based on a method of moments (MOM) formulation of bodies of revolution (BOR).

[[Image:ART RCS25.png|thumb|left|480px|Figure 25: Variation of normalized bistatic RCS (σ/λ²) of a long metallic cylindrical rod conesphere illuminated by a normally incident plane source with rounded ends TEz (horizontal) polarization as a function of elevation angle θ in ZX plane (φ = 0°), solid red line: [[EM.Libera]] results, solid blue line: [[EM.Tempo]] results.]]