Simulation study on the detection of size, shape and position of three different scatterers using Non-standard time domain time inverse Maxwell’s algorithm

Abstract

Inverse method has wide application on medical diagnosis where non-destructive evaluation is the key factor .Back scattered waves or echoes generated from the forward moving waves has information about its geometry, size and location. In this paper we have investigated how well different geometries of the object is determined from the back scattered waves by a high accuracy Non-Standard Finite Difference Time Inverse (NSFD-TI) Maxwell's algorithm and how the refractive index of the object plays a deterministic role on its size.

Supplementary document for High accuracy cross-sectional shape analysis by coherent soft X-ray diffraction - 4790761.pdf

“…S1 [2,3,[7][8][9]. In this report, two-layered rectangles are analyzed by CSDaVe, in addition to conventional ellipses, rectangles, and triangles [10][11][12]. At a minimum, CSDaVe's analysis is possible if the diffraction pattern can be calculated by RCWA without simulator power issues, and it can be assumed that the shape is one of these structures.…”

Electromagnetic Imaging of Two-Dimensional Geometries by Multipulse Interference Using the Inverse FDTD Method

“…The conventional phase interference technique [19] must detect both the scattered electric and magnetic fields in the entire space (all grid points), but this is the impractical measurement actually. To more closely mimic what might be experimentally observed, we employ a circular array of measurement points in common use [5,[15][16][17][18].…”

“…The crucial difference between the proposed method and the conventional interference technique [19] is the use of the pulse pair. The incident pulse should illuminate the object surface to detect the reflected wave from the surface, and thus the single directional pulse in the conventional method is not enough to accurately reconstruct the shape.…”

“…Using additional pulses in other directions would further improve the imaging quality, but would require more measurements in the observation step. To compare our imaging quality with the conventional interference technique [19], in Figure 3, we plot the square reconstruction with the original shape line using (a) our method and (b) the conventional method. As shown in Figure 3, our result accurately captures the size and boundary, whereas the conventional method merely reconstructs the rough shape.…”

“…Previous works successfully detected the position and size of the two-and three-dimensional objects [5][6][7][8][9], but the reconstructed geometries were unclear even for an object immersed in a uniform medium [12][13][14][15][16][17][18]. A comparatively successful imaging of the detailed geometry was demonstrated using phase interference with inverse FDTD simulations, in which the scattered field was calculated, and then using time reversal; the original shape was extracted from the interference patterns [19]. However this requires both the scattered electric and magnetic fields in the entire space, and it is difficult to clearly discern the original boundaries due to the continuities of electromagnetic fields unless the original shape is used in the visualization.…”