Accession Number : ADA293685

Title :   Two-Dimensional Finite Difference Time Domain (FD-TD) Model of Electromagnetic (EM) Scattering From a Buried Rectangular Object.

Descriptive Note : Final rept. Jun 93-Jun 94,

Corporate Author : ARMY RESEARCH LAB ABERDEEN PROVING GROUND MD

Personal Author(s) : Korjack, Thomas A.

PDF Url : ADA293685

Report Date : FEB 1995

Pagination or Media Count : 36

Abstract : A two-dimensional transverse-magnetic (TM) electromagnetic (EM) scattering problem from buried dielectric objects due to a Gaussian pulse is numerically solved using the Finite Difference Time Domain (FD-TD) method with absorbing boundary conditions via Maxwell's equations. The scatterers are rectangular cross sections in a multilayer media; the Gaussian pulse is reflected into a lossy earth by a finite, 450 plate that is part of the detector that receives the EM signal. Spatial distributions of electric field components are calculated over time for single and multiple land scatterers (mines). The scattered fields gradually diminish with time and are then eventually dissipated. Carpet plots are illustrated to depict the spatial distributions of the scattered field component at comparative time steps for one, two, and three distinct scatterers or land mines within the lossy media. Results clearly illustrate the typical wave patterns expected under the simulated conditions as presented in this report - i.e., conductivity (s) for the air is 0, conductivity for the earth is 0.01, conductivity for the grass is 0.005, and conductivity for the mines are 0, 0.02, and 0.008; permeability values ranged from 1 for air, 9 for earth, 5.5 for grass, and 2.3, 5.6, and 23.0 for the mines, respectively. Numerical analysis indicates that the difference of scattered signals between single and multiple scatterers are considerably obvious from the point of view of both time domain and frequency domain. (AN)

Descriptors :   *ELECTROMAGNETIC SCATTERING, *FINITE DIFFERENCE THEORY, *TIME DOMAIN, MATHEMATICAL MODELS, COMPUTERIZED SIMULATION, FOURIER TRANSFORMATION, SPATIAL DISTRIBUTION, TWO DIMENSIONAL, NUMERICAL ANALYSIS, DIELECTRICS, ELECTRIC FIELDS, ELECTRICAL CONDUCTIVITY, MATHEMATICAL PROGRAMMING, ELECTROMAGNETIC RADIATION, CROSS SECTIONS, RECTANGULAR BODIES, BURIED OBJECTS, MAXWELLS EQUATIONS, PERMEABILITY(MAGNETIC), FREQUENCY DOMAIN, LAND MINES, LAND AREAS.

Subject Categories : Electricity and Magnetism
      Operations Research
      Radiofrequency Wave Propagation

Distribution Statement : APPROVED FOR PUBLIC RELEASE