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Title: A Multi-Perspective Examination of the Physics of Electromagnetic Radiation
Abstract: Three different perspectives of electromagnetic radiation are presented here. The first employs the electric field kink model, the second is based on a technique called FARS(Far-Field Analysis of Radiation Sources), and the third uses time-domain solutions obtained from the TWTD (Thin-Wire Time Domain) model. The kink model demonstrates qualitatively that radiation is produced by "wriggling" a charge. The latter two provide more quantitative results, showing that radiation for a straight dipole can come not only from the source region and ends but also from along its length.
Author(s): E.K. Miller, G.J. Burke
File Type: Journal Paper
Issue:Volume: 16      Number: 3      Year: 2001
Download Link:Click here to download PDF     File Size: 1369 KB

Title: Debye Constants for Biological Tissues From 30 Hz to 20 GHz
Abstract: Debye modeling for the dielectric properties of dispersive materials facilities its incorporation into the FDTD formulation. This paper generates a comprehensive list of multi-term Debye coefficients for 16 biological tissues. A numerical technique is developed to accurately fit one, two, and three-term Debye equations with the published experimental data of biological tissues. Using the generated coefficients, the reconstructed complex permittivity is shown to be in excellent agreement with the corresponding measured data over the frequency rang 30 Hz to 20 GHz.
Author(s): Mohamed A. Eleiwa, Atef Z. Elsherbeni
File Type: Journal Paper
Issue:Volume: 16      Number: 3      Year: 2001
Download Link:Click here to download PDF     File Size: 758 KB

Title: Implementing the Parallel Approxmate Schur Complement Preconditioner
Abstract: A modified implementation of Saad's parallel approximate Schur complement preconditioner is presented that is shown to be faster than the original algorithm. This is evaluated for the solution of large sparse matrices as generated by the finite element time domain method. Results indicate that the preconditioner scales well with an increase in processors and problem size.
Author(s): D.H. Malan, A.C. Metaxas
File Type: Journal Paper
Issue:Volume: 16      Number: 3      Year: 2001
Download Link:Click here to download PDF     File Size: 356 KB

Title: Hybrid Integral Equation and Finite Difference Method for Low-Frequency Electric Induction
Abstract: Recently developed fast integral equations solution methods allow for the treatment of electrostatic problems involving perfect conductors of complicated shape. Using the precepts of Stevenson's method, external electrostatic solutions can be used in the solution of internal low frequency electric induction problems in electrically small isolated compact conducting bodies. A precorrected FFT algorithm is implemented to solve the electrostatic problem of an isolated human body situated in an external field. The resulting induced fields. It is shown that the resulting hybid cody produces results that are in excellent agreement with those produced by other methods, while being significantly more effiecient in terms of computer memory and time resources
Author(s): Trevor W. Dawson, Sanjay Velamparambil, Maria A. Stuchly
File Type: Journal Paper
Issue:Volume: 16      Number: 3      Year: 2001
Download Link:Click here to download PDF     File Size: 1015 KB

Title: The Electrically Small Dipole Loop
Abstract: A square loop, with feed at the center of one side, can be combined with a dipole, where the dipole is parallel with the loop axis, and shares the feed point; see Fig. 1. With the dipole length twice the loop side, there will be a frequency where the dipole reactance and loop reactance are equal and opposite. It has been suggested [1,2] that this loop dipole together with a second loop dipole fed 90 deq. out of phase provides broadband performances, in fact a Q equal to zero. The plane of the second loop dipole is normal to the plane of the first loop dipole. Because stored energy is an inevitable feature of electrically small antennas, the loop dipole is examined to determine bandwidth capabilities
Author(s): R.C. Hansen
File Type: Journal Paper
Issue:Volume: 16      Number: 3      Year: 2001
Download Link:Click here to download PDF     File Size: 184 KB