Engineering topics

Brand, J. C.

Publications and source records attributed to Brand, J. C..

3 records

NASA NTRS1985

The application of contraction theory to an iterative formulation of electromagnetic scattering

Contraction theory is applied to an iterative formulation of electromagnetic scattering from periodic structures and a computational method for insuring convergence is developed. A short history of spectral (or k-space) formulation is presented with an emphasis on application to periodic surfaces. To insure a convergent solution of the iterative equation, a process called the contraction corrector method is developed. Convergence properties of previously presented iterative solutions to one-dimensional problems are examined utilizing contraction theory and the general conditions for achieving a convergent solution are explored. The contraction corrector method is then applied to several scattering problems including an infinite grating of thin wires with the solution data compared to previous works.

Brand, J. C.↗

NASA NTRS1985

On the convergence of an iterative formulation of the electromagnetic scattering from an infinite grating of thin wires

Contraction theory is applied to an iterative formulation of electromagnetic scattering from periodic structures and a computational method for insuring convergence is developed. A short history of spectral (or k-space) formulation is presented with an emphasis on application to periodic surfaces. The mathematical background for formulating an iterative equation is covered using straightforward single variable examples including an extension to vector spaces. To insure a convergent solution of the iterative equation, a process called the contraction corrector method is developed. Convergence properties of previously presented iterative solutions to one-dimensional problems are examined utilizing contraction theory and the general conditions for achieving a convergent solution are explored. The contraction corrector method is then applied to several scattering problems including an infinite grating of thin wires with the solution data compared to previous works.

Brand, J. C.↗

NASA NTRS1983

Development of improved analytical models for mesh reflector surfaces

Several methods for computing the reflection coefficients from mesh surfaces are discussed. Some methods mentioned have severe limitations, and the spectral approach appears to be the most attractive alternative. In spite of some inherent problems, the solutions obtained with this method will offer not only the reflection coefficients but also the currents carried on the mesh. This would allow separation of the power lost to resistive terms from that due to transmission loss. Overall, good results and rapid convergence should be obtained from this method when proper care is applied.

Brand, J. C.↗