Accession Number : ADA184853

Title :   Efficient Computation of Periodic Green's Functions with Application to Grating Structures.

Descriptive Note : Technical rept.,

Corporate Author : ILLINOIS UNIV AT URBANA COORDINATED SCIENCE LAB

Personal Author(s) : Jorgenson, Roy ; Mittra, Raj

PDF Url : ADA184853

Report Date : Aug 1987

Pagination or Media Count : 90

Abstract : It is shown tht electromagnetic scattering from periodic structures may be formulated in terms of an integral equation that has its kernel a periodic Green's function. The periodic Green's function may be derived from two points of view: as a response to an array of line/point sources (spatial domain) or as a response from a series of current sheets (spectral domain). These responses are a Fourier transform pair and are slowly convergent summations. The convergence problems in each domain arise from unavoidable singularities in the reciprocal domain. A method is discussed to overcome the slow convergence by using the Poisson summation formula and summing in a combination of spectral and spatial domains. A parameter study is performed to determine an optimum way to weight the combination of domains. Simple examples of scattering from a one-dimensional array of strips and two-dimensional array of plates are used to illustrate the concepts.

Descriptors :   *ELECTROMAGNETIC SCATTERING, GREENS FUNCTION, PERIODIC VARIATIONS, ARRAYS, BANDS(STRIPS), KERNEL FUNCTIONS, INTEGRAL EQUATIONS, FOURIER TRANSFORMATION, POISSON EQUATION, GRATINGS(SPECTRA), POISSON EQUATION, METHOD OF MOMENTS, COMPUTATIONS, COMPUTER APPLICATIONS

Subject Categories : Electricity and Magnetism

Distribution Statement : APPROVED FOR PUBLIC RELEASE