Efficient Computation of Periodic Green's Functions with Application to Grating Structures.
ILLINOIS UNIV AT URBANA COORDINATED SCIENCE LAB
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It is shown tht electromagnetic scattering from periodic structures may be formulated in terms of an integral equation that has its kernel a periodic Greens function. The periodic Greens function may be derived from two points of view as a response to an array of linepoint 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.
- Electricity and Magnetism