Scattering from General Periodic Screens.
Abstract
The study of the interaction of waves with periodic structures dates to the late eighteenth century when diffraction gratings were used to separate white light into its spectral orders. At longer wavelengths--from the microwave to the infrared--the shape of the metallic grating, i.e., patch, within each periodic cell characterizes the spectral response of the screen. For patch sizes on the order of the excitation wavelength, a stopband is produced, allowing the periodic screen to act as a filter to the incident field. Applications range from satellite reflector antenna systems to solar collectors, with interesting natural occurrences discovered in the optics of insect compound eyes. This report considers an analysis of periodic screens which allows the study of arbitrarily shaped patches along with the cascading of the patch surfaces with multiple dielectric layers. The formulation is presented for screens which lie between surfaces of a constant variable in the separable rectangular, cylindrical, and spherical coordinate systems. A numerical solution using an iterative technique is outlined for the equations formulated. The patches may be perfectly conducting or lossy to account for resistive materials and the loss associated with metals at infrared wavelengths.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 01, 1986
- Accession Number
- ADA176405
Entities
People
- Raj Mittra
- Thomas Cwik
Organizations
- University of Illinois Urbana–Champaign