Abstract
A survey is given of the literature concerning the scattering properties of infinite plane wire gratings when illuminated by plane electromagnetic waves. As an introduction, a summary of the applications of wire gratings is included. A description is given of some alternative methods of treating the scattering problem, with particular reference to the application of Green's function to the single cylinder and its application to the plane grating. The literature concerned with multiple grating configurations is also surveyed. A polarisation cascade matrix is derived which describes the transmission of a normally incident elliptically polarised wave through a grating of parallel wires whose angle is arbitrary. The terms of the matrix contain the well-established complex reflection and transmission coefficients for a linearly polarised plane wave incident upon a grating. Hence the matrix can be adapted for gratings of strips or Wires of non-circular cross-section. The product of a series of matrices representing a series of gratings whose wires are at different angles to a fixed direction gives the total complex transmission and reflection coefficients. The results are shown to be in agreement with previously published work on a double grating system and experimentally verified for configurations of two and five gratings. These results confirm that such a series of gratings can be used to design either broad-band polarisation rotators for linear polarization, or broad-band circular or elliptical polarisers or analysers. A sharp resonance reflection condition when gratings are separated by approximately half a wavelength can also be used in the design of frequency filters.