Frequency-scanned reflection gratings consisting of ring patches

Abstract

A periodic array of thin conducting ring patches etched on a dielectric substrate and placed over a ground-plane is investigated for the use as a frequency-scanned reflection grating (blazed grating). The theoretical analysis used is based on Floquet's theorem and the method of moments. Numerical examples are presented showing that frequency-scanned gratings can be designed to operate for circular polarisation with high blazing efficiency, i.e. with the property of efficiently scattering the power of an incident electromagnetic wave into the first order diffracted wave.