A Thin Reflective Diffraction Grating Employing Resonant Structures

Reflective diffraction gratings consist of a periodic three-dimensional structure that produces appropriate constructive and destructive interference in order to redirect an incoming wave as a function of frequency. Depending upon the angle of incidence, the thickness required for this structure can range from a fraction of a wavelength to several wavelengths. While such a thickness does not present a problem for optical applications, it can make the diffraction grating very bulky for radio applications, notably in the lower frequency bands. This communication presents a new thin diffraction grating, employing resonant structures, whose thickness is only 1/34th of a wavelength. Simulations and measurements are presented for a thin diffraction grating, designed to operate in the VHF band in unfavorable outdoor conditions.