The evanescent waves in metallic strip gratings and complex structures in subwavelength regime

The paper investigates the formation of evanescent waves in metallic strip gratings on the Ag/ZnO/SiO2/Si structure with silver strips when TEz incident wave in the radiofrequency range was used. The Ag/ZnO/SiO2/Si structure was fabricated by vacuum thermal evaporation technique and Scanning Electron Microscopy was used to evidence its high quality structure with parallel silver strips of same width and thickness. Simulation of the evanescent wave formation at the edge of Ag strips, with thicknesses in the range of micrometers, was performed, before performing the test in the subwavelength regime by the mean of a new transducer improved with metamaterials lens. The generation in slits, in air, of the electric evanescent mode, when metallic strip grating was excited with a TEz polarized wave at a frequency of 474 MHz, was successfully demonstrated.