https://docs.lib.purdue.edu/nanopub/209/
"The Ag dielectric function in plasmonic metamaterials" by V. P. Drachev, Uday K. Chettiar et al.
Ag permittivity (dielectric function) in coupled strips is different from bulk and has been studied for strips of various dimensions and surface roughness....
dielectric functionplasmonic metamaterialsdrachevudaychettiar