Lattice Resonances in Double Comb Array

Lattice resonances in an infinite double comb array are analyzed. The problem was solved by the method of moments, Galerkine's scheme in which basis functions explicitly satisfy to the rectangular wedge condition. Also the Floquet theorem was applied to take into account the structure periodicity. H-type resonances were concerned. It was shown that except traditional resonances connected with the unit cell there are lattice resonances of an array type. For these resonances a new analytical formula which describes the resonant wave numbers was obtained. Also the resonant wave numbers versus geometrical parameters and resonant field distributions were calculated. The mode inter coupling phenomenon was found.