A theoretical comparison of the optical and electronic properties of metallic nanostructures characterized by complementary geometries is proposed in this work. Periodic array of nanoparticles on glass substrate and nano-holes on metal substrate have been analysed performing finite element analysis with the RF Module of COMSOL Multiphysics. Single and array of gold nanostructures have been studied, exploring several key parameters responsible for sensitivity enhancement of LSPR sensors. The analysed structures show a minimum in their spectral transmittance, confirming that regular arrays of nano-holes in thin metal films as well as nano-disk arrays may support localized surface plasmon resonance.