摘要
We propose a modification to the negative refractive index fishnet design and demonstrate numerically that this modification leads to an even lower refractive index resonance peak and higher gains compared to the fishnet design, this effect being sustained for design dimensions ranging from the nanometer up to the millimeter and for various materials. This modification, we called ‘bd design’, consists in a shift of the metallic arms to the extremities of the metallic slab, the structure remaining otherwise identical. We discuss the numerical comparison between the use of the fishnet design and the bd design, simulating three fishnet-based metamaterials presented in the literature and showing how a modification of these metamaterials to the bd design leads to improved performances. Finally, we present an explanation for the superior characteristics of the bd design.