This paper includes a brief introduction on surface plasmon resonance's (SPRs) theory, principle, and application, followed by describing the utility of metamaterials for this sensing paradigm. The bimetallic layers of gold and silver are crucial for SPR sensing, which is detailed. Finally, the matrix method for the calculation of reflectance for multiple layers is explained. The structures along with the corresponding graphs are discussed, including what happens when a metamaterial is used between two metal layers is derived. © 2001-2012 IEEE.