In the context of surface plasmon resonance (SPR) kinetic biochips, it is important to model the SPR phenomenon (i.e., extinction of reflectivity) toward biochip design and optimization. The Rouard approach that models reflectivity off a thin-film stack is shown to be extendable to any number of absorbing layers with no added complexity. Using the generalized Rouard method, the effect of SPR is simulated as a function of the wavelength for various metal thicknesses. Given an optimal metal thickness, the dependence of SPR on the angle of incidence and wavelength is also demonstrated. Such a model constitutes a potential basis for the efficient design and optimization of multidimensional sensors.