We discuss the design of two complimentary media for analog detection of sources placed at subwavelength separation using time reversal of observed signals. We have used two metasurfaces composed of bianisotropic structures to code and decode the evanescent fields of the sources to propagating waves. In order to reduce losses and create a perfect focus, resonances are avoided to achieve negative index. We have studied various shapes such as, split ring resonators to determine the least lossy structure for time reversal. We have used simulations to study the behavior of permittivity and permeability values of these structures at various frequencies. Shape parameters such as size of the gap and thickness is being optimized to achieve refractive index of ± 1 at the same frequency and minimize losses in the metasurfaces.