Dispersive FDTD modeling on near field imaging in multi-layer left-handed meta-materials at microwave frequencies

'Perfect' imaging in left-handed meta-materials (LHMs) is constrained by surface wave losses in near field. A multi-layer LHMs structure can be deployed to reduce the losses particularly in near field imaging. Furthermore, we demonstrate how to use a multiple-layer LHMs structure with variable gap distance to enhance near field image over large stack thickness in near field imaging at microwave frequencies. The theoretical prediction is verified with good agreement using a causal two-dimensional dispersive FDTD simulation.