Study on near field target detection and imaging by using flat LHM lens

The focus-scanning scheme with flat Left-Handed Metamaterial (LHM) lens provides new perspective for near field target detection and imaging. In this paper, concerning practical applications, we further investigate two representative models involving crack detection on the metal surface and the tumor detection in breast tissue. Numerical simulations with 2D FDTD method demonstrate that, when a 0.5 mm-thickness LHM lens being adopted, super-resolution is achieved for a tiny-size crack due to the contribution of evanescent waves; while a tumor cylinder with diameter of 2 mm in breast tissue can be detected by using a 6 cm-thick LHM lens. To improve the longitudinal resolution for the tumor detection, two-orthogonal scanning scheme is employed. Besides, it demonstrates that tissue heterogeneity with random variability of plusmn30% will affects the imaging performance to a limited extent. In the examination on influence factors of imaging resolution, the imaging resolution will become worse as the loss of the medium under detection or the depth of target inside the lossy medium increases.