Refocusing of backscattered microwaves in target detection by using LHM flat lens

When microwave emitted from a point source is focused on a target by using a left-handed metamaterial (LHM) flat lens, microwave backscattered from the target will be refocused by the LHM lens in the vicinity of the point source. Numerical simulations with two-dimensional (2D) finite-difference time-domain (FDTD) method demonstrate that, even for flat LHM lens of material losses to the order as that reported in some LHM microwave experiments and simulations, the refocusing of backscattered microwave will yield a sub-wavelength lateral resolution and remarkable enhancement of the backscattered microwave, which will benefit the detection and imaging of small target.