IMAGING OF OBJECTS THROUGH LOSSY LAYER WITH DEFECTS

—The imaging method when a lossy layer (e.g.,a defected metallic slab or a plasma layer) is present between the target and the sensor is demonstrated using the concept of active left-handed material (LHM). The effect of the lossy layer to the reflection coefficients measured by the receiver can be cancelled by imaginatively adding an active LHM layer,which has a same thickness as the lossy layer but an opposite sign of the constitutive parameters. Therefore,the updated reflection coefficients obtained after this data process look like the lossy layer has been removed,which leads to a significant improvement of the target imaging. When the lossy layer is inhomogeneous due to the existence of small defects,we use a homogenization procedure based on the Drude model to characterize its effective constitutive parameters. Our simulation examples shows the effectiveness of the proposed method.