Electromagnetic Time-Reversal Imaging Using Grouped Sub-Arrays for Resolution Enhancements

Abstract

A new time-reversal (TR) imaging method using grouped sub-arrays for resolution enhancements is presented in this work. The method gives the image of the searching space for each target or scattering center at its own optimum instant, in contrast to the traditional TR imaging method that shows a snapshot of the whole domain at a specified instant. By introducing a grouping scheme that divides the time-reversal mirror (TRM) as many sub-TRMs, resolution enhancements in both crossrange and co-range directions are realized by means of destructive multiplication and incoherent superposition of the normalized sub-TRM imaging signals at nontarget positions. The present method permits all targets or scattering centers to be rendered at equal visibility, and has no requirement on the number of transmitters. Several simulation examples are provided to examine the performance of the proposed method.