Superresolution of near or far field coherent targets using aperiodic antenna arrays

A technique for obtaining high resolution images of point-like coherent targets using aperiodic antenna arrays is developed. Whereas existing superresolution techniques can be used to image coherent targets located only in the far field of periodic receiving arrays, this technique can be used to obtain high resolution images of targets in the near field also. The key to this technique is the use of multiple transmitters. Completely correlated (coherent) targets are decorrelated by transmitting sequentially from different locations, thereby enabling the use of modern superresolution techniques to estimate the target locations. An expression for estimating the variance of the target locations is derived, and is verified by empirical methods. For the same amount of transmitted power and the same number of receivers, this variance is shown to be an order of magnitude smaller than that of existing superresolution techniques. The practicality of this technique is demonstrated with experimental microwave data.