Adaptive Processing at Multiple Frequencies Using the same Antenna Array Consisting of Dissimilar Non-uniformly Spaced Elements over an Imperfectly Conducting Ground

In this paper, an adaptive processing is carried out simultaneously at multiple frequencies using the same antenna array consisting of non-uniformly spaced dissimilar antenna elements. The antenna array may not be deployed in free space but may be located over an imperfect ground plane. First to correct for the various electromagnetic effects affecting the array performance, an electromagnetic transformation technique is described that can compensate for the various coupling effects in the non-planar array consisting of non-uniformly spaced dissimilar antenna elements operating over an imperfect ground. Then, a direct data domain least squares method is used to extract the signal-of-interest (SOI) in the presence of fluctuating jammer and clutter simultaneously at multiple frequencies, using a single snap shot of the data. In this procedure there is no need to have any information about noise or clutter, whatsoever.