Ismail, Taisir Hasan (1991) Null steering in phased and adaptive arrays by controlling the element positions. PhD thesis, King Fahd University of Petroleum and Minerals.
A new method for null steering in phased arrays by controlling the element positions is presented. This technique is studied both theoretically and experimentally for placing nulls in the radiation pattern to suppress interference and unwanted signals. The study shows the effectiveness of null steering to arbitrary directions while overcoming some of the limitations associated with other known techniques. The experimental results demonstrate the capability of this technique in forming nulls in the required directions. Many advantges can be achieved using this method. The phase shifters can be used solely for steering the main lobe towards the direction of the desired signal. This new technique allows the independent steering of the main beam and the nulls to arbitrary independent directions. It also possesses an even symmetry pattern cancellation which allows nulls to be imposed at symmetrical positions around the main beam. The position perturbations are symmetrical about the center of the array which results in reducing the amount of computation. In addition, if the number of jammers increases, then the formed pattern will be less sensitive to variation in element positions. This technique of null steering, based on the small element position perturbations, works satisfactorily as long as the nulls are imposed in the sidelobe region and the number of nulls is small compared to the number of elements. This technique is also capable of obtaining sidelobe cancellation and wide band signal rejection.
|Item Type:||Thesis (PhD)|
|Divisions:||College Of Engineering Sciences > Electrical Engineering Dept|
|Creators:||Ismail, Taisir Hasan|
|Committee Advisor:||Dawoud, Mahmoud M.|
|Committee Members:||Bettayeb, Mammar and Abdul-Jauwad, Samir H. and Ragheb, H. A. and Chaudhry, M. Aslam|
|Deposited By:||KFUPM ePrints Admin|
|Deposited On:||22 Jun 2008 16:54|
|Last Modified:||25 Apr 2011 10:00|
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