Adaptive sidelobe nulling using the positions of selected elements of the phased antenna array

In order to eliminate the effect of clutter or jamming interference signals in the phased antenna array and, consequently, increase the signal-to-noise ratio, the sidelobe level of the antenna pattern should be made zero in the direction of arrival of these signals. The paper presents a new method for forming nulls in the directions of interference signals by controlling the positions of selected elements of the antenna array and, in turn, reducing the number of mobilized elements of the array. The technique involves two steps. In the first step, the contribution of each element's position perturbation to the null location is evaluated using the linearized method of small phase perturbations (Steyskal, H. 1983; Ismail, T. and Dawoud, M., 1991). The second step is used to select the elements of the array which contribute the most to the null locations. Based on this selection, the new positions of the selected elements are calculated using a nonlinear programming technique (Chiba, I. and Mano, S., 1991). The results demonstrate the capability of this technique to form nulls in the required directions.