Fast Multinull Steering of Antenna Array

In this letter, a fast multinull steering technique is demonstrated by a linearly polarized linear antenna array. The new technique is based on the electric fields generated by each antenna element on a far-field arc of the antenna array, which are extracted in advance by simulation or measurement. The power transmission efficiency is used as the performance index to control the pattern nulls. By solving a matrix eigenvalue equation, in which the matrix is made up by selecting the corresponding electric fields on different positions on the arc standing for the null directions, the eigenvector corresponding to the zero eigenvalue is identified and used as the optimized distribution of excitations (ODEs) for the antenna array. Single-null and multinull patterns are tested from the ODEs and the results indicate that the number and directions of the multiple nulls can be controlled in the elevation space. The simulated and measured 2-D null patterns are shown in good agreement.