An adaptive weighting algorithm is proposed based on the adaptive null beamforming technology

which can be used for forming arbitrary sidelobe shape beam patter n for arbitrary structure arrays

considering the effect of element directivity at the same time.Three steps are given to implement the new algorithm;by presetting the sidelobe shape and sidelobe level and having cycle steps

the real beam patter n will close to the presetting one.The new algorithm is applied to arrays such as uniform linear array and parabola array as examples and compared with Dolph-Chebyshev ( DC ) weighting algorithm

and all the examples have the desired results.It is shown that the element directivity has little effect on the beamforming by the new algorithm and that the new algorithm can eliminate the effect of the broadband element directivity in broadband beamforming.