Wideband beamforming with broad nulls of nested array

A side lobe level constraints orthogonal method for wideband beamforming with broad nulls of harmonic nested array is proposed. Space-frequency structure based on nested array is applied. Nonuniform octave subband signals are implemented by harmonic nested array and general parameter filter banks with multirate method. The reference desired broad nulls pattern is designed with side lobe level constraints orthogonal method at the highest frequency bin. It is convenient to control side lobe level by this method. If we keep the side lobe levels within certain angle range low enough, it can be seen as a broad null within the frequency spans. Each subarray is operating with the lowest rate in parallel. Weightings and patterns are realized by IDFT and DFT. These contribute to decreasing the computational load significantly and improving the speed and performances as well. Simulations show that the proposed method is competent for broad nulls wideband beamforming.