Improved broadband frequency invariant beamforming algorithm with sensor delay lines

The design of frequency invariant beamformer (FIB) with tapped delay lines always suffers from heavy hardware load and high computational complexity. To alleviate this problem, a novel FIB algorithm with sensor delay lines (SDL) is proposed. Based on the SDL wideband model, the FIB design utilizes the constrained optimizing with and without interfering signals. The optimizing criterion of the proposed algorithm is minimizing the designed sidelobe level utmost while keeping the look direction response close to the unity response and the constraints of the sidelobe level, mainlobe width, spatial response variation (SRV) and so on. The constrained optimizing formula can be solved with interior-point method after being reformed to the form of standard second order cone programming (SOCP). The simulations illustrate that the beampattern with the frequency invariance in the whole field of view can be obtained, the convergence speed of the proposed method is faster and the computational complexity is lower.