This paper proposes a digital amplitude-phase weighting array based a minimum variance multi-frequency distortionless restriction (MVMFDR) to aviod the frequency band signal distortion in digital beamformer and too short time delay line (TDL) requirement in analoge wideband TDL array.
Cite
@article{arxiv.1005.3350,
title = {Minimum Variance Multi-Frequency Distortionless Restriction for Digital Wideband Beamformer},
author = {Yipeng Liu and Jia Xu and Qun Wan and Yingning Peng},
journal= {arXiv preprint arXiv:1005.3350},
year = {2011}
}