Beamforming of UWB pulse array and its implementation

This paper firstly introduces a realistic ultra-wideband (UWB) pulse model and discusses the principle of sensor array beamforming for UWB pulse signals. Then the differences between a UWB pulse array and narrowband sinusoidal array are studied. Based on it, the problem of realizing a digital and applicable variable delay circuit (VDC) to compensate the channel propagation delay accurately for UWB pulse array beamforming is addressed. In our work, fractional sample delay compensation filters (FDCF) are combined with delay lines to build up accurate VDCs. As a result, the Lagrange interpolation method based on maximally flat criterion is found to be most suitable for the fixed beam steering; and Farrow structure is recommended to satisfy the need of rapid beam adjustment. In the simulation experiments, two kinds of directivity pattern for an UWB pulse array are studied and compared with that of sinusoidal array. The effectiveness of the presented scheme is verified by the simulation results, which show that the VDC implementation by digital lines and FDCF can remarkably improve the performance of the directivity patterns of UWB pulse array especially for the system with low sampling rate.