Broadband nearfield beamforming using a simple recursive algorithm

The authors extend their design methodology for a far-field frequency invariant array to the near-field frequency invariant array design using a radial pattern transformation. This extension is suitable for an arbitrary desired near-field pattern, and particularly leads to an array with the minimum number of sensors required to avoid spatial aliasing. The feasibility of the design procedure is shown by the superposition of the patterns at the design and intermediate frequencies.