Low-Complexity DFT-Based Multibeamforming Arrays with Configurable Beam Profiles

A low-complexity multibeamforming scheme for uniform linear arrays is proposed based on warped and approximated discrete Fourier transform (DFT), albeit in the spatial domain. Conventional DFT- and approximated-DFT-based multibeamformers provide a low-complexity alternatives to produce multiple simultaneous beams with fixed beam profiles. The proposed approach aims to produce configurable (i.e., steerable) multibeam profiles using the warped DFT. Design examples are presented for an 8-element uniform linear array verifying, 81% and 18 % reduction in multiplier and adder complexities, respectively, when compared to a conventional narrowband multibeamformer having dedicated steering weights for each beam. Three system configurations are proposed using approximations for warped transform and the DFT. Hardware designs implemented on Xilinx Ultrascale KCU105 FPGA device verify 5.2 ns best case critical path delay.