Signal processing for wideband smart antenna array applications

In this article, we summarized the topics of array processing for wideband signals in smart antenna-based applications. For wideband beamforming, the TDF1B and FDFIB methods can provide the frequency-invariant beam-pattern over an arbitrarily wide bandwidth. The FDFIB method is applicable with arbitrary antenna arrays and suitable for switched beams and direction-finding approaches. The frequency-invariant beam-pattern can be designed with prescribed narrow main beam width and low SLL over a wide bandwidth by using two FDFIBs in a spatial interpolation process. For wideband DOA estimation, two main approaches based on the CSS method and beam-space processing has been introduced. The latest approach can provide lower resolution threshold, lower RMSE of estimate, and lower computational complexity. Finally, practical considerations in implementation of an antenna array regarding to array errors and mutual coupling have been considered. In the presence of array errors and mutual coupling, the performance of wideband DOA estimation is strongly degraded.