An FIR Filter Based Wideband Digital Array Mutual Coupling Estimation Method for High Accurate Beamforming

In this letter, an FIR filter based wideband digital array mutual coupling parameter estimation method (FBWMCE) is proposed. FBWMCE establishes a frequency-dependent model of mutual coupling parameters using FIR filters. By estimating the coefficients of FIR filters associated with the mutual coupling parameters and obtaining accurate estimates at any frequency within the passband, FBWMCE effectively mitigates the impact of mutual coupling on wideband beamforming performance. Simulation results demonstrate that FBWMCE achieves a rootmean-square error of 0.18 in mutual coupling estimation under an SNR of 10 dB. Furthermore, after applying FBWMCE for decoupling, there is a remarkable reduction in wideband multibeam pointing error from 3° to 0.3°.