Analyses of directivity function characteristics channel mismatch correction for DBF in subarray

We analyze the directivity functions of DBF in subarray under the ideal condition and with channel mismatch, and give the sum and difference directivity functions. We correct the reception channel mismatch by using the channel equalization method. The way, based on the principle of inverse filtering for recovering the ideal signals, can be realized both in time domain and in frequency domain. The method can correct the mismatch inside a channel and among channels, and is also suitable for both DBF in array element and DBF in subarray. Both of the analyses and the simulation results demonstrate that the method is fairly effective.