Analysis of Influence of Group Delay Distortion on Combining SNR of Antenna Arraying

The influence of the distributing difference of group delay distortion between channels of antenna arraying on the SNR of the combining signal is analyzed quantificationally. Firstly, the mathematic model of group delay distortion of the antenna arraying channel is established, and based on the mathematic model, a simulate model is established by using the fractional delay all-pass filter to compensate the group delay all-pass filter, and it enables the simulate model to simulate the characteristic of group delay distortion of the mathematic model accurately. Secondly, two theoretical formulas of the combining loss for single frequency signal and wideband signal are theoretically derived. Finally, the correctness of the theoretical analysis is verified by simulation experiments. Research shows that the more the antenna number, the wider the bandwidth and the larger the difference of group delay distribution, the greater the combining loss is. As for a large-scale and broadband antenna arraying which has 100 antennas and a bandwidth of 1 GHz, when the standard deviation of maximum group delay distortion of the band edge is greater than 4 ns, the combining loss will be greater than 0.5 dB.