A time domain beamforming method of UWB pulse array

Abstract

The principle of space-time processing is discussed here after a realistic UWB pulse model introduced in the paper. The problem of realization of variable delay circuits is addressed. Delay line is not enough for accurately beam steering. A digital filter method by compensating channel dispersed delay for time domain beamforming is presented here. An ideal system with fractional sample delay hat occurs in insufficient sample of UWB pulse signal is not realizable. The two filter approaches involving FIR and allpass filter are given to approximate casual and stable system with the fractional delay. The Lagrange interpolation for FIR filter and complex cepstral computation for allpass filter are examined. A comparison of UWB pulse array directivity versus conventional phased array directivity has been done. The effect of different sampling rate and noise level is discussed. In the experiment, the FIR and allpass filter with a capability of accurate propagation delay compensation improved the beamforming performance remarkably. The results indicate the feasibility and effectiveness of the method.