I. Introduction
The dispersion characteristics of elastic guided waves have attracted considerable attention and brought out many useful applications, such as seismic waves analysis [1]–[6], underwater acoustics [7]–[9], nondestructive evaluation [10]–[13], and biomedical applications [14]–[17]. Following the different implementations of signal recording, the dispersion characteristics extraction methods can mainly be classified into two categories, i.e., single-channel processing [7]–[9], [11], [14] and multichannel processing [4], [10], [15], [18]–[20].