A multiple V-groove guide is rigorously analyzed with the Fourier transform and mode matching. A new rigorous dispersion relation is presented in fast-convergent series, which is efficient for numerical calculation. The propagation characteristics and their H-2-field distributions are presented in terms of the double and triple V-groove guides. A closed-form dispersion relation based on a dominant-mode approximation is shown lo be accurate for most practical applications. (C) 2001 John Wiley & Sons, Inc.