Formulas for the Number of Surface Waves on Layered Structures

Closed-form expressions are derived for the number of surface waves propagating along a general multilayered structure with media having positive material parameters. The expressions shown here are also useful for the efficient numerical determination and ordering of the cutoff frequencies of surface waves on multilayered structures. The presented formulas are simple but exact. Validation is provided with full-wave dispersive analyses of several types of layered structures.