“…Replace by and by , where and are, respectively, inductance and capacitance per unit length. Assuming that and stay constant in the limit, we arrive at the continuum dispersion relation (5) which is the exact dispersion relation for the scalar wave equation (6) In previous derivations [1], we started with (3), then posited a continuous function such that , expanded and in Taylor series about , and thereby derived precisely the same PDE model (6). The derivation of (6) as a continuum model of (3) on the basis of exact/approximate dispersion relations has its own utility, as we now show.…”