Bloch wave – MoM method the wave numbers in any of the 3 periodic coordinate directions. This can happen for example when the free space wavelength exactly equals the lattice spacing. This is a statistically rare occurrence in computational practice and corresponds to a propagation anomaly similar to a Wood's reflection anomaly for gratings. To compute bands of the crystal (i.e. "k"-"k" diagrams), successive values of frequency ("k") are tried - in conjunction with pre-selected values of propagation constant ("k") and propagation direction (θ & φ) - until a combination is found which drives the determinant of the matrix to zero. Equation (4.2) has been
Propagation constant of transmission lines, the term transmission coefficient has a different meaning despite the similarity of name: it is the companion of the reflection coefficient. The propagation constant, symbol formula_1, for a given system is defined by the ratio of the complex amplitude at the source of the wave to the complex amplitude at some distance "x", such that, Since the propagation constant is a complex quantity we can write: where That "β" does indeed represent phase can be seen from Euler's formula: which is a sinusoid which varies in phase as "θ" varies but does not vary in amplitude because