An analytical approach based on the parametric representation of the wave propagation in non‐uniform media was considered. In addition to the previously developed theory of parametric antiresonance describing the field attenuation in stop bands, in the present paper, the behaviour of the Bloch wave in a transmission band was investigated. A wide class of exact solutions was found, and the correspondence to the quasi‐periodic Floquet solutions was shown. Copyright © 2012 John Wiley & Sons, Ltd.