Consideration is given to a microscale structure consisting of a thin porou
s medium filled with interstitial fluid or a microscale regime with binary
species of atoms. An example is a cellular membrane. This paper treats a on
e-dimensional model consisting of atoms of heavier mass M alternating with
atoms of lighter mass m arranged in a series. Like photons, elastic vibrati
ons of atoms or phonons propagate as waves. The problem of phonon transport
, referring to heat conduction in the microscale regime, is formulated in t
erms of the displacements of atoms from their equilibrium positions. With t
he displacements treated as a wave motion, the frequency-wave number relati
onship for the heterogeneous-atomic membrane is obtained. Two modes of wave
transport are obtained and their roles in phonon transport are discussed.