In superconductorsemiconductorsuperconductor (SuSmSu) junctions with superlattice structure, differential resistance as a function of voltage shows oscillatory behavior under the irradiation of radio-frequency (rf) waves with specific frequency regardless of the superconducting materials and the junction geometries. We interpret quantitatively this newly discovered phenomenon in terms of the coupling of superconducting quasiparticles with long-wavelength acoustic phonons indirectly excited by the rf waves. We propose that the strong coupling causes the formation of novel composite particles which we named Andreev polarons.