Full electrical characterization of aperiodic acoustic gratings by an enhanced delta-function model: theory and experiment.

We derive the admittance of an aperiodic one-dimensional acoustic grating with acoustically matched boundaries using an enhanced delta-function model combined with the Green's function approach. The expression obtained is compared with the classical delta-function model and with electric back reflection measurements on a linearly chirped bulk acoustic grating with matched boundaries formed in LiNbO3 by domain inversion and excited in "crossed-field" scheme. The agreement between calculated and measured results is excellent.