This work presents the modeling and the comparison between two transducers developed for the thermoacoustic signal and imagery. The thermoacoustic imagery is a nondestructive testing technique in which a laser beam generates acoustic waves by thermoelastic effect. The two transducers have been studied with a view to increase the signal-to-noise ratio of the overall measuring channel: one of them with a direct transmission of acoustic waves between the sample and the piezoelectric ceramic, and the other with matching media between the sample and the piezoelectric. A modeling scheme of the transducers in the form of blocks is proposed. This approach is justified by the experimental measurements, particularly concerning the forecast of the resonant frequency and the matching impedance values.