Avoiding diffraction grid effect in ultrasonic fields of 1-3 PZTpolymer piezocomposite transducers

摘要

Improvement of sensitivity in ultrasonic fields of piezocompositentransducers is limited because of diffraction effects arising from thenperiodic structure. We present a theoretical and experimental study ofnultrasonic fields of 1-3 PZT polymer piezocomposite transducers. Thenrelation between the composite grid periodicity and the wavelength isncritical in order to obtain a far field similar to that of homogeneousntransducers. If diffraction grid effect is present, it results in annimportant energy loss in the higher diffraction orders. These highernorders perturb the central field of the transducer because of multipathncontributions to the main lobe caused by reflections from the boundariesnof the test sample