Abstract:

In this paper 2-2 composite transducers with both regular and irregular kerfs have been studied by using FEM and experimental methods. Undesirable lateral modes are shown in the electrical impedance curves of periodic 2-2 composites. These lateral modes are well suppressed in a 2-2 composite with irregular kerfs when the ceramic volume percentage is low. However, the beam pattern shows some degree of distortion. In order to restore the beam pattern, mirror symmetry is introduced into a 2-2 composite with irregular kerfs, and the beam pattern of these 2-2 composites has been experimentally measured and calculated using FEM. Excellent agreement has been achieved. As expected, when the system is more disordered, the lateral modes are well suppressed, but the beam pattern is poorly focused. On the other hand, when the system is more ordered, the lateral modes are poorly suppressed, but the beam pattern is more focused. A trade-off is a sequence of 3; in this case the lateral modes can be effectively suppressed, and the beam pattern is also well focused.