PERFORMANCE OF A LEAKY-WAVE TRANSDUCER IN A LAYERED SUBSTRATE COMPOSED OF A THIN PIEZOELECTRIC PLATE AND A THIN GLASS PLATE

A leaky wave interdigital transducer on a layered substrate composed o f two thin plates, a piezoelectric ceramic thin plate and a glass thin plate, is described. The transducer has the function of multiple-mode operation for underwater ultrasound, while retaining sufficient mecha nical strength. The calculated results of the phase velocities are con firmed experimentally, including the case of using only a piezoelectri c ceramic plate as a substrate. The calculated electromechanical coupl ing constant and the mode conversion ratio obtained from the phase vel ocities under two kinds of electrical boundary conditions are also pre sented along with the experimental results of this type of transducer. The combination of a piezoelectric ceramic plate and a glass plate is a promising method far realizing a highly effective transducer for un derwater ultrasound.