SURFACE ACOUSTIC WAVE DEVICE

PURPOSE: To facilitate the manufacture and to realize an excellent frequency characteristic and phase characteristic by providing a direction inverting electrode adopting specific configuration for a basic structure to the surface of a piezoelectric substrate. CONSTITUTION: The device is provided with a piezoelectric substrate cut to have a natural single phase unidirectional converter characteristic and a direction inverting electrode formed on the surface. In this direction inverting electrode, a positive electrode 11 and a negative electrode 12 have respectively a width of λ/8 (λ is a wavelength of a surface acoustic wave) and have electrode fingers 11a, 12a arranged at a pitch of λ and they are combined interdigitally at an edge interval of λ/8 in the propagation direction of the surface acoustic wave as shown in the arrow. Furthermore, a floating electrode 13 whose width is 3/8λis arranged between the negative electrode finger 12a and the positive electrode finger 11a at an edge interval of λ/8. Thus, an electrode of a transmitter side and an electrode of a receiver side are made of the same material and since the electrode width and the edge interval are selected based on λ/8, the manufacture is facilitated and a desired characteristic is obtained.