Patent attributes
An elastic boundary wave device of the present invention includes a plurality of elastic boundary wave elements. The elastic boundary wave elements each include a piezoelectric material layer, an electrode disposed over the piezoelectric material layer, a first dielectric layer formed over the piezoelectric material layer so as to cover the electrode, and a second dielectric layer formed over the first dielectric layer. An acoustic velocity of the second dielectric layers is faster than an acoustic velocity of the first dielectric layers, and the acoustic velocity of the second dielectric layer of at least one elastic boundary wave element from among the plurality of elastic boundary wave elements is different from the acoustic velocity of the second dielectric layer of another of the elastic boundary wave elements. This enables improving the degree of suppression in use as a filter in the elastic boundary wave device.
