An acoustic wave device and filtering apparatus are provided

Abstract

The acoustic wave device comprises a substrate, a composite layer and an electrode layer which are sequentially stacked from bottom to top, the composite layer is provided with a closed groove in a preset shape, the composite layer comprises a temperature compensation layer and a piezoelectric layer which are stacked from bottom to top, and the electrode layer is located on the upper surface of the composite layer in the groove. Visibly, the composite layer is provided with a groove; the electrode layer is positioned on the upper surface of the composite layer in the groove; when sound waves are propagated along the transverse direction, the sound wave is reflected back by the edge of the piezoelectric layer positioned on the outer side of the groove; the energy of the sound wave is limited below the electrode layer, and transverse energy leakage is reduced; when sound waves are propagated in the longitudinal direction, due to the fact that the propagation speed of the sound waves of the substrate is higher than that of the composite layer, the sound waves are almost propagated only in the composite layer and cannot leak into the substrate, longitudinal energy leakage is restrained, the Q value is increased, and frequency deviation caused by temperature changes can be reduced due to the existence of the temperature compensation layer. The invention further provides a filteringdevice with the advantages.

Description

technical field [0001] The present application relates to the technical field of filtering devices, in particular to an acoustic wave device and a filtering device. Background technique [0002] A Surface Acoustic Wave (SAW) device is a device that uses interdigitated electrodes to convert electrical energy into acoustic energy, or vice versa, and is widely used in filters, delay lines, oscillators, etc. [0003] In recent years, piezoelectric materials on insulating substrates have been gradually applied in surface acoustic wave devices because of their high Q value and good temperature compensation effect. There is a problem of leakage, which in turn reduces the Q value of the surface acoustic wave device, and is prone to frequency shifts caused by temperature changes. [0004] Therefore, how to reduce the energy leakage of the surface acoustic wave device, improve the Q value, and reduce the frequency offset of the device should be focused on by those skilled in the art....

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Problems solved by technology

[0003] In recent years, piezoelectric materials on insulating substrates have been gradually applied in surface acoustic wave devices because of their high Q value and good temperature compensation effect. There is a problem of leakage, which reduces the Q value of the SAW device and is prone to frequency shifts due to temperature changes

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