Surface acoustic wave device

Abstract

A surface acoustic wave device capable of reducing the insertion loss in the passband and realizing narrow-band characteristics comprises a piezoelectric substrate, an interdigital transducer formed on the piezoelectric substrate and including at least one drive electrode for driving a surface acoustic wave, and reflectors arranged on both sides of the interdigital transducer. Each reflector is constructed to include an open electrode block having a plurality of electrically independent electrode fingers, and a short-circuit electrode block having a plurality of electrode fingers electrically short-circuited commonly at the ends.

Description

technical field [0001] The present invention relates to a surface acoustic wave device, and more particularly, to a surface acoustic wave device that can realize attenuation characteristics outside a passband and narrow band characteristics and is preferably used as a filter. Background technique [0002] Recently, radio equipment including portable phones, cordless phones, and radios are continuously becoming smaller and lighter, while their uses are rapidly expanding. For the high-frequency circuits of these radio devices, filter components are used as decisive key components. [0003] Accordingly, corresponding to the demand for smaller size and lighter weight of radio equipment, smaller and lighter filter elements are also required. As a structure to make the filter element smaller and lighter, a surface acoustic wave device is used. [0004] When using surface acoustic wave devices as filters, the key issues are reducing insertion loss and increasing the amount of att...

AI Technical Summary

Problems solved by technology

Another way to achieve a narrower band is to reduce the stopband width by reducing the reflection coefficient of the reflective electrodes 2 and 3, but this also tends to increase the insertion loss accordingly

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