| 摘要 |
PURPOSE: To improve power withstanding performance of a surface acoustic wave (SAW) filter and to simultaneously improve the power withstanding performance and squareness. CONSTITUTION: The SAW element in which a plurality of SAW resonators are connected in a ladder formation on a piezoelectric substrate satisfies 1.00fSav>fS1≧0.99fSav, where a resonance frequency of an SAW resonator, connected in series, of a first stage viewed from an input side is fS1, and an average resonance frequency of all the other SAW resonators connected in series is fSav. That is, the series resonance frequency is changed in a low direction within a band required in specifications. By setting conditions in this way, power consumption of the resonance frequency is reduced and the power withstanding performance is improved.
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