| 摘要 |
PURPOSE: To attain a wide-band and low-loss vertically coupled double mode SAW filter having a filter characteristic capable of sufficiently increasing the quantity of attenuation in the vicinity of a high frequency side by suppressing spurious radiation appearing in a high frequency side attenuation band of a conventional vertically coupled double mode SAW filter using primary and tertiary modes. CONSTITUTION: In the vertically coupled double mode SAW filter using the primary and tertiary modes, the inter-center intervals of the innermost electrode digits opposed to a center IDT 1 and both side IDTs 3 are different on right and left sides, approximately one is nλ/2 and the other is (2n-1)λ/4 (λis the wavelength of an excited SAW, n=1, 2,...).
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