| 摘要 |
PROBLEM TO BE SOLVED: To reduce the number of processes for forming electrodes to improve productivity with respect to a surface acoustic filter having a plurality of different frequency pass bands. SOLUTION: In two resonator type SAW filters arbitrarily selected from among a plurality of resonator type SAW filters, when defining a normalized film thickness difference=Δ(h/λ) and an electrode exponential logarithm difference=ΔN, -12,500≤ΔN/Δ(h/λ)≤-1,500 is established with regard to both of cord electrodes at input and output sides. By the electrode exponential logarithm thus established, a Q value can be uniformed for each of the resonator type SAW filters having the different frequency pass bands with the thickness (h) of the film kept constant, so that optimum filter characteristics can be obtained. COPYRIGHT: (C)2004,JPO
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