| 摘要 |
PROBLEM TO BE SOLVED: To obtain a surface acoustic wave filter element that can be miniaturized, whose manufacturing process can be simplified and whose design can relatively easily be conducted. SOLUTION: This surface acoustic wave filter element 10 is configured such that two filter sections, that is, a 1st filter section 20 and a 2nd filter section 30 are formed on the same piezoelectric substrate 11. Each of the filter sections 20, 30 has IDTs(interdigital transducers) and reflectors in a pair. The sections 20, 30 extract high frequency signals with different frequency bands and provide outputs of different output signals. The film thickness of the filter sections 20, 30 with the different pass bands differs from each other. Thus, the degree of design freedom can be extended in comparison with the case that the same film thickness is adopted for the filter sections 20, 30. Since the filter sections 20, 30 with the different pass bands are formed on the same substrate, miniaturization and simplicity of the manufacturing process can be promoted more than the case employing different piezoelectric substrates.
|
