摘要:
A duplexer includes a ladder filter and a multimode filter that are formed on the same surface of a predetermined substrate. In this duplexer, a first comb-like electrode of the ladder filter and a second comb-like electrode of the multimode filter have the same layer structure with the same film thickness. The first comb-like electrode and the second comb-like electrode are formed with single-layer films mainly containing aluminum. The relationship among the film thickness h of the first comb-like electrode and the second comb-like electrode, the center frequency f1 of the frequency band of the ladder filter, and the center frequency f2 of the frequency band of the multimode filter, is expressed as:300nullhnullf1null480300nullhnullf2null430.
摘要:
A surface acoustic wave element includes: metal patterns that include interdigital transducers, each of the metal patterns being formed with a first alloy or multi-layer film of metals having different standard electrode potentials; and metal films each formed with a second alloy or multi-layer film containing metals having different standard electrode potentials from the standard electrode potentials of the metals forming the first alloy or multi-layer film, the metal films being formed at least on a part of the regions other than the regions corresponding to the electrode fingers of the interdigital transducers of all the metal patterns that are electrically independent of one another.