| 摘要 |
PROBLEM TO BE SOLVED: To provide an elastic surface wave apparatus having a structure where insertion loss hardly occurs even if a band is narrowed for increasing an intermediate frequency and two stages of laterally-coupled double-mode resonant elastic surface acoustic wave filters are cascade-connected. SOLUTION: In the elastic surface wave apparatus 1, the first and second cascade-connected laterally-coupled double-mode resonant elastic surface acoustic wave filters 3, 4 are composed on piezoelectric substrates 2; the respective laterally-coupled double-mode resonant elastic surface acoustic wave filters 3, 4 are adjacently arranged in a direction where two one-port elastic surface acoustic wave resonators 31, 32, 41, 42 having an IDT electrode and a grating reflector electrode provided at both sides of a surface wave propagation direction in a region in which the IDT electrode is provided, orthogonally cross the surface wave propagation direction; and the standardization film thickness h/λ<SB>R</SB>of the electrode ranges from at least 0.002 to 0.028 and a coupling length G ranges from 1.43λ<SB>R</SB>or more to 1.55λ<SB>R</SB>or less in the case a wavelength of an elastic surface acoustic wave is set asλ<SB>R</SB>. COPYRIGHT: (C)2005,JPO&NCIPI
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