Acoustic wave device
An acoustic wave device includes: an IDT provided on a piezoelectric substrate; and gratings provided on both sides of the IDT, wherein: a slowness surface of an acoustic wave has a concave shape; a duty ratio of electrode fingers of the gratings is larger than that of the electrode fingers of the IDT, or a thickness of the electrode fingers of the gratings is larger than that of the electrode fingers of the IDT, or a thickness of an added film provided on the electrode fingers of the gratings is larger than that of an added film provided on the electrode fingers of the IDT; a pitch of the electrode fingers of the gratings is smaller than that of the electrode fingers of the IDT; and a resonant frequency of the gratings is substantially the same as that of the IDT.
1. An acoustic wave device comprising:
a piezoelectric substrate that is a rotated Y-cut LiTaO 3 substrate;
an Interdigital Transducer (IDT) that is provided on the piezoelectric substrate and excites an acoustic wave; and
gratings that are provided on both sides of the IDT in an aperture direction thereof,
wherein:
a duty ratio of electrode fingers of the gratings is larger than a duty ratio of the electrode fingers of the IDT, or a thickness of the electrode fingers of the gratings is larger than a thickness of the electrode fingers of the IDT, or a thickness of an added film provided on the electrode fingers of the gratings is larger than a thickness of an added film provided on the electrode fingers of the IDT;
a pitch of the electrode fingers of the gratings is smaller than a pitch of the electrode fingers of the IDT; and
a resonant frequency of the gratings is substantially the same as a resonant frequency of the IDT.
2. An acoustic wave device comprising:
a piezoelectric substrate that is a rotated Y-cut LiTaO 3 substrate;
an IDT that is provided on the piezoelectric substrate and excites an acoustic wave; and
gratings that are provided on both sides of the IDT in an aperture direction thereof,
wherein:
a duty ratio of electrode fingers of the gratings is larger than a duty ratio of the electrode fingers of the IDT, or a thickness of the electrode fingers of the gratings is larger than a thickness of the electrode fingers of the IDT, or a thickness of an added film provided on the electrode fingers of the gratings is larger than a thickness of an added film provided on the electrode fingers of the IDT;
a pitch of the electrode fingers of the gratings is smaller than a pitch of the electrode fingers of the IDT; and
the electrode fingers of the gratings and the electrode fingers of the IDT are connected to each other via bended regions.
3. An acoustic wave device comprising:
a piezoelectric substrate that is a rotated Y-cut LiTaO 3 substrate;
an IDT that is provided on the piezoelectric substrate and excites an acoustic wave; and
gratings that are provided on both sides of the IDT in an aperture direction thereof,
wherein:
a duty ratio of electrode fingers of the gratings is larger than a duty ratio of the electrode fingers of the IDT, or a thickness of the electrode fingers of the gratings is larger than a thickness of the electrode fingers of the IDT, or a thickness of an added film provided on the electrode fingers of the gratings is larger than a thickness of an added film provided on the electrode fingers of the IDT; and
the electrode fingers of the gratings are inclined with respect to the aperture direction.
4. An acoustic wave device comprising:
a piezoelectric substrate that is a rotated Y-cut LiNbO 3 substrate;
an IDT that is provided on the piezoelectric substrate and excites an acoustic wave; and
gratings that are provided on both sides of the IDT in an aperture direction thereof,
wherein:
a duty ratio of electrode fingers of the gratings is smaller than a duty ratio of the electrode fingers of the IDT, or a thickness of the electrode fingers of the gratings is smaller than a thickness of the electrode fingers of the IDT, or a thickness of an added film provided on the electrode fingers of the gratings is smaller than a thickness of an added film provided on the electrode fingers of the IDT;
a pitch of the electrode fingers of the gratings is larger than a pitch of the electrode fingers of the IDT; and
a resonant frequency of the gratings is substantially the same as a resonant frequency of the IDT.
5. An acoustic wave device comprising:
a piezoelectric substrate that is a rotated Y-cut LiNbO 3 substrate;
an IDT that is provided on the piezoelectric substrate and excites an acoustic wave; and
gratings that are provided on both sides of the IDT in an aperture direction thereof,
wherein:
a duty ratio of electrode fingers of the gratings is smaller than a duty ratio of the electrode fingers of the IDT, or a thickness of the electrode fingers of the gratings is smaller than a thickness of the electrode fingers of the IDT, or a thickness of an added film provided on the electrode fingers of the gratings is smaller than a thickness of an added film provided on the electrode fingers of the IDT;
a pitch of the electrode fingers of the gratings is larger than a pitch of the electrode fingers of the IDT; and
the electrode fingers of the gratings and the electrode fingers of the IDT are connected to each other via bended regions.