Acoustic wave device, high frequency front end circuit, and communication apparatus
An acoustic wave device includes a piezoelectric substrate made of LiNbO 3 , and a dielectric film provided on the piezoelectric substrate to cover first and second IDT electrodes on the piezoelectric substrate. The first and second IDT electrodes include main electrode layers. When wave lengths determined by electrode finger pitches of the first and second IDT electrodes are λ 1 and λ 2 , respectively, the average value thereof is λ 0 , λ 1 /λ 0 =1 +X, and λ 2 /λ 0 =1 −X, a relationship of 0.05≤X≤0.65 is satisfied. The wavelength λ 1 is the longest, and the wavelength λ 2 is the shortest. In Euler angles (φ, θ, ψ) of the piezoelectric substrate, φ is 0°±5°, ψ is 0°±10°, and θ satisfies Expression 1, wherein a relationship of B 1 <T×r≤0.10λ 0 and B 2 <T×r≤0.10λ 0 are satisfied.
1. An acoustic wave device comprising:
a piezoelectric substrate made of LiNbO 3 ;
a plurality of interdigital transducer (IDT) electrodes provided on the piezoelectric substrate and including a first IDT electrode and a second IDT electrode; and
a dielectric film provided on the piezoelectric substrate to cover the plurality of IDT electrodes; wherein
the first IDT electrode and the second IDT electrode include main electrode layers;
among the plurality of IDT electrodes, a wave length λ 1 determined by an electrode finger pitch of the first IDT electrode is the longest and a wave length λ 2 determined by an electrode finger pitch of the second IDT electrode is the shortest; and
in Euler angles (φ, θ, ψ) of the piezoelectric substrate, φ is 0° ±5° and ψ is 0° ±10°.
2. The acoustic wave device according to claim 1 , wherein a plurality of band pass filters belonging to communication bands of different pass bands are provided on the piezoelectric substrate.
3. The acoustic wave device according to claim 2 , wherein
an antenna terminal to be connected to an antenna is provided on the piezoelectric substrate; and
the plurality of band pass filters are commonly connected to the antenna terminal to define a composite filter.
4. The acoustic wave device according to claim 2 , wherein a composite filter is not defined by the plurality of band pass filters.
5. A high frequency front end circuit comprising:
acoustic wave device according to claim 1 ; and
a power amplifier.
6. A communication apparatus comprising:
the high frequency front end circuit according to claim 5 ; and
an RF signal processing circuit.
7. An acoustic wave device comprising:
a piezoelectric substrate made of LiNbO 3 ;
a plurality of interdigital transducer (IDT) electrodes provided on the piezoelectric substrate and including a first IDT electrode and a second IDT electrode; and
a dielectric film provided on the piezoelectric substrate to cover the plurality of IDT electrodes; wherein
the first IDT electrode and the second IDT electrode include main electrode layers;
among the plurality of IDT electrodes, a wave length λ 1 determined by an electrode finger pitch of the first IDT electrode is the longest and a wave length λ 2 determined by an electrode finger pitch of the second IDT electrode is the shortest; and
in Euler angles (φ, θ, ψ) of the piezoelectric substrate, ψ is 0° ±5° and ψ is 0° ±10°.
8. The acoustic wave device according to claim 7 , wherein a plurality of band pass filters belonging to communication bands of different pass bands are provided on the piezoelectric substrate.
9. The acoustic wave device according to claim 8 , wherein
an antenna terminal to be connected to an antenna is provided on the piezoelectric substrate; and
the plurality of band pass filters are commonly connected to the antenna terminal to define a composite filter.
10. The acoustic wave device according to claim 8 , wherein a composite filter is not defined by the plurality of band pass filters.
11. A high frequency front end circuit comprising:
acoustic wave device according to claim 7 ; and
a power amplifier.
12. A communication apparatus comprising:
the high frequency front end circuit according to claim 11 ; and
an RF signal processing circuit.