Acoustic wave device, high frequency front end circuit, and communication apparatus
AssigneeMurata Manufacturing Co., Ltd.
InventorMasakazu Mimura
Life of this patent
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Abstract
An acoustic wave device includes a piezoelectric substrate made of LiNbO3, 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 λ1 and λ2, respectively, the average value thereof is λ0, λ1/λ0=1+X, and λ2/λ0=1−X, a relationship of 0.05≤X≤0.65 is satisfied. The wavelength λ1 is the longest, and the wavelength λ2 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 B1<T×r≤0.10λ0 and B2<T×r≤0.10λ0 are satisfied.
Claims25
An acoustic wave device comprising:
- a piezoelectric substrate made of LiNbO3;
- 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 on the piezoelectric substrate and covering the plurality of IDT electrodes;
- wherein
- the first IDT electrode and the second IDT electrode include main electrode layers made of a material including W;
- among the plurality of IDT electrodes, a wave length λ1 determined by an electrode finger pitch of the first IDT electrode is the longest and a wave length λ2 determined by an electrode finger pitch of the second IDT electrode is the shortest;
- an average value λ0 of the wave length λ1 and the wave length λ2 is defined by equations of λ0=(λ1+λ2)/2, λ1/λ0=1+X, and λ2/λ0=1−X;
- X is not smaller than 0.05 and not larger than 0.65;
- and
- in Euler angles (φ, θ, ψ) of the piezoelectric substrate, φ is 0°±5° and ψ is 0°±10°.
An acoustic wave device comprising:
- a piezoelectric substrate made of LiNbO3;
- 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 on the piezoelectric substrate and covering the plurality of IDT electrodes;
- wherein
- the first IDT electrode and the second IDT electrode include main electrode layers made of a material including W;
- among the plurality of IDT electrodes, a wave length λ1 determined by an electrode finger pitch of the first IDT electrode is the longest and a wave length λ2 determined by an electrode finger pitch of the second IDT electrode is the shortest;
- an average value λ0 of the wave length λ1 and the wave length λ2 is defined by an equation of λ0=(λ1+λ2)/2;
- thicknesses of the main electrodes are not smaller than 0.049λ0/(ρ/ρPt) and not larger than 0.10λ0/(ρ/ρPt), ρ being a density of the material of the main electrode layers and ρPt being a density of Pt;
- and
- in Euler angles (φ, θ, ψ) of the piezoelectric substrate, φ is 0°±5° and ψ is 0°±10°.
An acoustic wave device comprising:
- a piezoelectric substrate made of LiNbO3;
- 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 on the piezoelectric substrate and covering the plurality of IDT electrodes;
- wherein
- the first IDT electrode and the second IDT electrode include main electrode layers made of a material including W;
- among the plurality of IDT electrodes, a wave length λ1 determined by an electrode finger pitch of the first IDT electrode is the longest and a wave length λ2 determined by an electrode finger pitch of the second IDT electrode is the shortest;
- an average value λ0 of the wave length λ1 and the wave length λ2 is defined by an equation of λ0=(λ1+λ2)/2;
- thicknesses of the main electrodes are not smaller than 0.049λ0/(ρ/ρPt) and not larger than 0.10 λ0/(ρ/ρPt), ρ being a density of the material of the main electrode layers and ρPt being a density of Pt;
- and
- the acoustic wave device uses a Rayleigh wave.
Dependencies are inferred from the claim text.