Elastic wave device, filter device, communication module and communication apparatus
AssigneeFujitsu Limited
InventorsMichio MIURA, Suguru Warashina, Takashi Matsuda
Life of this patent
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Abstract
An elastic wave device including a piezoelectric substrate, comb-like electrodes formed on the piezoelectric substrate, and a dielectric layer formed on the piezoelectric substrate. The dielectric layer formed on the piezoelectric substrate covers the comb-like electrodes and the thickness of the dielectric layer formed on the piezoelectric substrate is larger than the sum of the thickness of the comb-like electrodes and the thickness of the dielectric layer formed on the comb-like electrodes.
Claims8
An elastic wave device comprising a piezoelectric substrate, comb-like electrodes formed on the piezoelectric substrate, and a dielectric layer formed on the piezoelectric substrate so that the comb-like electrodes are covered with the dielectric layer, wherein the thickness of the dielectric layer formed on the piezoelectric substrate is larger than the sum of the thickness of the comb-like electrodes and the thickness of the dielectric layer formed on the comb-like electrodes.
A filter device comprising an input electrode, at least one resonator which allows only an electric signal of a given frequency among electric signals input through the input electrode to pass, and an output electrode which outputs the electric signal having passed through the resonator to the outside, wherein:
- the resonator includes an elastic wave device which has a piezoelectric substrate, comb-like electrodes formed on the piezoelectric substrate, and a dielectric layer formed on the piezoelectric substrate so that the comb-like electrodes are covered with the dielectric layer;
- and
- the elastic wave device is formed so that the thickness of the dielectric layer formed on the piezoelectric substrate is larger than the sum of the thickness of the comb-like electrodes and the thickness of the dielectric layer formed on the comb-like electrodes.
Dependencies are inferred from the claim text.