Acoustic wave bandpass filter comprising integrated acoustic guiding

• US 9,450,563 B2
• Filed: 10/11/2011
• Issued: 09/20/2016
• Est. Priority Date: 10/15/2010
• Status: Active Grant

• Current Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Original Assignee: Commissariat a L'Energie Atomique (French Alternative Energies and Atomic Energy Commission)
• Inventors: Gorisse, Marie, Reinhardt, Alexandre
• Primary Examiner(s): LEE, BENNY T
• Assistant Examiner(s): Salazar, Jr., Jorge
• Application Number:
  US13/879,598
• Publication Number:
  US 20130214878A1
• Time in Patent Office: 1,806 Days
• Field of Search: 333/133, 333/186, 333/187, 333/189, 333/190, 333/191, 333193-196, 310/312, 310/320
• US Class Current: 1/1
• CPC Class Codes: H03H 9/0033 having one acoustic track only
• CPC Class Codes: H03H 9/0095 using bulk acoustic wave devices
• CPC Class Codes: H03H 9/02015 Characteristics of piezoelectric layers, e.g. cutting angles
• CPC Class Codes: H03H 9/02047 Treatment of substrates
• CPC Class Codes: H03H 9/02086 Means for compensation or elimination of undesirable effects
• CPC Class Codes: H03H 9/02543 Characteristics of substrate, e.g. cutting angles
• CPC Class Codes: H03H 9/02653 Grooves or arrays buried in the substrate
• CPC Class Codes: H03H 9/02818 Means for compensation or elimination of undesirable effects
• CPC Class Codes: H03H 9/547 Notch filters, e.g. notch BAW or thin film resonator filters
• CPC Class Codes: H03H 9/564 implemented with thin-film techniques
• CPC Class Codes: H03H 9/6433 Coupled resonator filters
• CPC Class Codes: H03H 9/6436 having one acoustic track only
• CPC Class Codes: H03H 9/6453 by at least an interdigital transducer overlapping both tracks

Abstract

An acoustic wave bandpass filter comprises at least an input first acoustic wave resonator with an output surface, and an output second acoustic wave resonator with an input surface, said resonators being coupled to each other along a set direction, the input and output surfaces being substantially opposite, and at least one first phononic crystal structure between said input and output resonators and/or a second phonic crystal structure at the periphery of said resonators so as to guide the acoustic waves, generated by said input resonator, toward said output resonator along said set direction, the resonators ensuring an impedance conversion and/or a mode conversion.

Claims

1. An acoustic wave bandpass filter comprising:

an input acoustic wave resonator with an output surface;

a first output acoustic wave resonator with an input surface, the first output acoustic wave resonator being coupled to the input acoustic wave resonator along a set direction; and

at least one first phononic crystal structure between the input acoustic wave resonator and the first output acoustic wave resonator; and

a second phononic crystal structure at the periphery of the input acoustic wave resonator and the output acoustic wave resonator so as to guide acoustic waves generated by the input acoustic wave resonator toward the first output acoustic wave resonator along the set direction, and

wherein the input surface is substantially opposite to the output surface,

wherein the acoustic waves are guided along the set direction and the input acoustic wave resonator and the first output acoustic wave resonator ensure at least one of a mode conversion and an impedance conversion.

2. The acoustic wave bandpass filter as claimed in claim 1, wherein each of the input acoustic wave resonator and the first output acoustic wave resonator includes at least one electrode and at least one of a layer of piezoelectric material and a layer of electrostrictive material.

3. The acoustic wave bandpass filter as claimed in claim 2, wherein at least one of the at least one first phononic crystal structure and the second phononic crystal structure is located inside the at least one of the layer of piezoelectric and the layer of electrostrictive material.

4. The acoustic wave bandpass filter as claimed in claim 2, wherein at least one of the at least one first phononic crystal structure and the second phononic crystal structure includes features on a surface of the at least one of the layer of piezoelectric material and the layer of electrostrictive material.

5. The acoustic wave bandpass filter as claimed in claim 4, wherein the features on the surface are produced with at least one of the following materials:

SiO₂, SiN, Mo, W, AlN.

6. The acoustic wave bandpass filter as claimed in claim 2,

wherein at least one of the input acoustic wave resonator and the first output acoustic wave resonator includes the layer of piezoelectric material, and

wherein the piezoelectric material is a material chosen from AN, LiNbO₃, ZnO, PZT and quartz.

7. The acoustic wave bandpass filter as claimed in claim 2,

wherein at least one of the input acoustic wave resonator and the first output acoustic wave resonator includes the layer of electrostrictive material, and

wherein the electrostrictive material is a material chosen from BaSrTiO₃, SrTiO₃ and BaTiO₃.

8. The acoustic wave bandpass filter as claimed in claim 1,

wherein the second phononic crystal structure ensures a mirror function for the acoustic waves.

9. The acoustic wave bandpass filter as claimed in claim 1,

wherein the at least one first phononic crystal structure is an acoustic wave coupling structure, and

wherein an acoustic wave transmission coefficient of the second phononic crystal structures is smaller than an acoustic wave transmission coefficient of the at least one first phononic crystal structure.

10. The acoustic wave bandpass filter as claimed in claim 1,

further comprising a second output acoustic wave resonator,

wherein the input acoustic wave resonator is connected to a first potential and to ground,

wherein the first output acoustic wave resonator is connected to a second potential and to ground, and

wherein the second output acoustic wave resonator is connected to an inverse of the second potential and to ground to facilitate the mode conversion and the impedance conversion between the input acoustic wave resonator and the first output acoustic wave resonator and the second output acoustic wave resonator.

11. The acoustic wave bandpass filter as claimed in claim 1, wherein the input surface and the output surface are perpendicular to the set direction.

12. The acoustic wave bandpass filter as claimed in claim 1, wherein the output surface has a dimension different from a dimension of the input surface.

13. The acoustic wave bandpass filter as claimed in claim 1,

further comprising a first set of input acoustic wave resonators including the input acoustic wave resonator and a second set of output acoustic wave resonators including the first output acoustic wave resonator, and

wherein the at least one first phononic crystal structure is placed between the first set of input acoustic wave resonators and the second set of output acoustic wave resonators.

14. The acoustic wave bandpass filter as claimed in claim 1, wherein each of the at least one first phononic crystal structure and the second phononic crystal structure is one of one-dimensional, two-dimensional, and three-dimensional.

16. The acoustic wave bandpass filter as claimed in claim 1, wherein the at least one first phononic crystal structure is an acoustic lens structure.

17. The acoustic wave bandpass filter as claimed in claim 1, wherein at least one of the at least one first phononic crystal structure and the second phononic crystal structure includes atomic inclusions and/or diffused species.

18. The acoustic wave bandpass filter as claimed in claim 17, wherein the inclusions are obtained by implanting hydrogen atoms.

19. The acoustic wave bandpass filter as claimed in claim 1, wherein at least one of the at least one first phononic crystal structure and the second phononic crystal structure includes holes.

20. The acoustic wave bandpass filter as claimed in claim 1,

wherein the at least one phononic crystal structure includes a plurality of first phononic crystal structures, and

wherein certain first phononic crystal structures of the plurality of first phononic crystal structures have acoustic wave attenuation coefficients that are different from acoustic wave attenuation coefficients of other first phononic crystal structures of the plurality of first phononic crystal structures.

21. The acoustic wave bandpass filter as claimed in claim 1, wherein each of the input acoustic wave resonator and the first output acoustic wave resonator is a bulk wave resonator.

22. The acoustic wave bandpass filter as claimed in claim 1, wherein each of the input acoustic wave resonator and the first output acoustic wave resonator is a Lamb wave resonator including an upper electrode and a lower electrode.

23. The acoustic wave bandpass filter as claimed in claim 1, wherein each of the input acoustic wave resonator and the first output acoustic wave resonator is a surface wave resonator including electrodes positioned on a surface formed of a piezoelectric material.

15. The acoustic wave bandpass filter as claimed in claim further comprising:

a plurality of pairs of the input acoustic wave resonator and the first output acoustic wave resonator, and

the at least one first phononic crystal structure includes a phononic crystal structure placed between each pair of the input acoustic wave resonator and the first output acoustic wave resonator.

24. An acoustic wave bandpass filter comprising:

an input acoustic wave resonator with an output surface;

an output acoustic wave resonator with an input surface, the output acoustic wave resonator being coupled to the input acoustic wave resonator along a set direction; and

at least one phononic crystal structure between the input acoustic wave resonator and the output acoustic wave resonator,

wherein each of the input acoustic wave resonator and the output acoustic wave resonator is a bulk wave resonator,

wherein the input surface is substantially opposite to the output surface, and

wherein acoustic waves are guided by the at least one phononic crystal structure along the set direction and the input acoustic wave resonator and the output acoustic wave resonator ensure at least one of an impedance conversion and a mode conversion.

25. An acoustic wave bandpass filter comprising:

an input acoustic wave resonator with an output surface;

an output acoustic wave resonator with an input surface, the output acoustic wave resonator being coupled to the input acoustic wave resonator along a set direction; and

at least one of a first phononic crystal structure between the input acoustic wave resonator and the output acoustic wave resonator and a second phononic crystal structure at the periphery of the input acoustic wave resonator and the output acoustic wave resonator so as to guide acoustic waves generated by the input acoustic wave resonator toward the output acoustic wave resonator along the set direction,

wherein the output surface has a dimension different from a dimension of the input surface,

wherein the input surface is substantially opposite to the output surface, and

wherein the acoustic waves are guided along the set direction and the input acoustic wave resonator and the output acoustic wave resonator ensure at least one of an impedance conversion and a mode conversion.

26. An acoustic wave bandpass filter comprising:

an input acoustic wave resonator with an output surface;

an output acoustic wave resonator with an input surface, the output acoustic wave resonator being coupled to the input acoustic wave resonator along a set direction; and

a plurality of phononic crystal structures between the input acoustic wave resonator and the output acoustic wave resonator,

wherein the input surface is substantially opposite to the output surface,

wherein certain phononic crystal structures of the plurality of phononic crystal structures have acoustic wave attenuation coefficients that are different from attenuation coefficients of other phononic crystal structures of the plurality of phononic crystal structures, and

wherein acoustic waves are guided along the set direction and the input acoustic wave resonator and the output acoustic wave resonator ensure at least one of an impedance conversion and a mode conversion.