SURFACE ACOUSTIC WAVE RESONATOR MOUNTING WITH LOW ACCELERATION SENSITIVITY

• US 20120105175A1
• Filed: 11/02/2010
• Published: 05/03/2012
• Est. Priority Date: 11/02/2010
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Clark, Roger L., Berman, Seth A., Kozlowski, Robert E., Montress, Gary K.
• Granted Patent: US 8,610,517 B2
• Time in Patent Office: Days
• US Class Current: 333/195
• CPC Class Codes: G01P 15/0975 by acoustic surface wave resonators or delay lines
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H03H 2009/0019 Surface acoustic wave multichip
• CPC Class Codes: H03H 9/02228 Guided bulk acoustic wave devices or Lamb wave devices having interdigital transducers situated in parallel planes on either side of a piezoelectric layer
• CPC Class Codes: H03H 9/02818 Means for compensation or elimination of undesirable effects
• CPC Class Codes: H03H 9/02897 of strain or mechanical damage, e.g. strain due to bending influence
• CPC Class Codes: H03H 9/0552 the device and the other elements being mounted on opposite sides of a common substrate
• CPC Class Codes: H03H 9/0585 consisting of an adhesive layer
• CPC Class Codes: H03H 9/1092 the enclosure being defined by a cover cap mounted on an element forming part of the surface acoustic wave [SAW] device on the side of the IDT's

Abstract

A device, comprising a substrate having opposing first and second surfaces, a first surface acoustic wave resonator disposed on the first surface of the substrate, a second surface acoustic wave resonator disposed on the second surface of the substrate, a first adhesive layer sandwiched between the first surface acoustic wave resonator and the substrate, and a second adhesive layer sandwiched between the second surface acoustic wave resonator.

Claims

1. A device, comprising:

a substrate having opposing first and second surfaces;

a first surface acoustic wave resonator disposed on the first surface of the substrate;

a second surface acoustic wave resonator disposed on the second surface of the substrate;

a first adhesive layer sandwiched between the first surface acoustic wave resonator and the substrate; and

a second adhesive layer sandwiched between the second surface acoustic wave resonator and the substrate;

wherein the first adhesive layer includes a first cutout region and the second adhesive layer includes a second cutout region.

2. The device according to claim 1, wherein the first surface acoustic wave resonator includes an active surface and the second surface acoustic wave resonator includes an active surface facing an opposite direction as the active surface of the first surface acoustic wave resonator.

3. The device according to claim 2, wherein acceleration forces in a first direction cause deflection of the active surface of the first surface acoustic wave resonator to tension and deflection of the active surface of the second surface acoustic wave resonator to compression so that a summation of the mechanical strain on the first and second surface acoustic wave resonators is about zero to provide an acceleration insensitive device.

4. The device according to claim 1, wherein the first and second surface acoustic wave resonators are connected in parallel such that respective shifts in frequency for the first and second acoustic wave resonators substantially cancel each other.

5. The device according to claim 1, wherein the first and second surface acoustic wave resonators are symmetrical.

6. The device according to claim 1, further including a compliant adhesive about the substrate.

7. The device according to claim 1, wherein the first cutout region is rectangular.

8. The device according to claim 1, wherein the first cutout region has an aspect ratio approximating an acoustic length-to-width ratio of the first surface acoustic wave resonator.

9. The device according to claim 1, wherein the first surface acoustic wave resonator operates at frequency ranging from about 200 MHz to about 3 GHz.

10. The device according to claim 1, wherein the device forms a part of a low noise oscillator.

11. The device according to claim 10, wherein wirebonds provide electrical connections from the device.

12. The device according to claim 1, further including bonding pads on only one surface of the device.

13. The device according to claim 12, wherein wirebonds coupled to the bonding pads connect the first surface acoustic wave resonator to the second surface acoustic wave resonator in parallel.

14. A device, comprising:

a substrate having opposing first and second surfaces;

a first surface acoustic wave resonator disposed on the first surface of the substrate;

a second surface acoustic wave resonator disposed on the second surface of the substrate and electrically coupled to the first surface wave resonator;

a first adhesive layer sandwiched between the first surface acoustic wave resonator and the substrate;

a second adhesive layer sandwiched between the second surface acoustic wave resonator and the substrate; and

a tuning mechanism coupled to the first surface acoustic wave resonator to tune the first surface acoustic wave resonator with respect to the second surface acoustic wave resonator.

15. The device according to claim 14, wherein the tuning mechanism includes an RLC circuit.

16. The device according to claim 14, wherein the first surface acoustic wave resonator includes an active surface and the second surface acoustic wave resonator includes an active surface facing an opposite direction as the active surface of the first surface acoustic wave resonator.

17. The device according to claim 16, wherein acceleration forces in a first direction cause deflection of the active surface of the first surface acoustic wave resonator to tension and deflection of the active surface of the second surface acoustic wave resonator to compression so that a summation of the mechanical strain on the first and second surface acoustic wave resonators is about zero to provide an acceleration insensitive device.

18. The device according to claim 14, wherein the first and second surface acoustic wave resonators are connected in parallel such that respective shifts in frequency for the first and second acoustic wave resonators substantially cancel each other.

19. The device according to claim 14, wherein the first surface acoustic wave resonator operates at frequency ranging from about 200 MHz to about 3 GHz.

20. The device according to claim 14, further including bonding pads on only one surface of the device, wherein the wirebonds are coupled to the bonding pads for connecting the first surface acoustic wave resonator to the second surface acoustic wave resonator in parallel.