Component having an acoustically active material for tuning during operation

• US 6,847,271 B2
• Filed: 09/20/2001
• Issued: 01/25/2005
• Est. Priority Date: 09/25/2000
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Siemens AG
• Inventors: Ruile, Werner, Korden, Christian, Ostertag, Thomas
• Primary Examiner(s): Summons, Barbara
• Application Number:
  US10/381,364
• Publication Number:
  US 20040104789A1
• Time in Patent Office: 1,223 Days
• Field of Search: 333188-196, 310/311, 310/315, 310/313.R, 310313 A-313 D, 310/322, 310/346
• US Class Current: 333/188
• CPC Class Codes: H03H 2009/02196 operating on the FBAR element, e.g. by direct application of a tuning DC voltage
• CPC Class Codes: H03H 3/04 for obtaining desired frequency or temperature coefficient
• CPC Class Codes: H03H 9/6403 Programmable filters
• CPC Class Codes: H03J 3/08 by varying a second parameter simultaneously with the tuning, e.g. coupling bandpass filter
• CPC Class Codes: H03J 3/28 of more than one resonant circuit simultaneously, the tuning frequencies of the circuits having a substantially constant difference throughout the tuning range
• CPC Class Codes: H03J 5/0272 the digital values being used to preset a counter or a frequency divider in a phase locked loop, e.g. frequency synthesizer
• CPC Class Codes: H03L 7/0805 the loop being adapted to provide an additional control signal for use outside the loop
• CPC Class Codes: H03L 7/18 using a frequency divider or counter in the loop H03L7/20, H03L7/22 take precedence

Abstract

A component having an acoustically active material, whose acoustic constants can be at least partially altered. The acoustically active material is located at least partially at a phase transition point and/or in the vicinity of a phase transition point.

Claims

1. Filter for a telecommunications device, comprising an acoustically active material (2) whose acoustic constants for tuning the filter during operation are modifiable at least in part,

wherein the acoustically active material for tuning the filter during operation is located at least in part at a phase transition point and/or in the vicinity of a phase transition point,

wherein the acoustically active material for tuning the filter during operation is located, at least in part, proximate a phase transition point of the acoustically active material so that the acoustic constants of the acoustically active material are influenced to provide a minimum change in speed of 5%.

2. Filter according to claim 1, wherein the acoustically active material (2) is at least in part a piezoelectric material.

3. Filter according to claim 2, wherein the phase transition point is the phase transition point between the ferroelectric phase and the paraelectric phase.

4. Filter according to claim 1, wherein the acoustically active material for tuning the filter during operation is located, at least in part, proximate a phase transition point of the acoustically active material so that the acoustic constants of the acoustically active material are influenced to provide a minimum change in speed of 10%.

5. Filter according to claim 1, further comprising means (3, 4, 5) for modifying the acoustic constants of the acoustically active material and/or connections for such means.

6. Filter according to claim 5, wherein the means (3, 4) for modifying the acoustic constants contain elements for applying an electrical voltage, by means of which the acoustic constants of the acoustically active material (2) can be modified.

7. Filter according to claim 5, wherein the means (5) for modifying the acoustic constants contain elements for setting the temperature, by means of which the acoustic constants of the acoustically active material (2) can be modified.

8. Filter according to claim 1, wherein the filter is a surface acoustic wave component, a bulk acoustic wave component and/or a diaphragm resonator.

9. Method for the operation of a filter (1) having an acoustically active material (2), which comprises:

modifying the acoustic constants of the acoustically active material (2) for tuning the filter during operation, and

operating the acoustically active material (2) for tuning the filter during operation at least in part at a phase transition point and/or in the vicinity of a phase transition point so that the acoustically active material for tuning the filter during operation is located, at least in part, proximate a phase transition point of the acoustically active material so that the acoustic constants of the acoustically active material are influenced to provide a minimum change in speed of 5%.

10. Filter for a telecommunications device, comprising:

an acoustically active material (2) whose acoustic constants for tuning the filter during operation are modifiable, at least in part, so that the acoustically active material for tuning the filter during operation is located at least in part in the vicinity of a phase transition point; and

means (3, 4, 5) for modifying the acoustic constants of the acoustically active material including elements for setting the temperature to modify the acoustic constants of the acoustically active material (2).

11. Filter according to claim 10, wherein the acoustically active material for tuning the filter during operation is located at the phase transition point.

12. Filter according to claim 10, wherein the acoustically active material (2) is at least in part a piezoelectric material.

13. Filter according to claim 12, wherein the phase transition point is the phase transition point between the ferroelectric phase and the paraelectric phase.

14. Filter according to at least claim 10, wherein the means (3, 4) for modifying the acoustic constants contain elements for applying an electrical voltage to modify the acoustic constants of the acoustically active material (2).

15. Filter according to claim 10, wherein the filter is one of a surface acoustic wave component, a bulk acoustic wave component and a diaphragm resonator.

16. Filter according to claim 10, wherein the acoustically active material for tuning the filter during operation is located, at least in part, proximate a phase transition point of the acoustically active material so that the acoustic constants of the acoustically active material are influenced to provide a minimum change in speed of 10%.

17. Filter according to claim 10, wherein the acoustically active material for tuning the filter during operation is located, at least in part, proximate a phase transition point of the acoustically active material so that the acoustic constants of the acoustically active material are influenced to provide a minimum change in speed of 10%.