ISOTROPICALLY-ETCHED CAVITIES FOR EVANESCENT-MODE ELECTROMAGNETIC-WAVE CAVITY RESONATORS

• US 20130278609A1
• Filed: 04/19/2012
• Published: 10/24/2013
• Est. Priority Date: 04/19/2012
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Stephanou, Philip Jason, Park, Sang-June, Shenoy, Ravindra V.
• Granted Patent: US 9,178,256 B2
• Time in Patent Office: Days
• US Class Current: 345/501
• CPC Class Codes: H01P 1/202 Coaxial filters cascaded coaxial cavities H01P1/205
• CPC Class Codes: H01P 1/208 Cascaded cavities; Cascaded resonators inside a hollow waveguide structure H01P1/205 takes precedence
• CPC Class Codes: H01P 1/2084 with dielectric resonators
• CPC Class Codes: H01P 11/007 Manufacturing frequency-selective devices resonators H01P11/008
• CPC Class Codes: H01P 11/008 Manufacturing resonators
• CPC Class Codes: H01P 7/04 Coaxial resonators
• CPC Class Codes: H01P 7/06 Cavity resonators

Abstract

This disclosure provides implementations of electromechanical systems (EMS) resonator structures, devices, apparatus, systems, and related processes. In one aspect, a device includes an evanescent-mode electromagnetic-wave cavity resonator. In some implementations, the resonator includes an isotropically-etched cavity operable to support one or more evanescent electromagnetic wave modes. In some implementations, the resonator also includes a cavity ceiling arranged to form a volume in conjunction with the isotropically-etched cavity. In some implementations, the resonator also includes a capacitive tuning structure having a portion that is located at least partially within the volume so as to support the evanescent electromagnetic wave modes. In some implementations, a distal surface of the tuning structure is separated from the closest surface to it by a gap distance, a resonant electromagnetic wave mode of the cavity resonator being dependent at least partially on the gap distance.

Claims

1. A device comprising:

an evanescent-mode electromagnetic-wave cavity resonator including;

an isotropically-etched cavity operable to support one or more evanescent electromagnetic wave modes, the isotropically-etched cavity including an inner cavity surface and a mating surface around a periphery of the cavity, the inner cavity surface having a conductive layer deposited or patterned thereon;

a cavity ceiling arranged to form a volume in conjunction with the isotropically-etched cavity, the cavity ceiling including a cavity ceiling surface having a conductive layer deposited or patterned thereon; and

a capacitive tuning structure having a portion that is located at least partially within the volume so as to support the one or more evanescent electromagnetic wave modes, the tuning structure being formed from a conductive material or having a conductive layer deposited or patterned thereon, a distal surface of the tuning structure being separated from the closest surface thereto by a gap distance, a resonant electromagnetic wave mode of the cavity resonator being dependent at least partially on the gap distance.

2. The device of claim 1, wherein the isotropically-etched cavity is substantially hemispheric.

3. The device of claim 1, wherein the isotropically-etched cavity is of a shape that is characteristically like a half of an ellipsoid wherein the mating surface of the isotropically-etched cavity is coplanar with a plane parallel to both the major axis and the minor axis of the half of the ellipsoid.

4. The device of claim 1, wherein:

the inner cavity surface of the cavity has a first approximately planar inner bottom surface parallel to the mating surface of the isotropically-etched cavity; and

the inner cavity surface of the cavity has a second curved inner side surface that connects the mating surface of the isotropically-etched cavity with the first planar inner bottom surface.

5. The device of claim 1, wherein the isotropically-etched cavity includes a first isotropically-etched cavity and a second isotropically-etched cavity having a mating surface that is coplanar with a mating surface of the first isotropically-etched cavity, a circumference of the first isotropically-etched cavity overlapping a circumference of the second isotropically-etched cavity.

6. The device of claim 1, wherein the tuning structure includes a post.

7. The device of claim 6, wherein:

the post is a vertically-extending post that extends distally from a central region of the inner cavity surface of the cavity.

8. The device of claim 7, wherein the post has a circular or elliptical cross-section.

9. The device of claim 8, wherein the post is integrally formed with the isotropically-etched cavity as a result of an isotropic etching process used to form the cavity.

10. The device of claim 7, wherein a distal surface of the post is coplanar with the mating surface of the isotropically-etched cavity.

11. The device of claim 7, further including a post top concentric with the post and having a radius larger than a radius of the post.

12. The device of claim 11, wherein a distal surface of the post top opposite a distal surface of the post is coplanar with the mating surface of the isotropically-etched cavity.

13. The device of claim 6, wherein:

the post is an in-plane post extending radially or transversely across the isotropically-etched cavity; and

a proximate surface of the in-plane post is coplanar with the mating surface of the isotropically-etched cavity.

14. The device of claim 13, further including a post end positioned at a distal end of the post and coplanar with the post and having a distal surface that is separated from an inner circumferential surface region of the isotropically-etched cavity by a gap.

15. The device of claim 1, wherein the tuning structure is a suspended ring tuning structure.

16. The device of claim 1, wherein the gap distance is adjustable to dynamically change a resonant frequency or mode of the cavity resonator.

17. The device of claim 1, further including one or more tuning elements arranged within the gap distance and actuatable to adjust the magnitude of the gap distance to effect the change in the resonant mode of the resonator.

18. The device of claim 17, wherein the one or more tuning elements include one or more arrays of one or more tuning elements, each individual tuning element or tuning element array being selectively actuatable such that each individual tuning element or array, respectively, functions as a bit and such that, collectively, the combinations of actuatable bits provide for a multi-discrete state tuning structure.

19. The device of claim 17, wherein each tuning element is electrostatically-actuatable.

20. The device of claim 17, wherein each tuning element is piezoelectrically-actuatable.

21. The device of claim 17, wherein each tuning element includes one or more microelectromechanical systems (MEMS).

22. The device of claim 1, further including one or more dielectric spacers arranged within the gap distance, the one or more dielectric spacers defining a static magnitude of the gap distance between a distal surface of the tuning structure and the cavity ceiling.

23. The device of claim 17, further including one or more dielectric spacers arranged within the gap distance, the one or more dielectric spacers defining a static magnitude of the gap distance between a distal surface of the tuning structure and the cavity ceiling.

24. The device of claim 1, further including:

a display;

a processor configured to communicate with the display, the processor being configured to process image data; and

a memory device configured to communicate with the processor.

25. The device of claim 24, further including:

a driver circuit configured to send at least one signal to the display; and

a controller configured to send at least a portion of the image data to the driver circuit.

26. A method comprising:

producing a cavity substrate;

positioning the cavity substrate over an etch-stop substrate;

connecting a lower surface of the cavity substrate with an upper surface of the etch-stop substrate; and

isotropically etching the cavity substrate to produce a plurality of cavities, each cavity being suitable for use in an evanescent-mode electromagnetic wave cavity resonator.

27. The method of claim 26, wherein:

isotropically etching the cavity substrate to produce a plurality of cavities includes continuing to isotropically etch the cavity substrate after the etching has exposed the etch-stop substrate until a desired region of the etch-stop substrate is exposed within each corresponding cavity;

the lower surface of each cavity is planar and defined by the upper surface of the etch-stop substrate within the respective cavity; and

the side surface of each cavity is curved as a result of the isotropic etching.

28. The method of claim 27, wherein isotropically etching the cavity substrate to produce a plurality of cavities includes continuing to isotropically etch the cavity substrate after the etching has exposed the etch-stop substrate until a desired region of the etch-stop substrate is exposed within each corresponding cavity while leaving a portion of the material within each cavity so as to form a capacitive tuning structure within each cavity.

29. The method of claim 26, wherein the exposed region of the etch-stop in each of the cavities includes a conductive surface of the respective cavity.

30. The method of claim 26, wherein:

one or more of the cavities each comprise a truncated substantially hemispheric shape.

31. The method of claim 26, wherein one or more of the cavities each comprise a truncated ellipsoidal shape.

32. A device comprising:

an evanescent-mode electromagnetic-wave cavity resonating means including;

an isotropically-etched cavity means operable to support one or more evanescent electromagnetic wave modes, the isotropically-etched cavity means including an inner cavity surface and a mating means around a periphery of the cavity, the inner cavity surface having a conducting means deposited or patterned thereon;

a cavity ceiling means arranged to form a volume in conjunction with the isotropically-etched cavity means, the cavity ceiling means including a cavity ceiling surface having a conducting means deposited or patterned thereon; and

a capacitive tuning means having a portion that is located at least partially within the volume so as to support the one or more evanescent electromagnetic wave modes, the tuning means being formed from a conductive material or having a conductive means deposited or patterned thereon, a distal surface of the tuning means being separated from the closest surface thereto by a gap distance, a resonant electromagnetic wave mode of the cavity resonating means being dependent at least partially on the gap distance.

33. The device of claim 32, wherein the isotropically-etched cavity means is substantially hemispheric.

34. The device of claim 32, wherein the tuning means includes a post.

35. The device of claim 34, wherein the post is integrally formed with the isotropically-etched cavity means as a result of an isotropic etching process used to form the cavity means.

36. The device of claim 34, further including a post top concentric with the post and having a radius or width larger than a corresponding radius or width of the post.

37. The device of claim 32, wherein the gap distance is adjustable to dynamically change a resonant frequency or mode of the cavity resonating means.

38. The device of claim 32, further including one or more spacer means arranged within the gap distance, the one or more spacer means defining a static magnitude of the gap distance between a distal surface of the tuning means and the cavity ceiling means.