Filter using micro-mechanical resonator

• US 20040080382A1
• Filed: 01/31/2003
• Published: 04/29/2004
• Est. Priority Date: 02/01/2002
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Nakamura, Kunihiko, Nakanishi, Yoshito
• Granted Patent: US 6,828,877 B2
• Time in Patent Office: Days
• US Class Current: 333/186
• CPC Class Codes: H03H 2009/02496 Horizontal, i.e. parallel to the substrate plane
• CPC Class Codes: H03H 2009/02511 Vertical, i.e. perpendicular to the substrate plane
• CPC Class Codes: H03H 9/2405 of microelectro-mechanical resonators
• CPC Class Codes: H03H 9/462 Microelectro-mechanical filters

Abstract

An electric signal fed into a line generates electric field in response to its frequency, and a resonator placed closely to the line and in a substantially vacuum condition not higher than 100 pascal is excited by electrostatic force of the electric field and vibrates. Detecting means converts mechanical vibrations of the resonator into a signal in another form than the electric signal, then it detects the vibrations. The foregoing structure allows the resonator to be a micro-body and to process properly a high-frequency input signal of MHz or GHz band. A tight space between an input side and an output side does not permit an electric signal fed into the line to couple directly to the output side, and the resonator downsized to a micro-body is not subject to viscosity of air.

Claims

1. A filter comprising:

(a) a line to which an electric signal fed into;

(b) a resonator, disposed in vacuum and closely to said line, for resonating by electrostatic force generated in response to a frequency of the electric signal; and

(c) detecting means for detecting mechanical vibrations of said resonator,

wherein said detecting means converts the mechanical vibrations into a signal in another form than the electric signal for the mechanical vibrations to be detected.

2. The filter of claim 1, wherein the electric signal has a frequency not lower than 10 MHz.

3. The filter of claim 2, wherein said resonator has a longer side of which length is shorter than a width of said line.

4. The filter of claim 3, wherein a plurality of said resonators are coupled together sequentially in parallel with respect to said line and said detecting means, and the plurality of said resonators have an identical resonance frequency.

5. The filter of claim 3, wherein plurality of said resonators are coupled to each other in parallel with respect to said line and said detecting means, and the plurality of said resonators have a resonance frequency different from each other.

6. The filter of claim 3, wherein said resonator is equipped with DC control means which applies a direct potential between said line and said resonator for controlling operation of said resonator.

7. The filter of claim 3 further comprising a dielectric layer between said resonator and said line.

8. The filter of claim 3, wherein the signal in another form than the electric signal is at least one of interfered light produced by interference between reference light and detected light reflected from said resonator, a tunnel current running between an electrode disposed closely to said resonator and said resonator, inter-molecular force between the electrode disposed closely to said resonator and said resonator, and inter-atomic force between the electrode disposed closely to said resonator and said resonator.

9. The filter of claim 8, wherein the interfered light is interfered with laser beam using a laser heterodyne method.

10. The filter of claim 8, wherein the reference light is irradiated to a selected resonator via a movable mirror which can change a reflecting direction.

11. The filter of claim 8, wherein the interfered light is further converted into an electric signal via a wave-guide.

12. The filter of claim 3, wherein said resonators having a longer side of which length is shorter than the width of said line are arranged in a diffraction grating shape.

13. The filter of claim 2, wherein a plurality of said resonators are coupled to each other in parallel with respect to said line and said detecting means, and the plurality of said resonators have a resonance frequency different from each other.

14. The filter of claim 13, wherein said resonators are equipped with DC control means respectively which applies a direct potential between said line and said resonators for controlling operation of said resonators.

15. The filter of claim 13 further comprising a dielectric layer between said resonator and said line.

16. The filter of claim 13, wherein the signal in another form than the electric signal is at least one of interfered light produced by interference between reference light and detected light reflected from said resonator, a tunnel current running between an electrode disposed closely to said resonator and said resonator, inter-molecular force between the electrode disposed closely to said resonator and said resonator, and inter-atomic force between the electrode disposed closely to said resonator and said resonator.

17. The filter of claim 16, wherein the interfered light is interfered with laser beam using a laser heterodyne method.

18. The filter of claim 16, wherein the reference light is irradiated to a selected resonator via a movable mirror which can change a reflecting direction.

19. The filter of claim 16, wherein the interfered light is further converted into an electric signal via a wave-guide.

20. The filter of claim 2, wherein a plurality of said resonators are coupled to each other in parallel with respect to said line and said detecting means, and the plurality of said resonators have an identical resonance frequency.

21. The filter of claim 20, wherein said resonators are placed along both ends of said line in pairs.

22. The filter of claim 2, wherein said resonators are equipped with DC control means respectively which applies a direct potential between said line and said resonators for controlling operation of said resonators.

23. The filter of claim 2 further comprising a dielectric layer between said resonator and said line.

24. The filter of claim 2, wherein the signal in another form than the electric signal is at least one of interfered light produced by interference between reference light and detected light reflected from said resonator, a tunnel current running between an electrode disposed closely to said resonator and said resonator, inter-molecular force between the electrode disposed closely to said resonator and said resonator, and inter-atomic force between the electrode disposed closely to said resonator and said resonator.

25. The filter of claim 24, wherein the interfered light is interfered with laser beam using a laser heterodyne method.

26. The filter of claim 24, wherein the reference light is irradiated to a selected resonator via a movable mirror which can change a reflecting direction.

27. The filter of claim 24, wherein the interfered light is further converted into an electric signal via a wave-guide.