MEMS controlled oscillator

• US 8,049,580 B2
• Filed: 11/02/2010
• Issued: 11/01/2011
• Est. Priority Date: 11/09/2005
• Status: Expired due to Fees

• Current Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Original Assignee: Cornell Research Foundation Incorporated (Cornell University)
• Inventors: Aubin, Keith, Zalalutdinov, Maxim, Craighead, Harold G., Parpia, Jeevak M., Reichenbach, Robert B.
• Primary Examiner(s): TAKAOKA, DEAN O
• Application Number:
  US12/938,126
• Publication Number:
  US 20110043405A1
• Time in Patent Office: 364 Days
• Field of Search: 333/186, 333/197, 333/198, 333/199, 331/154
• US Class Current: 333/186
• CPC Class Codes: G01S 7/032 Constructional details for solid-state radar subsystems
• CPC Class Codes: H01Q 3/26 varying the relative phase or relative amplitude of energisation between two or more active radiating elements; varying the distribution of energy across a radiating aperture H01Q3/12, H01Q3/22, H01Q3/24 take precedence
• CPC Class Codes: H03H 3/0072 of microelectro-mechanical resonators or networks micromembranes or microbeams B81B2203/01; manufacture of microstructural devices in general B81C
• CPC Class Codes: H03H 9/02401 by annealing
• CPC Class Codes: H03H 9/2436 Disk resonators

Abstract

An array of micromechanical oscillators have different resonant frequencies based on their geometries. In one embodiment, a micromechanical oscillator has a resonant frequency defined by an effective spring constant that is modified by application of heat. In one embodiment, the oscillator is disc of material supported by a pillar of much smaller diameter than the disc. The periphery of the disc is heated to modify the resonant frequency (or equivalently the spring constant or stiffness) of the disc. Continuous control of the output phase and frequency may be achieved when the oscillator becomes synchronized with an imposed sinusoidal force of close frequency. The oscillator frequency can be detuned to produce an easily controlled phase differential between the injected signal and the oscillator feedback. A phased array radar may be produced using independent phase controllable oscillators.

Claims

1. A phased array system comprising:

an array of microelectromechanical independently phase modulated resonators;

an exciter to drive the resonators in the array to resonate at their resonant frequencies, wherein each resonator is coupled to an antenna to transmit and receive signals;

a receiver coupled to receive signals from the resonators; and

a circulator coupled between the array and the exciter and receiver to control signal propagation direction.

2. The system of claim 1 wherein the resonators are selected from the group consisting of a disc supported by a pillar, a cantilevered beam and a bridge.

3. A phased array system comprising:

an array of microelectromechanical independently phase modulated resonators;

an exciter to drive the resonators in the array to resonate at their resonant frequencies, wherein each resonator is coupled to an antenna to transmit and receive signals;

a receiver coupled to receive signals from the resonators; and

a variable phase element coupled to each resonator.

4. The system of claim 3 wherein the variable phase element is to control phase change over the array to shape and control radar beams.

5. The system of claim 4 wherein the phase is controlled to change linearly across the array.

6. The system of claim 4 wherein the phase is controlled to provide two sets of linear phases.

7. The system of claim 4 wherein the phase is controlled to follow objects moving in different directions.

8. The system of claim 3 wherein each phase modulated resonator includes a high power amplifier to provide signals for transmitting via the antenna, and includes a low noise amplifier to amplify signals received from the antenna.

9. The system of claim 8 wherein each phase modulated resonator further includes a circulator to control signal propagation direction to and from the antenna.

14. The system of claim 3 wherein the variable phase element is to control phase change over the array to shape and control radar beams.

15. The system of claim 4 wherein the phase is controlled to change linearly across at least a portion of the array.

10. A phased array system comprising:

an array of modules having microelectromechanical independently phase modulated resonators, each module including a phase modulating element, a high power amplifier to provide signals to be transmitted from an antenna, and a low noise amplifier to amplify signals received from the antenna;

an exciter coupled to the modules via a feed network to drive the resonators in the array to resonate at their resonant frequencies; and

a receiver coupled to receive signals from the resonators.

11. The system of claim 10 wherein the phased array system is a phased array radar system.

12. The system of claim 10 wherein each module further includes a switch to select between the low noise amplifier and the high power amplifier.

13. The system of claim 10 wherein the resonators are selected from the group consisting of a disc supported by a pillar, a cantilevered beam and a bridge.

16. A method comprising:

coupling an exciter to an array of microelectromechanical independently phase modulated resonators to drive the resonators in the array to resonate at their resonant frequencies;

controlling phase changes over the array of resonators;

transmitting signals from the resonators via an antenna to shape and control beams as a function of the phase changes; and

receiving signals via the antenna.

17. The method of claim 16 wherein the phase is controlled to change linearly across the array.

18. The method of claim 16 wherein the phase is controlled to provide two sets of linear phases.

19. The method of claim 16 wherein the phase is controlled to follow objects moving in different directions.