Method and apparatus for converting electromagnetic energy of objects

• US 6,819,246 B1
• Filed: 01/07/2002
• Issued: 11/16/2004
• Est. Priority Date: 06/08/1999
• Status: Expired due to Fees

• Current Assignee: Mind Fusion, LLC (Ascend Innovation Management, LLC)
• Original Assignee: Valtion Teknillinen Tutkimuskeskus
• Inventors: Seppä, Heikki
• Primary Examiner(s): Wu, Daniel J.
• Assistant Examiner(s): Nguyen, Tai T.
• Application Number:
  US09/980,860
• Time in Patent Office: 1,044 Days
• Field of Search: 340/572.7, 340/572.3, 340/572.1, 340/10.1, 340/10.3, 340/10.4, 310/313.A, 310/313.B, 310/313.C, 310/313.D
• US Class Current: 340/572.7
• CPC Class Codes: G01S 13/753 using frequency selective elements, e.g. resonator
• CPC Class Codes: G06K 19/0672 with resonating marks
• CPC Class Codes: G06K 19/0717 the sensor being capable of sensing environmental conditions such as temperature history or pressure
• CPC Class Codes: G06K 19/0723 the record carrier comprising an arrangement for non-contact communication, e.g. wireless communication circuits on transponder cards, non-contact smart cards or RFIDs
• CPC Class Codes: G06K 19/0726 the arrangement including a circuit for tuning the resonance frequency of an antenna on the record carrier
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves

Abstract

The invention relates to a method for identifying objects, in which method electromagnetic radiation is imposed on the object (22-25) to be identified. According to the invention, such an identification component is used that includes a plurality of vibrating beams (4), and the electrical energy converted from said mechanical energy of the vibrating beams (4) is detected.

Claims

1. A method for converting electromagnetic energy into mechanical energy, in which the electromagnetic energy is imposed on an identification component, the method comprising:

using the identification component which comprises at least one vibrating element capable of converting the electromagnetic energy imposed thereon into mechanical energy, and capable of converting the mechanical energy of the at least one vibrating element into electrical energy,

wherein a wavelength of electromagnetic field of the electromagnetic energy is measured substantially in microwave or millimeter wavelength ranges, and

wherein the at least one vibrating element is a micromechanical pendulum whose motion is determined by a differential equation $m<br><br>\frac{{<br><br>}^2<br><br>x}{<br><br>t^2}+\mathrm{\eta <br><br>}<br><br>\frac{<br><br>x}{<br><br>t}+\mathrm{kx}=F<br><br>\left(t\right)$

where m is a mass of an electrode, η

is a loss factor, k is a spring constant, x is a displacement of the electrode from its equilibrium position, and F(t) is a sum of the mechanical and electrostatic forces.

2. Method according to claim 1, wherein the at least one vibrating element during the measurement is adjusted from its quiescent position closer to its counterelectrode.

3. Method according to claim 2, wherein during the measurement, a position of the at least one vibrating element is further adjusted relative to its counterelectrode in order to vary the measurement frequency.

4. Method according to claim 2, wherein the at least one vibrating element is a cantilever beam.

5. Method according to claim 1, 2 or 3, wherein a plurality of said vibrating elements are arranged to implement a microwave camera detector element.

6. Method according to claim 5, wherein the plurality of said vibrating elements are silicon micromechanical elements.

7. Method according to claim 6, wherein the microwave camera detector element is implemented by arranging the silicon micromechanical elements into at least one of a linear array and a matrix.

8. A transducer apparatus for converting electromagnetic emission of radiation via mechanical energy into another form of energy, said apparatus comprising:

an identification component, which comprises;

at least one vibrating element capable of converting an electromagnetic energy imposed thereon into the mechanical energy, wherein the at least one vibrating element is a micromechanical pendulum whose motion is determined by a differential equation $m<br><br>\frac{{<br><br>}^2<br><br>x}{<br><br>t^2}+\mathrm{\eta <br><br>}<br><br>\frac{<br><br>x}{<br><br>t}+\mathrm{kx}=F<br><br>\left(t\right)$

where m is a mass of an electrode, η

is a loss factor, k is a spring constant, x is a displacement of the electrode from its equilibrium position, and F(t) is a sum of the mechanical and electrostatic forces;

means for converting the mechanical energy forward into a form of electrical energy; and

means for measurement of power level at substantially microwave or millimeter wavelengths frequencies; and

a transmitter for emitting a signal of electromagnetic radiation toward said identification component.

9. Apparatus according to claim 8, further comprising means for adjusting a position of the at least one vibrating element during measurement in order to vary the transducer sensitivity and/or measurement frequency.

10. Apparatus according to claim 9, wherein the at least one vibrating element is a cantilever beam.

11. Apparatus according to claim 8, wherein the at least one vibrating element is a cantilever beam.

12. An identification component for converting energy of electromagnetic radiation into another form of energy, comprising:

at least one vibrating element capable of converting the energy of the electromagnetic radiation imposed thereon into mechanical energy, wherein the at least one vibrating element is a micromechanical pendulum whose motion is determined by a differential equation $m<br><br>\frac{{<br><br>}^2<br><br>x}{<br><br>t^2}+\mathrm{\eta <br><br>}<br><br>\frac{<br><br>x}{<br><br>t}+\mathrm{kx}=F<br><br>\left(t\right)$

where m is a mass of an electrode, η

is a loss factor, k is a spring constant, x is a displacement of the electrode from its equilibrium position, and F(t) is a sum of the mechanical and electrostatic forces;

means for converting the mechanical energy to electrical energy; and

means for measurement of power level at substantially microwave or millimeter wavelengths frequencies.

13. Apparatus according to claim 12, further comprising means for adjusting a position of the at least one vibrating element during measurement in order to vary the transducer sensitivity and/or measurement frequency.

14. Apparatus according to claim 13, wherein the at least one vibrating element is a cantilever beam.

15. Apparatus according to claim 12, wherein the at least one vibrating element is a cantilever beam.

16. A method for converting electromagnetic energy, comprising:

receiving the electromagnetic energy whose wavelength substantially measures in microwave or millimeter wavelength ranges; and

converting the electromagnetic energy into mechanical energy using at least one vibrating element, wherein the at least one vibrating element is a micromechanical pendulum whose motion is determined by a differential equation $m<br><br>\frac{{<br><br>}^2<br><br>x}{<br><br>t^2}+\mathrm{\eta <br><br>}<br><br>\frac{<br><br>x}{<br><br>t}+\mathrm{kx}=F<br><br>\left(t\right)$

where m is a mass of an electrode, η

is a loss factor, k is a spring constant, x is a displacement of the electrode from its equilibrium position, and F(t) is a sum of the mechanical and electrostatic forces.

17. The method of claim 16, further comprising converting the mechanical energy into a response electrical energy.

18. The method of claim 17, wherein the conversion of mechanical energy into the response electrical energy is direct.

19. The method of claim 17, wherein the at least vibrating element is tuned to a predetermined resonant frequency.

20. The method of claim 19, wherein the response electrical energy is at a different voltage and/or frequency relative to the electromagnetic energy.

21. The method of claim 20, wherein the voltage of the response electrical energy is compatible with voltage requirements of circuits fabricated using silicon semiconductor technology.

22. An apparatus for converting electromagnetic energy, comprising:

a receiver configured to receive the electromagnetic energy whose wavelength substantially measures in microwave or millimeter wavelength ranges; and

at least one vibrating element configured to convert the electromagnetic energy into mechanical energy, wherein the at least one vibrating element is a micromechanical pendulum whose motion is determined by a differential equation $m<br><br>\frac{{<br><br>}^2<br><br>x}{<br><br>t^2}+\mathrm{\eta <br><br>}<br><br>\frac{<br><br>x}{<br><br>t}+\mathrm{kx}=F<br><br>\left(t\right)$

where m is a mass of an electrode, η

is a loss factor, k is a spring constant, x is a displacement of the electrode from its equilibrium position, and F(t) is a sum of the mechanical and electrostatic forces.

23. The apparatus of claim 22, wherein the at least one vibrating element is further configured to convert the mechanical energy into a response electrical energy.

24. The apparatus of claim 22, wherein the at least one vibrating element is a cantilever beam.

25. The method of claim 24, wherein the cantilever beam directly converts the mechanical energy into the response electrical energy.

26. The method of claim 22, wherein the at least vibrating element is tuned to a predetermined resonant frequency.

27. The method of claim 26, wherein the response electrical energy is at a different voltage and/or frequency relative to the electromagnetic energy.

28. The method of claim 27, wherein the voltage of the response electrical energy is compatible with voltage requirements of circuits fabricated using silicon semiconductor technology.