SELF-POWERED, PIEZO-SURFACE ACOUSTIC WAVE APPARATUS AND METHOD

• US 20110241839A1
• Filed: 11/10/2009
• Published: 10/06/2011
• Est. Priority Date: 11/10/2008
• Status: Active Grant

• Current Assignee: Cornell University
• Original Assignee: Cornell University
• Inventors: Tin, Steven, Lal, Amit
• Granted Patent: US 8,860,553 B2
• Time in Patent Office: Days
• US Class Current: 340/10.1
• CPC Class Codes: G21H 1/02 Cells charged directly by beta radiation
• CPC Class Codes: H03B 5/326 the resonator being an acoustic wave device, e.g. SAW or BAW device
• CPC Class Codes: H03H 9/0542 consisting of a lateral arrangement H03H9/0566 takes precedence
• CPC Class Codes: H03H 9/145 for networks using surface acoustic waves

Abstract

An autonomous, self-powered device includes a radioisotope-powered current impulse generator including a spring assembly comprising a cantilever, and a piezoelectric-surface acoustic wave (P-SAW) structure connected in parallel to the current impulse generator. Positive charges are accumulated on an electrically isolated ⁶³Ni thin film due to the continuous emission of β-particles (electrons), which are collected on the cantilever. The accumulated charge eventually pulls the cantilever into the radioisotope thin-film until electrical discharge occurs. The electrical discharge generates a transient magnetic and electrical field that can excite the RF modes of a cavity in which the electrical discharge occurs. A piezoelectric-SAW resonator is connected to the discharge assembly to control the RF frequency output. A method for generating a tuned RF signal includes inputting an energy pulse to a P-SAW resonator, exciting the resonant frequency thereof, and outputting an RF signal having a frequency tuned to the resonator frequency.

Claims

1. A self-powered device, comprising:

a radioisotope-powered current impulse generator including a spring assembly comprising a cantilever having at least one fixed end attached to a base and a reciprocable region, further including a radioactive particle emitter; and

a piezoelectric-surface acoustic wave (P-SAW) structure including an input port electrically connected in parallel to the current impulse generator and an output port.

2. The device of claim 1, wherein the cantilever is a simple cantilever beam having a fixed, proximal end and a freely reciprocable, distal end.

3. The device of claim 1, wherein the cantilever is a clamped-clamped cantilever having two fixed ends and an intermediate reciprocable region.

4. The device of claim 1, wherein the cantilever is a serpentine beam having a fixed, proximal end and a freely reciprocable, distal end.

5. The device of claim 1, wherein the P-SAW import port is electrically coupled to the spring assembly proximate the at least one fixed end of the cantilever.

6. The device of claim 1, wherein the P-SAW import port is electrically coupled to the spring assembly proximate the reciprocable region of the cantilever.

7. The device of claim 1, wherein the spring assembly is structurally integrated with the P-SAW transducer in a vacuum environment.

8. The device of claim 1, wherein the spring assembly is disposed in a vacuum environment and the P-SAW transducer is disposed in a non-vacuum environment.

9. The device of claim 1, further comprising an RF antenna coupled to the P-SAW output port.

10. The device of claim 1, further comprising a radioactive particle receiver that is attached to one of the reciprocable region of the cantilever and the spring assembly at an opposing distance above or below the reciprocable region of the cantilever.

11. The device of claim 1, wherein each of the input port and the output port include a plurality of interdigitated electrodes.

12. The device of claim 11, wherein the interdigitated electrodes of the input port have a selected gap-spacing that determines a selected resonant frequency of the P-SAW transducer.

13. The device of claim 1, comprising a plurality of spring assemblies and interconnected P-SAW structures having different resonant frequencies.

14. The device of claim 1, wherein the P-SAW structure includes a signal modulation component disposed intermediate the import port and the output port.

15. The device of claim 14, wherein the signal modulation component comprises at least one of a mass sensor and an RFID code comprising interdigitated transducer (IDT) fingers.

16. The device of claim 15, wherein the IDT is connected to at least one of an external analog and a digital circuit.

17. The device of claim 10, wherein the distance between the radioactive particle emitter and the radioactive particle receiver is a maximum operable distance to maximize energy output.

18. The device of claim 11, characterized by an operable distance between the radioactive particle emitter and the radioactive particle receiver that is a maximum distance and the interdigitated electrodes of the input port have a maximum number of electrode fingers.

19. The device of claim 1, characterized by a Nickel-63 radioisotope powered P-SAW structure.

20. A method for generating an RF signal having a tuned signal frequency, comprising:

generating energy through an energy pulse from an autonomous electrical discharge system having a charging cycle and a discharge cycle;

inputting the energy to an input port of a piezoelectric-SAW (P-SAW) structure characterized by a resonant frequency, wherein, during the charging cycle, storing an electrical component of the energy and a mechanical component of the energy in the P-SAW structure;

during the discharge cycle, exciting the resonant frequency of the P-SAW structure; and

outputting an RF signal having a frequency tuned to the P-SAW resonant frequency from an output port of the P-SAW structure.

21. The method of claim 20, wherein the step of generating energy through an energy pulse from an autonomous electrical discharge system comprises collecting emitted electrons from a radioactive source to generate the electrical discharge.

22. The method of claim 20, wherein the discharge cycle has a duration equal to or less than one nanosecond.

23. The method of claim 20, wherein the charging cycle has a duration between about three to five minutes.

24. The method of claim 20, wherein the step of outputting the RF signal comprises generating a relatively shorter duration, higher voltage component and a relatively longer duration, lower voltage component of the signal.

25. The method of claim 24, comprising time delaying the relatively longer duration, lower voltage component with respect to the relatively shorter duration, higher voltage component.

26. The method of claim 20, wherein the input port of the P-SAW structure is comprised of an interdigitated transducer electrode.

27. The method of claim 20, wherein the step of outputting the RF signal further comprises modulating the RF signal via a signal modulation component disposed intermediate the input port and at least one output port of the P-SAW structure.