Rectenna for high-voltage applications

• US 6,369,759 B1
• Filed: 06/08/2000
• Issued: 04/09/2002
• Est. Priority Date: 06/09/1999
• Status: Expired due to Fees

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Khan, Abdur R., Epp, Larry W.
• Primary Examiner(s): Wong, Don
• Assistant Examiner(s): VANNUCCI, JAMES
• Application Number:
  US09/591,184
• Time in Patent Office: 670 Days
• Field of Search: 343/700.MS, 343/824, 343/846, 343/893, 343/848, 343/841
• US Class Current: 343/700.0MS
• CPC Class Codes: H01Q 1/248 provided with an AC/DC converting device, e.g. rectennas
• CPC Class Codes: H01Q 21/065 Patch antenna array
• CPC Class Codes: H01Q 9/0457 electromagnetically coupled to the feed line
• CPC Class Codes: H02J 50/005 Mechanical details of housing or structure aiming to accommodate the power transfer means, e.g. mechanical integration of coils, antennas or transducers into emitting or receiving devices
• CPC Class Codes: H02J 50/27 characterised by the type of receiving antennas, e.g. rectennas
• CPC Class Codes: H02J 50/402 the two or more transmitting or the two or more receiving devices being integrated in the same unit, e.g. power mats with several coils or antennas with several sub-antennas
• CPC Class Codes: H02J 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields

Abstract

An energy transfer system is disclosed. The system includes patch elements, shielding layers, and energy rectifying circuits. The patch elements receive and couple radio frequency energy. The shielding layer includes at least one opening that allows radio frequency energy to pass through. The openings are formed and positioned to receive the radio frequency energy and to minimize any re-radiating back toward the source of energy. The energy rectifying circuit includes a circuit for rectifying the radio frequency energy into dc energy. A plurality of energy rectifying circuits is arranged in an array to provide a sum of dc energy generated by the energy rectifying circuit.

Claims

1. An energy transfer system, comprising:

antenna elements arranged to face a source of energy, said energy coupled thereto, each of said antenna elements having a first surface facing the source of energy, and a second surface opposite said first surface and facing away from the source of energy;

a plurality of shielding layers, each shielding layer located facing said second surface, such that each of said antenna elements is coupled between said source of energy and said each shielding layer, said each shielding layer including

first and second apertures arranged to receive the energy, said first and second apertures operating to separate a first part of the energy having a first polarization from a second part of the energy having a second polarization, where said first aperture is positioned to receive said first part of the energy, and said second aperture is positioned to receive said second part of the energy;

a plurality of energy receiving boards, each board including

first and second circuit portions spaced apart from each other,

said first circuit portion including a first diode and operative to couple said first part of the energy to produce a first output signal corresponding to said first polarization,

said second circuit portion including a second diode and operative to couple said second part of the energy to produce a second output signal corresponding to said second polarization, said second circuit portion using same antenna element as said first circuit portion to couple the energy; and

means for appropriately coupling said first and second output signals to sum the energy received by said each board of said plurality of energy receiving boards; and

a plurality of resistors, each resistor coupled between each shielding layer, said plurality of resistors arranged to appropriately reverse bias said first and second diodes when the energy is being received, and said plurality of resistors are arranged to provide a discharging path to protect said first and second diodes when the energy is removed,

wherein said first and second output signals of each antenna element are connected in a series connection or a parallel connection such that said antenna elements are connected.

2. The system of claim 1, wherein said each shielding layer is a dc isolated ground plane.

3. The system of claim 2, wherein said means for appropriately coupling said first and second signals includes a series dc path provided by said dc isolated ground plane operating to combine said first and second energy polarizations of each antenna element by summing said first and second signals, and by said plurality of resistors arranged to provide appropriate signal ratios between said dc isolated ground planes.

4. The system of claim 3, wherein said plurality of resistors are arranged to provide appropriate signal ratios between antenna elements when energy from each antenna element is combined with a next antenna element.

5. The system of claim 2, wherein said dc isolation is provided by a square ring slot etched on said each shielding layer.

6. The system of claim 2, wherein said first and second diodes are connected to said each shielding layer or dc isolated ground plane through a via connection.

7. The system of claim 1, wherein each of said plurality of resistors are connected between said plurality of shielding layers, where said plurality of resistors provide further isolation of said plurality of shielding layers and provide static discharge protection between said plurality of shielding layers.

8. The system of claim 1, wherein each of said first and second apertures includes a rectangular slot having a length along an axial direction, said axial direction of said first aperture facing in a different direction than said axial direction of said second aperture, said each aperture receiving a different portion of energy in conjunction with each antenna element, where energy from said first aperture is coupled to said first diode, and energy from said second aperture is coupled to said second diode.

9. The system of claim 1, wherein said antenna element is a patch antenna element.

10. The system of claim 1, wherein said antenna elements are arranged as an array in such a configuration as to minimize a total effective area of the system and increase overall system efficiency.

11. The system of claim 1, further comprising:

a plurality of surface wave reducing layers, each surface wave reducing layer coupled between each of said antenna elements and said each shielding layer.

12. The system of claim 11, wherein said each surface wave reducing layer is formed of a low-dielectric lightweight material.

13. A method of receiving and transducing energy, comprising:

separating a first part of the energy having a first polarization from a second part of the energy having a second polarization in a first cell;

coupling said first part of the energy to a first circuit portion of an energy receiving board to produce a first output signal;

coupling said second part of the energy to a second circuit portion of the energy receiving board to produce a second output signal, said second circuit portion spaced apart from said first circuit portion;

appropriately coupling energy of said first and second output signals to sum the energy received by said energy receiving board; and

providing dc isolation to said first cell.

14. The method of claim 13, further comprising:

inserting a shielding layer to shield said first and second circuit portions from RF energy.

15. A method of receiving and transducing energy, comprising:

separating a first part of the energy having a first polarization from a second part of the energy having a second polarization;

coupling said first part of the energy to a first circuit portion of an energy receiving board to produce a first output signal;

coupling said second part of the energy to a second circuit portion of the energy receiving board to produce a second output signal, said second circuit portion spaced apart from said first circuit portion;

appropriately coupling energy of said first and second output signals to sum the energy received by said energy receiving board;

inserting a shielding layer to shield said first and second circuit portions from RF energy;

isolating a plurality of shielding layers; and

coupling said plurality of shielding layers with a plurality of resistors.

16. The method of claim 15, wherein said appropriately coupling energy includes making serial or parallel connection between each of a plurality of first and second circuit portions in said energy receiving boards.

17. The method of claim 15, further comprising:

providing said energy to a load; and

transducing actuators.

18. A circuit for coupling and receiving RF energy and converting the RF energy to rectified dc energy, comprising:

an array of energy receiving elements arranged to face a source of RF energy;

a plurality of rectifying circuits operating to convert the RF energy into stable dc energy, each rectifying circuit including at least two diodes arranged in an opposing manner, said each rectifying circuit serially connected to adjacent rectifying circuits to sum energy coupled in said at least two diodes; and

a plurality of ground planes, each ground plane coupled between each energy receiving element and said each rectifying circuit to minimize any re-radiating back toward the source of RF energy, said each ground plane dc isolated and connected to adjacent ground planes through resistors.