Generating DC electric power from ambient electromagnetic radiation

• US 8,330,298 B2
• Filed: 06/17/2010
• Issued: 12/11/2012
• Est. Priority Date: 06/17/2010
• Status: Expired due to Fees

• Current Assignee: Scarf Technologies LLC
• Original Assignee: Scarf Technologies LLC
• Inventors: Scherbenski, Josh, Cullom, Freeman
• Primary Examiner(s): Dberadinis, Robert L.
• Application Number:
  US12/818,103
• Publication Number:
  US 20110309686A1
• Time in Patent Office: 908 Days
• Field of Search: 307/104
• US Class Current: 307/104
• CPC Class Codes: H02J 50/001 Energy harvesting or scavenging
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• 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

Abstract

At least certain embodiments describe methods, apparatuses, and systems for converting energy from electro-magnetic (EM) radiation into electric power using a simultaneous collector of ambient radio frequencies (SCARF) circuit. In one embodiment this is done by capturing EM radiation from a plurality of ambient signals using an array of antennae where each signal has a resonant frequency and aggregating the ambient signals to generate an aggregated signal having a single frequency with greater AC power than the AC power of each of the plurality of ambient signals individually. The single frequency can be produced by either the sum of the resonant frequencies of the ambient signals or the difference between the resonant frequencies of the ambient signals. The aggregated signal is then converted into useable electric power using a rectifying circuit such that for every incremental increase in the AC power of the aggregated signal, there is a corresponding exponential increase in DC power at the output of the rectifying circuit.

Claims

1. A method of converting RF energy from ambient electro-magnetic (EM) radiation into useable electric power using a simultaneous collector of ambient radio frequencies (SCARF) circuit, the method comprising:

simultaneously capturing EM radiation from a plurality of ambient RF or microwave signals using an array of antennae having at least two antennae, each signal having a different resonant frequency;

aggregating the plurality of ambient signals to generate an aggregated signal having a single predetermined intermediate frequency signal with greater AC power than AC power of each of the plurality of ambient signals individually, wherein the single predetermined intermediate frequency is either a sum of the resonant frequencies of the plurality of ambient signals or a difference between the resonant frequencies of the plurality of ambient signals; and

converting the aggregated signal into useable electric power using a rectifying circuit, wherein for every incremental increase in the AC power of the aggregated signal, there is a corresponding exponential increase in DC power at the output of the rectifying circuit.

2. The method of claim 1, further comprising optimizing the rectifying circuit to match the single predetermined intermediate frequency and to generate an output signal such that DC power of the output signal has a peak AC to DC power conversion.

3. The method of claim 2, further comprising:

selecting a first antenna having a first resonant frequency and a second antenna having a second resonant frequency different from the first resonant frequency, wherein the first and the second antennae are selected to provide a single predetermined intermediate frequency optimized for the rectifying circuit coupled at an output of the SCARF circuit;

aggregating the first and second resonant frequencies using a first mixer within the SCARF circuit to generate the single predetermined intermediate frequency, wherein the first mixer includes a first input coupled with the first antenna and a second input coupled with the second antenna, and wherein the single predetermined intermediate frequency is either a sum of the first and second resonant frequencies or a difference between the first and second resonant frequencies; and

passing the single predetermined intermediate frequency and rejecting other frequencies using a first filter coupled with an output of the first mixer.

4. The method of claim 3, further comprising:

selecting a third antenna having a third resonant frequency and a fourth antenna having a fourth resonant frequency different from the third resonant frequency, wherein the third and fourth antennae are selected to provide the single predetermined intermediate frequency optimized for the rectifying circuit at the output of the SCARF circuit; and

aggregating the third and fourth resonant frequency using a second mixer within the SCARF circuit to generate the single predetermined intermediate frequency, wherein the second mixer includes a first input coupled with the third antenna and a second input coupled with the fourth antenna, and wherein the single predetermined intermediate frequency is either a sum of the third and fourth resonant frequencies or a difference between the third and fourth resonant frequencies; and

passing the single predetermined intermediate frequency and rejecting other frequencies using a second filter coupled with an output of the second mixer.

5. The method of claim 4, further comprising transferring a sum of the output of the first filter and the second filter to the rectifying circuit using a voltage summer coupled between the first and second filters and the rectifying circuit, wherein the voltage summer includes a first input coupled with an output of the first filter and a second input coupled with the output of the second filter, and an output coupled with an input of the rectifying circuit.

6. The method of claim 5, wherein the SCARF circuit further comprises a phase lock loop coupled between the outputs of the first and second filters and the voltage summer.

7. The method of claim 6, wherein the phase lock loop comprises:

a phase detector circuit configured to detect a phase difference between the output of the first filter and the output of the second filter;

a first voltage divider coupled between the output of the first filter and a first input of the phase detector circuit, the first voltage divider configured to provide a first low-amplitude version of the single predetermined intermediate frequency to the first input of the phase detector circuit;

a second voltage divider coupled between the output of the second filter and a second of input of the phase detector circuit, the second voltage divider configured to provide a second low-amplitude version of the single predetermined intermediate frequency to the second input of the phase detector circuit; and

a phase shifter coupled between the output of the second filter and the second voltage divider, the phase shifter having an input coupled with the output of the phase detector circuit, wherein the phase shifter is configured such that a phase between an output frequency of the first filter and an output frequency of the second filter is zero.

8. The method of claim 7, wherein the phase detector circuit includes a small-signal mixer coupled with a low pass filter and the phase shifter includes a varactor phase shifter.

9. The method of claim 6, further comprising coupling together a plurality of pairs SCARF circuits, wherein each pair of SCARF circuits is coupled together such that an output of a first of the pair of SCARF circuits is coupled with a first input of a second-level phase lock loop and an output of a second of the pair of SCARF circuits is coupled with a second input of the second-level phase lock loop, wherein an output of the second-level phase lock loop is coupled with an input of a second-level voltage summer, and wherein an output of the second-level voltage summer is coupled with the input of the rectifying circuit.

10. An RF energy harvesting device configured to convert energy from ambient electro-magnetic (EM) radiation into useable electric power, the RF energy harvesting device comprising:

a simultaneous collector of ambient radio frequencies (SCARF) circuit including;

(1) an antennae array having at least two antennae, the antennae array configured to simultaneously capture EM radiation from a plurality of ambient RF or microwave signals, each signal having a different resonant frequency; and

(2) an aggregation circuit configured to aggregate the plurality of ambient signals to generate an aggregated signal having a single predetermined intermediate frequency with greater AC power than the AC power of each of the plurality of ambient signals individually, wherein the single predetermined intermediate frequency is either a sum of the resonant frequencies of the plurality of ambient signals or a difference between the resonant frequencies of the plurality of ambient signals; and

a rectifying circuit configured to convert the aggregated signal into useable electric power, wherein for every incremental increase in the AC power of the aggregated signal, there is a corresponding exponential increase in DC power at the output of the rectifying circuit.

11. The RF energy harvesting device of claim 10, wherein the rectifying circuit is coupled with an output of the first filter, the rectifying circuit configured to:

match the single predetermined intermediate frequency; and

generate an output signal such that DC power of the output signal has a peak AC to DC power conversion.

12. The RF energy harvesting device of claim 10, wherein the SCARF circuit further comprises:

(1) the antenna array having a first antenna and a second antenna, wherein the first antenna is configured to capture a first signal having a first resonant frequency and the second antenna is configured to capture a second signal having a second resonant frequency different from the first resonant frequency, wherein the first and second antennae are selected to provide the single predetermined intermediate frequency optimized for the rectifying circuit;

(2) a first mixer coupled with each of the first and second antennae, the first mixer configured to aggregate the resonant frequencies of the first and second signals and to generate an aggregated signal having the single predetermined intermediate frequency with greater AC power than the AC power of each of the first and second signals individually, wherein the single predetermined intermediate frequency is either the sum of the first and second resonant frequencies or the difference between the first and second resonant frequencies; and

(3) a first filter coupled with an output of the first mixer, the first filter configured to pass the single predetermined intermediate frequency and to reject other frequencies.

13. The RF energy harvesting device of claim 12, wherein the SCARF circuit further comprises:

(4) a third antenna having a third resonant frequency and a fourth antenna having a fourth resonant frequency different from the first, second, and third resonant frequencies, wherein the third and fourth antennae are selected to provide the single predetermined intermediate frequency optimized for the rectifying circuit;

(5) a second mixer coupled with outputs of each of the third and fourth antennae, the second mixer configured to aggregate the resonant frequencies of the third and fourth signals and to generate an aggregated signal having the single predetermined intermediate frequency with greater AC power than the AC power of each of the third and fourth signals individually, wherein the single predetermined intermediate frequency is either the sum of the third and fourth resonant frequencies or the difference between the third and fourth resonant frequencies; and

(6) a second filter coupled with an output of the second mixer, the second filter configured to pass the single predetermined intermediate frequency and to reject other frequencies.

14. The RF energy harvesting device of claim 13, further comprising a voltage summer coupled between the first and second filters and the rectifying circuit, the voltage summer having a first input coupled with an output of the first filter and a second input coupled with the output of the second filter, wherein the output of the voltage summer produces a sum of the outputs of the first and second filters.

15. The RF energy harvesting device of claim 14, further comprising a phase lock loop coupled between the outputs of the voltage summer and the first and second filters.

16. The RF energy harvesting device of claim 15, wherein the phase lock loop comprises:

a phase detector circuit configured to detect a phase difference between the output of the first filter and the output of the second filter;

a first voltage divider coupled between the output of the first filter and a first input of the phase detector circuit, the first voltage divider configured to provide a first low-amplitude version of the single predetermined intermediate frequency to the first input of the phase detector circuit;

a second voltage divider coupled between the output of the second filter and a second input of the phase detector circuit, the second voltage divider configured to provide a second low-amplitude version of the single predetermined intermediate frequency to the second input of the phase detector circuit; and

a phase shifter coupled between the output of the second filter and the second voltage divider, the phase shifter having an input coupled with the output of the phase detector circuit, wherein the phase shifter is configured such that a phase between an output frequency of the first filter and an output frequency of the second filter is zero.

17. The RF energy harvesting device of claim 16, wherein the phase detector circuit includes a small-signal mixer coupled with a low pass filter, and the phase shifter includes a varactor phase shifter.

18. The RF energy harvesting device of claim 15, further comprising a plurality of pairs of SCARF circuits, wherein each pair of SCARF circuits is coupled together such that the output of a first of the pair of SCARF circuits is coupled with a first input of a second-level phase lock loop and the output of a second of the pair of SCARF circuits is coupled with a second input of the second-level phase lock loop, and wherein an output of the second-level phase lock loop is coupled with an input of a second-level voltage summer, and wherein an output of the second-level voltage summer is coupled with the input of the rectifying circuit.

19. A system having a first simultaneous collector of ambient radio frequencies (SCARF) circuit coupled with a second SCARF circuit, wherein each SCARF circuit comprises:

an antennae array having at least two antennae, the antennae array configured to simultaneously capture EM radiation from a plurality of ambient RF or microwave signals, each signal having a different resonant frequency; and

an aggregation circuit configured to aggregate the plurality of ambient signals to generate an aggregated signal having a single predetermined intermediate frequency with greater AC power than AC power of each of the plurality of ambient signals individually, wherein the single predetermined intermediate frequency is either a sum of the resonant frequencies of the plurality of ambient signals or a difference between the resonant frequencies of the plurality of ambient signals.

20. The system of claim 19, further comprising a rectifying circuit coupled to outputs of the first and second SCARF circuits, the rectifying circuit configured to:

match the single predetermined intermediate frequency; and

generate an output signal such that DC power of the output signal has a peak AC to DC power conversion.

21. The system of claim 19, wherein each SCARF circuit further comprises:

(1) the antenna array having a first antenna and a second antenna, wherein the first antenna is configured to capture a first signal having a first resonant frequency and the second antenna is configured to capture a second signal having a second resonant frequency different from the first resonant frequency, wherein the first and second antennae are selected to provide the single predetermined intermediate frequency optimized for the rectifying circuit;

(2) a first mixer coupled with each of the first and second antennae, the first mixer configured to aggregate the resonant frequencies of the first and second signals and to generate an aggregated signal having the single predetermined intermediate frequency with greater AC power than the AC power of each of the first and second signals individually, wherein the single predetermined intermediate frequency is either the sum of the first and second resonant frequencies or the difference between the first and second resonant frequencies; and

(3) a first filter coupled with an output of the first mixer, the first filter configured to pass the single predetermined intermediate frequency and to reject other frequencies.

22. The system of claim 21, wherein each SCARF circuit further comprises:

(4) a third antenna having a third resonant frequency and a fourth antenna having a fourth resonant frequency different from the first, second, and third resonant frequencies, wherein the third and fourth antennae are selected to provide the single predetermined intermediate frequency optimized for the rectifying circuit;

(5) a second mixer coupled with outputs of each of the third and fourth antennae, the second mixer configured to aggregate the resonant frequencies of the third and fourth signals and to generate an aggregated signal having the single predetermined intermediate frequency with greater AC power than the AC power of each of the third and fourth signals individually, wherein the single predetermined intermediate frequency is either the sum of the third and fourth resonant frequencies or the difference between the third and fourth resonant frequencies; and

(6) a second filter coupled with an output of the second mixer, the second filter configured to pass the single predetermined intermediate frequency and to reject other frequencies.

23. The system of claim 22, further comprising a voltage summer coupled between the first and second filters and the rectifying circuit, the voltage summer having a first input coupled with an output of the first filter and a second input coupled with the output of the second filter, wherein the output of the voltage summer produces a sum of the outputs of the first and second filters.

24. The system of claim 23, wherein each SCARF circuit further comprises a phase lock loop coupled between the voltage summer and the outputs of the first and second filters.

25. The system of claim 24, wherein the phase lock loop of each SCARF circuit comprises:

a phase detector circuit configured to detect a phase difference between the output of the first filter and the output of the second filter;

a first voltage divider coupled between the output of the first filter and a first input of the phase detector circuit, the first voltage divider configured to provide a first low-amplitude version of the single predetermined intermediate frequency to the first input of the phase detector circuit;

a second voltage divider coupled between the output of the second filter and a second input of the phase detector circuit, the second voltage divider configured to provide a second low-amplitude version of the single predetermined intermediate frequency to the second input of the phase detector circuit; and

a phase shifter coupled between the output of the second filter and the second voltage divider, the phase shifter having an input coupled with the output of the phase detector circuit, wherein the phase shifter is configured such that a phase between an output frequency of the first filter and an output frequency of the second filter is zero.

26. The system of claim 25, wherein the phase detector circuit for each SCARF circuit includes a small-signal mixer coupled with a low pass filter and the phase shifter includes a varactor phase shifter.

27. The system of claim 26, wherein the rectifying circuit for each SCARF circuit is selected from the group consisting of:

a half-wave rectifying circuit optimized for high frequencies;

a full-wave rectifying circuit optimized for low frequencies; and

a voltage multiplier optimized for ultra-low frequencies.