Near-field RF charging pad with multi-band antenna element with adaptive loading to efficiently charge an electronic device at any position on the pad

• US 10,079,515 B2
• Filed: 12/06/2017
• Issued: 09/18/2018
• Est. Priority Date: 12/12/2016
• Status: Active Grant

• Current Assignee: Energous Corporation
• Original Assignee: Energous Corporation
• Inventors: Hosseini, Alister, Leabman, Michael A.
• Primary Examiner(s): Parihar, Suchin
• Application Number:
  US15/833,790
• Publication Number:
  US 20180166924A1
• Time in Patent Office: 286 Days
• Field of Search: 320108
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/23 characterised by the type of transmitting antennas, e.g. directional array antennas or Yagi antennas
• CPC Class Codes: H02J 50/40 using two or more transmitting or receiving devices H02J50/50 takes precedence
• CPC Class Codes: H02J 7/0042 characterised by the mechanical construction
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer
• CPC Class Codes: H04W 4/80 Services using short range communication, e.g. near-field communication [NFC], radio-frequency identification [RFID] or low energy communication
• CPC Class Codes: Y02B 40/00 Technologies aiming at improving the efficiency of home appliances, e.g. induction cooking or efficient technologies for refrigerators, freezers or dish washers

Abstract

An example radio frequency (RF) charging pad includes: at least one processor for monitoring an amount of energy that is transferred from the RF charging pad to an RF receiver of an electronic device. The pad also includes: one or more transmitting antenna elements that are in communication with the processor for transmitting RF signals to the RF receiver. In some embodiments, each respective transmitting antenna element includes: (i) a conductive line forming a meandered line pattern; (ii) a first terminal of the conductive line for receiving current at one or more frequencies controlled by the processor; and (iii) one or more adaptive load terminals coupled with a plurality of respective components that allows for modifying an impedance value at each of the adaptive load terminals. In some embodiments, the processor adaptively adjusts the frequency and/or the impedance value to optimize the amount of energy that is transferred from the one or more transmitting antenna elements to the RF receiver.

Claims

1. A radio frequency (RF) charging pad, comprising:

one or more processors for monitoring an amount of energy that is transferred from the RF charging pad to an RF receiver of an electronic device; and

one or more transmitting antenna elements that are configured to communicate with the one or more processors for transmitting RF signals to the RF receiver of the electronic device, each respective transmitting antenna element including;

a conductive line forming a meandered line pattern;

an input terminal at a first end of the conductive line for receiving current that flows through the conductive line at a frequency controlled by the one or more processors; and

a plurality of adaptive load terminals, distinct from the input terminal and distinct from each other, at a plurality of positions of the conductive line, each respective adaptive load terminal of the plurality of adaptive load terminals coupled with a respective component that is configured to be controlled by the one or more processors and is configured to allow modifying a respective impedance value at each respective adaptive load terminal,

wherein the one or more processors are configured to adaptively adjust at least one of the frequency and a respective impedance value at one or more of the plurality of adaptive load terminals to optimize the amount of energy that is transferred from the one or more transmitting antenna elements to the RF receiver of the electronic device.

2. The RF charging pad of claim 1, wherein the frequency is in a first frequency band, and at least one of the one or more transmitting antenna elements is configured to operate at a second frequency band based on adaptive adjustments, by the one or more processors, to respective impedance values at one or more of the plurality of adaptive load terminals of the at least one transmitting antenna element.

3. The RF charging pad of claim 1, further comprising an input circuit that is coupled with the one or more processors and is configured to provide the current to the input terminal at the first end of the conductive line,

wherein the one or more processors are configured to adaptively adjust the frequency by instructing the input circuit to generate the current with a new frequency that is distinct from the frequency.

4. The RF charging pad of claim 3, wherein the one or more processors are configured to adaptively adjust the frequency by instructing the feeding element to generate the current with a plurality of different frequencies that are determined using predetermined increments.

5. The RF charging pad of claim 3, wherein:

a respective conductive line for at least one of the one or more transmitting antenna elements has a respective meandered line pattern that allows the at least one transmitting antenna element to efficiently transmit RF signals having at least one of the frequency and the new frequency,

at least two adjacent segments of the respective conductive line having the respective meandered line pattern have different geometric dimensions relative to each other, and

the respective conductive line has a length that remains the same when the at least one transmitting antenna element is configured to transmit RF signals having at least one of the frequency and the new frequency.

6. The RF charging pad of claim 3, wherein:

at least one transmitting antenna element of the one or more transmitting antenna elements has a first segment and a second segment, the first segment including the input terminal, and the at least one transmitting antenna element is configured to;

operate at the frequency while the first segment is not coupled with the second segment, and

operate at the new frequency while the first segment is coupled with the second segment; and

the one or more processors are configured to couple the first segment with the second segment in conjunction with instructing the feeding element to generate the current with the new frequency that is distinct from the frequency.

7. The RF charging pad of claim 1, wherein the one or more processors are configured to:

adaptively adjust at least one of the frequency and a respective impedance value associated with a first transmitting antenna element of the one or more transmitting antenna elements to cause the first transmitting antenna element to operate in a first frequency band, and

adaptively adjust at least one of the frequency and the respective impedance value associated with a second transmitting antenna element of the one or more transmitting antenna elements to cause the second transmitting antenna element to operate in a second frequency band, wherein the first frequency band is distinct from the second frequency band.

8. The RF charging pad of claim 1, wherein the electronic device is placed in contact with or close to a top surface of the RF charging pad.

9. The RF charging pad of claim 1, wherein the respective component is a mechanical relay coupled with the respective adaptive load terminal for switching the respective adaptive load terminal between open and short states, and the impedance value is adaptively adjusted at the respective adaptive load terminal of the respective transmitting antenna element by opening or closing the mechanical relay to switch between an open or short circuit, respectively.

10. The RF charging pad of claim 1, wherein the respective component is an application-specific integrated circuit (ASIC), and the respective impedance value is adaptively adjusted by the ASIC to within a range of values.

11. The RF charging pad of claim 1, wherein the one or more processors are configured to:

adaptively adjust at least one of the frequency and the respective impedance value by adaptively adjusting the frequency and a respective impedance value at one or more of the plurality of adaptive load terminals to determine a relative maximum amount of energy that is transferred to the RF receiver of the electronic device, and

once the maximum amount of energy is determined, cause each of the one or more transmitting antenna elements to respectively transmit the RF signals at a respective frequency and using a respective impedance value that resulted in the maximum amount of energy transferred to the RF receiver.

12. The RF charging pad of claim 1, wherein the one or more processors monitor the amount of energy that is transferred to the RF receiver based at least in part on information received from the electronic device, the information identifying energy received at the RF receiver from the RF signals.

13. The RF charging pad of claim 12, wherein the information received from the electronic device identifying received energy is sent using a wireless communication protocol.

14. The RF charging pad of claim 13, wherein the wireless communication protocol is bluetooth low energy (BLE).

15. The RF charging pad of claim 1, wherein the one or more processors monitor the amount of energy transferred based at least in part on an amount of energy that is detected at the respective adaptive load terminal.

16. A method of charging an electronic device through radio frequency (RF) power transmission, the method comprising:

providing a charging pad that includes a transmitter comprising one or more RF antennas, wherein each RF antenna of the one or more RF antennas comprises;

a conductive line forming a meandered line pattern;

an input terminal at a first end of the conductive line for receiving current that flows through the conductive line at a frequency controlled by one or more processors; and

a plurality of adaptive load terminals, distinct from the input terminal and distinct from each other, at a plurality of positions of the conductive line, each respective adaptive load terminal of the plurality of adaptive load terminals coupled with a respective component that is configured to be controlled by the one or more processors and is configured to allow modifying a respective impedance value at each respective adaptive load terminal;

transmitting, via the one or more RF antennas, one or more RF signals;

monitoring an amount of energy that is transferred via the one or more RF signals from the one or more RF antennas to an RF receiver; and

adaptively adjusting a characteristic of the transmitter using the one or more processors of the transmitter to optimize the amount of energy that is transferred from the one or more RF antennas to the RF receiver, wherein the characteristic is selected from a group consisting of (i) a frequency of the one or more RF signals, (ii) an impedance of the transmitter, and (iii) a combination of (i) and (ii), and further wherein the impedance of the transmitter is adaptively adjusted at a respective one or more of the plurality of adaptive load terminals of the one or more RF antennas using the one or more processors of the transmitter.

17. The method of claim 16, wherein the frequency is in a first frequency band, and at least one of the one or more RF antennas is configured to operate at a second frequency band based on adaptive adjustments, by the one or more processors, to respective impedance values at one or more of the plurality of adaptive load terminals of the at least one RF antenna.

18. The method of claim 16, wherein:

a respective conductive line for at least one of the one or more RF antennas has a respective meandered line pattern that allows the at least one RF antenna to efficiently transmit the one or more RF signals having at least one of the frequency and a new frequency,

at least two adjacent segments of the respective conductive line having the respective meandered line pattern have different geometric dimensions relative to each other, and

the respective conductive line has a length that remains the same when the at least one RF antenna is configured to transmit the one or more RF signals having at least one of the frequency and the new frequency.

19. The method of claim 16, wherein:

at least one RF antenna of the one or more RF antennas has a first segment and a second segment, the first segment including the input terminal, and the at least one RF antenna is configured to;

operate at the frequency while the first segment is not coupled with the second segment, and

operate at a new frequency while the first segment is coupled with the second segment; and

the one or more processors are configured to couple the first segment with the second segment in conjunction with instructing a feeding element at the input terminal to generate the current with the new frequency that is distinct from the frequency.

20. A non-transitory computer-readable storage medium comprising executable instructions that, when executed by one or more processors that are coupled with a radio frequency (RF) charging pad that includes one or more transmitting antenna elements, cause the one or more processors to:

monitor an amount of energy that is transferred from the RF charging pad to an RF receiver of an electronic device;

communication with the one or more transmitting antenna elements for transmitting RF signals to the RF receiver of the electronic device, each respective transmitting antenna element including;

a conductive line forming a meandered line pattern;

an input terminal at a first end of the conductive line for receiving current that flows through the conductive line at a frequency controlled by the one or more processors; and

a plurality of adaptive load terminals, distinct from the input terminal and distinct from each other, at a plurality of positions of the conductive line, each respective adaptive load terminal of the plurality of adaptive load terminals coupled with a respective component that is configured to be controlled by the one or more processors and is configured to allow modifying a respective impedance value at each respective adaptive load terminal; and

adaptively adjust at least one of the frequency and a respective impedance value at one or more of the plurality of adaptive load terminals to optimize the amount of energy that is transferred from the one or more transmitting antenna elements to the RF receiver of the electronic device.