Radiative wireless charging system
The technology provides for a wireless charger. The wireless charger may have a transmitter antenna array, one or more detectors, one or more sensors, and one or more processors. For instance, the processors may determine, based on signals from the detectors, that one or more receiver antennas are located within a near-field range of the transmitter antenna array. The processors may then control the transmitter antenna array to focus electromagnetic waves on a first receiver antenna of the one or more receiver antennas, and control the transmitter antenna array to transmit power to the first receiver antenna. In some instances, the processors may further determine, based on signals from the sensors, that a person is located within the near-field range of the transmitter antenna array. Based on this determination, the processors may control the transmitter antenna array to stop transmitting power to the first receiver antenna.
1. A wireless charger, comprising:
a transmitter antenna array including a plurality of radiating elements;
one or more detectors configured to collect signals from one or more receiver antennas;
one or more sensors configured to generate signals indicating presence of a person;
one or more processors configured to:
determine, based on the signals from the one or more detectors, that one or more of the receiver antennas are located within a near-field range of a transmission field of the transmitter antenna array, the near-field range being a sub-region of the transmission field;
control the plurality of radiating elements to focus electromagnetic waves on a first focal point within the near-field range, the first focal point corresponding to a first receiver antenna of the one or more receiver antennas;
control the transmitter antenna array to transmit power to the first receiver antenna;
determine, based on the signals from the one or more sensors, that the person is located within the near-field range of the transmitter antenna array; and
control the transmitter antenna array to stop transmitting power to the first receiver antenna.
2. The wireless charger of claim 1 , wherein the one or more processors are further configured to:
determine, based on the signals from the one or more detectors and the signals from the one or more sensors, whether the person is located in a direction of the power transmission, wherein controlling the transmitter antenna array to stop transmitting power to the first receiver antenna is further based on determining that the detected person is located in the direction of the power transmission.
3. The wireless charger of claim 2 , wherein the one or more processors are further configured to:
determine, based on the signals from the one or more detectors and the signals from the one or more sensors, that the person is not located in a direction of a second receiver antenna of the one or more receiver antennas;
control the plurality of radiating elements to focus electromagnetic waves on the second receiver antenna; and
control the transmitter antenna array to transmit power to the second receiver antenna.
4. The wireless charger of claim 1 , wherein the one or more sensors include at least one of: an optical sensor, a camera, a motion sensor, a radar, or an RF sensor.
5. The wireless charger of claim 1 , wherein an operating frequency of the transmitter antenna array is outside frequency ranges for wireless communication.
6. The wireless charger of claim 1 , wherein an operating frequency of the transmitter antenna array is 24 GHz.
7. The wireless charger of claim 1 , wherein dimensions of the transmitter antenna array are within a range of 10 cm-20 cm.
8. The wireless charger of claim 1 , wherein spacings between the plurality of radiating elements are within a range of 0.5 cm-lcm.
9. The wireless charger of claim 1 , wherein the plurality of radiating elements are provided on a two-dimensional surface.
10. The wireless charger of claim 1 , wherein the plurality of radiating elements are provided on one or more surfaces of a three-dimensional structure.
11. The wireless charger of claim 1 , wherein a boundary of the near-field range is between 0.5-2 meter.
12. The wireless charger of claim 1 , further comprising:
one or more phase shifters configured to change phases of the electromagnetic waves from the plurality of radiating elements, wherein the one or more processors are further configured to control the one or more phase shifters to focus the electromagnetic waves on the first receiver antenna.
13. The wireless charger of claim 1 , further comprising:
one or more amplifiers configured to change amplitudes of the electromagnetic waves from the plurality of radiating elements, wherein the one or more processors are configured to control the one or more amplifiers to focus the electromagnetic waves on the first receiver antenna.
14. The wireless charger of claim 1 , wherein the one or more detectors are further configured to:
receive measurements of power received by the first receiver antenna through a Bluetooth link, wherein the one or more processors are further configured to control the plurality of radiating elements to focus the electromagnetic waves on the first receiver antenna based on the measurements of power received.
15. The wireless charger of claim 1 , wherein the one or more processors are further configured to:
determine, based on the signals from the one or more detectors, that the one or more receiver antennas include a plurality of receiver antennas; and
determine a time division to focus the electromagnetic waves and transmit power to each of the plurality of receiver antennas.
16. The wireless charger of claim 1 , wherein the transmission field includes a non-radiative range and a far-field range.
17. An antenna system, comprising:
a transmitter antenna array comprising a plurality of radiating elements, the transmitter antenna array having an operating frequency higher than frequency ranges for wireless communication;
one or more receiver antenna arrays each comprising a plurality of radiating elements, the one or more receiver antenna arrays being located within a near-field range of a transmission field of the transmitter antenna array, the near-field range being a sub-region of the transmission field; and
the transmitter antenna array configured to stop transmitting power to the one or more receiver antenna arrays when a person is located within the near-field range of the transmitter antenna array.
18. The antenna system of claim 17 , further comprising:
one or more rectifier configured to convert RF received by the one or more receiver antenna arrays into electrical energy; and
one or more energy storage units configured to store the electrical energy.
19. The antenna system of claim 17 , further comprising:
one or more feedback devices configured to:
generate measurements on power received by the one or more receiver antenna arrays; and
send the measurements to one or more processors associated with the transmitter antenna array through a Bluetooth link.
20. The antenna system of claim 17 , wherein a boundary of the near-field range of the transmitter antenna array is at 0.5-2 meter.
21. An antenna array, comprising:
a plurality of antenna radiating elements,
wherein an operating frequency of the antenna array is higher than frequency ranges for wireless communication,
wherein a near-field range of a transmission field of the antenna array is between 0.5-2 meter, the near-field range being a sub-region of the transmission field, and
wherein the plurality of antenna radiating elements are configured to stop transmitting to a receiver when a person is located within the near-field range of the antenna array.