Radio power-fed terminal, system, and method

• US 8,095,159 B2
• Filed: 02/12/2009
• Issued: 01/10/2012
• Est. Priority Date: 03/27/2008
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Oodachi, Noriaki, Inagaki, Hiroki, Ootaka, Shoji
• Primary Examiner(s): Cho, James H
• Application Number:
  US12/369,857
• Publication Number:
  US 20090247199A1
• Time in Patent Office: 1,062 Days
• Field of Search: 455/67, 455/500
• US Class Current: 455/500
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/20 using microwaves or radio frequency waves
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H04B 5/00 Near-field transmission systems, e.g. inductive or capacitive transmission systems
• CPC Class Codes: H04B 5/26 using coils
• CPC Class Codes: H04B 5/79 for data transfer in combination with power transfer

Abstract

A power-fed terminal includes a first reception unit receiving, from another terminal, first information containing at least one frequency candidate that fails to be used by any other communication system, the frequency candidate being used for transmitting a first microwave, a second reception unit receiving the first microwave transmitted by the another terminal using the frequency candidate, a conversion unit converts an energy of the first microwave into a first DC energy, a transmission unit transmitting, to the another terminal, second information containing an optimum frequency corresponding to a maximum energy of the first DC energy, wherein the second reception unit receives a second microwave transmitted based on the second information by the another terminal, the conversion unit converts an energy of the second microwave into a second DC energy, the terminal further includes a secondary cell acquiring the second DC energy at the optimum frequency.

Claims

1. A power-fed terminal comprising:

a first reception unit configured to receive, from another terminal, first information containing at least one frequency candidate that fails to be used by any other communication system, the frequency candidate being used for transmitting a first microwave;

a second reception unit configured to receive the first microwave transmitted by the another terminal using the frequency candidate;

a conversion unit configured to convert an energy of the first microwave into a first DC energy; and

a transmission unit configured to transmit, to the another terminal, second information containing an optimum frequency corresponding to a maximum energy of the first DC energy,

wherein the second reception unit is configured to receive a second microwave transmitted based on the second information by the another terminal, the conversion unit is configured to convert an energy of the second microwave into a second DC energy,

the terminal further comprising a secondary cell acquiring the second DC energy at the optimum frequency.

2. The terminal according to claim 1, wherein the second reception unit includes a microwave reception antenna, and

the conversion unit includes:

a rectifying circuit converting the microwave received by the microwave reception antenna into a DC current;

a measuring unit configured to measure a current value of the DC current for each frequency candidate to obtain a plurality of measured current values;

a selection unit configured to select an optimum frequency corresponding to a maximum current value of the measured current values from the frequency candidate; and

a switch configured to switch a connection destination of the DC current between the measuring unit and the secondary cell.

3. The terminal according to claim 2, wherein the rectifying circuit has two states including a high gain state and a low gain state, if the measured current value in the low gain state is more than a threshold value, the rectifying circuit is switched to the high gain state, and if the measured current value in the low gain state is not more than the threshold value, the rectifying circuit maintains the low gain state.

4. The terminal according to claim 1, further comprising an acquisition unit configured to acquire first position information of self-terminal, and

wherein the first reception unit receives second position information of the another terminal, and the power-fed terminal further comprises a controller computing a distance between the self-terminal and the another terminal based on the first position information and the second position information, and operating the conversion unit and the transmission unit only if the distance is smaller than a threshold value.

5. The terminal according to claim 1, wherein the second reception unit receives, via an antenna formed of a coil, a microwave transmitted via an antenna formed of a coil.

6. The terminal according to claim 1, wherein the second reception unit receives, via an antenna having a resonance frequency, a microwave transmitted via an antenna having the resonance frequency.

7. A power-fed terminal comprising:

a first reception unit configured to receive, from another terminal, first information containing at least one frequency candidate that fails to be used by any other communication system, the frequency candidate being used for transmitting a first microwave;

a second reception unit configured to receive the first microwave transmitted by the another terminal using the frequency candidate;

a conversion unit configured to convert an energy of the first microwave into a first DC current;

a measuring unit configured to measure a current value of the first DC current for each frequency candidate to obtain a plurality of measured current values;

a selection unit configured to select an optimum frequency corresponding to a maximum current value of the measured current values from the at least one frequency candidate; and

a transmission unit configured to transmit second information containing the optimum frequency to the another terminal,

wherein the second reception unit is configured to receive a second microwave transmitted based on the second information by the another terminal, the conversion unit is configured to convert an energy of the second microwave into a second DC energy,

the terminal further comprising a secondary cell acquiring the second DC current at the optimum frequency.

8. A radio power supply system including a first terminal which requests another terminal to supply power, and a second terminal which receives the request from the first terminal and transmits a microwave to the first terminal,

the second terminal comprising:

a first selection unit configured to select at least one frequency candidate that fails to be used by any other communication system, the frequency candidate being used for transmitting a first microwave;

a first transmission unit configured to transmit first information containing the frequency candidate to the first terminal; and

a second transmission unit configured to transmit the first microwave to the first terminal by using the frequency candidate,

the first terminal comprising;

a first reception unit configured to receive the first information;

a second reception unit configured to receive the first microwave using the frequency candidate contained in the first information;

a conversion unit configured to convert the first microwave into a first DC current;

a measuring unit configured to measure a current value of the first DC current for each frequency candidate to obtain a plurality of measured current values;

a second selection unit configured to select an optimum frequency corresponding to a maximum current value of the measured current values from the at least one frequency candidate; and

a third transmission unit configured to transmit second information containing the optimum frequency to the second terminal,

the second terminal further comprising a third reception unit configured to receive the second information,

wherein the second transmission unit is configured to transmit a second microwave to the first terminal by using the optimum frequency contained in the second information, the second reception unit is configured to receive the second microwave, the conversion unit is configured to convert an energy of the second microwave into a second DC energy,

the first terminal further comprising a secondary cell acquiring the second DC current at the optimum frequency.

9. The system according to claim 8, wherein the first selection unit comprises:

an antenna receiving a plurality of microwaves of frequencies;

a determination unit configured to determine, using a signal received via the antenna, whether a signal used in a first communication system exists at a frequency;

a storage unit configured to store information about a second communication system that is already used and a frequency used by the second communication system; and

a third selection unit configured to select, from frequencies which fails to be used by any other communication system and are included in the storage unit, at least one frequency candidate for which the determination unit determines that no signal by a communication system exists.

10. The system according to claim 8, wherein

the first terminal further comprises a first acquisition unit configured to acquire first position information of the first terminal,

the second terminal further comprises a second acquisition unit configured to acquire second position information of the second terminal,

the first reception unit receives the second position information, and

the first terminal further comprises a controller computing a distance between the first terminal and the second terminal based on the first position information and the second position information, and operating the conversion unit, the measuring unit, the second selection unit, and the third transmission unit only if the distance is smaller than a threshold value.

11. The system according to claim 8, wherein the second transmission unit transmits the first microwave via an antenna formed of a coil, and the second reception unit receives the first microwave via an antenna formed of a coil.

12. The system according to any one of claim 8, wherein the second transmission unit transmits the first microwave via an antenna having a resonance frequency, and the second reception unit receives the first microwave via an antenna having the resonance frequency.

13. A radio power supply method comprising:

receiving, from another terminal, first information containing at least one frequency candidate that fails to be used by any other communication system, the frequency candidate being used for transmitting a first microwave;

receiving the first microwave transmitted by the another terminal using the frequency candidate;

converting an energy of the first microwave into a first DC energy;

transmitting, to the another terminal, second information containing an optimum frequency corresponding to a maximum energy of the first DC energy;

receiving a second microwave transmitted based on the second information by the another terminal;

converting an energy of the second microwave into a second DC energy; and

preparing a secondary cell acquiring the second DC energy at the optimum frequency.

14. A radio power supply method in a radio power supply system including a first terminal which requests another terminal to supply power, and a second terminal which receives the request from the first terminal and transmits a microwave to the first terminal, comprising:

in the second terminal;

selecting at least one frequency candidate that fails to be used by any other communication system, the frequency candidate being used for transmitting a first microwave;

transmitting first information containing the frequency candidate to the first terminal; and

transmitting the first microwave to the first terminal by using the frequency candidate,

in the first terminal;

receiving the first information;

receiving the first microwave using the frequency candidate contained in the first information;

converting the first microwave into a first DC current;

measuring a current value of the first DC current for each frequency candidate to obtain a plurality of measured current values;

selecting an optimum frequency corresponding to a maximum current value of the measured current values from the at least one frequency candidate; and

transmitting second information containing the optimum frequency to the second terminal,

in the second terminal, further comprising;

receiving the second information; and

transmitting a second microwave to the first terminal by using the optimum frequency contained in the second information, and

in the first terminal, further comprising;

receiving the second microwave;

converting an energy of the second microwave into a second DC energy; and

preparing a secondary cell acquiring the second DC current at the optimum frequency.