System and method for detecting the proximity of a body

• US 7,053,629 B2
• Filed: 09/28/2001
• Issued: 05/30/2006
• Est. Priority Date: 09/28/2001
• Status: Expired due to Fees

• Current Assignee: Nokia Siemens Networks GmbH & Company KG (Nokia Corporation)
• Original Assignee: Siemens Communications Incorporated (Siemens AG)
• Inventors: Nevermann, Peter
• Primary Examiner(s): KARLSEN, ERNEST F
• Application Number:
  US09/968,346
• Publication Number:
  US 20030062907A1
• Time in Patent Office: 1,705 Days
• Field of Search: 324/637, 324/644, 455/1, 455/115.1, 455/117, 455/126, 361/1, 330/51, 340/552, 307/326
• US Class Current: 324/644
• CPC Class Codes: G01D 5/48 using wave or particle radiation means G01D5/26 takes precedence
• CPC Class Codes: H04B 1/3838 Arrangements for reducing RF exposure to the user, e.g. by changing the shape of the transceiver while in use

Abstract

A system and method for sensing the proximity of an electronic device, in particular, a radio frequency mobile communication device such as a mobile telephone, wireless modem equipped portable computer, or the like to a body employs an antenna capable of altering its impedance for changing the amount of radio frequency electromagnetic energy reflected by the antenna when the antenna is in proximity to the body. The radio frequency electromagnetic energy reflected by the antenna is measured and used for determining proximity of the antenna to the body.

Claims

1. A system for detecting the proximity of a body, comprising:

a sensor for sensing radio frequency electromagnetic energy within a predetermined frequency band;

an antenna capable of having its impedance altered for changing the amount of radio frequency electromagnetic energy provided to the antenna via an antenna feed and reflected onto the antenna feed when the antenna is in proximity to the body, the antenna being detuned when not in proximity to the body and becoming tuned when in proximity to the body; and

a coupler for directing at least a part of the radio frequency electromagnetic energy reflected by the antenna to the sensor,

wherein the sensor senses radio frequency electromagnetic energy reflected by the antenna for determining the proximity of the antenna to the body.

2. The system as claimed in claim 1, further comprising a controller for determining proximity of the antenna to the body based on the radio frequency electromagnetic energy sensed by the sensor.

3. The system as claimed in claim 2, wherein the controller controls a function of the system when the antenna is determined to be in proximity to the body.

4. The system as claimed in claim 3, wherein said function comprises changing operation of the system by reducing power, by issuing a warning regarding an unsuitable power level, or any combination thereof.

5. The system as claimed in claim 4, wherein the sensor measures the power of the radio frequency electromagnetic energy reflected by the antenna, and wherein the power of the radio frequency electromagnetic energy reflected by the antenna decreases when the antenna is in proximity to the body.

6. The system as claimed in claim 4, wherein the controller determines a reflection coefficient from the radio frequency electromagnetic energy reflected by the antenna, the determined reflection coefficient deviating from a predetermined reflection coefficient for the antenna in free space when the antenna is in proximity to the body.

7. The system as claimed in claim 6, wherein the controller compares the reflection coefficient for the antenna with a threshold reflection coefficient for determining when the antenna is in proximity to the body.

8. The system as claimed in claim 7, wherein the controller determines that the antenna is in proximity to the body when the reflection coefficient is less than the threshold coefficient.

9. The system as claimed in claim 3, wherein said controller also controls said function of the system based on a current traffic mode and/or a current power level needed for maintaining the wireless communication link of the system.

10. The system as claimed in claim 3, wherein said system comprises an electronic device comprising a mobile telephone or a mobile palmtop computing device or a mobile laptop computer.

11. A system for detecting the proximity of a body, comprising:

an antenna capable of having its impedance altered for changing the amount of radio frequency electromagnetic energy provided to the antenna via an antenna feed and reflected onto the antenna feed when the antenna is in proximity to the body, the antenna being detuned when not in proximity to the body and becoming tuned when in proximity to the body;

means for sensing radio frequency electromagnetic energy within a predetermined frequency band, the sensing means senses radio frequency electromagnetic energy reflected by the antenna;

means for directing at least a part of the radio frequency electromagnetic energy reflected by the antenna to the sensing means; and

means for determining proximity of the antenna to the body, the proximity determining means calculating a reflection coefficient from the radio frequency electromagnetic energy reflected by the antenna, the calculated reflection coefficient deviating from a predetermined reflection coefficient for the antenna in free space when the antenna is in proximity to the body,

wherein the proximity determining means compares the reflection coefficient for the antenna with a threshold reflection coefficient for determining the proximity of the antenna to the body.

12. The system as claimed in claim 11, wherein the proximity determining means determines that the antenna is in proximity to the body when the reflection coefficient is less than the threshold reflection coefficient.

13. The system as claimed in claim 11, wherein said proximity determining means controls a function of the system when the antenna is determined to be in proximity to the body.

14. The system as claimed in claim 13, wherein the sensing means measures the power of the radio frequency electromagnetic energy reflected by the antenna, and wherein the power of the radio frequency electromagnetic energy reflected by the antenna decreases when the antenna is in proximity to the body.

15. The system as claimed in claim 13, wherein said function comprises limiting operation of the system by reducing power, by issuing a warning regarding an unsuitable power level, or any combination thereof.

16. The system as claimed in claim 13, wherein said proximity determining means also controls said function of the system based on a current traffic mode and/or a current power level needed for maintaining the wireless communication link of the system.

17. The system as claimed in claim 13, wherein said system comprises an electronic device comprising a mobile telephone or a mobile palmtop computing device or a mobile laptop computer.

18. An electronic device, comprising:

an antenna capable of having its impedance altered for changing the amount of radio frequency electromagnetic energy provided to the antenna via an antenna feed and reflected onto the antenna feed when the antenna is in proximity to the body, the antenna being detuned when not in proximity to the body and becoming tuned when in proximity to the body;

a sensor for sensing radio frequency electromagnetic energy reflected by the antenna within a predetermined frequency band;

a coupler for directing at least a part of the radio frequency electromagnetic energy reflected by the antenna to the sensor; and

a controller for determining a reflection coefficient from the radio frequency electromagnetic energy reflected by the antenna, the determined reflection coefficient deviating from a predetermined reflection coefficient for the antenna in free space when the antenna is in proximity to the body,

wherein the controller compares the determined reflection coefficient for the antenna with a threshhold reflection coefficient for determining the proximity of the antenna to the body.

19. The electronic device as claimed in claim 18, wherein the controller determines that the antenna is in proximity to the body when the reflection coefficient is less than the threshold reflection coefficient.

20. The electronic device as claimed in claim 18, wherein the controller controls a function of the electronic device when the antenna is determined to be in proximity to the body.

21. The electronic device as claimed in claim 20, wherein the sensor measures the power of the radio frequency electromagnetic energy reflected by the antenna, and wherein the power of the radio frequency electromagnetic energy reflected by the antenna decreases when the antenna is in proximity to the body.

22. The electronic device as claimed in claim 20, wherein said function comprises changing operation of the electronic device by reducing power or by issuing a warning regarding an unsuitable power level.

23. The electronic device as claimed in claim 20, wherein said controller also controls said function of the electronic device based on a current traffic mode and/or a current power level needed for maintaining the wireless communication link of the electronic device.

24. The electronic device as claimed in claim 20, wherein said electronic device comprises a mobile telephone or a mobile palmtop computing device or a mobile laptop computer.

25. A system for detecting the proximity of a body, comprising:

an antenna capable of having its impedance altered for changing the amount of radio frequency electromagnetic energy provided to the antenna via an antenna feed and reflected onto the antenna feed when the antenna is in proximity to the body, the antenna being detuned when not in proximity to the body and becoming tuned when in proximity to the body;

a sensor for sensing radio frequency electromagnetic energy reflected by the antenna within a predetermined frequency band;

a coupler for directing at least a part of the radio frequency electromagnetic energy reflected by the antenna to the sensor; and

a controller for determining a reflection coefficient from the radio frequency electromagnetic energy reflected by the antenna, the determined reflection coefficient deviating from a predetermined reflection coefficient for the antenna in free space when the antenna is in proximity to the body,

wherein the controller compares the determined reflection coefficient for the antenna with a threshold reflection coefficient for determining the proximity of the antenna to the body.

26. The system as claimed in claim 25, wherein the controller determines that the antenna is in proximity to the body when the reflection coefficient is less than the threshold reflection coefficient.

27. The system as claimed in claim 25, wherein the controller controls a function of the system when the antenna is determined to be in proximity to the body.

28. The system as claimed in claim 27, wherein the function comprises changing operation of the system by reducing power, by issuing a warning regarding an unsuitable power level, or any combination thereof.

29. The system claimed in claim 27, wherein the controller further controls the function of the system based on at least one of a current traffic mode and a current power level needed for maintaining the wireless communication link of the system.

30. The system as claimed in claim 25, wherein said system comprise an electronic device comprising at least one of a mobile telephone, a mobile palmtop computing device, and a mobile laptop computer.

31. A hand-held electronic device, comprising:

an antenna capable of having its impedance altered for changing the amount of radio frequency electromagnetic energy provided to the antenna via an antenna feed and reflected onto the antenna feed when the antenna is in proximity to the body;

a sensor for sensing a radio frequency electromagnetic energy within a predetermined frequency band, the radio frequency electromagnetic energy reflected by the antenna is measured for determining the proximity of the antenna to the body;

a coupler for directing at least a part of the radio frequency electromagnetic energy reflected by the antenna to the sensor; and

a controller for determining proximity of the antenna to the body based on the radio frequency electromagnetic energy sensed by the sensor,

wherein the controller lowers the power of the radio frequency electromagnetic energy provided to the antenna via the antenna feed when the antenna is in proximity to a body.

32. The hand-held electronic device as claimed in claim 31, wherein the controller determines a reflection coefficient from the radio frequency electromagnetic energy reflected by the antenna, the determined reflection coefficient deviating from a predetermined reflection coefficient for the antenna in free space when the antenna is in proximity to the body.

33. The hand-held electronic device as claimed in claim 32, wherein the antenna is detuned when not in proximity to the body and becomes tuned when in proximity to the body.

34. The hand-held electronic device as claimed in claim 33, wherein the controller compares the reflection coefficient for the antenna with a threshold reflection coefficient for determining when the antenna is in proximity to the body.

35. The hand-held electronic device as claimed in claim 34, wherein the controller determines that the antenna is in proximity to the body when the reflection coefficient is less than the threshold reflection coefficient.

36. The hand-held electronic device as claimed in claim 32, wherein the controller compares the reflection coefficient with a lower threshold reflection coefficient and an upper threshold reflection coefficient for determining when the antenna is in proximity to the body.

37. The electronic device as claimed in claim 36, wherein the reflection coefficient is one of greater than the lower threshold reflection coefficient and less than the upper threshold reflection coefficient when the antenna is not in proximity to the body.

38. The hand-held electronic device as claimed in claim 31, wherein the controller determines at least one of a current traffic mode and a current power level needed for maintaining the wireless communication link of the electronic device prior to lowering the power of the radio frequency electromagnetic energy provided to the antenna.

39. The hand-held electronic device as claimed in claim 31, wherein the hand-held electronic device comprises at least one of a mobile telephone, a mobile palmtop computing device, and a mobile laptop computer.