Wireless communication device with variable antenna radiation pattern and corresponding method

• US 20040214621A1
• Filed: 04/25/2003
• Published: 10/28/2004
• Est. Priority Date: 04/25/2003
• Status: Active Grant

• Current Assignee: Google Technology Holdings LLC (Alphabet Inc.)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Stratis, Glafkos, Ponce De Leon, Lorenzo A., Kontogeorgakis, Christos, Eisenhauer, Gary L., Baracat, Frederick A., Kroegel, Robert Andrew, Zax, Glenn Scott
• Granted Patent: US 7,024,232 B2
• Time in Patent Office: Days
• US Class Current: 455/575.8
• CPC Class Codes: H01Q 1/242 specially adapted for hand-held use
• CPC Class Codes: H01Q 1/245 with means for shaping the antenna pattern, e.g. in order to protect user against rf exposure
• CPC Class Codes: H01Q 19/005 Patch antenna using one or more coplanar parasitic elements
• CPC Class Codes: H01Q 19/10 using reflecting surfaces
• 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
• CPC Class Codes: H04M 2250/12 including a sensor for measuring a physical value, e.g. temperature or motion telephones including GPS signal receivers H04M2250/10

Abstract

A communication device 10 and a corresponding method are arranged for changing the radiation pattern of an antenna 14, where the radiation pattern of the antenna 14 is set to a half-space pattern if the communication device 10 is in close proximity to an object. A reflector 18 is activated to produce the half space radiation pattern. The reflector 18 is deactivated to produce the full space pattern. A switching device 26 determines the state of the reflector 18. A sensing and control device 23 controls the state of the switching device 26.

Claims

1. A wireless communication device comprising:

a transmitter;

an antenna coupled to the transmitter for transmitting radio waves;

a reflector element, which cooperates with the antenna to permit the communication device to transmit radio waves in full space when inactive and to cause the communication device to transmit in half-space when active; and

a switching device for activating and deactivating the reflector element.

2. The wireless communication device according to claim 1, wherein the communication device further comprises a proximity sensing circuit for determining whether the communication device is in close proximity to an object, and the proximity sensing circuit causes the switch to activate the reflector element when the communication device is in close proximity to an object.

3. The wireless communication device according to claim 1, wherein the communication device further comprises a proximity sensing circuit for determining whether the communication device is in close proximity to a human head, and the proximity sensing circuit causes the switch to activate the reflector element when the communication device is in close proximity to a human head.

4. The wireless communication device according to claim 1, wherein the communication device includes a proximity sensing circuit for determining whether the communication device is in close proximity to an object, and the proximity sensing circuit causes the switch to activate the reflector element when the communication device is in close proximity to an object, wherein the proximity sensing circuit senses the reflected energy of the antenna, and the sensed reflected energy is used to determine the state of the switching device.

5. The wireless communication device according to claim 4, wherein the proximity sensing circuit includes a VSWR sensor for detecting the VSWR of the antenna.

6. The communication device according to claim 1, wherein the switching device creates ohmic contact between a chassis of the communication device when closed.

7. The communication device according to claim 1, wherein the switching device electrically couples the reflector element to a ground plane of the communication device when closed.

8. The communication device according to claim 1, wherein the switching device includes a first switch, which is located at a first end of the reflector element, and a second switch, which is located at a second end of the reflector element, wherein the second end of the reflector element is opposite to the first end of the reflector element, and the first switch couples the first end of the reflector element to a corresponding end of a chassis of the communication device, and the second switch couples the second end of the reflector element to a corresponding end of the chassis.

9. The communication device according to claim 2, wherein the proximity sensing circuit senses whether the communication device is in close proximity to an object, and the circuit causes the switching device to open if the circuit determines that the communication device is in close proximity to the object.

10. The communication device according to claim 1, wherein the circuit senses whether the communication device is in close proximity to a user, and the circuit causes the switching device to open if the circuit determines that the communication device is in close proximity to the user.

11. A wireless communication device comprising:

a transmitter;

an antenna coupled to the transmitter;

a reflector element, wherein the reflector element cooperates with the antenna such that the device transmits radio waves in a limited pattern when the reflector element is activated;

a switching device for electrically coupling the reflector element to the communication device and for electrically isolating the reflector element from the communication device;

a sensing and control device for sensing whether the wireless communication device is in close proximity to a user, wherein the sensing and control device controls the switching device according to the sensed condition such that the radiation pattern is changed to the limited pattern at least when the communication device is in close proximity to a user.

12. The communication device according to claim 11, wherein the switching device electrically couples and decouples the reflector element to a ground plane of the communication device.

13. The wireless communication device according to claim 11, wherein the sensing and control device includes a reflected energy detection circuit for sensing the reflected energy of the antenna, wherein the sensed energy determines the state of the switching device.

14. A method for changing the radiation pattern of an antenna device that is coupled to a wireless communication device, wherein the method comprises:

setting the pattern to one of a full space pattern or a half space pattern by coupling or decoupling a reflector element of the antenna device;

determining whether the communication device is in a transmit mode;

sensing a condition of the transmitter;

switching the pattern to the other of the full space pattern or the half space pattern according to the sensed condition.

15. The method according to claim 14, wherein the coupling or decoupling is performed by closing or opening a switching device that couples a reflector element to a ground plane of the communication device.

16. The method according to claim 14, wherein the sensing includes sensing the proximity of a user of the communication device.

17. The method according to claim 14, wherein the sensing includes determining whether the communication device is in an idle state.

18. The method according to claim 14, wherein the sensing includes determining whether the communication device is operating in a hands-free mode.

19. The method of claim 14, wherein the sensing includes sensing the reflected energy of the antenna.

20. The method of claim 19, wherein the method includes switching the pattern to a half space pattern when the level of reflected energy is within a predetermined range, wherein the predetermined range corresponds to a condition in which the antenna is in close proximity to a human head.