Reduced operator emission exposure antennas for safer hand-held radios and cellular telephones

• US 5,541,609 A
• Filed: 03/08/1995
• Issued: 07/30/1996
• Est. Priority Date: 03/08/1995
• Status: Expired due to Fees

• Current Assignee: Virginia Tech Intellectual Properties, Inc.
• Original Assignee: The Center For Innovative Technology, Virginia Polytechnic Institute and State University, Virginia Tech Intellectual Properties, Inc.
• Inventors: Stutzman, Warren L., Nealy, J. Randall
• Primary Examiner(s): LE, HOANGANH T
• Application Number:
  US08/400,583
• Time in Patent Office: 510 Days
• Field of Search: 343/702, 343/790, 343/791, 343/792, 343/883, 343/878, 343/900, 343/901, 343/903, 343/876, 455/89, 455/90
• US Class Current: 343/702
• 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 21/10 Collinear arrangements of substantially straight elongated conductive units
• CPC Class Codes: H01Q 9/20 Two collinear substantially straight active elements; Substantially straight single active elements H01Q9/28 takes precedence

Abstract

An antenna for a personal communication device designed for reducing RF emissions to a user'"'"'s head and body comprises a single half-wave dipole antenna element mounted on the top of a telescoping rod such that the antenna element is raised above the user'"'"'s head when the rod is extended. The rod is completely inactive and serves only to elevate the active antenna element above the user'"'"'s head and away from the body. A built-in switch is provided which reduces the transmission RF power when the rod is retracted to further protect the user. In a second embodiment, a co-linear array of dipole antenna elements is used. The full array is active for reception. However, a proximity detector senses the proximity of a human body, and lowers the RF transmission power to those antenna elements in the array that are closest to the user'"'"'s head.

Claims

1. An antenna for a personal communication device for reducing RF emissions to a user, comprising:

a support rod suitable for mounting to a personal communication device;

an antenna element mounted atop said support rod;

a lead means for electrically connecting said antenna element to the personal communication device; and

transmission power control means for reducing transmission power of the personal communication device when said antenna element is close to a user.

2. An antenna for a personal communication device as recited in claim 1 wherein said antenna element is a half-wave dipole antenna.

3. An antenna for a personal communication device as recited in claim 1, wherein said support rod is a telescoping support rod.

4. An antenna for a personal communication device as recited in claim 3, further comprising:

a switch means, connected to said transmission power control means, for detecting when said telescoping support rod is in a retracted position.

5. An antenna for a personal communication device as recited in claim 4 wherein said switch means is a variable switch.

6. An antenna for a personal communication device for reducing RF emissions to a user, comprising:

a support rod suitable for mounting to a personal communication device;

an antenna element mounted to said telescoping support rod;

a lead means for electrically connecting said antenna element to the personal communication device;

means for determining proximity between said antenna element and the user; and

transmission power control means, connected to said means for determining proximity, for reducing transmission power supplied to said antenna element when said antenna element is close to a user.

7. An antenna for a personal communication device as recited in claim 6 wherein said antenna element is a half-wave dipole antenna.

8. An antenna for a personal communication device as recited in claim 6 wherein said antenna element is one of a plurality of discrete dipoles arranged in a co-linear array on said support rod.

9. An antenna for a personal communication device as recited in claim 6 wherein said means for determining proximity is an electronic proximity detector.

10. An antenna for a personal communication device as recited in claim 6 wherein said support rod is a flexible rod.

11. An antenna for a personal communication device as recited in claim 6 wherein said means for determining proximity is a switch.

12. An antenna for a personal communication device for reducing RF radiation exposure to a user, comprising:

an array of dipole antenna elements;

means for electrically connecting said array of dipole antenna elements to a personal communication device;

transmission power control means for selectively reducing RF transmission power to said array of dipole antenna elements; and

means for determining proximity between ones of said array of dipole antenna elements and the user, said transmission power control means reducing RF transmission power to ones of said co-linear array of dipole antenna elements closest to the user.

13. An antenna for a personal communication device as recited in claim 12 wherein said array of dipole elements are mounted on a flexible rod.

14. An antenna for a personal communication device as recited in claim 12 wherein said array of dipole elements are mounted within the chassis of said personal communication device.