Wearable electronic device and antenna therefor

• US 5,926,144 A
• Filed: 03/23/1998
• Issued: 07/20/1999
• Est. Priority Date: 03/23/1998
• Status: Expired due to Fees

• Current Assignee: Motorola, Inc. (Motorola Solutions, Inc.), Timex Corporation (Tanager Group BV)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Bolanos, Angel M., Parvin, Davar
• Primary Examiner(s): Le, Hoanganh
• Assistant Examiner(s): CHEN, SHIH CHAO
• Application Number:
  US09/046,202
• Time in Patent Office: 484 Days
• Field of Search: 343/718, 343/748, 343/866, 368/10
• US Class Current: 343/718
• CPC Class Codes: G04B 47/025 in musical instruments or loudspeakers sounding bodies with chimes G04B21/08; in alarm clocks G04B23/028; cases with arrangements for enhancing the sound production G04B37/0075
• CPC Class Codes: G04G 21/04 using radio waves radio-controlled time-pieces G04R
• CPC Class Codes: G04R 60/10 inside cases
• CPC Class Codes: H01Q 1/273 Adaptation for carrying or wearing by persons or animals
• CPC Class Codes: H01Q 7/00 Loop antennas with a substantially uniform current distribution around the loop and having a directional radiation pattern in a plane perpendicular to the plane of the loop

Abstract

An internal antenna (302) for a wearable electronic device (1000) includes first and second elongated conductor segments (416, 418) which are fabricated in a form of an arc to conform substantially to a portion of a substantially circular housing cavity, and first and second shortened conductor segments (420, 422). The first and second elongated conductor segments (416, 418) and the first and second shortened conductor segments (420, 422) are formed into a single turn loop having a rectangular antenna aperture (436). Connection tabs (424) are formed contiguous with, and located symmetrically about, a midpoint of one of the first and second elongated conductor segments (416, 418) and couple the antenna (302) to a receiver (1104) which is located on a circuit substrate (406) which is positioned between the first and second elongated conductor segments (416, 418).

Claims

1. A wearable electronic device comprising:

a receiver mounted on a circuit substrate which has a substantially circular outline, said circuit substrate being secured into a housing having a side wall which defines a substantially circular cavity; and

a loop antenna, comprising;

a conductor formed into a single turn loop comprising two elongated sides and two shortened sides which form a rectangular antenna aperture, wherein said two elongated sides include an upper elongated side and a lower elongated side which are fabricated in a form of an arc which conforms substantially to said substantially circular cavity of said housing, and wherein said circuit substrate is positioned between said upper elongated side and said lower elongated side, and

said single turn loop terminating in connection tabs, located symmetrically about a midpoint of one of said two elongated sides, for coupling to the receiver.

2. The wearable electronic device of claim 1, wherein said conductor has a flat cross-section having a width substantially greater than its thickness, and wherein said width of said conductor forming said two elongated sides is perpendicular to the side wall of said substantially circular cavity.

3. The wearable electronic device of claim 1, wherein the wearable electronic device is attached to a wrist with a wrist band, and the wrist band has an axis which extends circumferentially around the wrist, and wherein said rectangular antenna aperture projects onto a plane which is perpendicular to the axis of the wrist band.

4. The wearable electronic device of claim 3, wherein said wrist band axis bisects said rectangular antenna aperture of said single turn loop.

5. The wearable electronic device of claim 1, wherein said two elongated sides have a length which subtends an arc of at least 45°

.

6. The wearable electronic device of claim 1, wherein said two elongated sides have a length which subtends an arc less than or equal to 180°

.

7. The wearable electronic device of claim 1, wherein said two shortened sides have a length which is substantially equal in height to said side wall of said substantially circular cavity.

8. The wearable electronic device of claim 1, wherein said upper elongated side is positioned at least 1.8 millimeters from said circuit substrate.

9. The wearable electronic device of claim 1, wherein said conductor is fabricated from a sheet metal which is selected from a groups of sheet metals consisting of beryllium copper, copper, and phosphor bronze.

10. The wearable electronic device of claim 1, wherein said single turn loop is direct current isolated from ground.

11. The wearable electronic device according to claim 1, further comprising a metal shield which isolates said circuit substrate from a second circuit substrate, and wherein said metal shield includes a portion separated from said loop antenna by a predetermined distance, wherein said portion of said metal shield is fabricated with an arc which corresponds to said arc of said upper elongated side of said loop antenna.

12. The wearable electronic device of claim 1 wherein said circuit substrate includes an internal ground plane which attenuates interfering signals which are generated by electrical circuits present on said circuit substrate, thereby maximizing performance of said loop antenna.

13. The wearable electronic device of claim 1, further comprising:

a watch circuit for generating watch functions; and

a display for displaying the watch functions generated.

14. The wearable electronic device of claim 1, wherein said single turn loop intercepts selective call signals, and wherein the electronic device further comprises:

a decoder, coupled to said receiver, for decoding the selective call signals, and for generating a control signal when the selective call signals match a predetermined address stored within the electronic device; and

an alerting circuit for generating an alert in response to the control signal being generated.

15. The wearable electronic device of claim 14, wherein said single turn loop further intercepts message signals, and wherein the electronic device further comprises:

message decoder, for decoding the message signals to recover a message in response to the control signal being generated; and

a display for displaying the message.

16. An internal antenna for a wearable electronic device, comprising:

first and second elongated conductor segments which are fabricated in a form of an arc to conform substantially to a portion of a circle;

first and second shortened conductor segments,

said first and second elongated conductor segments and said first and second shortened conductor segments being formed into a single turn loop having a rectangular antenna aperture; and

connection tabs, formed contiguous with and located symmetrically about a midpoint of one of said first and second elongated conductor segments, for coupling the antenna to a receiver which is located on a circuit substrate which is positioned between said first elongated conductor segment and said second elongated conductor segment.

17. The internal antenna of claim 16, wherein said first and second elongated conductor segments have a length which subtends an arc of at least 45°

.

18. The internal antenna of claim 16, wherein said first and second elongated conductor segments have a length which subtends an arc less than or equal to 180°

.

19. The internal antenna of claim 16, wherein said first and second elongated conductor segments and said first and second shortened conductor segments are formed from sheet metal which is selected from a groups of sheet metals consisting of beryllium copper, copper, and phosphor bronze.