Hybrid radio frequency/inductive loop charger

Patent metadata

Field	Value
Publication number	US-9543636-B2
Application number	US-201514880703-A
Country	US
Kind code	B2
Filing date	Oct 12, 2015
Priority date	Jan 15, 2013
Publication date	Jan 10, 2017
Grant date	Jan 10, 2017

Abstract

Biometric monitoring devices, including various technologies that may be implemented in such devices, are discussed herein. Additionally, techniques, systems, and apparatuses are discussed herein for providing a hybrid antenna including an RF radiator and an electrically coupled inductive loop. The hybrid antenna is capable of providing both RF and induction functionality, e.g., radio frequency transmission/reception capabilities for Bluetooth as well as near-field-communications (NFC) functionality via the inductive loop. The inductive loop may be in conductive contact with the RF radiator or may be inductively coupled with the RF radiator and not in conductive contact with the RF radiator. The inductive loop may act as a planar element of a planar inverted-F antenna (PIFA).

First claim

What is claimed is:

1. An apparatus comprising:
a ground plane;
a radio-frequency radiator;
a feed post conductively connected to the radio-frequency radiator; and
an inductive charging system including a multi-turn inductive charging loop configured to couple electrically with the radio-frequency radiator, wherein the multi-turn inductive charging loop is configured to inductively couple with an electromagnetic field to provide power to the inductive charging system, wherein the multi-turn inductive charging loop is separated from the radio-frequency radiator by a first gap and the multi-turn inductive charging loop is electrically coupled with the radio-frequency radiator and not in conductive contact with the radio-frequency radiator, and wherein the multi-turn inductive charging loop, the radio-frequency radiator, the ground plane, and the feed post together form at least in part an antenna configured to produce and receive electromagnetic radio-frequency signals, wherein the antenna is a mono-pole, inverted-F antenna, or planar inverted-F antenna.

2. The apparatus of claim 1 , wherein the radio-frequency radiator is offset from the ground plane by at least a first distance.

3. The apparatus of claim 1 , wherein the multi-turn inductive charging loop is offset from the ground plane in a direction normal to the around plane.

4. The apparatus of claim 1 , wherein the multi-turn inductive charging loop, the radio-frequency radiator, the ground plane, and the feed post together form a planar inverted-F antenna (FIFA).

5. The apparatus of claim 1 , wherein the radio-frequency radiator at least partially overlaps the turns in the multi-turn inductive charging loop.

6. The apparatus of claim 5 , wherein the turns in the multi-turn inductive charging loop that the radio-frequency radiator at least partially overlaps are the outermost turns of the multi-turn inductive charging loop.

7. The apparatus of claim 5 , wherein the radio-frequency radiator follows a path that is substantially aligned with paths followed by the turns of the multi-turn inductive charging loop with which the radio-frequency radiator at least partially overlaps.

8. The apparatus of claim 1 , wherein the turns in the multi-turn inductive charging loop follow a path that defines a major surface that faces towards the radio-frequency radiator.

9. The apparatus of claim 1 , wherein the turns of the multi-turn inductive charging loop at least partially overlaps the ground plane.

10. The apparatus of claim 1 , wherein the radio-frequency radiator at least partially overlaps between about 1% and about 20% of the turns in the multi-turn inductive charging loop.

11. The apparatus of claim 1 , further comprising:
a first housing portion of a wearable device; and
a second housing portion of the wearable device and mated to the first housing portion, wherein the radio-frequency radiator is supported in a recess between the first housing portion and the second housing portion.

12. The apparatus of claim 11 , wherein the first housing portion and the second housing portion are mated such that the inductive charging system and the radio-frequency radiator are separated by the first gap.

13. The apparatus of claim 1 , further comprising:
a housing having a first surface and a second surface, wherein the first surface and the second surface are nominally on opposing sides of a portion of the housing and define the first gap, the radio-frequency radiator is formed by a metallization layer deposited on the first surface, the inductive charging system is located on or adjacent to the second surface such that the second surface is interposed between the first surface and the inductive charging system.

14. The apparatus of claim 1 , wherein the ground plane is provided by a structure located on an opposite side of the first housing portion from the radio-frequency radiator, wherein the structure is selected from the group consisting of: a printed circuit board, a flexible circuit board, a metal plate contained within the apparatus, and a metal plate at least partially providing an exterior surface of the apparatus.

15. The apparatus of claim 1 , wherein the radio-frequency radiator has a nominal width of between about 0.5 mm and 1.5 mm and an average length of between about 10 mm and 25 mm, and the multi-turn inductive charging loop has an average path length of about 500 mm to 600 mm.

16. The apparatus of claim 1 , wherein the radio-frequency radiator is substantially the shape of a rectangle having a length-to-width aspect ratio of at least 10:1.

17. The apparatus of claim 1 , wherein the radio-frequency radiator is L-shaped, U-shaped, or C-shaped.

18. The apparatus of claim 1 , wherein the inductive charging system includes a rechargeable battery, a capacitor, or a capattery.

19. The apparatus of claim 1 , wherein the radio-frequency radiator is offset from the ground plane by a distance between about 0.5 mm and 10 mm.

20. The apparatus of claim 1 , wherein the ground plane is a non-planar surface.

21. The apparatus of dam 1 , wherein the radio-frequency radiator and the multi-turn inductive charging loop are formed from the same electrically conductive trace.

22. The apparatus of claim 1 , further comprising:
a shorting post conductively connecting the radio-frequency radiator to the ground plane, wherein the multi-turn inductive charging loop, the radio-frequency radiator, the ground plane, the shorting post, and the feed post together form a planar inverted-F antenna (PIFA) configured to produce and receive electromagnetic radio-frequency signals in a Bluetooth-compatible frequency band, wherein the multi-turn inductive charging loop serves as a radiator extension to the radiofrequency radiator when producing and receiving electromagnetic radio-frequency signals in the Bluetooth-compatible frequency band.

23. The apparatus of claim 1 , further comprising:
a shorting post conductively connecting the radio-frequency radiator to the ground plane, wherein the multi-turn inductive charging loop, the radio-frequency radiator, the ground plane, the shorting post, and the feed post together form a planar inverted-F antenna (PIFA) configured to produce and receive electromagnetic radio-frequency signals in a GPS-compatible frequency band, wherein the multi-turn inductive charging loop serves as a radiator extension to the radio-frequency radiator when producing and receiving the electromagnetic radio-frequency signals in the GPS-compatible frequency band.

24. The apparatus of claim 1 , wherein the radio-frequency radiator, the ground plane, and the multi-turn inductive charging loop are located on a common, non-recurvate reference surface.

25. The apparatus of claim 24 , wherein the radio-frequency radiator, the ground plane, and the multi-turn inductive charging loop are formed from a common conductive trace.

Assignees

• Fitbit Inc

Inventors

• Baringer William B
• Martinez Mark Manuel

Classifications

• H02J7/025

  Electricity · mapped topic

• H01Q1/22 Primary

  by structural association with other equipment or articles · CPC title

• A61B5/1123

  Discriminating type of movement, e.g. walking or running (A61B5/1116, A61B5/112 take precedence) · CPC title

• H04W4/008

  Electricity · mapped topic

• H04W4/027

  using movement velocity, acceleration information · CPC title