Grounded antenna for a wireless communication device and method
View Patent ↗A wireless communication device includes an antenna for wireless communication with a remote interrogator. Several embodiments are disclosed to increase the options available to designers of wireless communication devices. In some embodiments, the antenna is a quarter wavelength long with one end of the antenna being grounded to provide desired impedance matching characteristics. The position of the ground plane relative to the antenna is also varied between embodiments. The connection from a wireless communication chip to the antenna is also varied between embodiments to provide alternate structures.
1. A wireless communication device, comprising:
a substrate;
a wireless communication chip positioned on said substrate;
a ground plane positioned on said substrate;
a first antenna operating at a first operating frequency and electrically coupled to said wireless communication chip by a coupling element, said first antenna also electrically coupled to said ground plane; and
said coupling element being arranged to act as a second antenna at a second operating frequency.
2. The wireless communication device of claim 1 , wherein said wireless communication chip is positioned on a first side of said substrate and said pound plane is positioned on an opposite side of said substrate.
3. The wireless communication device of claim 1 , wherein said wireless communication chip is directly coupled to said ground plane.
4. The wireless communication device of claim 1 , wherein said wireless communication chip is reactively coupled to said ground plane.
5. The wireless communication device of claim 1 , wherein said wireless communication chip is positioned along an axis substantially perpendicular to a primary axis of said first antenna.
6. The wireless communication device of claim 1 , wherein said wireless communication chip is positioned along an axis substantially parallel to a primary axis of said first antenna.
7. The wireless communication device of claim 1 , wherein said first antenna and said ground plane are connected by an antenna grounding element.
8. The wireless communication device of claim 1 , wherein said ground plane and said first antenna are positioned on one side of said substrate.
9. The wireless communication device of claim 1 , wherein said wireless communication chip is capacitively coupled to said first antenna.
10. The wireless communication device of claim 9 , wherein said wireless communication chip is capacitively coupled to said first antenna by a non-conductive adhesive being interposed between a feed line extending from said wireless communication chip and said first antenna.
11. The wireless communication device of claim 9 , wherein said wireless communication chip is capacitively coupled to said first antenna by at least one inter digital stub.
12. The wireless communication device of claim 1 , wherein said second antenna is a patch antenna.
13. The wireless communication device of claim 1 , wherein said first antenna acts as a feed line to couple capacitively said second antenna to said wireless communication chip.
14. The wireless communication device of claim 1 , wherein said first antenna and said ground plane are cut from a unitary piece of conductive foil.
15. The wireless communication device of claim 1 , wherein said substrate comprises a plastic material.
16. A method of constructing a wireless communication device, comprising:
creating an ground plane and at least one antenna component from a unitary piece of conductive foil;
creating a chip component comprising a feed line, a chip grounding line, and a wireless communication chip;
wrapping said ground plane and at least one antenna component around a substrate such that an antenna portion of said ground plane and at least one antenna component is positioned on a side opposite that where a ground plane portion of said ground plane and at least one antenna component is positioned; and
wrapping said chip component around said substrate such that the chip is grounded by the chip grounding line and coupled to said antenna component of said ground plane and at least one antenna portion by said feed line.
17. The method of claim 16 , further comprising adhering said ground plane and at least one antenna component to said substrate.
18. The method of claim 16 , further comprising adhering said chip component to said substrate.
19. The method of claim 16 , wherein wrapping said chip component around a side of said substrate such that the chip is grounded by the chip grounding line and coupled to said antenna portion by said feed line comprises capacitively coupling said feed line to said antenna portion of said ground plane and at least one antenna component.
20. A wireless communication device, comprising:
a substrate;
a ground plane positioned on one side of the substrate;
a wireless communication chip electrically connected to said ground plane and proximate thereto;
a first antenna having a first end and a second end, said first end electrically connected to said ground plane, and said second end comprising an open circuit; and
the first antenna coupled to said wireless communication chip by a coupling element arranged to act as a second antenna.
21. The wireless communication device of claim 20 , wherein said wireless communication chip is positioned on a side of the substrate opposite that of the ground plane.
22. The wireless communication device of claim 21 , wherein said wireless communication chip is generally parallel to said first antenna.
23. The wireless communication device of claim 21 , wherein said wireless communication chip is generally perpendicular to said first antenna.
24. The wireless communication device of claim 20 , wherein said first antenna quarter wavelength long.
25. The wireless communication device of claim 20 , wherein said ground plane is positioned on the same side of the substrate as the wireless communication chip.
26. The wireless communication device of claim 20 , wherein said wireless communication chip is separated from said first antenna by a non-conductive adhesive.
27. The wireless communication device of claim 20 , wherein said wireless communication chip is reactively coupled to said first antenna by at least one inter digital capacitive coupling stub.
28. The wireless communication device of claim 20 , wherein said first antenna is a patch antenna.
29. The wireless communication device of claim 20 , wherein said said second antenna is electrically coupled to said wireless communication chip.
30. The wireless communication device of claim 29 , wherein said second antenna comprises a tab capacitively coupling said wireless communication chip to said first antenna.
31. The wireless communication device of claim 20 wherein said coupling element comprises a surface mount capacitor.