Hexaferrite slant and slot MIMO antenna element

Patent metadata

Field	Value
Publication number	US-9711869-B1
Application number	US-201313789023-A
Country	US
Kind code	B1
Filing date	Mar 7, 2013
Priority date	Mar 7, 2013
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A MIMO antenna for mobile devices has a system board, and two or more microstrip lines extending along a top surface of the system board. The MIMO antenna additionally includes a ground plane extending along a bottom surface of the system board, wherein the ground plane has a Y-shaped slot. The MIMO antenna further includes one or more pairs of miniature antenna elements attached to the top surface of system board in contact with the at least two microstrip lines, wherein the antenna elements are slanted at ±45° with respect to a center Z of an X Y coordinate system, and center of a radiation sphere, located proximate the Y-shaped slot.

First claim

What is claimed is:

1. A hexaferrite slant and slot MIMO antenna for mobile devices, the antenna comprising:
a system board;
a ground plane extending along a bottom surface of the system board, wherein the ground plane has a Y-shaped slot;
a first lumped port and a second lumped port at a first side of the system board;
at least two microstrip lines, where a first microstrip line extends from the first lumped port and a second microstrip line extends from the second lumped port in parallel fashion along a top surface of the system board to a second side of the system board and past a narrow end of the Y-shaped slot; and
at least one pair of miniature antenna elements attached to the top surface of the system board in contact with the at least two microstrip lines, wherein the miniature antenna elements are slanted at ±45° with respect to a center Z of an X Y coordinate system, and a center of a radiation sphere, located proximate to the Y-shaped slot;
where the Y-shaped slot has a narrow end oriented away from the at least one pair of miniature antenna elements, a wide end oriented toward the at least one pair of miniature antenna elements, and an expansion region in which sides of the Y-shaped slot extend in diverging fashion toward the at least one pair of miniature antenna elements.

2. The MIMO antenna of claim 1 , wherein the system board is predominately made of double-sided copper clad laminate.

3. The MIMO antenna of claim 1 , wherein the system board has a width 60 mm and a length L of 90 mm, yielding permittivity and loss tangent values of the system board of 4.4 and 0.02, respectively.

4. The MIMO antenna of claim 1 , where the first lumped port and the second lumped port at the first side of the system board are opposite a second end of the system board that is proximate to the pair of antenna elements.

5. The MIMO antenna of claim 4 , wherein the ground plane longitudinally extends a length of about 70 mm from the first and second lumped ports along the bottom surface of the system board.

6. The MIMO antenna of claim 1 , wherein the least two microstrip lines measure 2.4×77 mm 2 .

7. The MIMO antenna of claim 1 , wherein the ground plane has a width of 60 mm.

8. The MIMO antenna of claim 1 , wherein the center Z of the X Y coordinate system, and the center of the radiation sphere, are located proximate an origin of the expansion region.

9. The MIMO antenna of claim 1 , wherein the narrow end has a width of 4 mm and the wide end has a width of 8 mm.

10. The MIMO antenna of claim 1 , wherein sides of the Y-shaped slot extend in parallel from the narrow end a length equal to 10 mm before beginning to expand apart from one another to form the expansion region.

11. The MIMO antenna of claim 1 , wherein the Y-shaped slot has an overall length of 25 mm.

12. The MIMO antenna of claim 1 , wherein the miniature antenna elements of the at least one pair of miniature antenna elements are spaced apart from one another approximately 30 mm.

13. The MIMO antenna of claim 1 , wherein the pair of miniature antenna elements includes half-cycle, microstrip meander structures having a hexaferrite substrate below each meander structure.

14. The MIMO antenna of claim 13 , wherein the hexaferrite substrate has dimensions substantially equal to 6×10×1.5 mm 3 .

15. The MIMO antenna of claim 13 , wherein the hexaferrite substrate exhibits a relative permeability μ r substantially equal to 1.66 (tan δ μ =0.112) and a relative permittivity ε r substantially equal to 6.5 (tan δ ε =0.014).

16. The MIMO antenna of claim 13 , wherein copper (Cu) tape is attached to the hexaferrite substrate to provide the half-cycle, microstrip meander structure, as well as an electrical connection to the microstrip lines, and 1×1 mm 2 solder pads.

17. The MIMO antenna of claim 1 , wherein the MIMO antenna exhibits a radiation efficiency of at least 82% at 2.45 GHz.

18. The MIMO antenna of claim 1 , wherein the at least one pair of miniature antenna elements exhibit orthogonal 2D patterns, including a two lobe pattern set and an omnidirectional flower pattern set.

19. A method of performing wireless communications, comprising:
utilizing a MIMO antenna to transmit and receive wireless signals, wherein the MIMO antenna comprises:
a system board;
a ground plane extending along a bottom surface of the system board, wherein the ground plane has a Y-shaped slot;
a first lumped port and a second lumped port at a first side of the system board;
at least two microstrip lines, where a first microstrip line extends from the first lumped port and a second microstrip line extends from the second lumped port in parallel fashion along a top surface of the system board to a second side of the system board and past a narrow end of the Y-shaped slot; and
at least one pair of miniature antenna elements attached to the top surface of the system board in contact with the at least two microstrip lines, wherein the miniature antenna elements are slanted at ±45° with respect to a center Z of an X Y coordinate system, and a center of a radiation sphere, located proximate to the Y-shaped slot;
where the Y-shaped slot has a narrow end oriented away from the at least one pair of miniature antenna elements, a wide end oriented toward the at least one pair of miniature antenna elements, and an expansion region in which sides of the Y-shaped slot extend in diverging fashion toward the at least one pair of miniature antenna elements.

20. The method of claim 19 , wherein utilizing a MIMO antenna includes utilizing a MIMO antenna wherein the system board is predominately made of double-sided copper clad laminate.

21. The method of claim 19 , wherein utilizing a MIMO antenna includes utilizing a MIMO antenna wherein the system board measured a width 60 mm and a length L of 90 mm, thereby yielding permittivity and loss tangent values of the system board of 4.4 and 0.02, respectively.

22. The method of claim 19 , wherein utilizing a MIMO antenna includes utilizing a MIMO antenna where the first lumped port and the second lumped port at the first side of the system board are provided opposite a second end of the system board that is proximate to the pair of antenna elements.

23. The method of claim 22 , wherein utilizing a MIMO antenna includes utilizing a MIMO antenna wherein the ground plane longitudinally extends a length of about 70 mm from the first and second lumped ports along the bottom surface of the system board.

24. The method of claim 19 , wherein utilizing a MIMO antenna includes utilizing a MIMO antenna wherein the least two microstrip lines measure 2.4×77 mm 2 .

25. The method of claim 19 , wherein utilizing a MIMO antenna includes utilizing a MIMO antenna wherein the ground plane has a width of 60 mm.

26. The method of claim 19 , wherein utilizing a MIMO antenna includes utilizing a MIMO antenna wherein the center Z of the X Y coordinate system, and the center of the radiation sphere, are located proximate an origin of the expansion region.

27. The method of claim 19 , wherein utilizing a MIMO antenna includes utilizing a MIMO antenna wherein the narrow end has a width of 4 mm and the wide end has a width of 8 mm.

28. The method of claim 19 , wherein utilizing a MIMO antenna includes utilizing a MIMO antenna wherein sides of the Y-shaped slot extend in parallel from the narrow end a length equal to 10 mm bef

Assignees

• Univ Wichita State
• The Univ Of Alabama

Inventors

• Kwon Hyuck M
• Jayasooriya Chandana K K
• Hong Yang-Ki
• Syslo Ryan

Classifications

• H01Q1/48

  Earthing means; Earth screens; Counterpoises · CPC title

• H01P11/001

  Manufacturing waveguides or transmission lines of the waveguide type · CPC title

• H01Q21/0075

  Stripline fed arrays (H01Q21/065 takes precedence) · CPC title

• H01Q21/0006 Primary

  Particular feeding systems · CPC title

• H01Q1/36

  Structural form of radiating elements, e.g. cone, spiral, umbrella; {Particular materials used therewith}(H01Q1/08, H01Q1/14 take precedence) · CPC title