Dual band multiple-input multiple-output antennas

1. A dual-band multiple-input multiple-output (MIMO) antenna comprising:

a flexible printed circuit board (PCB) including first and second antenna radiating elements at opposite corners of the flexible printed circuit board that are diagonally across from one another, and defining a single structure having a flattened flexible PCB layout or pattern development; and

at least two antenna feeding elements extending from the first and second antenna radiating elements, wherein:

each of the at least two antenna feeding elements is electrically connected with a different one of the first and second antenna elements; and

each of the at least two antenna feeding elements extends beyond an edge of the flexible printed circuit board at an orientation of ninety degrees with respect to one another; and

wherein the flexible printed circuit board comprises a ground element including a first portion, a middle portion, and a second portion, wherein the first portion and the second portion are positioned at other opposite corners of the flexible printed circuit board that are diagonally across from one another, and wherein the middle portion connects the first portion and the second portion.

2. The antenna of claim 1 , wherein the single structure having the flattened flexible PCB layout or pattern development defined by the flexible printed circuit board including the first and second antenna radiating elements is foldable into a three-dimensional dual-band antenna array assembly.

3. The antenna of claim 1 , wherein the first antenna radiating element and the second antenna radiating element are each oriented at a ninety degree angle with respect to one another.

4. The antenna of claim 1 , wherein the first antenna radiating element and the second antenna radiating element comprise identical dual band planar inverted-F antenna elements.

5. The antenna of claim 1 , wherein the flexible printed circuit board including the first and second antenna radiating elements is folded into a three-dimensional dual-band antenna array assembly.

6. The antenna of claim 1 , further comprising an adhesive layer positioned on at least one side of the flexible printed circuit board for mounting the antenna to a surface.

7. The antenna of claim 1 , wherein:

the first and second portions of the ground element comprise first and second arrow portions, respectively;

the second arrow portion is larger than the first arrow portion;

the first arrow portion and the second arrow portion are positioned at the other opposite corners of the flexible printed circuit board that are diagonally across from one another; and

the middle portion linearly connects the first arrow portion and the second arrow portion along a line that bisects the first arrow portion and the second arrow portion.

8. The antenna of claim 1 , wherein:

each of the first and second antenna radiating elements is configured to operate in at least a first frequency range of about 2.4 GHz to 2.48 GHz; and

each of the first and second antenna radiating elements is configured to operate in at least a second frequency range of about 4.9 GHz to 5.9 GHz.

9. An antenna comprising:

a circuit board;

a first planar inverted-F antenna element positioned on the circuit board;

a second planar inverted-F antenna element positioned on the circuit board; and

a ground element positioned on the circuit board, the ground element including a first arrow portion, a middle portion, and a second arrow portion, wherein:

the second arrow portion is larger than the first arrow portion;

the first arrow portion and the second arrow portion are positioned at opposite corners of the circuit board that are diagonally across from one another; and

the middle portion linearly connects the first arrow portion and the second arrow portion along a line that bisects the first arrow portion and the second arrow portion.

10. The antenna of claim 9 , wherein:

the circuit board includes at least two layers;

the first planar inverted-F antenna element and the second planar inverted-F antenna element are located on a first one of the at least two layers; and

the ground element is located on a second one of the at least two layers, said second layer different from the first layer.

11. The antenna of claim 10 , wherein:

at least a portion of the first planar inverted-F antenna element overlaps at least a portion of the ground element in a direction perpendicular to planes of the first planar inverted-F antenna element and the ground layer; and

at least a portion of the second planar inverted-F antenna element overlaps at least another portion of the ground element in a direction perpendicular to planes of the second planar inverted-F antenna element and the ground layer.

12. The antenna of claim 11 , wherein the portions of the first planar inverted-F antenna element and the second planar inverted-F antenna element overlap at least part of the second arrow portion of the ground element.

13. The antenna of claim 9 , wherein the first planar inverted-F antenna element, the second planar inverted-F antenna element, and the ground element are positioned on a same layer of the circuit board.

14. The antenna of claim 13 , wherein the ground element is positioned between the first planar inverted-F antenna element and the second planar inverted-F antenna element.

15. The antenna of claim 9 , wherein the first planar inverted-F antenna element and the second planar inverted-F antenna element are oriented at a ninety degree angle with respect to one another.

16. The antenna of claim 9 , wherein the first planar inverted-F antenna element, the second planar inverted-F antenna element and the ground element are positioned to create an isolation value of at least fifteen decibels (dB).

17. The antenna of claim 9 , wherein the first planar inverted-F antenna element, the second planar inverted-F antenna element, and the ground element each comprise one or more copper traces of a flexible printed circuit board.

18. The antenna of claim 9 , wherein:

the antenna comprises a dual-band multiple-input multiple-output (MIMO) antenna;

each of the first and second planar inverted-F antenna elements is configured to operate in at least a frequency range of about 2.4 GHz to 2.48 GHz; and

each of the first and second planar inverted-F antenna elements is configured to operate in at least a frequency range of about 4.9 GHz to 5.9 GHz.