Modified printed dipole antennas for wireless multi-band communications systems

1. A dipole antenna for a wireless communication device comprising:

a first conductive element superimposed a portion of and separated from a second conductive element by a first dielectric layer;

a first conductive via connects the first and second conductive elements through the first dielectric layer;

the second conductive element being generally U-shaped;

the second conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

at least one of the strips on each leg being T-shape;

each strip extending from a leg being dimensioned for a different λo than another strip of the leg;

a ground plane conductor superimposed and separated from the second conductive element by a second dielectric layer;

a third conductive element superimposed and separated from the strips of the second conductive element by the first dielectric layer; and

a second conductive via connecting the third conductive element to the ground conductor through the dielectric layers.

2. The antenna according to claim 1 , wherein the first conductive element is L-shaped.

3. The antenna according to claim 2 , wherein one of the legs of the L-shape is superimposed one of the legs of the U-shape.

4. The antenna according to claim 3 , wherein the first conductive via connects the other leg of the L-shape to the other leg of the U-shape.

5. The antenna according to claim 2 , wherein the first conductive via connects an end of one of the legs of the L-shape to one of the legs of the U-shape.

6. The antenna according to claim 1 , wherein the first and second conductive elements are each planar.

7. The antenna according to claim 1 , wherein each strip has a width less than 0.05 λo and a length of less than 0.5 λo.

8. The antenna according to claim 1 , wherein the first and third conductive elements are co-planar.

9. The antenna according to claim 1 , wherein the third conductive element includes a plurality of fingers superimposed a portion of lateral edges of each of the strips.

10. The antenna according to claim 1 , wherein a first and last finger superimposed a first and last strip on each leg of the U-shape extend laterally beyond the lateral edges of the respective strips.

11. The antenna according to claim 1 , wherein the permeability of the first dielectric layer is substantially greater than the permeability of the second dielectric layer.

12. The antenna according to claim 11 , wherein the thickness of the first dielectric layer is substantially less than the thickness of the second dielectric layer.

13. The antenna according to claim 1 , wherein the thickness of the first dielectric layer is at least half the thickness of the second dielectric layer.

14. The antenna according to claim 1 , wherein the first dielectric layer is a substrate, and the first and second conductive elements are printed elements on the substrate.

15. The antenna according to claim 1 , wherein the plurality of strips are parallel to each other.

16. The antenna according to claim 1 , wherein at least one of the strips is generally shaped as a claw hammer.

17. A wireless communication device including the antenna of claim 1 .

18. A dipole antenna for a wireless communication device comprising:

a first conductive element superimposed a portion of and separated from a second conductive element by a first dielectric layer;

a first conductive via connects the first and second conductive elements through the first dielectric layer;

the second conductive element being generally U-shaped;

the second conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

each strip extending from a leg being dimensioned for a different γo than another strip of the leg; and

a pair of conductive plates, each adjacent the strips of a leg of the U-shape at a pre-selected position.

19. The antenna according to claim 18 , wherein the conductive plates position is adjustable.

20. A dipole antenna for a wireless communication device comprising:

a first conductive element superimposed a portion of and separated from a second conductive element by a first dielectric layer;

a first conductive via connects the first and second conductive elements through the first dielectric layer;

the second conductive element being generally U-shaped;

the second conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

one of the strips on each leg being T-shape;

one of strips on each leg including a trapezoidal shaped portion and a uniform width portion extending from the trapezoid shaped portion; and

each strip extending from a leg being dimensioned for a different λo than another strip of the leg.

21. A dipole antenna for a wireless communication device comprising:

a first conductive element superimposed a portion of and separated from a second conductive element by a first dielectric layer;

a first conductive via connects the first and second conductive elements through the first dielectric layer;

the second conductive element being generally U-shaped;

the second conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

one of the strips on each leg being T-shape;

one of the strips on each leg being adjacent the T-shaped strip and including a portion at an acute angle so as to be spaced adjacent the head of the T-shaped; and

each strip extending from a leg being dimensioned for a different λo than another strip of the leg.

22. A dipole antenna for a wireless communication device comprising:

a first conductive element superimposed a portion of and separated from a second conductive element by a first dielectric layer;

a first conductive via connects the first and second conductive elements through the first dielectric layer;

the second conductive element being generally U-shaped;

the second conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

one of the strips on each leg is T-shape having a base and a head;

one of the strips on each leg being adjacent the T-shaped strip, having an inverted L-shape, having a shorter length than the length of the base of the T-shaped strip, and extending from the leg of the U-shape below the head of the T-shaped strip; and

each strip extending from a leg being dimensioned for a different λo than another strip of the leg.

23. A dipole antenna for a wireless communication device comprising:

a first conductive element superimposed a portion of and separated from a second conductive element by a first dielectric layer;

a first conductive via connects the first and second conductive elements through the first dielectric layer;

the second conductive element being generally U-shaped;

the second conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

at least one of the strips on each leg being T-shape which includes a portion extending from one side of the head of the T-shape back towards the leg of the U-shape; and

each strip extending from a leg being dimensioned for a different λo than another strip of the leg.

24. A dipole antenna for a wireless communication device comprising:

a first conductive element superimposed a portion of and separated from a second conductive element by a first dielectric layer;

a first conductive via connects the first and second conductive elements through the first dielectric layer;

the second conductive element being generally U-shaped;

the second conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

each strip extending from a leg being dimensioned for a different λo than another strip of the leg; and

at least one of the strips including a first portion extending transverse to the leg of the U-shape, and a second portion extending transverse to the first portion and a third portion extending into the first dielectric layer from the second portion.

25. A dipole antenna for a wireless communication device comprising:

a generally U-shaped first conductive element on a first dielectric layer;

the first conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

one of the strips on each leg being T-shaped;

one the of strips on each leg having a trapezoidal shaped portion and a uniform width portion extending from the step shaped portion;

each strip extending from a leg being dimensioned for a different λo than another strip of the leg; and

a coaxial feed having inner and outer conductors, each connected to a leg of the U-shape.

26. The antenna according to claim 25 , wherein the first dielectric layer is a substrate, and the first conductive element is printed on the substrate.

27. The antenna according to claim 25 , wherein the plurality of strips are parallel to each other.

28. The antenna according to claim 25 , wherein at least one of the strips is generally shaped as a claw hammer.

29. The antenna according to claim 25 , including a second conductive element having first and second portions each superimposed the strips extending from one of the legs of the U-shape and separated there from by the first conductive layer.

30. A wireless communication device including the antenna of claim 25 .

31. A dipole antenna for a wireless communication device comprising:

a generally U-shaped first conductive element on a first dielectric layer;

the first conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

one of the strips on each leg being T-shaped;

one of the strips on each leg being adjacent the T-shaped strip and including a portion at an acute angle so as to be spaced adjacent the head of the T-shaped;

each strip extending from a leg being dimensioned for a different λo than another strip of the leg; and

a coaxial feed having inner and outer conductors, each connected to a leg of the U-shape.

32. A dipole antenna for a wireless communication device comprising:

a generally U-shaped first conductive element on a first dielectric layer;

the first conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

one of the strips on each leg being T-shaped and having a base and a head;

one of the strips on each leg adjacent the T-shaped strip being an inverted L-shape, having a shorter length than the length of the base of the T-shaped strip, and extending from the leg of the U-shape below the head of the T-shaped strip; and

each strip extending from a leg being dimensioned for a different λo than another strip of the leg.

33. A dipole antenna for a wireless communication device comprising:

a generally U-shaped first conductive element on a first dielectric layer;

the first conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

at lease one of the strips on each leg being T-shaped which includes a portion extending from one side of the head of the T-shape back towards the leg of the U-shape;

each strip extending from a leg being dimensioned for a different λo than another strip of the leg; and

a coaxial feed having inner and outer conductors, each connected to a leg of the U-shape.

34. A dipole antenna for a wireless communication device comprising:

a generally U-shaped first conductive element on a first dielectric layer;

the first conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

each strip extending from a leg being dimensioned for a different λo than another strip of the leg;

a coaxial feed having inner and outer conductors, each connected to a leg of the U-shape; and

at least one of the strips including a first portion extending transverse to the leg of the U-shape, a second portion extending transverse to the first portion and a third portion extending into the first dielectric layer from the second portion.

35. A dipole antenna for a wireless communication device comprising:

a generally U-shaped first conductive element on a first dielectric layer;

the first conductive element including a plurality of spaced conductive strips extending transverse from adjacent ends of the legs of the U-shape;

each strip extending from a leg being dimensioned for a different λo than another strip of the leg;

a coaxial feed having inner and outer conductors, each connected to a leg of the U-shape; and

a pair of conductive plates, each adjacent the strips of a leg of the U-shape at a pre-selected position.

36. The antenna according to claim 35 , wherein the conductive plates position is adjustable.