Loaded antenna
A novel loaded antenna is defined in the present invention. The radiating element of the loaded antenna consists of two different parts: a conducting surface and a loading structure. By means of this configuration, the antenna provides a small and multiband performance, and hence it features a similar behavior through different frequency bands.
1. A portable communications device comprising:
a case operable to be held in a user's hand;
a grounding element;
an antenna mounted within the case in operative relation to the grounding element and operable to both radiate and receive electromagnetic waves across at least one industry-standard frequency band;
wherein the antenna comprises:
a radiating element disposed relative to the grounding element in a monopole configuration and comprising a first part and a second part;
wherein the first part comprises at least one conducting surface;
wherein the second part comprises a loading structure;
wherein the loading structure comprises at least one conducting strip connected at least two points on an edge of the at least one conducting surface;
wherein the maximal width of the at least one conducting strip is less than a quarter of the longest straight edge of the at least one conducting surface; and
wherein the loading structure causes the antenna to radiate and receive electromagnetic waves across at least one more industry-standard frequency band compared to an identical antenna without the loading structure.
2. The portable communications device of claim 1 , wherein the grounding element comprises a ground plane.
3. The portable communications device of claim 2 , wherein at least a part of the ground plane is formed by at least a portion of the case.
4. The portable communications device of claim 1 , wherein:
a shape of at least one of the at least one conducting strip comprises a curve;
the curve comprises a minimum of two segments and a maximum of nine segments; and
each of the segments forms an angle with an adjacent segment of the segments so that no pair of adjacent segments of the segments defines a larger straight segment.
5. The portable communications device of claim 1 , wherein two tips of at least one of the at least one conducting strip are connected at two points on a perimeter of the first part.
6. The portable communications device of claim 1 , wherein:
the loading structure comprises at least two conducting strips; and
a tip of a first of the at least two conducting strips and a tip of a second of the at least two conducting strips are connected on an edge of the at least one conducting surface.
7. The portable communications device of claim 1 , wherein:
the loading structure comprises at least two conducting strips; and
both tips of a first of the at least two conducting strips are connected to a second of the at least two conducting strips.
8. The portable communications device of claim 1 , wherein:
the loading structure comprises at least two conducting strips; and
a first tip of a first of the at least two conducting strips is connected to a second of the at least two conducting strips; and
a second tip of the first of the at least two conducting strips is connected to the at least one conducting surface.
9. The portable communications device of claim 1 , wherein the loading structure comprises at least two conducting strips connected at a plurality of points on a perimeter of the at least one conducting surface.
10. The portable communications device of claim 1 , wherein at least one conducting surface and the loading structure lie on a common flat or curved surface.
11. The portable communications device of claim 1 , wherein:
the antenna comprises at least two conducting surfaces;
a second conducting surface of the at least two conducting surfaces features a smaller area than a first conducting surface of the at least two conducting surfaces; and
at least one conducting strip of the at least one conducting strip is connected to the first conducting surface at a first end and to the second conducting surface at a second end.
12. The portable communications device of claim 1 , wherein a perimeter of the at least one conducting surface is of shaped as one of a triangle, a square, a rectangle, a trapezoid, a pentagon, a hexagon, a heptagon, an octagon, a circle, and an ellipse.
13. The portable communications device of claim 1 , wherein a perimeter of the at least one conducting surface is polygonal in shape.
14. The portable communications device of claim 1 , wherein at least a part of a perimeter of the at least one conducting surface is shaped as a space-filling curve.
15. The portable communications device of claim 1 , wherein at least a portion of the at least one conducting surface is shaped as a multilevel structure.
16. The portable communications device of claim 1 , wherein:
the at least one conducting strip comprises a first conducting strip and a second conducting strip;
the first conducting strip is connected at least one point to a perimeter of the at least one conducting surface; and
a tip of the second conducting strip is connected to the first conducting strip.
17. The portable communications device of claim 1 , wherein the maximal width of the at least one conducting strip is measured perpendicularly to a main axis along a length of the at least one conducting strip.
18. The portable communications device of claim 6 , wherein a maximal width of each of the at least two conducting strips is measured perpendicularly to a main axis along a length thereof.
19. The portable communications device of claim 7 , wherein a maximal width of each of the at least two conducting strips is measured perpendicularly to a main axis along a length thereof.
20. The portable communications device of claim 8 , wherein a maximal width of each of the at least two conducting strips is measured perpendicularly to a main axis along a length thereof.
21. The portable communications device of claim 9 , wherein a maximal width of each of the at least two conducting strips is measured perpendicularly to a main axis along a length thereof.
22. The portable communications device of claim 1 , wherein the antenna is operable to radiate and receive electromagnetic waves across at least three industry-standard frequency bands.
23. The portable communications device of claim 22 , wherein the at least three industry-standard frequency bands comprise GSM 900.
24. The portable communications device of claim 22 , wherein the three industry-standard frequency bands comprise GSM 1800.
25. The portable communications device of claim 22 , wherein the at least three industry-standard frequency bands comprise UMTS.