Antenna apparatus

• US 20030160728A1
• Filed: 04/22/2003
• Published: 08/28/2003
• Est. Priority Date: 03/15/2001
• Status: Active Grant

• Current Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Original Assignee: Matsushita Electric Industrial Company Limited (Panasonic Holdings Corporation)
• Inventors: Yuda, Naoki, Fukushima, Susumu
• Granted Patent: US 6,836,248 B2
• Time in Patent Office: Days
• US Class Current: 343/702
• CPC Class Codes: H01Q 1/242 specially adapted for hand-held use
• CPC Class Codes: H01Q 13/085 Slot-line radiating ends
• CPC Class Codes: H01Q 5/371 Branching current paths
• CPC Class Codes: H01Q 5/378 Combination of fed elements with parasitic elements
• CPC Class Codes: H01Q 9/0421 with a shorting wall or a shorting pin at one end of the element H01Q9/0414 takes precedence
• CPC Class Codes: H01Q 9/0442 with particular tuning means

Abstract

A small antenna device having a wide frequency band suitable for being built in mobile communications apparatuses. This antenna device includes a planar radiating element (radiating plate) and a grounding plate provided in parallel to and facing the radiating plate. A feeding line is disposed at approximately the end center of the radiating plate, and supplies high-frequency signals. A shorting portion shorts the radiating plate and grounding plate at near the feeding line. A slit is provided at an end face of the radiating plate approximately opposing the feeding line to form two resonators. A coupling level between two resonators is optimized by adjusting the shape or dimensions of this slit, or loading a reactance element or conductive plate on this slit. Accordingly, a small and short antenna with a preferred characteristic is achieved.

Claims

1. (Amended) An antenna device comprising:

a radiating plate;

a feeding line provided to one of a side and an end of said radiating plate;

a grounding plate provided facing said radiating plate; and

a shorting portion whose one end is disposed near said feeding line and an other end is connected to said grounding plate;

wherein two resonators including a first resonator and a second resonator are formed on said radiating plate by providing a slit on a side face or an end face of said radiating plate approximately opposing said feeding line, and said antenna device has an wide band frequency range responsive to a coupling level between said two resonators.

2. The antenna device as defined in claim 1, wherein said slit is one of a rough T-shape and tongue shape.

3. The antenna device as defined in claim 1, wherein a conductive coupling plate is provided near said radiating plate, via an insulating member, across said slit.

4. The antenna device as defined in claim 1, wherein a coupling level between said two resonators is adjusted by partially changing a width of said slit.

5. The antenna device as defined in claim 3, wherein a coupling level of said two resonators is adjusted by partially changing the size of said coupling plate.

6. The antenna device as defined in claim 1, wherein a part of said slit is progressively made longer to decrease a resonance frequency of said resonator.

7. The antenna device as defined in claim 1, wherein said radiating plate and said grounding plate are formed on a surface of one of dielectric, magnetic substance, and a mixture of dielectric and magnetic substance.

8. The antenna device as defined in claim 1, wherein a space exists between said radiating plate and said grounding plate.

10. The antenna device as defined in claim 1, wherein a reactance element is one of added to and formed on between said grounding plate and a part of at least one of said two resonators.

11. The antenna device as defined in claim 1, wherein a reactance element is one of added to and formed on a part of said slit.

12. The antenna device as defined in one of claims 10 and 11, wherein said reactance element is formed by at least one of a coupling plate, comb element, microstrip line, chip capacitor, and chip inductor.

13. The antenna device as defined in claim 4, wherein said coupling plate and at least one of said two resonators are shorted.

14. The antenna device as defined in claim 12, wherein a capacitance of said element is adjusted by changing a teeth shape of said element.

15. The antenna device as defined in claim 1, wherein said slit is branched to a rough T-shape about midway, and at least one of said two resonators includes at least one of:

a capacitance element one of added to and formed on an area where a high-frequency electric field is dominant; and

an inductance element one of added to and formed on an area where a high-frequency magnetic field is dominant.

16. The antenna device as defined in claim 1, wherein

said slit is branched to a rough T-shape about midway, and at least one of these branched slits is bent approximately perpendicularly at near a side of said radiating plate toward a start point of said slit, and at least one of said two resonators includes at least one of:

a capacitance element one of add to and formed on an area where a high-frequency electric field is dominant; and

an inductance element one of added to and formed on an area where a high-frequency magnetic field is dominant.

17. The antenna device as defined in claim 1, wherein;

said radiating plate is divided into two areas by a rough perpendicular bisector to a line from a point where said shorting portion is provided (shorting point) and a start point of said slit, said two areas being an area where said start point is present (first area) and an area where said shorting point is present (second area); and

when an end point of said slit lies on said second area;

a capacitance element is one of added to and formed on said first area; and

an inductance element is one of added to and formed on said second area.

18. The antenna device as defined in claim 1, wherein said radiating plate is divided into two areas by a rough perpendicular bisector to a line from a point where said shorting portion is provided (shorting point) and a start point of said slit, said two areas being an area where said start point is present (first area) and an area where said shorting point is present (second area);

and

a capacitance element is one of added to and formed on said second area when said slit is progressively made longer passing through said second area and its end point of the slit is present in said first area.

19. The antenna device as defined in claim 1, wherein said radiating plate is divided into two areas by a rough perpendicular bisector to a line from a point where said feeding line is provided (feeding point) and a start point of said slit, said two areas being an area where said start point is present (first area) and an area where said feeding point is present (second area);

and

when an end point of said slit lies on said second area;

a capacitance element is one of added to and formed on said first area; and

an inductance element is one of added to and formed on said second area.

20. The antenna device as defined in claim 1, wherein said radiating plate is divided into two areas by a rough perpendicular bisector to a line from a point where said feeding line is provided (feeding point) and a start point of said slit, said two areas being an area where said start point is present (first area) and an area where said feeding point is present (second area);

and

a capacitance element is one of added to and formed on said second area when said slit is progressively made longer passing through said first area and an end point of the slit is present in said first area.

21. The antenna device as defined in claim 1, wherein said slit is branched to said first resonator side and said second resonator side about midway as a first slit and a second slit, and said radiating plate is divided into two areas by a perpendicular bisector to a line from a point where a shorting portion is provided (shorting point) on said radiating plate and a start point of said slit, said areas being an area where said start point is present (first area) and an area where said shorting point is present (second area);

when an end point of said first slit lies on said second area, said first resonator has;

a capacitance element is one of added to and formed on said first area; and

an inductance element one of added to and formed on said second area in said first resonator; and

when said second slit passes through said second area and an end point of said second slit lies on said first area, said second resonator has;

a capacitance element one of added to and formed on said second area in said second resonator.

22. The antenna device as defined in claim 1, wherein said slit is branched to said first resonator side and said second resonator side about midway as a first slit and a second slit, and said radiating plate is divided into two areas by a perpendicular bisector to a line from a point where a feeding line is provided (feeding point) on said radiating plate and a start point of said slit, said areas being an area where said start point is present (first area) and an area where said feeding point is present (second area);

when an end point of said first slit lies on said second area, said first resonator has;

an capacitance element is one of added to and formed on said first area; and

an inductance element is one of added to and formed on said second area in said first resonator; and

when said second slit passes through said second area and an end point of said second slit lies on said first area, said second resonator has;

a capacitance element is one of added to and formed on said second area in said second resonator.

23. The antenna device as defined in one claims 15 to 22, wherein at least one of a capacitance element and an inductance element is one of added to and formed on at least one of between said slits and between said radiating plate and said grounding plate.

24. The antenna device as defined in one of claims 1 and 9, wherein said resonators have a meander shape.

9. (Amended)An antenna device comprising:

a radiating plate;

a feeding line provided on one of a side and an end of said radiating plate;

a grounding plate provided facing said radiating plate; and

a shorting portion whose one end is provided near said feeding line and the other end is connected to said grounding plate;

wherein a plurality of resonators are formed on said radiating plate by providing a plurality of slits on one of a side and an end face of said radiating plate approximately opposing said feeding line, and said antenna device has an wide band frequency range responsive to a coupling level between said plurality of resonators.