Dual-band antenna having small size and low height

• US 20050057400A1
• Filed: 08/25/2004
• Published: 03/17/2005
• Est. Priority Date: 09/01/2003
• Status: Active Grant

• Current Assignee: Alps Alpine Co., Ltd.
• Original Assignee: ALPS Electric Company Limited (Alps Alpine Co., Ltd.)
• Inventors: Yuanzhu, Dou
• Granted Patent: US 6,977,616 B2
• Time in Patent Office: Days
• US Class Current: 343/700.MS
• 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

Abstract

There is provided a dual-band antenna having small size and low height which has a characteristic of not affecting a bandwidth of signal waves of a low band in its miniaturized state. In a dual-band antenna 11, a first radiating conductive plate 13 is arranged to oppose a surface of a grounding conductor 12 in an approximately parallel manner, being excited at a first frequency. A feeding conductive plate 14 extends approximately orthogonally from an outer edge of the first radiating conductive plate 13 and is connected to a feeding circuit A second radiating conductive plate 15 is stood downward the first radiating conductive plate 13, whose lower end is connected to the feeding conductive plate 14. The second radiating conductive plate 15 is excited at a second frequency. A third radiating conductive plate 17 is arranged to oppose the surface of the grounding conductor 12 in an approximately parallel manner on a surface of the grounding conductor and to be adjacent to the first radiating conductive plate 13. A slit 18 is interposed between both radiating conductive plates 13 and 17. A shorting conductive plate 19 extends approximately orthogonally from an outer edge of the third radiating conductive plate 17 and is connected to the surface of the grounding conductor 12. The feeding conductive plate 14 and the shorting conductive plate 19 is arranged close to each other, such that, when a power is supplied, the feeding conductive plate 14 and the shorting conductive plate 19 is electromagnetically coupled.

Claims

1. A dual-band antenna, comprising:

a first radiating conductive plate arranged to oppose a grounding conductor in an approximately parallel manner on a surface of the grounding conductor, the first radiating conductive plate being excited at a first frequency;

a feeding conductive plate extending approximately orthogonally from an outer edge of the first radiating conductive plate and connected to a feeding circuit;

a second radiating conductive plate extending in approximately parallel to the feeding conductive plate, whose lower end is connected to the feeding conductive plate and an upper end opposes a bottom surface of the first radiating conductive plate;

a third radiating conductive plate arranged to oppose a grounding conductor in an approximately parallel manner on a surface of the grounding conductor, the third radiating conductive plate being adjacent to the first radiating conductive plate with a slit interposed therebetween; and

a first shorting conductive plate extending approximately orthogonally from an outer edge of the third radiating conductive plate and connected to the surface of the grounding conductor,

wherein the second radiating conductive plate is excited at a second frequency which is higher than the first frequency, and the first shorting conductive plate is arranged close to the feeding conductive plate such that the first shorting conductive plate is electromagnetically coupled to the feeding conductive plate.

2. The dual-band antenna according to claim 1, wherein the feeding conductive plate extends from the outer edge of the first radiating conductive plate adjacent to the slit, and the first shorting conductive plate extends from the outer edge of the third radiating conductive plate adjacent to the slit.

3. The dual-band antenna according to claim 1, further comprising:

an impedance matching shorting conductive plate extending approximately orthogonally from the outer edge of the first radiating conductive plate and connected to the surface of the grounding conductor.

4. A dual-band antenna, comprising:

a cylindrical insulating base member mounted on a supporting substrate having a grounding conductor;

a fourth radiating conductive plate having a pair of divided conductive plates provided in parallel to a slit interposed therebetween and mounted at positions covering opening ends of the insulating base member;

a feeding conductive plate and a second shorting conductive plate provided in an inner space of the insulating base member, whose upper ends are respectively connected to an outer edge of one divided conductive plate of the pair of divided conductive plates adjacent to the slit;

a third shorting conductive plate provided in the inner space of the insulating base member, whose upper end is connected to an outer edge of the other divided conductive plate of the pair of divided conductive plates adjacent to the slit; and

a fifth radiating conductive plate provided in the inner space of the insulating base member, whose lower end is connected to the feeding conductive plate and the height is lower than that of the fourth radiating conductive plate,

wherein a lower end of the feeding conductive plate is connected to a feeding circuit and lower ends of the second and third shorting conductive plates are connected to the grounding conductor, such that in a state in which the third shorting conductive plate is electromagnetically coupled to the feeding conductive plate, the fourth radiating conductive plate is resonated at a first frequency, and the fifth radiating conductive plate is resonated at a second frequency which is higher than the first frequency.

5. The dual-band antenna according to claim 4, wherein the pair of divided conductive plates is respectively provided with windows which are approximately the same shape.

6. The dual-band antenna according to claim 4, wherein an upper end of the fifth radiating conductive plate extends in approximately parallel to the grounding conductor.