MULTI-BAND ANTENNA

• US 20140043198A1
• Filed: 07/26/2013
• Published: 02/13/2014
• Est. Priority Date: 08/08/2012
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Shimura, Hajime
• Granted Patent: US 9,287,621 B2
• Time in Patent Office: Days
• US Class Current: 343/843
• CPC Class Codes: H01Q 1/12 Supports; Mounting means
• CPC Class Codes: H01Q 1/243 with built-in antennas
• CPC Class Codes: H01Q 5/10 Resonant antennas
• CPC Class Codes: H01Q 5/307 Individual or coupled radiating elements, each element being fed in an unspecified way
• CPC Class Codes: H01Q 5/371 Branching current paths
• CPC Class Codes: H01Q 9/04 Resonant antennas
• CPC Class Codes: H01Q 9/0407 Substantially flat resonant element parallel to ground plane, e.g. patch antenna dipole H01Q9/285; monopole H01Q9/40
• CPC Class Codes: H01Q 9/065 Microstrip dipole antennas patch antenna H01Q9/0407
• CPC Class Codes: H01Q 9/42 with folded element, the folded parts being spaced apart a small fraction of the operating wavelength

Abstract

An antenna which operates in a plurality of frequency bands includes a feeding point, a first conductor which is connected to the feeding point, and at least two second conductors which are branched from the first conductor, have a linear shape, and include open ends as ends on a side opposite to the first conductor. The open ends of the two second conductors face in almost the same direction substantially parallel to a side closest to the feeding point out of the sides of an antenna region. The two second conductors include a part at which the distance between the two conductors at a portion parallel to the side is a first distance, and another part at which the distance is a second distance shorter than the first distance, and are electromagnetically coupled at, at least the other part.

Claims

1. A multi-band antenna which operates in a plurality of frequency bands, comprising:

a feeding point;

a first conductor which is connected to said feeding point; and

at least two second conductors which are branched from said first conductor, have a linear shape, and include open ends as ends on a side opposite to said first conductor,

wherein the open ends of said two second conductors face in substantially the same direction substantially parallel to a side closest to said feeding point out of sides of a region where the antenna is formed,

said two second conductors include a part at which a distance between said two conductors at a portion parallel to the side is a first distance, and another part at which the distance is a second distance shorter than the first distance, and

said two second conductors are electromagnetically coupled at, at least the other part.

2. The antenna according to claim 1, wherein said two second conductors have different lengths and have different operating frequencies at which said two second conductors contribute.

3. The antenna according to claim 2, wherein the operating frequency of one of said second conductors is a 2.4-GHz band, and the operating frequency of said other second conductor is a 5-GHz band.

4. The antenna according to claim 2, wherein a sum of a length of one of said second conductors and a length of said first conductor is smaller than ¼

of a wavelength at the operating frequency at which said one of second conductors contributes.

5. The antenna according to claim 2, wherein the open end of one of said two second conductors for which the contributory operating frequency is to be decreased is included as the other part.

6. The antenna according to claim 1, wherein at least one of said at least two second conductors has a meander line shape.

7. The antenna according to claim 1, wherein the multi-band antenna is formed on a flat surface.

8. The antenna according to claim 1, wherein at the other part, one of said at least two second conductors is arranged on a first flat surface, and the other one of said at least two second conductors is arranged on a second flat surface different from the first flat surface.

9. The antenna according to claim 8, wherein the first flat surface is a front surface of a substrate on which the multi-band antenna is formed, and the second flat surface is a back surface of the substrate.

10. The antenna according to claim 8, wherein the first flat surface is a flat surface between a first layer and second layer of a multilayer substrate on which the multi-band antenna is formed, and the second flat surface is a flat surface between the second layer and a third layer of the substrate.

11. The antenna according to claim 9, wherein the substrate includes a dielectric substrate.

12. The antenna according to claim 8, wherein one of said at least two second conductors arranged on the first flat surface and the other one of said at least two second conductors arranged on the second flat surface are arranged at positions where said at least two second conductors face each other at the other part.

13. The antenna according to claim 1, further comprising a dielectric substance which has a relative dielectric constant of larger than 1, and is arranged and added in contact with or at a predetermined distance from the multi-band antenna.

14. The antenna according to claim 13, wherein the dielectric substance includes a dielectric sheet, and is adhered to the entire multi-band antenna.

15. The antenna according to claim 13, wherein the dielectric substance is arranged and added in contact with or at a predetermined distance from only one of said two second conductors for which an operating frequency is to be shifted to be low.

16. The antenna according to claim 1, wherein antenna ground is arranged to set a distance between at least one of the open ends of said second conductors and the antenna ground to be not larger than a predetermined length.