Dual-band inverted-F antenna

Description

FIELD OF THE INVENTION

The present invention relates to a dual-band inverted-F antenna. More particularly, it relates to an inverted-F printed antenna that can be operated in two separate bands.

BACKGROUND OF THE INVENTION

To follow the advancement of the communication technology, the applications using communication technologies have been increased significantly and the related products have become more diversified. Especially, consumers have more demands for the functions of communication applications, so that there are many communication applications with different designs and functions issued continuously. For example, the products with one-piece design of dual-band or triple-band, and even the implementations of multi-band operation using one single antenna are the main streams. Moreover, by utilizing IC technologies, the size of products will become smaller in future.

Microstrip antennas or printed antennas are becoming more attractive, because they are very suitable for applications in present-day communication products. Among various types of designs, the inverted-F antenna has the attractive features of small volume, simple structure, easy design, etc., and the inverted-F antenna has been utilized popularly in various products and communication systems in recent years, especially in the products required for easy, convenient, and good receiving/transmitting capabilities.

However, a conventional inverted-F antenna only has a function of single operating frequency. If the conventional inverted-F antenna is utilized in dual-band products or multi-band products, two or more inverted-F antennas are required for the multi-band operation. Therefore, the difficulty in the design of products increases, and the size and cost of products increase accordingly.

SUMMARY OF THE INVENTION

In the view of the background of the invention described above, an antenna is an important part in wireless communications, since the performance of wireless communications is greatly affected by the antenna. Therefore, low cost, high efficiency and simple implementation are the major trends for the design of antenna. The conventional inverted-F antenna has several features, such as small volume, simple structure, easy design, etc., so that the conventional inverted-F antenna has been used widely. However, the conventional inverted-F antenna has the disadvantage that it can be operated in a single band only.

It is the principal object of the present invention to provide a dual-band inverted-F antenna. More particularly, the present invention relates to an inverted-F printed antenna that can be operated in two separate bands. More complete functions and wider operating frequency range are attained and provided, because the dual-band inverted-F antenna of the present invention can be operated both in a low frequency band and in a high frequency band. Moreover, the implementation of the present invention is valuable in industrial field, because the dual-band inverted-F antenna of the present invention can be operated in two separate bands, and can be printed on a microwave substrate, which makes it easy to integrate with other associated microwave circuitry.

In accordance with the aforementioned purpose of the present invention, the present invention provides a dual-band inverted-F antenna. The main radiating component of the dual-band inverted-F antenna of the present invention is two stacked radiating metal lines that are fed and driven by a same feeding line. According to the different lengths, widths and shapes of the two stacked radiating metal lines, the dual-band inverted-F antenna of the present invention can be operated in a low frequency band and a high frequency band, and their frequency ratio can also be adjusted easily. Moreover, since the radiating metal lines and the ground plane are printed directly on a substrate, the cost is thus lower and the manufacturing can be processed easily.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:

FIG. 1

is a top view of the structure of an embodiment of the dual-band inverted-F antenna of the present invention.

FIG. 2

is a side view along the x direction according to FIG.

1

.

FIG. 3

is a diagram showing measured return loss of the embodiment of the present invention according to FIG.

1

.

FIG. 4

is a diagram showing measured radiation pattern in x-z plane when the embodiment of the present invention shown in

FIG. 1

is operated at 2450 MHz.

FIG. 5

is a diagram showing measured radiation pattern in x-y plane when the embodiment of the present invention shown in

FIG. 1

is operated at 2450 MHz.

FIG. 6

is a diagram showing measured radiation pattern in y-z plane when the embodiment of the present invention shown in

FIG. 1

is operated at 2450 MHz.

FIG. 7

is a diagram showing measured radiation pattern in x-z plane when the embodiment of the present invention shown in

FIG. 1

is operated at 5250 MHz.

FIG. 8

is a diagram showing measured radiation pattern in x-y plane when the embodiment of the present invention shown in

FIG. 1

is operated at 5250 MHz.

FIG. 9

is a diagram showing measured radiation pattern in y-z plane when the embodiment of the present invention shown in

FIG. 1

is operated at 5250 MHz.

FIG. 10

is a diagram showing measured antenna gain of an embodiment of the present invention operated in a range from 2380 MHz to 2500 MHz according to FIG.

1

.

FIG. 11

is a diagram showing measured antenna gain of an embodiment of the present invention operated in a range from 5100 MHz to 5400 MHz according to FIG.

1

.

FIG. 12

to

FIG. 17

are top views of the structures of dual-band inverted-F antenna of the other embodiments of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The structure of the dual-band inverted-F antenna of the present invention is simple and is different from the conventional inverted-F antenna whose shorted radiating metal patch is placed above the ground plane in a three-dimensional structure. The metal patch or metal line of the dual-band inverted-F antenna of the present invention is printed directly on a microwave substrate in a two-dimensional structure so that the implementation is more convenient.

Referring to FIG.

1

and

FIG. 2

,

FIG. 1

shows a top view of the structure of an embodiment of the dual-band inverted-F antenna of the present invention, and

FIG. 2

shows a side view along the x direction according to FIG.

1

. As shown in

FIG. 1

, a metal line

40

, a metal line

42

, a feeding metal line

60

providing signals to the metal line

40

and the metal line

42

through a feeding point

62

and a feeding point

64

, and a connecting line

26

used to connect the metal line

40

and the metal line

42

to a shorting pin

22

shown in

FIG. 2

are printed on the first surface

12

of a substrate

10

. A shorting pin

22

shown in

FIG. 2

is located in the substrate

10

, and is used to connect the metal line

40

and the metal line

42

to the ground plane

20

on the second surface

14

of the substrate

10

. Further, the connecting line

26

and the shorting pin

22

are made of metal line.

As shown in

FIG. 1

, a stacked structure comprising the metal line

40

and the metal line

42

is the major radiating part of the dual-band inverted-F antenna of the present invention, and the metal line

40

and the metal line

42

are connected to the feeding metal line

60

, wherein the connecting location thereof is not limited. In

FIG. 1

, the feeding point

62

and feeding point

64

through which the feeding metal line

60

is connected to the metal line

40

and metal line

42

are located respectively at about the middle points of the metal line

40

and the metal line

42

.

The dual-band inverted-F antenna of the present invention can be operated in different frequency bands by using the same feeding metal line, wherein the high frequency operation is controlled by the metal line

40

shown in

FIG. 1

, and the low frequency operation is controlled by the metal line

42

shown in FIG.

1

.

Through different designs of length, width and shape of the metal line

40

and the metal line

42

, the frequency ratio demanded can be achieved easily. Through many different studies, the embodiment of the present invention shown in

FIG. 1

can be operated in two separate bands (about 2450 MHz and about 5250 MHz). Referring to

FIG. 3

,

FIG. 3

is a diagram showing measured return loss of the embodiment of the present invention according to FIG.

1

. As shown in

FIG. 3

, the return loss that indicated by the dotted line

80

is about 14 dB, wherein the dotted line

80

is a return-loss reference of the embodiment of the present invention shown in FIG.

1

. From

FIG. 3

, when the embodiment of the present invention shown in

FIG. 1

is operated in a range from about 2380 MHz to about 2500 MHz, the return loss is better than 14 dB, and the return loss reaches about 18 dB when the embodiment of the present invention shown in

FIG. 1

is operated at about 2500 MHz. When the embodiment of the present invention shown in

FIG. 1

is operated in a range from about 5100 MHz to about 5400 MHz, the return loss is also better than 14 dB, and the return loss reaches about 29 dB when the embodiment of the present invention shown in

FIG. 1

is operated at about 5200 MHz. Therefore, good impedance matching can be obtained whether the embodiment of the present invention shown in

FIG. 1

is operated in the low frequency band (from about 2380 MHz to about 2500 MHz) or in the high frequency band (from about 5100 MHz to about 5400 MHz).

When the embodiment of the present invention shown in

FIG. 1

is operated in the low frequency band, the signal of low frequency is provided by the feeding metal line

60

to the metal line

42

through the feeding point

64

, and the measured radiation patterns in principal planes are shown in

FIG. 4

to FIG.

6

.

FIG. 4

is a diagram showing measured radiation pattern in x-z plane when the embodiment of the present invention shown in

FIG. 1

is operated at 2450 MHz.

FIG. 5

is a diagram showing measured radiation pattern in x-y plane when the embodiment of the present invention shown in

FIG. 1

is operated at 2450 MHz.

FIG. 6

is a diagram showing measured radiation pattern in y-z plane when the embodiment of the present invention shown in

FIG. 1

is operated at 2450 MHz. In

FIG. 4

, FIG.

5

and

FIG. 6

, the variations of the component of electrical field in θ direction is indicated by a thick black line, and that in φ direction is indicated by a thin black line. As shown in

FIG. 5

, the measured radiation pattern in x-y plane is close to omnidirectional, so that good azimuthal coverage can be provided.

Moreover, referring to

FIG. 10

,

FIG. 10

is a diagram showing measured antenna gain of an embodiment of the present invention that is operated in a range from about 2380 MHz to about 2500 MHz according to FIG.

1

. The antenna gain of an embodiment of the present invention shown in

FIG. 1

that is operated in a range from about 2380 MHz to about 2500 MHz is from about 0 dBi to about 1 dBi.

When the embodiment of the present invention shown in

FIG. 1

is operated in the high frequency band, the signal of high frequency is provided by the feeding metal line

60

to the metal line

40

through the feeding point

62

, and the measured radiation patterns in principal planes are shown in

FIG. 7

to FIG.

9

.

FIG. 7

is a diagram showing measured radiation pattern in x-z plane when the embodiment of the present invention shown in

FIG. 1

is operated at 5250 MHz.

FIG. 8

is a diagram showing measured radiation pattern in x-y plane when the embodiment of the present invention shown in

FIG. 1

is operated at 5250 MHz.

FIG. 9

is a diagram showing measured radiation pattern in y-z plane when the embodiment of the present invention shown in

FIG. 1

is operated at 5250 MHz. In

FIG. 7

, FIG.

8

and

FIG. 9

, the variations of the component of electrical field in θ direction is indicated by a thick black line, and that in φ direction is indicated by a thin black line. As shown in

FIG. 7

to

FIG. 9

, the radiation patterns of the embodiment of the present invention that operated at 5250 MHz are in general similar to (except that there are more ripples in the radiation patterns) those of the embodiment of the present invention that operated at 2450 MHz.

Moreover, referring to

FIG. 11

,

FIG. 11

is a diagram showing measured antenna gain of an embodiment of the present invention that is operated from about 5100 MHz to about 5400 MHz according to FIG.

1

. The antenna gain of an embodiment of the present invention shown in

FIG. 1

that is operated at from about 5100 MHz to about 5400 MHz is from about 0 dBi to about 0.5 dBi.

Referring to

FIG. 12

to

FIG. 17

, they are top views of the structures of dual-band inverted-F antenna of the other embodiments of the present invention, wherein the metal line

40

and the metal line

42

can be in the same shape and width or not. For example, the metal line

40

and the metal line

42

are in the same shape, and are with the corresponding connecting line

26

and connecting line

28

, and are with the shorting pin

22

and shorting pin

24

connected with the ground plane

20

, and the signal is fed by the feeding metal line

60

to the metal line

40

and metal line

42

through the feeding point

62

and feeding point

64

, wherein the connecting line

28

and the shorting pin

24

are made of metal lines. In the embodiment of the present invention from

FIG. 13

to

FIG. 15

, different operating frequencies can be obtained by changing the layout of connecting line

26

and the feeding metal line. In the embodiment of the present invention from

FIG. 16

to

FIG. 17

, different operating frequencies can be obtained by changing the layout of the metal line

40

and the metal line

42

.

The advantage of the present invention is to provide a dual-band inverted-F antenna. More particularly, the present invention relates to an inverted-F printed antenna that can be operated in two separate bands. The dual-band inverted-F antenna of the present invention can be operated in different bands by changing the length, width and shape of the radiating metal lines. Moreover, the demands of bandwidth can be satisfied within the frequency band required. Therefore, the dual-band inverted-F antenna of the present invention has better properties, and in addition, can be manufactured easily on a microwave substrate, so that the cost is lower and the implementation is easily achieved.

As is understood by a person skilled in the art, the foregoing preferred embodiments of the present invention are illustrated of the present invention rather than limiting of the present invention. It is intended to cover various modifications and similar arrangements included within the spirit and scope of the appended claims, the scope of which should be accorded the broadest interpretation so as to encompass all such modifications and similar structures.

Claims

1. A dual-band inverted-F antenna, comprising:a substrate, which consists of a first surface and a second surface, wherein the first surface is located on one side of the substrate and the second surface is located on the other side of the substrate; a ground plane, which is located on the second surface of the substrate; a first radiating metal line, which is located on the first surface of the substrate and has a first shape and a first width; a second radiating metal line, which is located on the first surface of the substrate and has a second shape and a second width; a feeding metal line, which is located on the first surface of the substrate and is connected to a position of the first radiating metal line and a position of the second radiating metal line; a connecting line, which is located on the first surface of the substrate and is used to connect with one end of the first radiating metal line and one end of the second radiating metal line at the same time; and a shorting pin, which is located in the substrate and one end of the shorting pin is connected with the ground plane, and the other end of the shorting pin is connected with the connecting line.
2. The dual-band inverted-F antenna of claim 1, wherein the connecting line is a metal line.
3. The dual-band inverted-F antenna of claim 1, wherein the shorting pin is a shorting metal pin.
4. The dual-band inverted-F antenna of claim 1, wherein the first shape of the first radiating metal line is the same as the second shape of the second radiating metal line.
5. The dual-band inverted-F antenna of claim 1, wherein the first width of the first radiating metal line is the same as the second width of the second radiating metal line.
6. The dual-band inverted-F antenna of claim 1, wherein the first width of the first radiating metal line is different from the second width of the second radiating metal line.
7. A dual-band inverted-F antenna, comprising:a substrate, which consists of a first surface and a second surface, wherein the first surface is located on one side of the substrate and the second surface is located on the other side of the substrate; a ground plane, which is located on the second surface of the substrate; a first radiating metal line, which is located on the first surface of the substrate, and has a first shape and a first width; a second radiating metal line, which is located on the first surface of the substrate and has a second shape and a second width; a feeding metal line, which is located on the first surface of the substrate and is connected to a position of the first radiating metal line and a position of the second radiating metal line; a first connecting line, which is located on the first surface of the substrate and is used to connect with one end of the first radiating metal line; a second connecting line, which is located on the first surface of the substrate and is used to connect with one end of the second radiating metal line; a first shorting pin, which is located in the substrate, and one end of the first shorting pin is connected with the ground plane and the other end of the first shorting pin is connected with the first connecting line; and a second shorting pin, which is located in the substrate, and one end of the second shorting pin is connected with the ground plane and the other end of the second shorting pin is connected with the second connecting line.
8. The dual-band inverted-F antenna of claim 7, wherein the first connecting line is a metal line.
9. The dual-band inverted-F antenna of claim 7, wherein the second connecting line is a metal line.
10. The dual-band inverted-F antenna of claim 7, wherein the first shorting pin is a first shorting metal pin.
11. The dual-band inverted-F antenna of claim 7, wherein the second shorting pin is a second shorting metal pin.
12. The dual-band inverted-F antenna of claim 7, wherein the first shape of the first radiating metal line is the same as the second shape of the second radiating metal line.
13. The dual-band inverted-F antenna of claim 7, wherein the first width of the first radiating metal line is the same as the second width of the second radiating metal line.
14. The dual-band inverted-F antenna of claim 7, wherein the first width of the first radiating metal line is different from the second width of the second radiating metal line.

Priority Claims (1)

Number	Date	Country	Kind
90124455 A	Oct 2001	TW

US Referenced Citations (5)

Number	Name	Date	Kind
6008762	Ngheim	Dec 1999	A
6100849	Tsubaki et al.	Aug 2000	A
6218991	Sanad	Apr 2001	B1
6268831	Sanford	Jul 2001	B1
6346914	Annamaa	Feb 2002	B1

Dual-band inverted-F antenna

Information

Patent Number

Date Filed

Date Issued

Inventors

Original Assignees

Examiners

Agents

CPC

US Classifications

Field of Search

US

International Classifications

Abstract

Description

Claims

Priority Claims (1)

US Referenced Citations (5)