CN106033836A - Monopole antenna - Google Patents

Abstract

The invention discloses a monopole antenna, which comprises a ground plane and a radiation main body. The radiation body includes a feed-in connection portion, a first radiation branch portion, a second radiation branch portion and a third radiation branch portion. The feed-in connecting part is adjacent to the grounding surface. The first radiation branch part is connected with one side of the feed-in connecting part and extends along a first direction. The first radiation branch part comprises a metal patch, and the width of the metal patch is reduced towards the first direction. The second radiation branch part is connected with the side edge of the feed-in connecting part and is adjacent to the ground plane compared with the first radiation branch part, and the second radiation branch part extends along the first direction. The third radiation branch part is connected with the other side edge of the feed-in connecting part and extends along a second direction opposite to the first direction.

Description

monopole antenna

technical field

The present invention relates to an antenna, and in particular to a multi-band monopole antenna.

Background technique

With the development of communication technology, wireless communication devices, such as notebook computers, mobile phones, wireless access points (Access Point, AP), etc., often need to have the ability to operate in different frequency bands. In order to cope with wireless data transmission in different frequency bands, a broadband antenna or a multi-band antenna is traditionally used as a radio frequency front-end component of the device.

However, the design of traditional multi-frequency antennas is not easy to make adaptive adjustments for each operating frequency band, and the low-frequency bandwidth is also easily limited.

Therefore, how to provide an antenna that can adaptively adjust multiple frequency bands and has good antenna characteristics is one of the topics that the industry is currently working on.

Contents of the invention

The object of the present invention is to provide a multi-band monopole antenna to solve the above problems.

According to a monopole antenna proposed by the present invention, the monopole antenna is printed on a substrate and includes a ground plane and a radiation body. The radiation body includes a feeding connection part, a first radiation branch, a second radiation branch and a third radiation branch. The feeding connection part is adjacent to the ground plane. The first radiating branch is connected to one side of the feeding connection part and extends along a first direction. The first radiating branch is responsible for a first operating frequency of the monopole antenna. The first radiation branch includes a metal patch, and the width of the metal patch shrinks toward the first direction. The second radiating branch is connected to the side of the feeding connection part and is closer to the ground plane than the first radiating branch. The second radiating branch extends along the first direction and is responsible for a second of the monopole antenna. operating frequency. The third radiating branch is connected to the other side of the feeding connection part and extends along a second direction opposite to the first direction, the third radiating branch is responsible for a third operating frequency of the monopole antenna . Wherein the second operating frequency is higher than the third operating frequency, and the third operating frequency is higher than the first operating frequency.

In order to have a better understanding of the above-mentioned and other aspects of the present invention, the preferred embodiments are specifically cited below, together with the accompanying drawings, and described in detail as follows:

Description of drawings

FIG. 1 is a schematic diagram of a monopole antenna according to an embodiment of the present invention;

2A is a schematic diagram of a current path of a radiation subject at a first radiation frequency according to an embodiment of the present invention;

2B is a schematic diagram of a current path of a radiation subject at a second radiation frequency according to an embodiment of the present invention;

2C is a schematic diagram of a current path of a radiation subject at a third radiation frequency according to an embodiment of the present invention;

3A is a schematic diagram of a radiation unit according to another embodiment of the present invention;

3B is a schematic diagram of a radiation unit according to another embodiment of the present invention;

Fig. 4A is a schematic diagram of radiation according to another embodiment of the present invention;

Fig. 4B is a schematic diagram of a radiation unit according to another embodiment of the present invention;

FIG. 5A is a side view of a monopole antenna according to an embodiment of the present invention;

5B is a side view of a monopole antenna according to another embodiment of the present invention;

6 is a measurement diagram of the reflection coefficient of a monopole antenna according to an embodiment of the present invention;

FIG. 7 is a simulation diagram of radiation efficiency of a monopole antenna according to an embodiment of the present invention.

Symbol Description

100: monopole antenna

102: Ground plane

104, 304, 304’, 404, 404’: radiating body

106: Feed-in connection part

108, 308, 308': the first radial branch

110, 410, 410': Second Radiant Branch

112: The Third Radiant Branch

114, 314, 314': metal patches

116: Signal feed-in area

D1, D2: direction

FP: Feed Point

CB: cable

R1, R2, R3: current path

M1, M2: metal layer

DL: dielectric layer

detailed description

The following examples are provided for detailed description, and the examples are only used as examples for illustration and will not limit the scope of protection of the present invention. In addition, the drawings in the embodiments omit unnecessary elements to clearly show the technical characteristics of the present invention.

Please refer to FIG. 1 , which shows a schematic diagram of a monopole antenna 100 according to an embodiment of the present invention. As shown in FIG. 1 , the monopole antenna 100 includes a ground plane 102 and a radiation body 104 . The monopole antenna 100 is printed on a substrate. The radiation body 104 and the ground plane 102 can be disposed on the same side surface of the substrate, or respectively disposed on two side surfaces of the substrate. Generally speaking, in order to avoid damaging the characteristics of the monopole antenna 100 , no other metal patterns or elements are disposed in the substrate area where the radiation body 104 is projected.

The radiation body 104 includes a feeding connection part 106 , a first radiation branch 108 , a second radiation branch 110 and a third radiation branch 112 . The feeding connection portion 106 is adjacent to the ground plane 102 , but not directly connected to the ground plane 102 . In one embodiment, one end of the feeding connection portion 106 adjacent to the ground plane 102 includes a signal feeding area 116 extending toward the direction D2, and the signal feeding area 116 is used for receiving radio frequency signals. For example, a 50-ohm cable CB can be soldered to a feed point FP in the signal feed area 116 (for example, located at the upper right corner of the signal feed area 116 ) to directly feed the monopole antenna 100 with RF signals. However, the present invention is not limited thereto, and the monopole antenna 100 can also receive radio frequency signals through transmission lines printed on the substrate or other existing signal transmission elements. In this embodiment, the impedance matching of the monopole antenna 100 can be effectively improved by adding the signal feeding area 116 extending in the direction D2 to the feeding connecting portion 106 .

The first radiation branch 108 is connected to a first side of the feeding connection portion 106 and extends along the direction D1 (towards the bottom of FIG. 1 ). The first radiation branch 108 is mainly responsible for a first operating frequency of the monopole antenna 100 . In one embodiment, among the plurality of operating frequencies excited by the monopole antenna 100 , the first operating frequency is a relatively low frequency. By adjusting the length of the first radiation branch 108 , the position of the first operating frequency can be correspondingly adjusted. Generally speaking, the length from the feeding point FP to the end of the first radiation branch 108 can be designed to be approximately a quarter wavelength of the first operating frequency.

In one embodiment, the first radiation branch 108 can be bent to reduce the size of the overall antenna. As shown in FIG. 1 , the end of the first radiating branch 108 is bent upward toward the ground plane 102 (direction D2 ). It can be understood that the first radiation branch 108 can also be bent in other ways to increase the overall current path and reduce the size of the antenna.

The first radiation branch 108 includes a metal patch 114, the length of which extends toward the direction D1 is smaller than the length of the first radiation branch 108 extending toward the direction D1, and the position is adjacent to the first side of the feeding connection part 106 and away from the first radiation. The ends of the branches 108 extend toward the direction D1. As shown in FIG. 1 , the width of the metal patch 114 shrinks toward the direction D1 , and the length of the metal patch 114 is greater than the length of the second radiation branch 110 . Through this configuration, the current path leading to the first radiation branch 108 can be increased, thereby increasing the operating bandwidth of the antenna. The metal patch 114 can also be used to adjust the impedance matching of the monopole antenna 100 so that the monopole antenna 100 has lower reflection loss.

The second radiating branch 110 is connected to the first side of the feeding connection portion 106 and is closer to the ground plane 102 than the first radiating branch 108 . That is to say, both the second radiating branch 110 and the first radiating branch 108 are connected to the same side of the feeding connection part 106 . The second radiation branch 110 extends along the direction D1 and is responsible for a second operating frequency of the monopole antenna 100 . In one embodiment, among the plurality of operating frequencies excited by the monopole antenna 100 , the second operating frequency is a relatively high frequency. By adjusting the length of the second radiation branch 110 , the position of the second operating frequency can be correspondingly adjusted. Generally speaking, the length from the feeding point FP to the end of the second radiation branch 110 can be designed to be approximately a quarter wavelength of the second operating frequency.

In one embodiment, the width of the second radiating branch 110 increases toward the direction D1. As shown in FIG. 1 , the width of the middle and end sections of the second radiating branch 110 is wider than that of the front section (connecting with the feed-in connection portion 106 ). In this embodiment, when the width of the second radiating branch 110 increases toward the direction D1, not only the bandwidth of the second operating frequency of the monopole antenna 100 can be effectively increased, but also the capacitance of the second radiating branch 110 to the ground plane 102 can be compensated, Inductive effect, thereby improving the impedance matching of the antenna.

The third radiating branch portion 112 is connected to a second side of the feed-in connection portion 106 , and the second side is disposed corresponding to the first side. That is to say, the third radiating branch 112 and the first and second radiating branches 108 , 110 are respectively located on different sides connected to the feed-in connection part 106 . As shown in FIG. 1 , the third radiating branch 112 extends along a direction D2 opposite to the direction D1 . In one embodiment, the position where the first radiating branch 108 and the third radiating branch 112 are connected to the feed-in connection 106 is adjacent to the other end of the feed-in connection 106 away from the ground plane 102, so that the feed-in connection 106, the first radiating branch 108 and the third radiating branch 112 are arranged in a T-shape, wherein the first radiating branch 108 and the third radiating branch 112 feed into the connecting portion 106 vertically, and the first radiating branch 108 and the third radiating branch 112 are arranged oppositely at 180 degrees.

The third radiation branch 112 is responsible for a third operating frequency of the monopole antenna 100 . In one embodiment, among the plurality of operating frequencies excited by the monopole antenna 100 , the third operating frequency is a relative intermediate frequency. By adjusting the length of the third radiation branch 112 , the position of the third operating frequency can be correspondingly adjusted. Generally speaking, the length from the feeding point FP to the end of the third radiation branch 112 can be designed to be approximately a quarter wavelength of the third operating frequency.

In one embodiment, the third radiating branch 112 can be bent to reduce the size of the overall antenna. As shown in FIG. 1 , the end of the third radiating branch 112 is bent toward the ground plane 102 . It can be understood that the third radiating branch 112 can also be bent in other ways to increase the overall current path and reduce the size of the antenna.

Please refer to FIG. 2A , FIG. 2B , and FIG. 2C . FIG. 2A is a schematic diagram of a current path R1 of the radiation body DL104 at a first radiation frequency according to an embodiment of the present invention. FIG. 2B is a schematic diagram of the current path R2 of the radiation body 104 at the second radiation frequency according to an embodiment of the present invention. FIG. 2C is a schematic diagram of the current path R3 of the radiation body 104 at the third radiation frequency according to an embodiment of the present invention.

As mentioned above, since the first radiating branch 108 is mainly responsible for exciting the radiation mode of the monopole antenna 100 at the first operating frequency, the length of the current path R1 from the feeding point FP to the end of the first radiating branch 108 is approximately the first A quarter wavelength of the operating frequency. Similarly, since the second radiating branch 110 is mainly responsible for exciting the radiation mode of the monopole antenna 100 at the second operating frequency, the length of the current path R2 from the feeding point FP to the end of the second radiating branch 110 is approximately a quarter wavelength of the frequency. Similarly, since the third radiating branch 112 is mainly responsible for exciting the radiation mode of the monopole antenna 100 at the third operating frequency, the length of the current path R3 from the feeding point FP to the end of the third radiating branch 112 is approximately the third operation a quarter wavelength of the frequency. In this embodiment, the second operating frequency is higher than the third operating frequency, and the third operating frequency is higher than the first operating frequency. Therefore, the length of the current path R1 is the longest, followed by the current path R3, and the length of the current path R2 is the shortest.

FIG. 3A is a schematic diagram of a radiation unit 304 according to another embodiment of the present invention. The main difference between the radiation unit 304 and the radiation unit 104 in FIG. 1 is that the width of the metal patch 314 of the first radiation branch 308 shrinks toward the direction D1 in N steps, where N is a positive integer greater than 2. As shown in FIG. 3A , the width of the metal patch 314 decreases in four steps toward the direction D1 . Compared with FIG. 1 , the width of the metal patch 114 is reduced in two steps toward the direction D1 . However, the present invention is not limited thereto, as long as the width of the metal patch of the first radiating branch portion of the radiating unit gradually decreases in a stepwise manner toward the direction D1, it falls within the spirit of the present invention.

Fig. 3B is a schematic diagram of a radiation unit 304' according to yet another embodiment of the present invention. The main difference between the radiating unit 304' in FIG. 3B and the radiating unit 104 in FIG. 1 is that the width of the metal patch 304' of the first radiating branch 308' shrinks smoothly and gradually in the direction D1. As shown in FIG. 3B, one side of the metal patch 304' is a curved smooth curve. In another embodiment, one side of the metal patch 304' can be an oblique line.

FIG. 4A is a schematic diagram of a radiation unit 404 according to yet another embodiment of the present invention. The main difference between the radiation unit 404 in FIG. 4A and the radiation unit 104 in FIG. 1 is that the width of the second radiation branch 410 increases in M steps toward the direction D1, where M is a positive integer greater than 1. As shown in FIG. 4A , the width of the second radiating branch 410 increases toward the direction D1 in three steps. In contrast, the width of the second radiating branch 110 in FIG. 1 increases in 2 steps toward the direction D1. However, the present invention is not limited thereto, as long as the width of the second radiating branch portion of the radiating unit gradually increases in a stepwise manner toward the direction D1, it falls within the spirit of the present invention.

Fig. 4B is a schematic diagram of a radiation unit 404' according to yet another embodiment of the present invention. The main difference between the radiation unit 404' in FIG. 4B and the radiation unit 104 in FIG. 1 is that the width of the second radiation branch 410 increases smoothly toward the direction D1. As shown in FIG. 4B , one side of the second radiating branch 410 is an oblique line. In another embodiment, one side of the second radiating branch 410 may be a smooth curve with a radian.

It can be understood that the monopole antenna produced by adjusting and modifying the above embodiments also falls within the scope of the spirit of the present invention. For example, the metal patch 114 of the monopole antenna 100 can be replaced by the metal patch 314, 314' in FIG. 3A or FIG. 3B, and the second radiation branch 110 can be replaced by the second radiation branch 410, 410' in FIG. 4A or FIG. 4B replace.

Please refer to FIG. 5A and FIG. 5B . FIG. 5A illustrates a side view of a monopole antenna according to an embodiment of the present invention. FIG. 5B shows a side view of a monopole antenna according to another embodiment of the present invention.

As mentioned above, the monopole antenna of the embodiment of the present invention is printed on a substrate, wherein the radiation body and the ground plane can be disposed on the same side surface of the substrate, or respectively disposed on both sides of the substrate. FIG. 5A shows a double-layer board structure, in which the radiation body of the monopole antenna is printed on the metal layer M1, for example. Below the metal layer M1 is a dielectric layer DL. 5B is a three-layer board structure, in which the radiation body of the monopole antenna is printed on the metal layer M1, for example, the ground plane is printed on the metal layer M2, and the dielectric layer DL is between the metal layer M1 and the metal layer. Between M2. As mentioned above, when a three-layer board structure is adopted, metal patterns or components are generally not printed on the substrate area where the radiation body is projected.

FIG. 6 is a measurement diagram of the reflection coefficient ( S11 ) of the monopole antenna according to an embodiment of the present invention. It can be seen from Figure 6 that in the frequency band of 724MHz to 960MHz, the reflection coefficient is below -5dB; in the frequency range of 1.17GHz to 2.17GHz, the reflection coefficient is below -14dB; In the frequency band, the reflection coefficient is about below -12dB.

FIG. 7 is a simulation diagram of radiation efficiency of a monopole antenna according to an embodiment of the present invention. It can be seen from FIG. 7 that the monopole antenna of the embodiment of the present invention has three operating frequency bands, all of which have good radiation efficiency.

In summary, the monopole antenna of the embodiment of the present invention not only has an independent frequency band adjustment mechanism, but also provides good impedance matching and operating bandwidth. In addition, the monopole antenna of the embodiment of the present invention can be operated on an independent printed circuit board or used together with a system ground, which can be conveniently applied to different systems.

Although the present invention has been disclosed in conjunction with the above preferred embodiments, they are not intended to limit the present invention. Those skilled in the technical field of the present invention can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (10)

1. A monopole antenna printed on a substrate, comprising: ground plane; and Radiating subjects, including: The feed-in connection part is adjacent to the ground plane; The first radiating branch is connected to one side of the feeding connection part and extends along a first direction. The first radiating branch is responsible for a first operating frequency of the monopole antenna. The first radiating branch includes: metal a patch, the width of the metal patch shrinks toward the first direction; The second radiation branch is connected to the side of the feeding connection part and is closer to the ground plane than the first radiation branch. The second radiation branch extends along the first direction and is responsible for a second of the monopole antenna. frequency of operation; and The third radiating branch is connected to the other side of the feeding connection part and extends along a second direction opposite to the first direction, the third radiating branch is responsible for a third operating frequency of the monopole antenna ; wherein the second operating frequency is higher than the third operating frequency, and the third operating frequency is higher than the first operating frequency. 2. The monopole antenna according to claim 1, wherein the feed-in connection portion, the first radiating branch and the third radiating branch are arranged in a T shape, wherein the first radiating branch and the third radiating branch are perpendicular to the The position of the feed-in connection part is one end far away from the ground plane, and the first radiating branch and the third radiating branch are oppositely arranged by 180 degrees. 3. The monopole antenna as claimed in claim 1, wherein the width of the metal patch decreases smoothly and gradually toward the first direction. 4. The monopole antenna as claimed in claim 1, wherein the width of the metal patch gradually decreases in a stepwise manner toward the first direction. 5. The monopole antenna as claimed in claim 1, wherein the length of the metal patch is greater than the length of the second radiation branch. 6 . The monopole antenna as claimed in claim 1 , wherein an end of the metal patch extending toward the first direction adjacent to the side of the feeding connection portion and away from the first radiation branch portion. 7 . 7. The monopole antenna as claimed in claim 1, wherein a width of the second radiating branch increases toward the first direction. 8 . The monopole antenna as claimed in claim 1 , wherein an end of the feeding connection part adjacent to the ground plane comprises a signal feeding area extending toward the second direction, and the signal feeding area is used for receiving radio frequency signals. 9. The monopole antenna as claimed in claim 1, wherein the radiation body and the ground plane are disposed on the same side surface of the substrate. 10. The monopole antenna as claimed in claim 1, wherein the radiation body and the ground plane are respectively disposed on two side surfaces of the substrate.