A high-gain antenna circuit

Abstract

The present invention relates to a high-gain antenna circuit, comprising: a circuit board configured to carry radiation units; and a plurality of radiation units configured to receive and / or transmit wireless signals and including a first radiation unit and a second radiation unit, wherein the first radiation unit has a first center operating frequency and a first operating frequency band, and the second radiation unit has a second center operating frequency and a second operating frequency band, wherein the plurality of radiation units are configured such that the first center operating frequency is different from the second center operating frequency and the first operating frequency band and the second operating frequency band at least partially overlap each other. By the present invention, it is possible to increase the gain of the antenna in various application environments while increasing the antenna bandwidth without increasing the circuit area.

Description

Technical Field

[0001] The present invention generally relates to the technical field of antennas, and more particularly, to a high-gain antenna circuit. Background Art

[0002] In recent years, with the progress of wireless communication technology, multiple high-tech industries based on this technology have flourished. For example, in industries such as logistics, smart home, intelligent access control, and security, a large number of technological innovations based on wireless communication and business model innovations based on this have emerged.

[0003] An important component of wireless communication is the antenna. The function of the antenna is to optionally receive and transmit wireless signals. The performance of the antenna will greatly affect the efficiency and quality of wireless communication. For example, in some situations in the Internet of Things field, the signal strength is weak, and the commonly used omnidirectional antenna design often cannot provide good signals due to its low-gain characteristics, and thus cannot meet the requirements of some applications. This is especially the case in safes, iron cabinets with serious signal shielding, and inside door locks far from the wireless router. Generally speaking, external antennas often have better signal quality, but often require a dedicated antenna housing and openings to be designed for the antenna, and RF connectors are used to connect the antenna and the internal circuit, which will result in higher product costs, such as more complex product processes and larger product volumes, and do not meet the miniaturization requirements of the Internet of Things market.

[0004] The parameters of the antenna are affected by many factors. For example, factors such as whether the environment around the antenna is close to ferromagnetic substances or large objects that absorb or reflect electromagnetic waves will directly affect the performance of the antenna. That is to say, in different situations, the performance of the antenna may change due to changes in the operating environment, and even drop below the communication requirements. However, with the popularization of Internet of Things devices, the mobility of products is getting higher and higher, and a product often needs to be used in many situations. This has resulted in more and more complex usage situations for the antenna. Therefore, it is necessary to reduce the restrictions on the usage situations of the antenna to make the product more adaptable and thus have a larger market.

[0005] On the other hand, the design cost and modification cost of the antenna are relatively high. This is because, in order to reduce costs, the antenna is often constructed on a printed circuit board (PCB). Its design and debugging process is time-consuming and complex, and involves various considerations, such as material dielectric constant, material thickness, material impedance, etc. Once the design is completed, the cost of design modification will be relatively high. Moreover, a well-designed antenna often requires re-testing and adjustment of relevant radio frequency parameters when changing the PCB supplier. If the impact is significant, it may also be necessary to correct the geometric design of the antenna itself. In order to ensure the quality of the wireless communication signal of the product, it is often necessary to specify the raw material manufacturer and production process of the PCB. Due to such restrictions on the manufacturer, it is often impossible to freely change the manufacturer in a timely manner according to the technological development of the PCB. Therefore, there is also a need for an antenna circuit that can be applied to more application scenarios without circuit modification. Summary of the Invention

[0006] The task of the present invention is to provide a high-gain antenna circuit. Through this antenna circuit, while increasing the antenna bandwidth and without increasing the circuit area, the gain of the antenna in various application environments can be increased.

[0007] Through the present invention, this task is solved by a high-gain antenna circuit, which includes:

[0008] A circuit board configured to carry a radiation unit; and

[0009] A plurality of radiation units configured to receive and / or transmit wireless signals and including a first radiation unit and a second radiation unit, wherein the first radiation unit has a first center operating frequency and a first operating frequency band, and the second radiation unit has a second center operating frequency and a second operating frequency band, wherein the plurality of radiation units are configured such that the first center operating frequency is different from the second center operating frequency and the first operating frequency band and the second operating frequency band overlap at least partially with each other.

[0010] In the present invention, the term "radiating element" refers to a structure in an antenna for receiving and / or transmitting signals, such as an antenna transceiver unit, an antenna branch unit, and the like. The term "operating frequency band (or operating band) of the radiating element" refers to the frequency range in which the radiating element can receive and transmit signals, or the frequency band defined according to technical specifications, such as the bandwidth when the antenna gain drops by three decibels, or the operating bandwidth of the antenna under a specified voltage standing wave ratio. The term "center operating frequency of the radiating element" refers to the frequency at which the radiating element achieves the maximum receiving and transmitting power in the operating frequency band. In the present invention, in order to achieve different center operating frequencies and overlapping operating frequency bands for each radiating element, various parameters of each radiating element can be made different from each other. These parameters include, but are not limited to, dimensions (such as length, width, thickness, etc.), shapes (such as tortuous, arc-shaped, linear, etc.), material types (such as selecting different radiating branch materials), material parameters (dielectric constant of the radiating branch material, resistance matching degree between materials, etc.), and so on.

[0011] In a preferred embodiment of the present invention, it is stipulated that the circuit board has a first side and a second side opposite to the first side, and each radiating element includes:

[0012] A first radiating branch and a second radiating branch, wherein the first radiating branch is on the first side and the second radiating branch is on the second side, and the radiating branches on the same side of adjacent radiating elements are connected in parallel to each other and connected to a feeder; and

[0013] A plurality of feeders, wherein each of the plurality of feeders is assigned to one or more of the plurality of radiating elements, and the plurality of feeders are connected to each other and connected to a power source or a signal source.

[0014] In another preferred embodiment of the present invention, it is stipulated that the difference between the first center operating frequency and the second center operating frequency is more than 2% of the smaller of the first center operating frequency and the second center operating frequency, such as 10% or 90%. Through this preferred embodiment, the operating frequency band of the entire antenna circuit can be optimally extended. For example, in the case of using a broadband radiating element, the upper limit of the difference between the first dimension and the second dimension can be greater than 90%, such as 200%.

[0015] In still another preferred embodiment of the present invention, it is stipulated that the radiating branch of the first radiating element has a first dimension, and the radiating branch of the second radiating element has a second dimension, wherein the first dimension is different from the second dimension, and the difference between the first dimension and the second dimension is more than 2% of the smaller of the first dimension and the second dimension, so that the first center operating frequency is different from the second center operating frequency and the first operating frequency band and the second operating frequency band overlap with each other at least partially. The above dimensions are preferably the lengths of the radiating branches. However, under the teaching of the present invention, other parameters are also conceivable, such as the width and thickness of the radiating branches.

[0016] In another preferred embodiment of the present invention, it is provided that the radiation branches of the first radiation unit have a first shape, and the radiation branches of the second radiation unit have a second shape, wherein the first shape is different from the second shape, such that the first center operating frequency is different from the second center operating frequency and the first operating frequency band and the second operating frequency band overlap at least partially with each other. The shape of the radiation branch is, for example, meandering, arc-shaped, straight-line-shaped, wavy, sinusoidal, broken-line-shaped, triangular, butterfly-shaped, etc. By setting different shapes, excessive size differences between the radiation branches can be avoided, thereby simplifying the design and possibly saving circuit area. For example, when different shapes are set, the lengths of the radiation branches can be substantially the same.

[0017] In an extended embodiment of the present invention, it is provided that the first radiation branches and the second radiation branches of the plurality of radiation units have the same or different shapes and / or lengths. By making the two radiation branches of the same radiation unit have different shapes and lengths, the center operating frequency and the operating frequency band of each radiation unit can be adjusted more flexibly, which is beneficial to optimizing the gain and total bandwidth of the antenna.

[0018] In a preferred embodiment of the present invention, it is provided that the plurality of radiation units include 4 radiation units, wherein the first and second radiation units are arranged adjacent to each other, and the third and fourth radiation units are adjacent to each other. When 4 radiation units are provided, a good compromise can be achieved between the total bandwidth of the antenna and the circuit complexity and the circuit length. Under the teaching of the present invention, other numbers of radiation units are also conceivable.

[0019] In another preferred embodiment of the present invention, it is provided that the radiation branches of the first radiation unit and the radiation branches of the third radiation unit have a first size, and the radiation branches of the second radiation unit and the fourth radiation unit have a second size, wherein the first size is different from the second size, and the difference between the first size and the second size is more than 2% of the smaller of the first size and the second size, such that the first center operating frequency is different from the second center operating frequency and the first operating frequency band and the second operating frequency band overlap at least partially with each other. In this preferred embodiment, by making the first and third radiation units and the second and fourth radiation units have radiation branches of the same size, the antenna circuit design can be simplified.

[0020] In an extended embodiment of the present invention, it is provided that the plurality of feeders include a first feeder and a second feeder, the first feeder is assigned to the first and second radiation units and the second feeder is assigned to the third and fourth radiation units, and wherein the shape and / or size of the first feeder is different from the shape and / or size of the second feeder. Through this extended embodiment, the feeding of each radiation unit can be optimized.

[0021] In another extension of the present invention, it is stipulated that the shape of the first feeder or the second feeder includes: a straight shape, a bent shape, and an arc shape. Under the teachings of the present invention, other shapes are also conceivable.

[0022] In yet another extension of the present invention, it is stipulated that the first radiation unit has a first number of radiation branches, and the second radiation unit has a second number of radiation branches, where the first number is different from the second number, such that the first center operating frequency is different from the second center operating frequency and the first operating frequency band and the second operating frequency band overlap at least partially with each other. By making the radiation units have different numbers of radiation branches, the center operating frequency and the operating frequency band of each radiation unit can be adjusted accordingly, and the sizes of the radiation units can be made substantially the same, thus simplifying the design.

[0023] In another extension of the present invention, it is stipulated that the high-gain antenna circuit is configured for 2.4 GHz wireless communication.

[0024] The present invention has at least the following beneficial effects: Based on unique research, the present inventors have found that when existing antennas are arranged under materials of different thicknesses and types such as plastics and woods, the receiving ability of the antennas will change greatly, and even the signal will be so poor that it cannot be received. The main reason is that existing antennas are composed of multiple radiation units with the same frequency characteristics (i.e., multiple radiation units have the same center operating frequency), which will cause: once the signals of these radiation units are shielded by a covering of a certain material, the signal gain of the entire antenna will be greatly reduced; while if multiple radiation units with different center operating frequencies (the difference is more than 2%) but partially overlapping operating frequency bands are provided in the antenna, this situation can be better avoided. This is based on the following insight of the present inventors: Generally speaking, a specific material will only have a large attenuation on the signals of a certain frequency point or a narrow frequency band. Since the antenna of the present invention has multiple radiation units with different center operating frequencies, even if the material has significant shielding and attenuation on the signals of one radiation unit in the antenna, the other radiation units in the antenna can still receive and transmit signals normally due to their different center operating frequencies; thus, the gain of the antenna in various application scenarios can be improved, and the frequency band width of the antenna can be expanded. Description of the Drawings

[0025] The present invention will be further elaborated below in conjunction with the specific embodiments with reference to the drawings.

[0026] Figures 1 to 3 Shows a first embodiment of an antenna circuit according to the present invention; and

[0027] Figures 4 to 15 Shows other embodiments of the antenna according to the present invention. Specific Embodiments

[0028] It should be noted that the components in the respective drawings may be exaggerated for illustrative purposes and are not necessarily to scale. In the respective drawings, the same or functionally identical components are provided with the same reference numerals.

[0029] In the present invention, unless otherwise specified, "arranged on", "arranged above", and "arranged over" do not exclude the presence of intermediates therebetween. In addition, "arranged on or above" merely represents the relative positional relationship between two components, and in certain cases, such as after reversing the product direction, it can also be converted to "arranged under or below", and vice versa.

[0030] In the present invention, the respective embodiments are merely intended to illustrate the solutions of the present invention and should not be construed as restrictive.

[0031] In the present invention, unless otherwise specified, the quantifiers "a" and "one" do not exclude the scenario of multiple elements.

[0032] It should also be noted here that in the embodiments of the present invention, for the sake of clarity and simplicity, only a part of the components or assemblies may be shown, but those of ordinary skill in the art can understand that, under the teaching of the present invention, the required components or assemblies can be added according to the specific scenario requirements.

[0033] It should also be noted here that within the scope of the present invention, the terms "same", "equal", "equivalent", etc. do not mean that the two values are absolutely equal, but allow a certain reasonable error, that is, the said terms also cover "substantially the same", "substantially equal", "substantially equivalent". By analogy, in the present invention, the directional terms "perpendicular to", "parallel to", etc. also cover the meanings of "substantially perpendicular to" and "substantially parallel to".

[0034] The present invention will be further described below in conjunction with the specific embodiments with reference to the drawings.

[0035] Figures 1 to 3 A first embodiment of the antenna circuit according to the present invention is shown. In this embodiment, the antenna circuit 100 is shown as being arranged on the first side A and the second side B of the printed circuit board PCB and having four radiation units. In other embodiments, other forms of circuit boards and other numbers of radiation units may be employed.

[0036] As Figure 1 shown is a view of the antenna as viewed from side A. The antenna circuit 100 includes four radiation units 101 - 104, which include:

[0037] · The first radiation unit 101 has first and second radiation branches 101A and 101B. The first radiation branch 101A is arranged on the first side A of the PCB, and the second radiation branch 101B is arranged on the second side B of the PCB circuit board. The first and second radiation branches 101A and 101B are respectively connected to the feed lines 105A and 105B.

[0038] · The second radiation unit 102 has first and second radiation branches 102A and 102B. The first radiation branch 102A is arranged on the first side A of the PCB, and the second radiation branch 102B is arranged on the second side B of the PCB circuit board. The first and second radiation branches 102A and 102B are respectively connected to the feed lines 105A and 105B.

[0039] · The third radiation unit 103 has first and second radiation branches 103A and 103B. The first radiation branch 103A is arranged on the first side A of the PCB, and the second radiation branch 103B is arranged on the second side B of the PCB circuit board. The first and second radiation branches 103A and 103B are respectively connected to the feed lines 105A and 105B.

[0040] · The fourth radiation unit 104 has first and second radiation branches 104A and 104B. The first radiation branch 104A is arranged on the first side A of the PCB, and the second radiation branch 104B is arranged on the second side B of the PCB circuit board. The first and second radiation branches 104A and 104B are respectively connected to the feed lines 105A and 105B.

[0041] · The feed line 105 includes first and third feed lines 105A and 106A arranged on the first side A, and second and fourth feed lines 105B and 106B arranged on the second side B. The first feed line 105A and the third feed line 106A are continuous conductors, and the second feed line 105B and the fourth feed line 106B are continuous conductors. The first feed line 105A is used to connect the first radiation branches 101A and 102A of the first and second radiation units 101 and 102 arranged on the first side A. The second feed line 105B is used to connect the second radiation branches 101B and 102B of the first and second radiation units 101 and 102 arranged on the second side B. The third feed line 106A is used to connect the first radiation branches 103A and 104A of the third and fourth radiation units 103 and 104 arranged on the first side A. The fourth feed line 106B is used to connect the second radiation branches 103B and 104B of the third and fourth radiation units 103 and 104 arranged on the second side B. The third feed line and the fourth feed line are connected to the input / output port 107.

[0042] In the present invention, in order to achieve different center operating frequencies and overlapping operating frequency bands for each radiation unit, various parameters of each radiation unit 101-104 of the antenna 100 can be different from each other. These parameters include, but are not limited to, dimensions (such as length, width, thickness, etc.), shapes (such as zigzag, arc-shaped, linear, etc.), material types (such as selecting different radiation branch materials), material parameters (dielectric constant of the radiation branch material, degree of resistance matching between materials, etc.), and so on. In the present invention, the center operating frequencies and operating frequency bands of each radiation unit 101-104 can be set, for example, to be suitable for 2.4G or 5G wireless communication.

[0043] Figure 2 , Figure 3 respectively show the graphic designs of an antenna embodiment of the present invention on the first side A and the second side B of the PCB.

[0044] In an embodiment of the present invention, the PCB is made of FR4 material, with a thickness of 1.6 mm and is a double-sided board. The copper foil thickness is 0.5 ounce. The horizontal branch lengths of the radiation branches in its layout designs 101A and 102A, 101B and 102B, 103A and 104A, 103B and 104B are 22.3 mm, and the widths are 1.0 mm. The vertical branch lengths are 4.5 mm, and the widths are 1.0 mm. The lengths of the feed lines 105A on the first side A and the feed line 105B on the B side are both 47 mm, and the widths are both 1.5 mm. The lengths of the feed lines 106A on the A side and the feed line 106B on the B side are both 22 mm, and the width is 2.8 mm. The signal connection of the signal input / output port 107 uses Figure 6The coplanar waveguide described above. The simulation results show that the maximum gain is 4.10 dBi. For example, for the WI-FI band, the allowable value of the dielectric constant is between 5.1 and 5.2, and the bandwidth with a standing wave ratio less than 2 is about 95 MHz. Such a PCB dielectric constant generally needs to be customized, which will inevitably increase the product cost and inconvenience of product production. By adopting the technology of the present invention, the radiation branch lengths of the 103B and 104B are increased by 4.5 mm, that is, the length is increased by 7%, while the other radiation units remain unchanged. The simulation results show that the maximum gain is 3.98 dBi, and the bandwidth with a standing wave ratio less than 2 at the WI-FI center frequency point is increased to 500 MHz. In other words, compared with the prior art antenna with the same material, the antenna circuit of the present invention has a significant increase in bandwidth, thereby improving the antenna performance in multiple scenarios. In addition, for example, in the WI-FI band range, the simulation shows that the allowable range of the PCB dielectric constant is extended to 3.8 - 4.9, and the standing wave ratio can still be guaranteed to be less than 2 within the 2.4G WI-FI band range. The slight decrease in the maximum gain has no substantial impact on the antenna performance, and such a PCB with a dielectric constant range can be obtained only by using inexpensive PCB materials and ordinary PCB production processes without customization. Therefore, the present invention can also help improve the product yield rate and reduce the PCB cost.

[0045] In some embodiments, other branches or structures can be added to the structure of the antenna to adjust the antenna performance, such as fine-tuning the resonant frequency or adding a structure to improve the bandwidth of the resonant band. In Figure 4 the embodiment shown in, the short branches of 41, 42, 43, and 44 are used to further improve the return loss characteristics.

[0046] In some embodiments, the radiation branches can have different widths or different lengths. For example, the lengths of 101A and 101B can be different from those of 102A and 102B, and they can be used as antennas for two frequencies. The widths of the PCB traces can also be different widths.

[0047] Such as Figure 4 In an embodiment shown as the B-plane view, the feed lines 105A and 105B are configured as bent broken lines, and the feed lines 106A and 106B are substantially straight lines. In other embodiments, the feed lines 105A and 105B can also be configured as arc-shaped. By constructing the feed lines in different shapes, the adjustment of the center operating frequency and operating frequency band of the relevant radiation units can be achieved, thereby realizing different center operating frequencies of the radiation units and at least partially overlapping operating frequency bands with each other. By setting the length of the feed line 105, the signal phase difference between the radiation units 101, 102 and 103, 104 can also be adjusted, so as to adjust the radiation pattern of the antenna.

[0048] Such asFigure 5 As shown, in one embodiment, the radiation branches can be configured to be bent or arc-shaped. This can reduce the total PCB area occupied by the antenna.

[0049] As Figure 6 shown is an embodiment using a coplanar waveguide to feed the antenna. Among them, 600 is a via connecting the ground wires on the A side and the B side, and 4 vias are shown in the figure. 602 is the antenna signal input / output line. 601 is the ground wire that wraps the signal line 602 on the first side A, and 603 is the ground wire on the B side. 601 and 603 are electrically connected through vias. The feeder 106A on the first side A is directly connected to the signal line 602, and there is at least a safety distance specified by the process of the PCB manufacturer between the signal line 602 and the ground wire 601. This distance is generally more than 6 mil. The feeder and the ground wire on the second side B are directly connected.

[0050] As Figure 7 shown, in one embodiment, the input signal can also be replaced by a coaxial cable instead of PCB traces. 73 is the input cable. 71 is the copper layer of the input port on the first side A, which is connected to the outer copper layer of the coaxial cable and is connected to the first feeder on the second side B through a via. The input signal of the cable is connected to the position shown by the inner conductor of the cable to the input cable 72 and is directly connected to the feeder on the first side A.

[0051] Although in the figures of the present invention, the opposite radiation branches are distributed on the A and B sides of the PCB, such as 101A and 101B are placed on both sides of the PCB. But they can also be partially or entirely placed on the same surface of the PCB. This often introduces the problem of trace crossing. But the trace crossing problem can be solved by appropriate PCB traces, using vias, or using conventional technical methods such as coaxial cables.

[0052] Figure 8 、 9 show embodiments lacking radiation branches. Here, the first radiation unit 101 lacks the first radiation branch, and the fourth radiation unit 104 lacks the first radiation branch. Constrained by the design conditions of the actual product, in order to meet certain requirements, such as for size, or appearance, or to avoid conflicts between internal components, in an embodiment, it can also be designed to lack one or two radiation branches. Its performance will decrease slightly, but it can still work normally and has high gain characteristics.

[0053] In Figure 10 、 Figure 11 and Figure 12 of the embodiments, the feeder and the radiation branches are connected to another plane through vias. Among them, 110 is the via for realizing the connection.

[0054] In Figure 12In the embodiment, the feeder and most of the radiation units are located in the A and B planes, and one radiation branch 101A is located in the third plane different from other radiation units.

[0055] In Figure 13 , 14 's embodiment, the radiation branch adopts an embodiment with a special shape. Only a part of the radiation branches are shown, and the other radiation branches can be the same or different.

[0056] In Figure 15 's embodiment, the radiation branches corresponding to the shown radiation units use triangles, making the radiation units become broadband butterfly antenna radiation units.

[0057] The present invention has at least the following beneficial effects: Based on unique research findings, the reason why the reception ability of existing antennas varies greatly or even the signal becomes too poor to be received when the antennas are arranged under materials with different thicknesses and types such as plastics and woods is mainly that existing antennas are composed of multiple radiation units with the same frequency characteristics (i.e., multiple radiation units have the same center operating frequency). This will cause: once the signals of these radiation units are shielded by a covering of a certain material, the signal gain of the entire antenna will be greatly reduced; while if multiple radiation units with different center operating frequencies (the difference is more than 2%) but partially overlapping operating frequency bands are set in the antenna, this situation can be better avoided. This is based on the following insight of the inventor: Generally, a specific material will only have a large attenuation on the signals of a certain frequency point or a narrow frequency band. Since the antenna of the present invention has multiple radiation units with different center operating frequencies, even if the material has significant shielding and attenuation on the signal of one radiation unit in the antenna, the other radiation units in the antenna can still receive and transmit signals normally due to their different center operating frequencies; thus, the gain of the antenna in various application scenarios can be improved, and the frequency band width of the antenna can be expanded.

[0058] In the embodiments of the present invention, the radiation units of the antenna are all taken as dipole antenna units, but the radiation units can also be other forms of antennas. For example, the radiation units can be, but are not limited to, the following types of antennas: such as monopole antennas, cloverleaf antennas, conical slot antennas, inverted F antennas, planar inverted F antennas, patch antennas, folded dipole antennas, loop antennas, butterfly antennas, helical antennas, log-periodic antennas, log-periodic dipole antennas, slot antennas, waveguide antennas, parabolic reflector antennas, etc.

[0059] Although some embodiments of the present invention have been described in this application document, those skilled in the art can understand that these embodiments are merely shown as examples. Those skilled in the art can conceive of numerous variations, alternatives, and improvements under the teachings of the present invention without departing from the scope of the present invention. The appended claims are intended to define the scope of the present invention and thus cover the methods and structures within the scope of these claims themselves and their equivalent transformations.

Claims

1. A high-gain antenna circuit, comprising: A circuit board configured to carry radiation units; And A plurality of radiation units configured to receive and / or transmit wireless signals and including a first radiation unit and a second radiation unit, wherein the first radiation unit has a first center operating frequency and a first operating frequency band, and the second radiation unit has a second center operating frequency and a second operating frequency band, wherein the plurality of radiation units are configured such that the first center operating frequency is different from the second center operating frequency and the first operating frequency band and the second operating frequency band at least partially overlap each other, The circuit board has a first surface and a second surface opposite the first surface, and each radiation unit includes: a first radiation branch and a second radiation branch, wherein the first radiation branch is on the first surface and the second radiation branch is on the second surface, wherein the radiation branches on the same surface of adjacent radiation units are connected in parallel to each other and connected to a feeder; and a plurality of feeders, each of the plurality of feeders being assigned to one or more of the plurality of radiation units, and the plurality of feeders are connected to each other and connected to a power source or a signal source, The radiation branches of the first radiation unit have a first size, and the radiation branches of the second radiation unit have a second size, wherein the first size is different from the second size, and the difference between the first size and the second size is more than 2% of the smaller of the first size and the second size, such that the first center operating frequency is different from the second center operating frequency and the first operating frequency band and the second operating frequency band at least partially overlap each other, Wherein the first radiation branches and the second radiation branches of the plurality of radiation units have the same or different shapes and / or lengths, The plurality of radiation units include 4 radiation units, wherein the first and second radiation units are arranged adjacent to each other, and the third and fourth radiation units are adjacent to each other, The plurality of feeders include a first feeder and a second feeder, the first feeder is assigned to the first and second radiation units and the second feeder is assigned to the third and fourth radiation units, and wherein the shape and / or size of the first feeder is different from the shape and / or size of the second feeder, The shape of the first feeder or the second feeder includes: straight, bent, and arc-shaped, Wherein the first radiation unit has a first number of radiation branches, and the second radiation unit has a second number of radiation branches, wherein the first number is different from the second number, such that the first center operating frequency is different from the second center operating frequency and the first operating frequency band and the second operating frequency band at least partially overlap each other.

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