Multi-parasitic element radiation array antenna implementation structure

Abstract

The invention discloses a radiation array antenna implementation structure with multiple parasitic elements, and belongs to the field of antenna design. The invention relates to a radiation array antenna implementation structure with multiple parasitic elements, and provides an antenna implementation structure which can ensure that the structural design is simple and attractive, can be applied to a complex antenna environment, and can remarkably improve the antenna efficiency. According to the multi-parasitic unit radiation array antenna implementation structure, the body radiation branch knot and the parasitic radiation branch knot are adopted to participate in the radiation design at the same time, so that the purpose of improving the antenna performance is achieved; and the number of the parasitic radiation branches can be selected according to the antenna performance requirement, so that the antenna is suitable for various antenna modes, such as application in a single FPC or PCB form, application in combination with a cavity antenna, bracket and FPC soft board attachment in various forms, bracket and LDS / LCP forms in various forms, bracket and iron piece forms and single iron piece forms, and the antenna is suitable for various antenna modes. And the wide applicability of the antenna implementation structure provided by the scheme is ensured.

Description

Technical Field

[0001] The invention relates to the field of antenna design, and in particular to an implementation structure of a multiple parasitic unit radiation array antenna. Background Art

[0002] With the development of the times and people's continuous demand for the network performance of electronic products, antennas, as key components, directly affect the network performance of products and users' comprehensive evaluation of products. With the continuous emergence of new technologies, the importance of antenna performance in product promotion has become increasingly prominent, and users have also paid more and more attention to product antenna performance.

[0003] At present, various electronic products are generally developing in the direction of multi-function, large screen, all-metal, narrow frame, etc. These design trends make traditional antennas face space limitations and performance challenges. For example, traditional antennas usually require large clearance and height, and an environment away from metal parts, otherwise their performance will be seriously affected. However, the space compression and material selection of modern product design limit the development space of traditional antennas and become the bottleneck of their development. In turn, these limitations lead to narrow bandwidth and low efficiency of traditional antennas, which are difficult to meet the needs of modern electronic products for broadband and high efficiency.

[0004] In summary, electronic products now require antennas to not only have good performance, but also meet aesthetic requirements. Each antenna faces the challenge of gradually decreasing space requirements and lower height requirements. Therefore, the market urgently needs a new antenna technology with small clearance requirements, low height requirements, wide bandwidth and high performance to meet the complexity and diversity of modern electronic product design. Summary of the invention

[0005] The disclosed embodiment provides a multi-parasitic unit radiation array antenna implementation structure, which can solve the problem in the related art that traditional antennas are difficult to adapt to the complex requirements of modern electronic products for multi-function, beauty and high performance due to strict requirements on space and materials. The technical solution is as follows:

[0006] A multi-parasitic unit radiation array antenna implementation structure is provided, the structure is suitable for the implementation layout of the antenna component, and the structure includes:

[0007] An antenna feed point position 10, a main body radiation branch 20 and at least one parasitic radiation branch 30, wherein the frequency band of the parasitic radiation branch 30 is the same as or different from the frequency band of the main body radiation branch 20;

[0008] The main radiation branch 20 is led out at the antenna feeding point position 10 ; the parasitic radiation branch 30 extends out at a position parallel to the main radiation branch 20 .

[0009] Optionally, the main radiation branch 20 is in a form of one of monopole, IFA, PIFA and Loop.

[0010] Optionally, there is a parallel gap between the parasitic radiation branch 30 and the main radiation branch 20, and the size of the parallel gap is determined according to the coupling amount.

[0011] Optionally, the parasitic radiation branch 30 wraps around the end of the main radiation branch 20 to increase the coupling amount between the parasitic radiation branch 30 and the main radiation branch 20 .

[0012] Optionally, the number of the parasitic radiation branches 30 is determined according to a preset optimal antenna performance.

[0013] Optionally, the main radiation branch 20 and the parasitic radiation branch 30 participate in radiation at the same time.

[0014] Optionally, the frequency band of each branch is adjusted by changing the effective electrical length of the main radiation branch 20 and the parasitic radiation branch 30 .

[0015] Optionally, in response to the existence of at least N parasitic radiation branches 30, N is a positive integer, and is recorded as the Nth parasitic radiation branch in sequence according to the neighbor relationship;

[0016] The first parasitic radiation branch extends out at a position parallel to the main radiation branch 20 , and the Nth parasitic radiation branch is arranged in a line in parallel along the main radiation branch 20 in sequence.

[0017] Optionally, when N is 2, the range of the first parasitic radiation branch node to the main radiation branch node 20 is zero to one-quarter of the wavelength of the first frequency band, and the range of the second parasitic radiation branch node to the first parasitic radiation branch node is zero to one-quarter of the wavelength of the second frequency band, wherein the first frequency band is the frequency band corresponding to the first parasitic radiation branch, and the second frequency band is the frequency band corresponding to the second parasitic radiation branch.

[0018] In the design of the present invention, the multiple parasitic unit radiating array antenna implementation structure provides an antenna implementation structure that can ensure a simple and beautiful structural design, can be applied to complex antenna environments, and can significantly improve antenna efficiency. The multiple parasitic unit radiating array antenna implementation structure uses the main body radiation branches and parasitic radiation branches to participate in the radiation design at the same time to achieve the purpose of improving antenna performance; and the number of parasitic radiation branches can be selected according to the antenna performance requirements, that is, it is suitable for a variety of antenna modes, such as single FPC or PCB applications, such as combined cavity antenna applications, such as various forms of bracket + FPC soft board attachment, various forms of bracket + LDS / LCP forms, such as bracket + iron form, single iron form, to ensure the wide applicability of the antenna implementation structure provided by this solution. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic structural diagram of a multiple parasitic element radiation array antenna implementation structure of Example 1 is shown;

[0020] Figure 2 A schematic front view of a physical simulation of an antenna assembly of Example 1 is shown;

[0021] Figure 3 A schematic side view of a physical simulation of an antenna assembly of Example 1 is shown;

[0022] Figure 4 A bottom schematic diagram of a physical simulation of an antenna assembly of Example 1 is shown;

[0023] Figure 5 The VSWR data diagram of the antenna of the conventional solution of Example 1 is shown;

[0024] Figure 6 An antenna VSWR data diagram of the multiple parasitic element radiating array antenna implementation structure of Example 1 is shown;

[0025] Figure 7 A schematic structural diagram of a multiple parasitic element radiation array antenna implementation structure of Example 2 is shown;

[0026] Figure 8 A schematic front view of a physical simulation of an antenna assembly of Example 2 is shown;

[0027] Fig. 9 A schematic diagram of a side view interface of a physical simulation of the antenna assembly of Example 2 is shown;

[0028] Fig.10 A partially enlarged schematic side cross-sectional view of a physical simulation of the antenna assembly of Example 2 is shown;

[0029] Fig.11 A bottom schematic diagram of a physical simulation of an antenna assembly of Example 2 is shown;

[0030] Fig.12 The VSWR data diagram of the antenna of the conventional solution of Example 2 is shown;

[0031] Fig.13 The antenna VSWR data diagram of the multiple parasitic element radiation array antenna implementation structure of Example 2 is shown. DETAILED DESCRIPTION

[0032] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0033] The term "multiple" as used herein refers to two or more than two. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the related objects are in an "or" relationship.

[0034] In each example of the present application, considering the quantity feature of at least one parasitic radiation branch, the embodiment is described in Example 1 and Example 2. Example 1 corresponds to a scenario with one parasitic radiation branch, and Example 2 corresponds to a scenario with two parasitic radiation branches.

[0035] Example 1

[0036] Please refer to Figure 1 , Figure 1 A schematic structural diagram of a multiple parasitic unit radiation array antenna implementation structure of Example 1 is shown, and the structure is suitable for the implementation layout of the antenna assembly.

[0037] The structure includes an antenna assembly, an antenna feed point position 10, a main radiation branch 20 and a parasitic radiation branch 30. The frequency band of the parasitic radiation branch 30 is the same as or different from the frequency band of the main radiation branch 20. In the example of the present application, the frequency band of the parasitic radiation branch 30 and the frequency band of the main radiation branch 20 are both 2.4 GHz target frequency bands for illustration.

[0038] Optionally, the main radiation branch 20 is in a form of one of monopole, IFA, PIFA and Loop.

[0039] like Figure 1 As shown, there is a parallel gap between the parasitic radiation branch 30 and the main radiation branch 20, and the size of the parallel gap is determined according to the coupling amount.

[0040] Furthermore, the parasitic radiation branch 30 wraps around the end of the main radiation branch 20, so as to increase the coupling between the parasitic radiation branch 30 and the main radiation branch 20. The main radiation branch 20 and the parasitic radiation branch 30 participate in radiation at the same time.

[0041] The number of parasitic radiation branches 30 is determined according to a preset optimal antenna performance, wherein the optimal antenna performance is based on the S11 parameter and the efficiency actually measured in a microwave darkroom.

[0042] Among them, the S11 parameter is one of the important indicators used to describe antenna performance, usually referred to as reflection coefficient or return loss. It measures the strength of the signal reflected from the transmission line at the antenna port. Specifically, the S11 parameter indicates the degree of matching between the input signal and the antenna, that is, how much energy in the input signal is reflected back instead of being radiated by the antenna. The S11 parameter is usually expressed in decibels (dB). The lower the value, the smaller the reflection loss of the antenna and the better the performance.

[0043] In order to obtain the best antenna performance, the S11 parameter is used as the evaluation standard in this application because the S11 parameter directly reflects the matching effect of the antenna in a specific frequency band. By measuring the S11 parameter with a network analyzer, the reflection loss of the antenna under actual working conditions can be accurately evaluated. Further, after the S11 is debugged, the antenna radiation efficiency and gain are tested in a microwave darkroom to determine the quality of the antenna design.

[0044] In a specific solution, in order to optimize the antenna performance, a multiple parasitic unit radiation array antenna structure is adopted. This antenna structure enhances the performance of the antenna by introducing parasitic radiation branches next to the main radiation branches. The following is a description of how to obtain the best antenna performance in combination with the content of this application.

[0045] First, select the antenna type and layout. For various antenna types, such as monopole, IFA, PIFA, and loop, select the appropriate antenna type as the main body radiation branch according to actual needs.

[0046] Introduce parasitic radiation branches. Parasitic radiation branches are introduced next to the main radiation branches. These parasitic radiation branches are arranged in parallel with the main radiation branches, and the coupling effect is adjusted by controlling the gap between them. The number of parasitic radiation branches can be determined according to the actual debugging results to achieve the best antenna performance.

[0047] Debugging and optimization. Based on the measurement results of the S11 parameters and the efficiency measured in the microwave darkroom, the antenna is repeatedly debugged and optimized. The debugging method includes changing the effective electrical length of the main radiation branch and the parasitic radiation branch, and adjusting their position and gap to maximize the radiation efficiency and frequency band coverage performance of the antenna.

[0048] Finally, performance evaluation and comparison. The performance of the conventional antenna solution and the multi-parasitic element radiation array antenna solution are compared using microwave anechoic chamber measured data. For example, the following chart shows the performance improvement of the new solution compared to the conventional antenna solution in the 2.4GHz frequency band. These data help confirm the superiority of the new design.

[0049] For example, Example 1 and Example 2 show how to select and arrange parasitic radiation branches according to specific needs to optimize the antenna performance in the 2.4GHz band. Example 2 uses two parasitic radiation branches, which has a more significant performance improvement compared to the single parasitic radiation branch in Example 1, proving the effectiveness of improving antenna performance by increasing the number of parasitic radiation branches.

[0050] Therefore, combining the measurement of the S11 parameter and the evaluation of the actual efficiency can effectively guide the antenna design and debugging process to ensure the best antenna performance in a specific frequency band. In one possible implementation, the frequency band of each branch is debugged by changing the effective electrical length of the main radiation branch 20 and the parasitic radiation branch 30, wherein the effective electrical length (i.e., the length, thickness, various winding shapes, gaps between branches, etc.) of the antenna branch.

[0051] The main radiating element is the main radiating element in the antenna design, which is used to transmit and receive wireless signals in a specific frequency band (such as 2.4GHz or 5GHz). It can be different types of antenna elements, such as monopole, IFA (Inverted F Antenna), PIFA (Planar Inverted F Antenna), Loop, etc.

[0052] A parasitic radiating element is a passive element that is usually not directly connected to the feed point, but affects the performance of the main antenna through electromagnetic coupling. The length and position of the parasitic radiating element will affect the coupling effect between it and the main radiating element.

[0053] In antenna design, in order to optimize the performance of a specific frequency band, the present application proposes to perform debugging by changing the effective electrical length of the main radiation branch and the parasitic radiation branch. That is, the physical size or geometric shape of these antenna elements is adjusted to better match the operating frequency of each branch frequency band and optimize the radiation characteristics. The specific debugging process may include the following steps.

[0054] Determine the antenna frequency band and type. First, determine the frequency band that needs to be optimized (such as 2.4GHz) and select the appropriate type of main body radiation branch (such as monopole, IFA, etc.).

[0055] Design and adjust parasitic radiating branches. Determine the location and length of parasitic radiating branches according to the design requirements. These radiating branches are usually parallel to the main radiating branches, and their coupling with the main radiating branches can be controlled by adjusting their length and location.

[0056] Optimize the coupling effect. By adjusting the position and shape of the parasitic radiation branches, ensure that the coupling between them and the main radiation branches is optimal. The optimization of the coupling amount can be carried out through actual electromagnetic simulation software or physical testing.

[0057] Physical simulation and performance comparison. Perform physical simulation or actual testing to compare the performance difference between the multi-parasitic element radiating array antenna structure (i.e., the structure containing parasitic radiating branches) and the conventional antenna solution. For example, in the 2.4GHz frequency band, the author improved the performance of the antenna by adding parasitic radiating branches and achieved a gain of about 2dB.

[0058] Result analysis and adjustment: Analyze and compare data, and adjust the number and position of parasitic radiation branches according to actual test results to further optimize the performance of the antenna.

[0059] In one example, the antenna design in Example 1 uses a single parasitic radiating branch, while the following Example 2 uses multiple parasitic radiating branches. These designs optimize the performance in different antenna environments by adjusting the length and position of each parasitic radiating branch and their coupling mode with the main radiating branch.

[0060] In summary, the method of optimizing the performance of a specific frequency band by adjusting the design of the main radiation branches and parasitic radiation branches in the antenna is not only applicable to the 2.4 GHz band, but can also be extended to the antenna design of other frequency bands to improve the antenna efficiency and performance of other frequency bands.

[0061] A schematic diagram of a physical simulation example is provided below to compare with a conventional antenna implementation structure solution.

[0062] like Figure 2 , Figure 3 and Figure 4 As shown, a physical simulation schematic diagram of the antenna assembly is shown. Figure 2 is the front view, Figure 3 is a top view, Figure 4 This is the bottom view.

[0063] As can be seen from the figure, the antenna assembly is located at the camera decoration at the bottom of the all-metal flat plate. The antenna environment is relatively poor and is surrounded by metal all around. Only the metal at the camera decoration has an opening. In this antenna environment, the antenna performance of the conventional antenna solution and the multiple parasitic unit radiation array antenna structure solution are compared. By comparing the data, it is found that the antenna performance of the multiple parasitic unit radiation array antenna structure solution is better than the conventional antenna solution. The comparison data of the antenna performance of the conventional structure solution and the multiple parasitic unit radiation array antenna structure solution are shown in the figure. Figure 5 and Figure 6 As shown, and the respective antenna efficiencies and gains are shown in Tables 1 and 2.

[0064] Table 1. Antenna efficiency and gain of conventional solution in Example 1

[0065]

[0066] Table 2. Example 1: Efficiency and gain of multiple parasitic element radiating array antenna solution

[0067]

[0068] It can be seen from the comparison data of the above two antenna schemes that the multiple parasitic unit radiation array antenna scheme improves the antenna performance of 2.4G by 2dB. Under the same antenna environment, the performance improvement is obvious. The antenna implementation structure of the present application is adopted, that is, the new scheme in the 2.4G frequency band adds a 2.4G parasitic radiation branch, thereby improving the overall antenna performance.

[0069] Example 2

[0070] Please refer to Figure 7 , Figure 7 A schematic structural diagram of a multiple parasitic unit radiation array antenna implementation structure of Example 2 is shown, and the structure is suitable for the implementation layout of the antenna assembly.

[0071] The structure includes an antenna assembly, an antenna feed point position 10, a main radiation branch 20 and two parasitic radiation branches, which are respectively denoted as a first parasitic radiation branch 30 and a second parasitic radiation branch 40.

[0072] Further, for the case where there is more than one parasitic radiation branch similar to Example 2, the following description is given: In response to the existence of at least N parasitic radiation branches, N is a positive integer, and is recorded as the Nth parasitic radiation branch in sequence according to the neighbor relationship.

[0073] As described above, the first parasitic radiation branch extends from a position parallel to the main radiation branch 20 , and starting from the second section, that is, when N≥2, the Nth parasitic radiation branch is arranged in a row in parallel along the main radiation branch 20 in sequence.

[0074] Further, taking N as 2 as an example, when N is 2, the range of the first parasitic radiation branch node from the main radiation branch node 20 is zero to one-quarter of the wavelength of the first frequency band, and the range of the second parasitic radiation branch node from the first parasitic radiation branch node is zero to one-quarter of the wavelength of the second frequency band, wherein the first frequency band is the frequency band corresponding to the first parasitic radiation branch, and the second frequency band is the frequency band corresponding to the second parasitic radiation branch.

[0075] The following is a schematic diagram of Example 2 of a physical simulation to compare with a conventional antenna implementation structure solution.

[0076] like Figure 8 , Fig. 9 , Fig.10 and Fig.11 As shown, a physical simulation schematic diagram of the antenna assembly is shown. Figure 8 A schematic front view of a physical simulation of an example 2 antenna assembly is shown; Fig. 9 A schematic diagram of a side view interface of a physical simulation of an example 2 antenna assembly is shown; Fig.10 A partially enlarged schematic side cross-sectional view of a physical simulation of an antenna assembly of Example 2 is shown; Fig.11 A bottom schematic diagram of a physical simulation of an example second antenna assembly is shown.

[0077] As can be seen from the figure, the antenna assembly is located between the all-metal flat screen and the metal bottom shell. There is a gap between the back frame of the all-metal flat screen and the side of the metal bottom shell, and the energy of the antenna assembly radiates outward from the gap.

[0078] In Example 2, the antenna is implemented as a cavity antenna composed of PCB + shielding cover, the front end (i.e., the side gap between the back basket and the metal bottom shell of the all-metal flat screen) is the antenna Pattern, and the rear end (i.e., between the back basket and the metal bottom shell of the all-metal flat screen) is a cavity formed by the PCB and the shielding cover (the shielding cover is patched onto the PCB and forms five sealing surfaces, one of which is open to the antenna Pattern surface), and the medium in the cavity is air, that is, the front end of the antenna assembly is the antenna Pattern, and the rear end of the antenna assembly is a cavity composed of the PCB and the shielding cover, and the medium in the cavity is air.

[0079] In this antenna environment, the applicant compared the antenna performance of the conventional antenna scheme and the multiple parasitic unit radiating array antenna scheme. The comparative data of the antenna performance of the conventional structure scheme and the multiple parasitic unit radiating array antenna structure scheme are as follows: Fig.12 and Fig.13 As shown, and the respective antenna efficiencies and gains are shown in Tables 3 and 4. Table 3. Antenna efficiency and gain of conventional solution in Example 2

[0080]

[0081] Table 4. Efficiency and gain of multiple parasitic element radiating array antenna solution in Example 2

[0082]

[0083] From Example 2, it can be seen that the multiple parasitic unit radiation array antenna solution provided in this application improves the antenna performance of 2.4G by 2dB. Under the same antenna environment, the performance improvement is obvious, that is, by adding two 2.4G parasitic radiation branches in the 2.4G frequency band, the overall antenna performance is improved.

[0084] To summarize, the above takes the improvement of the 2.4 GHz frequency band as an example to demonstrate the implementation details. First, a 2.4 GHz main body radiation branch is led out from the antenna feed. The antenna form of the main body radiation branch can be various (monopole, IFA, PIFA, Loop, etc.). In addition, a 2.4 GHz parasitic radiation branch is extended at a position parallel to the main body radiation branch. The parasitic radiation branch is parallel to the main body radiation branch and maintains a certain gap (to control the coupling amount). The parasitic radiation branch can also wrap around the end of the local radiation branch (to increase the coupling amount) as in Example 1. The parasitic radiation branch can be increased according to the actual debugging conditions to achieve the best antenna performance. For example, one parasitic radiation branch is used in Example 1 and two parasitic radiation branches are used in Example 2. The specific applications of this solution are diverse, including but not limited to the following types: single FPC or PCB form applications (Example 1), combined cavity antenna applications (Example 2), various forms of brackets + FPC soft board attachment, various forms of brackets + LDS / LCP forms, brackets + iron parts, single iron parts, and other antenna forms that can use this solution. The application scope of this solution includes but is not limited to the 2.4G+5G+6E antenna frequency bands shown in the above examples, and can also be used for antenna design of any other frequency bands. The implementation method remains unchanged, and the corresponding frequency band can be adjusted to the required frequency band by changing the effective electrical length of the main radiation branches and parasitic radiation branches.

[0085] In the design of the present invention, the multiple parasitic unit radiation array antenna implementation structure provides an antenna implementation structure that can ensure that the structural design is simple and beautiful, can be applied to complex antenna environments, and can significantly improve the antenna efficiency. The multiple parasitic unit radiation array antenna implementation structure uses the main radiation branches and parasitic radiation branches to participate in the radiation design at the same time to achieve the purpose of improving the antenna performance. And the number of parasitic radiation branches can be selected according to the antenna performance requirements, that is, it is suitable for a variety of antenna modes, such as single FPC or PCB form applications, such as combined cavity antenna applications, such as various forms of brackets + FPC soft board attachment, various forms of brackets + LDS / LCP forms, such as brackets + iron parts, single iron parts, to ensure the wide applicability of the antenna implementation structure provided by this solution.

[0086] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A multiple parasitic element radiating array antenna implementation structure, characterized in that: The structure is suitable for the implementation layout of the antenna assembly, and the structure includes: An antenna feed point position (10), a main body radiation branch (20) and at least one parasitic radiation branch (30), wherein the frequency band of the parasitic radiation branch (30) is the same as or different from the frequency band of the main body radiation branch (20); The main body radiation branch (20) is led out at the antenna feeding point position (10); and the parasitic radiation branch (30) extends out at a position parallel to the main body radiation branch (20).

2. The implementation structure of the multiple parasitic element radiation array antenna according to claim 1, characterized in that: The main body radiation branch (20) is in the form of one of monopole, IFA, PIFA and Loop.

3. The implementation structure of the multiple parasitic element radiation array antenna according to claim 1, characterized in that: There is a parallel gap between the parasitic radiation branch (30) and the main radiation branch (20), and the size of the parallel gap is determined according to the coupling amount.

4. The implementation structure of the multiple parasitic element radiation array antenna according to claim 1, characterized in that: The parasitic radiation branch (30) wraps around the end of the main radiation branch (20) to increase the coupling amount between the parasitic radiation branch (30) and the main radiation branch (20).

5. The implementation structure of the multiple parasitic element radiation array antenna according to claim 1, characterized in that: The number of the parasitic radiation branches (30) is determined according to a preset optimal antenna performance.

6. The implementation structure of the multiple parasitic element radiation array antenna according to claim 1, characterized in that: The main radiation branch (20) and the parasitic radiation branch (30) participate in radiation at the same time.

7. The multiple parasitic element radiation array antenna implementation structure according to any one of claims 1 to 6, characterized in that: The frequency band of each branch is adjusted by changing the effective electrical length of the main radiation branch (20) and the parasitic radiation branch (30).

8. The multiple parasitic element radiating array antenna implementation structure according to any one of claims 1 to 6, characterized in that: In response to the existence of at least N parasitic radiation branches (30), N is a positive integer, and is sequentially recorded as the Nth parasitic radiation branch according to the neighbor relationship; The first parasitic radiation branch extends out at a position parallel to the main body radiation branch (20), and the Nth parasitic radiation branch is arranged in a row in parallel along the main body radiation branch (20).

9. The implementation structure of the multiple parasitic element radiation array antenna according to claim 8, characterized in that: When N is 2, the range of the first parasitic radiation branch node to the main radiation branch node (20) is zero to one-quarter of the wavelength of the first frequency band, and the range of the second parasitic radiation branch node to the first parasitic radiation branch node is zero to one-quarter of the wavelength of the second frequency band, wherein the first frequency band is the frequency band corresponding to the first parasitic radiation branch, and the second frequency band is the frequency band corresponding to the second parasitic radiation branch.

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