Direction finding antenna

Abstract

The embodiment of the invention discloses a direction finding antenna, and relates to the technical field of radio monitoring direction finding, a PCB dielectric substrate is adopted to carry antenna units, the antenna is combined in an upper and lower layered mode through a step-shaped structure of the antenna, the miniaturization design of the antenna is achieved, the first antenna unit and the second antenna unit which are arranged on the upper and lower layers respectively cover different frequency bands, and the antenna performance is improved. The antenna unit is arranged on the PCB dielectric substrate to ensure the expansion of the working coverage frequency band of the antenna, the dielectric substrates are arranged in a crossed manner, the stability of the dielectric substrates is realized on the premise of ensuring the relative position relation of the antenna and the feed transmission lines, and the feed transmission lines corresponding to the antenna units are arranged on the PCB dielectric substrate to ensure the stability of the relative position relation of the antenna and the feed transmission lines. The influence of the antenna itself and the feed transmission line on the performance of other antennas can be reduced, so that the stability of the antenna performance is ensured, and the miniaturization design and the antenna performance of the direction-finding antenna are both considered.

Description

Technical Field

[0001] The present application relates to the technical field of radio monitoring and direction finding, and in particular to a direction finding antenna. Background Art

[0002] Radio monitoring and direction finding refers to the activities of detecting, searching, and intercepting radio signals within the radio management area, analyzing, identifying, monitoring, and obtaining technical information such as technical parameters, working characteristics, and radiation position of the radio signals. It is an important means of effectively implementing radio management and an important branch of radio spectrum management. With the rapid development of economy and technology, various radio services have penetrated into all areas of social and economic life and are widely used in broadcasting, television, mobile communications, and aerospace. The frequency coverage of the main radio signals ranges from 20MHz to 26.5GHz, and even higher millimeter wave bands.

[0003] There are many types of radio monitoring and direction-finding equipment, mainly including fixed stations, vehicle-mounted stations, transportable, portable, handheld, backpack, etc. The frequency bands required to be covered by the antenna mainly include 20MHz-1.300GHz, 1.3GHz-3GHz, 3GHz-8GHz, 8GHz-26.5GHz, etc. Multiple antennas are usually used to achieve full-band coverage, and combiners or switches are used between antennas to achieve connection or switching. Especially at the low end, conventional multi-element interferometers are large in size and heavy in weight, and cannot be used in portable or backpack devices. At the same time, large-size antenna arrays also interfere more seriously with other frequency bands, and space needs to be opened to reduce mutual influence, which is contrary to the purpose of miniaturization of antenna arrays. Summary of the invention

[0004] The main purpose of the present application is to provide a direction-finding antenna, aiming to solve the problem in the prior art that it is difficult to balance the miniaturization design and antenna performance of the direction-finding antenna.

[0005] The technical solutions adopted in this application are as follows:

[0006] A direction-finding antenna comprises: at least two PCB dielectric substrates, wherein the plurality of PCB dielectric substrates are cross-arranged and their axes coincide with each other, the PCB dielectric substrates are stepped to form an upper dielectric substrate and a lower dielectric substrate, a first antenna unit is arranged on the upper dielectric substrate, a second antenna unit is arranged on the lower dielectric substrate, the second antenna unit is connected to a second feeding transmission line, the first antenna unit is connected to the second feeding transmission line via the first feeding transmission line, the first feeding transmission line and the second feeding transmission line are arranged on the PCB dielectric substrate, the first antenna unit covers a first frequency band, and the second antenna unit covers a second frequency band.

[0007] Optionally, the second antenna unit adopts a decoupling design; through a specific circuit or component design, the mutual influence or interference between different parts in the circuit is removed or weakened, thereby improving the performance and stability of the entire system.

[0008] Optionally, the decoupling design includes: cutting the second antenna unit into multiple sections and connecting inductors or filter devices in series between two adjacent sections; on the one hand, cutting the lower antenna into multiple sections can change its original current distribution and radiation characteristics. Through a reasonable cutting method, the radiation performance of the antenna in a specific frequency band can be significantly optimized, while reducing interference with other antennas. On the other hand, the series inductor, as an energy storage element, can store magnetic field energy and affect the flow of current. Connecting an inductor in series between two adjacent antenna sections can adjust the current distribution on the antenna, thereby changing its radiation and reception characteristics. In addition, the inductor can also play a filtering role, reducing the impact of unnecessary frequency components on antenna performance.

[0009] Optionally, the first antenna unit is symmetrically distributed about the central axis on the upper dielectric substrate, and the second antenna unit is symmetrically distributed about the central axis on the lower dielectric substrate; in order to ensure the optimization and stability of the antenna performance, a strategy of as uniform distribution as possible is adopted in the structure. Metal obstructions will have an adverse effect on the performance of the antenna. In order to reduce this effect, it is necessary to ensure that the distance from the obstruction to the antenna remains stable, so that the degree of impact is kept at a predictable or fixed level.

[0010] Optionally, the first feeding transmission line and the second feeding transmission line adopt transmission lines based on PCB design; the same pair of feeding transmission lines and the antenna unit are distributed together on the same PCB dielectric substrate 5, so as to ensure that the positional relationship between the feeding transmission line and the antenna unit remains unchanged, even if their positional relationship is fixed.

[0011] Optionally, the first feeding transmission line is a microstrip feeding transmission line; a microstrip feeding transmission line is a transmission line in which a layer of conductive metal (such as copper foil or aluminum foil) is plated on the surface of a dielectric substrate, and a certain air or dielectric gap is left between the metal layer and the substrate, thereby forming a planar transmission line structure. This structural feature makes the microstrip line highly integrated and miniaturized.

[0012] Optionally, the second feeding transmission line adopts an RF cable, and the direction-finding antenna also includes a magnetic ring, which is sleeved on the outer conductor of the RF cable; when the RF cable is adopted, a scheme of adding a magnetic ring is designed for the direction-finding antenna, and the magnetic ring is sleeved on the outer conductor of the RF cable. By arranging the magnetic rings at intervals or covering them completely, the induced current on the cable can be effectively weakened or shielded, thereby weakening or eliminating the adverse effects of the cable on the antenna radiation pattern.

[0013] Optionally, the angles formed between adjacent PCB dielectric substrates are the same; the antenna structure is further optimized to improve the performance and efficiency of the antenna, ensure that the signal coverage of the antenna is more uniform, and at the same time improve the transmission efficiency and stability of the signal.

[0014] Optionally, the first antenna unit and the second antenna unit are in the form of dipole antennas; dipole antennas are composed of a pair of symmetrically placed conductors, and the two ends of the two conductors close to each other are respectively connected to the feeder lines. They have the characteristics of simple structure, easy production, and relatively low cost. At the same time, they also have good radiation characteristics and receiving performance.

[0015] Optionally, the number of the first antenna unit and the second antenna unit is N times of 2, where N is the number of PCB dielectric substrates; the setting of the lower antenna is the same as that of the upper antenna, and a symmetrical distribution strategy is adopted to further improve the performance and efficiency of the antenna.

[0016] Compared with the prior art, the embodiment of the present application proposes an innovative direction-finding antenna design, which utilizes a PCB (printed circuit board) dielectric substrate as its main supporting structure. Through a carefully designed step-shaped structure, the antenna unit can achieve a combination of upper and lower layers. Such a design not only helps to miniaturize the antenna, but also can cover a wider frequency band by respectively setting the first antenna unit and the second antenna unit on the upper and lower layers of the dielectric substrate, thereby ensuring that the antenna can cover a wider frequency range when working. In addition, the cross-setting mode of the dielectric substrate not only ensures the stability of the relative position relationship between the antenna and the feeding transmission line, but also enhances the stability of the dielectric substrate itself. The feeding transmission lines corresponding to all antenna units are precisely arranged on the PCB dielectric substrate, which further ensures the stability of the relative position relationship between the antenna and the feeding transmission line, while reducing the interference that the antenna itself and the feeding transmission line may cause to the performance of other antennas. Therefore, this design not only realizes the miniaturization of the direction-finding antenna, but also ensures the stability of the antenna performance, thereby satisfying the miniaturization design while also taking into account the optimization of the antenna performance.

[0017] When designing this direction-finding antenna, the present application fully considered the dual requirements of modern wireless communication systems for antenna size and performance. With the rapid development of wireless technology, antennas must not only be small and portable, but also have strong signal coverage and stability. Through in-depth research and multiple experiments, the present application finally determined this unique stepped structure, which not only achieved a breakthrough in physical size, but also reached a new height in performance. By carefully laying out the feed transmission line on the dielectric substrate, the present application successfully reduced signal loss and improved the signal transmission efficiency of the antenna. In addition, this design also has good anti-interference capabilities and can maintain stable performance even in complex electromagnetic environments.

[0018] In summary, it can be seen that a direction-finding antenna proposed in an embodiment of the present application adopts a PCB dielectric substrate to carry an antenna unit, and through its stepped structure, the antenna is combined in upper and lower layers to achieve a miniaturized design of the antenna. The first and second antenna units respectively arranged on the upper and lower layers cover different frequency bands, ensuring the expansion of the frequency band covered by the antenna. The dielectric substrate is cross-arranged to ensure the stability of the dielectric substrate under the premise of the relative position relationship between the antenna and the feeding transmission line. The feeding transmission line corresponding to each antenna unit is arranged on the PCB dielectric substrate, ensuring the stability of the relative position relationship between the antenna and the feeding transmission line, and reducing the influence of the antenna itself and the feeding transmission line on the performance of other antennas, thereby ensuring the stability of the antenna performance, thereby taking into account the miniaturized design of the direction-finding antenna and the antenna performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 A schematic diagram of the structure of the direction-finding antenna provided in an embodiment of the present application in a first implementation manner;

[0020] Figure 2 A front view of the direction-finding antenna provided in an embodiment of the present application in a first implementation manner;

[0021] Figure 3 A top view of the direction-finding antenna provided in an embodiment of the present application in a first implementation manner;

[0022] Figure 4 A schematic diagram of the structure of the direction-finding antenna provided in an embodiment of the present application under a second implementation mode;

[0023] Figure 5 A front view of the direction-finding antenna provided in an embodiment of the present application in a second implementation manner;

[0024] Figure 6 A top view of the direction-finding antenna provided in an embodiment of the present application in a second implementation manner;

[0025] Figure 7 A schematic diagram of the structure of a first antenna unit in a direction-finding antenna provided in an embodiment of the present application;

[0026] Figure 8 A schematic diagram of the structure of a second antenna unit in a direction-finding antenna provided in an embodiment of the present application;

[0027] Numbers in the figure: 1-first antenna unit, 2-second antenna unit, 3-first feeding transmission line, 4-second feeding transmission line, 5-PCB dielectric substrate, 6-series component. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0029] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the meaning of "and / or" appearing in the full text includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme that satisfies both A and B. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in the field to implement. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0030] Refer to the attached Figure 1 -Attached Figure 8 The embodiment of the present application provides a direction-finding antenna, comprising: at least two PCB dielectric substrates 5, as shown in the attached Figure 1 The first embodiment of setting two PCB dielectric substrates 5 is shown in FIG. Figure 4 The second embodiment of the present invention is to set three PCB dielectric substrates 5. In other embodiments, the number of PCB dielectric substrates 5 can be selected in other ways. Multiple PCB dielectric substrates 5 can be cross-set, as shown in FIG. Figure 2 The first embodiment shows the cross arrangement of two PCB dielectric substrates 5. Figure 5 The figure shows the cross arrangement of two PCB dielectric substrates 5 in the second embodiment. When the cross arrangement is performed, the central axes of the PCB dielectric substrates 5 coincide with each other, and the PCB dielectric substrates 5 are in a step shape. Figure 2 , Attachment Figure 5 As shown, an upper dielectric substrate and a lower dielectric substrate are formed, a first antenna unit 1 is arranged on the upper dielectric substrate, a second antenna unit 2 is arranged on the lower dielectric substrate, the second antenna unit 2 is connected to the second feeding transmission line 4, the first antenna unit 1 is connected to the second feeding transmission line 4 through the first feeding transmission line 3, the first feeding transmission line 3 and the second feeding transmission line 4 are arranged on a PCB dielectric substrate 5, the first antenna unit 1 covers a first frequency band, and the second antenna unit 2 covers a second frequency band.

[0031] In this embodiment, a PCB dielectric substrate 5 is used to carry the antenna unit, and the antenna is combined in layers through its stepped structure, thereby realizing a miniaturized design of the antenna. The first antenna unit 1 and the second antenna unit 2 are respectively arranged on the upper and lower layers of the dielectric substrate to cover different frequency bands respectively, ensuring that the antenna can cover a wider frequency band range when working. In order to further enhance the stability of the structure, the present application cross-arranges the dielectric substrate to achieve the stability of the dielectric substrate under the premise of ensuring the relative position relationship between the antenna and the feeding transmission line. The feeding transmission line corresponding to each antenna unit is arranged on the PCB dielectric substrate 5, ensuring the stability of the relative position relationship between the antenna and the feeding transmission line, and reducing the influence of the antenna itself and the feeding transmission line on the performance of other antennas, thereby ensuring the stability of the antenna performance, thereby taking into account the miniaturized design of the direction-finding antenna and the antenna performance.

[0032] In one embodiment, according to the research on antenna theory, it is found that the lower antenna will have a great influence on the upper antenna. These influences are multifaceted, not limited to the radiation of electromagnetic waves, but also include coupling between antennas and interaction between antennas. Specifically, for example, when the lower antenna is working, it will continuously generate electromagnetic waves. These electromagnetic waves propagate freely in space and may enter the space where the upper antenna is located during the free propagation process. If the receiving or transmitting frequency of the upper antenna is similar to or the same as the frequency of the electromagnetic waves generated by the lower antenna, then the electromagnetic waves generated by the lower antenna may interfere with the upper antenna to affect its normal operation; in a double-layer antenna structure, the electromagnetic field generated by the lower antenna may propagate to the upper antenna through the air or medium, thereby affecting its performance; in addition, the interaction between antennas is a complex process, which includes multiple modes such as the interaction of electromagnetic fields and the interaction of currents. These interactions may cause the radiation pattern, gain, impedance and other performance parameters of the upper antenna to change, thereby affecting the performance of the entire antenna system. Therefore, when designing and optimizing the antenna system, these factors must be taken into account to ensure that the antenna can work efficiently and stably.

[0033] Based on this, the embodiment of the present application provides a solution: the second antenna unit 2 is designed to be decoupled. Decoupling design refers to removing or reducing the mutual influence or interference between different parts of the circuit through a specific circuit or component design, thereby improving the performance and stability of the entire system. Specifically, the present application provides an implementation method, namely: the decoupling design includes: cutting the second antenna unit into multiple sections, and connecting a series component 6 such as an inductor or a filter device in series between two adjacent sections, as shown in the attached Figure 8As shown. Through the decoupling design, on the one hand, cutting the lower antenna into multiple sections can change its original current distribution and radiation characteristics. Through a reasonable cutting method, the radiation performance of the antenna in a specific frequency band can be significantly optimized, while reducing interference with other antennas. On the other hand, the series inductor, as an energy storage element, can store magnetic field energy and affect the flow of current. By connecting the inductor in series between two adjacent antenna sections, the current distribution on the antenna can be adjusted, thereby changing its radiation and reception characteristics. In addition, the inductor can also play a filtering role, reducing the impact of unnecessary frequency components on antenna performance. In addition to the inductor, other filtering components (such as capacitors, resistors, etc.) can also be considered to further optimize the performance of the antenna to achieve the best communication effect. This design not only improves the performance of the antenna, but also enhances its adaptability in complex electromagnetic environments, ensuring efficient and stable wireless communication. In practical applications, the antenna unit with this decoupling design can significantly improve the overall performance of the multi-antenna system and bring users a better communication experience.

[0034] This application significantly improves the overall performance of the antenna system by connecting filters in series. As a crucial electronic component, the filter can selectively transmit or attenuate certain spectral components of the input signal. This selective transmission and attenuation capability enables the filter to select and limit the signal frequency range. This plays an important role in improving the transmission efficiency of the system, reducing noise interference, and enhancing signal stability. Especially in complex and changeable wireless communication environments, this role of the filter is particularly important. In some application scenarios, in order to meet specific communication needs, the antenna needs to have specific directional characteristics. Therefore, this application uses filters in series to adjust the radiation pattern and directional pattern of the antenna, thereby optimizing its directivity to ensure that the signal can be more effectively transmitted to the predetermined target area, reduce interference to other areas, and improve the accuracy and reliability of communication.

[0035] For example, in the electromagnetic environment of a busy city, many wireless signals are intertwined. If there is a lack of effective signal screening mechanism, mobile phone communications, wireless networks and emergency communication systems will be seriously interfered. Filters play a vital role here. Their function is similar to that of a meticulous traffic commander, guiding the flow of signals to ensure smooth and accurate transmission of information to the intended recipient. In this context, the use of filters has significantly improved communication efficiency and enhanced the security and reliability of communications. Therefore, whether in a densely populated urban environment or in remote rural areas, filters play an irreplaceable role, making communication networks clearer and more orderly.

[0036] In one embodiment, in order to ensure the optimization and stability of antenna performance, the present application adopts a strategy of even distribution as much as possible in structure. Specifically, the angles formed between adjacent PCB dielectric substrates 5 are the same, for example, Figure 1 In the first embodiment shown, the antenna is designed using two PCB dielectric substrates 5, the front view of which is shown in the attached figure. Figure 2 As shown, after the cross setting, its top view is as shown in the attached Figure 3 As shown in the figure, it presents a cross-shaped distribution pattern. Figure 4 In the second embodiment shown, the antenna design uses three PCB dielectric substrates 5, and its front view is shown in the attached figure. Figure 5 As shown, after the cross setting, its top view is as shown in the attached Figure 6 As shown, it presents a cross-shaped distribution pattern.

[0037] In order to further improve the performance and efficiency of the antenna, the present application further optimizes the antenna structure. Specifically, in the first embodiment, the present application adopts a symmetrical distribution strategy, that is, the first antenna unit 1 is placed on the upper dielectric substrate and is symmetrically distributed about the central axis; at the same time, the second antenna unit 2 is arranged on the lower dielectric substrate and also follows the symmetrical distribution principle about the central axis. Figure 1 As shown, on the upper dielectric substrate of each PCB dielectric substrate 5, the present application symmetrically distributes two first antenna units 1, and the number of first antenna units 1 and second antenna units 2 in the single-layer antenna is set to N times of 2, where N is the number of PCB dielectric substrates 5, that is, under the above embodiment, a total of four first antenna units 1 are arranged in the upper antenna; each first antenna unit 1 is fed through the first feeding transmission line 3, and then transferred to the second feeding transmission line 4; the setting of the lower antenna is the same as that of the upper antenna, and a symmetrical distribution strategy is adopted, and two second antenna units 2 are symmetrically distributed on the lower dielectric substrate of each PCB dielectric substrate 5, and a total of four second antenna units 2 are arranged in the lower antenna; each second antenna unit 2 is fed through the second feeding transmission line 4. Through the above optimization process, the present application can ensure that the signal coverage of the antenna is more uniform, while improving the transmission efficiency and stability of the signal.

[0038] In one embodiment, when there is a metal shielding object in the surrounding environment of the antenna, and the size of the shielding object is comparable to the wavelength of the frequency covered by the antenna, the metal shielding object will have an adverse effect on the performance of the antenna. In order to reduce this effect, it is necessary to ensure that the distance from the shielding object to the antenna remains stable, so that the degree of influence is maintained at a predictable or fixed level. Based on this, the present application adopts a transmission line scheme based on a printed circuit board (PCB) design, that is, the first feeding transmission line 3 and the second feeding transmission line 4 are both transmission lines based on PCB design, and the same pair of feeding transmission lines and the antenna unit are distributed together on the same PCB dielectric substrate 5, so that the positional relationship between the feeding transmission line and the antenna unit can be ensured to remain unchanged, even if their positional relationship is fixed. The feeding transmission lines based on PCB design mainly include microstrip lines, strip lines, and grounded coplanar waveguides (GCPW) and other types. Among these types of feeding transmission lines, the first feeding transmission line 3 can adopt a microstrip feeding transmission line. The microstrip feeding transmission line is a transmission line with a layer of conductive metal (such as copper foil or aluminum foil) plated on the surface of a dielectric substrate. A certain air or dielectric gap will be left between the metal layer and the substrate, thus forming a planar transmission line structure. This structural feature makes the microstrip line highly integrated and miniaturized, so it is very suitable for use in high-frequency circuits, and can effectively reduce space occupancy and improve circuit performance.

[0039] In one embodiment, the second feed transmission line 4 in the present application can use a radio frequency cable to achieve signal transmission, but the feed cable will have a certain negative impact on the antenna pattern performance while transmitting the signal. To solve this problem, the present application designs a solution of adding a magnetic ring for the direction-finding antenna when using a radio frequency cable. The magnetic ring is set on the outer conductor of the radio frequency cable. By setting it at intervals or covering it with a full magnetic ring, the induced current on the cable can be effectively weakened or shielded, thereby weakening or eliminating the adverse effects of the cable on the antenna pattern, thereby improving the antenna performance without increasing additional costs, and ensuring the accuracy and reliability of signal transmission.

[0040] In one embodiment, the first antenna unit 1 and the second antenna unit 2 are both in the form of a dipole antenna, which is composed of a pair of symmetrically placed conductors, and the two ends of the two conductors close to each other are respectively connected to the feeder. They have the characteristics of simple structure, convenient production, relatively low cost, etc., and they also have the characteristics of good radiation characteristics and receiving performance. When used as a transmitting antenna, the electrical signal is fed into the two conductors from the center of the antenna; and when used as a receiving antenna, the receiving signal will also obtain the receiving signal from the conductor at the center of the antenna. The common dipole antenna is composed of two coaxial straight wires. The radiation field generated by this antenna at a distance is axisymmetric and can be strictly solved in theory. The application range of the dipole antenna is very wide, and it can be applied to various frequencies from long waves to microwaves. It can be used as a single antenna or an antenna array to meet different usage requirements.

[0041] In one embodiment, the first antenna unit 1 is designed to cover a specific frequency band range, namely the first frequency band; the second antenna unit 2 is designed to cover another frequency band range different from the first frequency band, namely the second frequency band. Through such a design, an ultra-wideband coverage effect is achieved. Specifically, the second antenna unit 2 covers the low-end second frequency band, namely the range from 20MHz to 500MHz; and the first antenna unit 1 covers the high-end first frequency band, namely the range extending from 500MHz to 3GHz. Based on this, the entire direction-finding antenna system can achieve a wide frequency coverage from 20MHz to 3GHz. In addition, the upper and lower antennas of the direction-finding antenna are tightly combined to form an antenna array. This integrated design makes the arrangement of the antenna array very compact. When the upper and lower antenna units are used in combination, their overall size can be controlled within a very small range, such as less than φ350mm*270mm, meeting the miniaturized design, so that the direction-finding antenna can be easy to carry and suitable for more space-constrained occasions.

[0042] The above description is only a preferred 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 should be included in the protection scope of the present application.

Claims

1. A direction-finding antenna, characterized in that: include: At least two PCB dielectric substrates, multiple PCB dielectric substrates are cross-arranged, and their axes coincide, the PCB dielectric substrates are stepped to form an upper dielectric substrate and a lower dielectric substrate, a first antenna unit is arranged on the upper dielectric substrate, a second antenna unit is arranged on the lower dielectric substrate, the second antenna unit is connected to a second feeding transmission line, the first antenna unit is connected to the second feeding transmission line through the first feeding transmission line, the first feeding transmission line and the second feeding transmission line are arranged on the PCB dielectric substrate, the first antenna unit covers a first frequency band, and the second antenna unit covers a second frequency band.

2. The direction-finding antenna according to claim 1, characterized in that: The second antenna unit adopts a decoupling design.

3. The direction-finding antenna according to claim 2, characterized in that: The decoupling design includes: cutting the second antenna unit into multiple sections and connecting an inductor or a filter device in series between two adjacent sections.

4. The direction-finding antenna according to claim 1, characterized in that: The first antenna units are symmetrically distributed on the upper dielectric substrate about the central axis, and the second antenna units are symmetrically distributed on the lower dielectric substrate about the central axis.

5. The direction-finding antenna according to claim 1, characterized in that: The first feeding transmission line and the second feeding transmission line are transmission lines designed based on PCB.

6. The direction-finding antenna according to claim 5, characterized in that: The first feeding transmission line is a microstrip feeding transmission line.

7. The direction-finding antenna according to claim 1, characterized in that: The second feeding transmission line adopts a radio frequency cable, and the direction-finding antenna further comprises a magnetic ring, which is sleeved on the outer conductor of the radio frequency cable.

8. The direction-finding antenna according to claim 1, characterized in that: The angles formed between adjacent PCB dielectric substrates are the same.

9. The direction-finding antenna according to claim 1, characterized in that: The first antenna unit and the second antenna unit are in the form of dipole antennas.

10. The direction-finding antenna according to claim 1, characterized in that: The number of the first antenna units and the second antenna units is N times of 2, where N is the number of the PCB dielectric substrates.

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