Antenna, antenna system and vehicle

Abstract

The present disclosure provides an antenna, an antenna system and an automobile, belonging to the field of wireless communication technologies. The antenna includes a main antenna, a parasitic antenna and a main board; the main antenna and the parasitic antenna are both located on the surface of the main board, and the plane where the main antenna is located is parallel to the plane where the parasitic antenna is located and the positions are opposite; the feeding point of the main antenna is connected to the feeding transmission line of the main board, and the parasitic antenna is connected to the second grounding end of the main board; wherein, the difference between the resonant frequency point of the main antenna and the resonant frequency point of the parasitic antenna is less than a target threshold. When this antenna is applied in an automobile as a communication antenna of the automobile, such as a 4G communication antenna or a 5G communication antenna, it can achieve 4G or 5G wide-bandwidth coverage, such as full-bandwidth coverage. In addition, this antenna can also improve the out-of-band suppression ratio and enhance the anti-foreign frequency interference characteristics.

Description

Technical Field

[0001] The present disclosure relates to the technical field of wireless communications, and in particular to an antenna, an antenna system and a car. Background Art

[0002] With the rapid development of intelligent network technology and the arrival of the fifth generation mobile communication technology (5G), it has become possible to connect cars to the Internet of Everything with high traffic, low latency and high speed.

[0003] Among them, the vehicle-mounted antenna is the core component for realizing communication between the vehicle and the outside world, and is usually arranged on the top of the vehicle, for example, in the luggage rack on the roof.

[0004] However, due to the limited height of the luggage rack, the size of the vehicle-mounted antenna will be limited. Since the radiation frequency of the antenna is related to the size of the antenna, it will be difficult for the vehicle-mounted antenna to achieve 5G wide-band coverage. Summary of the invention

[0005] The present disclosure provides an antenna, an antenna system and a car. The antenna is applied to the car to achieve 5G wide-band coverage. The technical solution is as follows:

[0006] In a first aspect, an antenna is provided, the antenna comprising a main antenna, a parasitic antenna and a mainboard;

[0007] The main antenna and the parasitic antenna are both located on the surface of the mainboard, and the plane where the main antenna is located is parallel to the plane where the parasitic antenna is located, and the positions are opposite;

[0008] The feeding point of the main antenna is connected to the feeding transmission line of the mainboard, and the parasitic antenna is connected to the second ground terminal of the mainboard;

[0009] Wherein, a difference between a resonant frequency point of the main antenna and a resonant frequency point of the parasitic antenna is smaller than a target threshold.

[0010] In the solution disclosed in the present disclosure, the difference between the resonant frequency of the main antenna and the resonant frequency of the parasitic antenna may be the absolute value of the absolute difference, specifically the absolute value of the difference between the resonant frequency of the main antenna and the resonant frequency of the parasitic antenna. For example, the resonant frequency of the main antenna is f1, and the resonant frequency of the parasitic antenna is f2, then the difference between the resonant frequency of the main antenna and the resonant frequency of the parasitic antenna is |f1-f2|.

[0011] Alternatively, the difference between the resonant frequency points of the main antenna and the parasitic antenna can also be the absolute value of the relative difference, specifically, the percentage of the absolute value of the difference between the resonant frequency points of the main antenna and the parasitic antenna to the intermediate value of the two. For example, if the resonant frequency point of the main antenna is f1 and the resonant frequency point of the parasitic antenna is f2, then the difference between the resonant frequency points of the main antenna and the parasitic antenna is

[0012] Then, if the difference between the resonant frequency points of the main antenna 1 and the parasitic antenna 2 is the absolute value of the absolute difference, the target threshold is a frequency value. And if the difference between the resonant frequency points of the main antenna 1 and the parasitic antenna 2 is the absolute value of the relative difference, the target threshold is a percentage.

[0013] In the solution shown in the present disclosure, the antenna includes a main antenna and a parasitic antenna, and the main antenna and the parasitic antenna are arranged relatively. Among them, the excitation signal of the main antenna is introduced by a feeder, and the excitation signal of the parasitic antenna is introduced by coupling with the electromagnetic field of the main antenna. The main antenna and the parasitic antenna are coupled to each other, which can broaden the bandwidth of the antenna. Then, when the antenna is applied in an automobile as a communication antenna of the automobile, such as a 4G communication antenna or a 5G communication antenna, it can achieve 4G or 5G broadband coverage, or even full bandwidth coverage.

[0014] In addition, the antenna can also improve the out-of-band suppression ratio and enhance the anti-interference characteristics of different frequencies. For example, the antenna can improve the out-of-band suppression ratio of the GNSS antenna, so that even if the GNSS antenna and the antenna described in this embodiment are arranged together, such as both arranged in a shark fin or both arranged in a luggage rack, the interference of the GNSS antenna to the antenna described in this embodiment can be reduced.

[0015] In a possible implementation manner, the feeding point of the main antenna is connected to the inner conductor of the feeding transmission line of the main board, the outer conductor of the feeding transmission line is connected to the first grounding end of the main board, and the first grounding end and the second grounding end are grounded together.

[0016] In the solution shown in the present disclosure, grounding together can eliminate the ineffective resonant modes excited after the coupling of the main antenna and the parasitic antenna, thereby slowing down the efficiency reduction rate of the effective resonant modes. For example, after the main antenna and the parasitic antenna are coupled, effective resonant mode 2 and ineffective resonant mode 3 can be excited, and the resonant points corresponding to these two resonant modes are relatively close. If the ineffective resonant mode 3 is eliminated through grounding, then, since in the radiation efficiency characteristic diagram, resonant point 3 is not at the corresponding minimum point, the radiation loss will not decrease rapidly from resonant point 2 to resonant point 3. Therefore, eliminating the ineffective resonant mode 3 can reduce the reduction rate of the radiation loss of resonant mode 2, that is, slow down the efficiency reduction rate of resonant mode 2.

[0017] In a possible implementation, the main antenna is a monopole antenna and the parasitic antenna is a loop antenna.

[0018] In the solution shown in the present disclosure, a monopole antenna is an antenna that can excite a specific wavelength line mode after an excitation signal is input thereto. For example, after an excitation signal is input to the monopole antenna, a resonant mode of a 1 / 4 wavelength line mode can be excited.

[0019] A loop antenna, which can also be referred to as a circular antenna, is a structure in which a metal wire is wound into a certain shape, such as a circle, a square, a triangle, etc., and the two ends of the conductor are used as output terminals. After an excitation signal is input to the loop antenna, a resonant mode of a specific wavelength loop mode can be excited. For example, a resonant mode of a 1 / 2 wavelength loop mode can be excited.

[0020] In a possible implementation, the starting end of the main antenna is a feeding point, and both ends of the parasitic antenna are connected to the second grounding end of the main board;

[0021] The distance between the starting end of the main antenna and the end of the parasitic antenna is less than a first value, and the distance between the ending end of the main antenna and the middle position of the parasitic antenna is less than a second value.

[0022] In the solution shown in the present disclosure, if the main antenna is a monopole antenna, the starting end is the position of the strong current point, corresponding to the strong magnetic field point, and the ending end is the position of the weak current point, corresponding to the strong electric field point. If the parasitic antenna is a loop antenna, both ends are the positions of the strong current points, corresponding to the strong magnetic field points, and the middle position is the position of the weak current point, corresponding to the strong electric field point.

[0023] Then, when adjusting the coupling degree between the main antenna and the parasitic antenna, it can be adjusted such that the starting end of the main antenna is relatively close to the end of the parasitic antenna, and the ending end of the main antenna is relatively close to the middle position of the parasitic antenna.

[0024] In the solution shown in the present disclosure, by adjusting the coupling degree between the main antenna and the parasitic antenna, the resonant frequency and bandwidth after mutual coupling can be adjusted to achieve broadband coverage of the antenna.

[0025] In the solution shown in the present disclosure, by adjusting the coupling degree between the main antenna and the parasitic antenna, the position of the out-of-band radiation zero point can also be adjusted.

[0026] In a possible implementation, the main antenna is a monopole antenna and the parasitic antenna is a monopole antenna.

[0027] In a possible implementation, the starting end of the main antenna is a feeding point, and the starting end of the parasitic antenna is connected to the second grounding end of the main board;

[0028] The distance between the starting end of the main antenna and the starting end of the parasitic antenna is less than a third value, and the distance between the ending end of the main antenna and the ending end of the parasitic antenna is less than a fourth value.

[0029] In the solution shown in the present disclosure, if the main antenna is a monopole antenna, the starting end is the position of the strong current point, corresponding to the strong magnetic field point, and the ending end is the position of the weak current point, corresponding to the strong electric field point. If the parasitic antenna is a monopole antenna, the starting end connected to the main board is the position of the strong current point, corresponding to the strong magnetic field point, and the ending end is the position of the weak current point, corresponding to the strong electric field point.

[0030] Then, when adjusting the coupling degree between the main antenna and the parasitic antenna, it can be adjusted such that the starting end of the main antenna is relatively close to the starting end of the parasitic antenna, and the ending end of the main antenna is relatively close to the ending end of the parasitic antenna.

[0031] In the solution shown in the present disclosure, by adjusting the coupling degree between the main antenna and the parasitic antenna, the resonant frequency and bandwidth after mutual coupling can be adjusted, realizing broadband coverage of the antenna.

[0032] In the solution shown in the present disclosure, by adjusting the coupling degree between the main antenna and the parasitic antenna, the position of the out-of-band radiation zero point can also be adjusted.

[0033] In a possible implementation manner, the main antenna is a loop antenna, and the parasitic antenna is a loop antenna or a monopole antenna.

[0034] In a possible implementation manner, the main antenna includes a first branch and a second branch;

[0035] One end of the first branch is vertically located on the surface of the main board, and the other end is connected to the second branch. The width of the second branch is greater than the width of the first branch.

[0036] In the solution shown in the present disclosure, since the second branch is relatively wide, there are multiple current paths distributed on the second branch. Although the electrical lengths corresponding to these current paths are not much different, there will still be slight differences. Different electrical lengths excite different resonant frequencies. Then, multiple different electrical lengths excite multiple resonant frequencies that are close but different, which is beneficial to broadening the bandwidth of the antenna.

[0037] In a possible implementation manner, the main antenna further includes a first matching branch;

[0038] There is a spacing between the second branch and the main board. The first matching branch is fixed to the main board and is located between the first branch and the second branch on one side of the first branch;

[0039] Between the mutually approaching edges of the first matching stub and the first stub, and / or between the mutually approaching edges of the first matching stub and the second stub, all are used to form a capacitor.

[0040] In the solution shown in the present disclosure, between the mutually approaching edges of the first matching stub and the first stub, and / or between the mutually approaching edges of the first matching stub and the second stub, a capacitor can be formed. The formed capacitor can be used to adjust the impedance matching between the antenna and the feeder line, so as to reduce the return loss and improve the radiation efficiency of the antenna.

[0041] In a possible implementation manner, the second stub includes a first branch and a second branch, and the first branch and the second branch are arranged side by side along the width direction of the second stub;

[0042] One end of the first branch is connected to one end of the second branch, and the other ends of the first branch and the second branch are both connected to the first stub.

[0043] In the solution shown in the present disclosure, since the second stub is relatively wide, then, a hollowing design can be carried out on the second stub, so that the second stub includes a hollow area, and the first branch and the second branch located on the left and right sides of the hollow area.

[0044] The second stub includes separate first and second branches. Then, the current distributed in the first branch can excite an electromagnetic wave of one resonant frequency, and the current distributed in the second branch can excite an electromagnetic wave of another resonant frequency, so that the number of resonant frequencies of the antenna can be increased, and the bandwidth of the antenna can be broadened by increasing the number of resonant frequencies.

[0045] In a possible implementation manner, the main antenna includes a first radiation arm, a second radiation arm, and a third radiation arm;

[0046] One end of the first radiation arm is vertically located on the surface of the main board, and the other end is vertically connected to one end of the second radiation arm, and the other end of the second radiation arm is vertically connected to one end of the third radiation arm.

[0047] In the solution shown in the present disclosure, the first radiation arm is arranged vertically with respect to the main board, the second radiation arm is arranged horizontally with respect to the main board, and the third radiation arm is arranged vertically with respect to the main board. The arrangement manner of the three radiation arms of the main antenna is beneficial to reducing the height and width, and making the structure of the main antenna more compact.

[0048] In a possible implementation manner, the total height of the main antenna is equal to the total height of the parasitic antenna, and the total width of the main antenna is equal to the total width of the parasitic antenna.

[0049] In the solution shown in the present disclosure, the total height of the main antenna is equal to or approximately equal to the total height of the parasitic antenna, and the total width of the main antenna is equal to or approximately equal to the total width of the parasitic antenna, which is beneficial for the main antenna and the parasitic antenna to make full use of the spatial dimensions.

[0050] In a possible implementation manner, the antenna further includes a dielectric plate, the dielectric plate is vertically located on the surface of the main board, the main antenna is located on the first surface of the dielectric plate, the parasitic antenna is located on the second surface of the dielectric plate, and the first surface and the second surface of the dielectric plate are opposite in position.

[0051] In the solution shown in the present disclosure, the dielectric plate is vertically located on the surface of the main board, and the main antenna and the parasitic antenna can be printed on two opposite surfaces of the dielectric plate. For example, the main antenna is located on the first surface of the dielectric plate, and the parasitic antenna is located on the second surface of the dielectric plate.

[0052] In the solution shown in the present disclosure, the main antenna and the parasitic antenna are arranged on two opposite surfaces of the dielectric plate, which can improve the seismic performance of the antenna. Then, when the antenna is applied to an automobile, the degree of the antenna shaking with the vehicle can be reduced.

[0053] In a second aspect, an antenna system is provided. The antenna system includes a radio frequency circuit and the antenna described in the first aspect, and the radio frequency circuit is used to enable the antenna to receive and transmit wireless signals.

[0054] In a third aspect, an automobile is provided. The automobile includes the antenna system described in the second aspect.

[0055] In a possible implementation manner, the antenna is located in the luggage rack of the automobile.

[0056] In the solution shown in the present disclosure, the antenna can be located in the luggage rack on the left side of the automobile body, or can be arranged in the luggage rack on the right side of the automobile body, or antennas can be arranged in both the luggage rack on the left side of the body and the luggage rack on the right side of the body.

[0057] In a possible implementation manner, the radio frequency circuit is arranged in the telematics box (T-BOX) of the automobile. The T-BOX is located in the back seat of the automobile and close to the tail of the tire, and the luggage rack where the antenna is located and the T-BOX are on the same side of the automobile body.

[0058] In the solution shown in the present disclosure, the T-BOX is located in the back seat of the automobile and close to the tail of the tire, and moreover, the luggage rack where the antenna is located and the T-BOX are on the same side of the automobile body, so that the spatial distance between the antenna and the T-BOX is close. Then, the wire harness of the signal cable is short, which can effectively reduce the link loss caused by the cable, thereby improving the system efficiency of the vehicle antenna.

[0059] In a possible implementation, the antenna is located in the shark fin of the vehicle. Description of the Drawings

[0060] Figure 1 is a schematic structural diagram of an antenna provided by the present disclosure;

[0061] Figure 2 is a schematic diagram of the current distribution of an excited 1 / 4 wavelength line mode provided by the present disclosure;

[0062] Figure 3 is a schematic diagram of the current distribution of an excited 1 / 2 wavelength loop mode provided by the present disclosure;

[0063] Figure 4 is a schematic structural diagram of a main antenna that is a monopole antenna provided by the present disclosure;

[0064] Figure 5 is a schematic structural diagram of a parasitic antenna that is a loop antenna provided by the present disclosure;

[0065] Figure 6 is a schematic structural diagram of an antenna provided by the present disclosure;

[0066] Figure 7 is a schematic diagram of the distribution of multiple current paths on the main antenna provided by the present disclosure;

[0067] Figure 8 is a schematic structural diagram of a main antenna with a hollowed-out area provided by the present disclosure;

[0068] Figure 9 is a schematic structural diagram of a main antenna with matching stubs provided by the present disclosure;

[0069] Figure 10 is a schematic structural diagram of a main antenna provided by the present disclosure;

[0070] Figure 11 is a schematic structural diagram of a parasitic antenna provided by the present disclosure;

[0071] Figure 12 is a schematic structural diagram of an antenna provided by the present disclosure;

[0072] Figure 13 provided by the present disclosure Figure 12 echo loss characteristic diagram of the antenna shown;

[0073] Figure 14 provided by the present disclosure Figure 12 radiation efficiency characteristic diagram of the antenna shown;

[0074] Figure 15 provided by the present disclosure Figure 12System efficiency characteristic diagram of the antenna shown

[0075] Figure 16 It is a schematic diagram of the current distribution exciting the 1 / 4 wavelength line mode provided by the present disclosure

[0076] Figure 17 It is a schematic diagram of the current distribution exciting the 1 / 4 wavelength line mode provided by the present disclosure

[0077] Figure 18 It is a schematic diagram of the structure of an antenna provided by the present disclosure

[0078] Figure 19 It is a schematic diagram of the current distribution on the main antenna and the parasitic antenna provided by the present disclosure, where (a) is the front view and (b) is the top view

[0079] Figure 20 It is a schematic diagram of the current distribution on the main antenna and the parasitic antenna provided by the present disclosure, where (a) is the front view and (b) is the top view

[0080] Figure 21 It is a schematic diagram of the current distribution on the main antenna and the parasitic antenna provided by the present disclosure, where (a) is the front view and (b) is the top view

[0081] Figure 22 It is a return loss characteristic diagram of an antenna provided by the present disclosure

[0082] Figure 23 It is a radiation efficiency characteristic diagram and a system efficiency characteristic diagram of an antenna provided by the present disclosure

[0083] Figure 24 It is a schematic diagram of the structure of an antenna installed in a luggage rack provided by the present disclosure

[0084] Figure 25 It is a schematic diagram of the structure of the main board of an antenna located in the metal base of a luggage rack provided by the present disclosure

[0085] Description of reference numerals

[0086] 1. Main antenna; 11. First radiation arm; 12. Second radiation arm; 13. Third radiation arm; 14. First matching stub; 15. Second matching stub; 111. First stub; 112. Second stub; 121. First inclined stub; 122. Horizontal stub; 123. Second inclined stub; 1120. Hollow area; 1121. First branch; 1122. Second branch

[0087] 2. Parasitic antenna

[0088] 3. Main board; 31. First ground plane; 32. Second ground plane Detailed implementation manners

[0089] Although the description of the present disclosure will be introduced in conjunction with some embodiments, this does not mean that the features of this application are limited to this implementation manner. On the contrary, the purpose of introducing the application in conjunction with the implementation manner is to cover other alternatives or modifications that may be extended based on the claims of the present disclosure. In order to provide a deep understanding of the present disclosure, many specific details will be included in the following description. The present disclosure can also be implemented without using these details. In addition, in order to avoid confusion or obscuring the key points of the present disclosure, some specific details will be omitted in the description. It should be noted that, without conflict, the embodiments in the present disclosure and the features in the embodiments can be combined with each other.

[0090] In the embodiments of the present disclosure, the terms "first", "second", "third", and "fourth" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first", "second", "third", and "fourth" may explicitly or implicitly include one or more of such features.

[0091] In the embodiments of the present disclosure, "and / or" is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article generally represents an "or" relationship between the associated objects before and after.

[0092] In the description of the embodiments of the present disclosure, it should be noted that unless otherwise clearly specified and limited, the terms "installation" and "connection" should be understood in a broad sense. For example, "connection" can be a detachable connection or a non-detachable connection; it can be a direct connection or an indirect connection through an intermediate medium. The orientation terms mentioned in the embodiments of the present disclosure, such as "upper", "lower", "left", "right", etc., are only references to the directions of the drawings. Therefore, the orientation terms used are for better and clearer illustration and understanding of the embodiments of the present disclosure, rather than indicating or implying that the indicated device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus cannot be understood as a limitation on the embodiments of the present disclosure.

[0093] This embodiment relates to an antenna for an automobile, which is used to realize communication between a vehicle and a base station and is usually arranged in a shark fin on the roof or a roof rack. However, due to the limited height of the shark fin and the roof rack, the size of the antenna will be limited, and the radiation frequency of the antenna is related to the size of the antenna. For example, the radiation frequency and the size of the antenna are negatively correlated, which then makes it difficult for the antenna to achieve wide-band coverage.

[0094] The antenna provided in this embodiment is applied in an automobile, which can broaden the working bandwidth of the antenna to achieve wide-band coverage. In addition, the antenna can also improve the out-of-band interference suppression ratio to resist the interference of out-of-band adjacent frequencies.

[0095] Among them, the antenna can be a transmitting antenna, a receiving antenna, or a transceiver antenna. This embodiment does not make specific limitations on this.

[0096] Specifically, the antenna can be an antenna of a cellular mobile communication system, such as an antenna of the 4th generation mobile networks (4G), or an antenna of the 5th generation mobile networks (5G). The antenna can also be a communication antenna of a wireless local area network (WLAN), vehicle-to-X (V2X), or bluetooth low energy (BLE), etc.

[0097] For example, the antenna can be a 4G full-frequency antenna or a 5G full-frequency antenna. Among them, this embodiment does not limit the type of the antenna.

[0098] Among them, before introducing this solution, the terms involved are first introduced.

[0099] The resonant frequency, also known as the resonant frequency point or resonant point, is generally the center frequency of the expected working frequency band. It is the frequency point at which the current and voltage of the antenna reach the maximum value. At this frequency point, the radiation efficiency of the antenna is the highest, and electrical energy can be converted into electromagnetic waves and transmitted.

[0100] The bandwidth, which is also the working frequency band of the antenna, generally covers the resonant frequency. It usually refers to the frequency range where the return loss is less than a certain dB value. For example, the frequency range where the return loss is less than -5 dB can be defined as the bandwidth of the antenna.

[0101] The return loss is the ratio of the reflected power to the incident power at the joint of the antenna, which reflects the impedance matching characteristic between the antenna and the feed transmission line. For example, the better the impedance matching between the antenna and the feed transmission line, the smaller the return loss.

[0102] In the return loss characteristic diagram of this embodiment, the return loss is characterized by a negative value. Then, the smaller the return loss, the better the impedance matching characteristic of the antenna, and the return loss of 0 dB corresponds to the worst impedance matching.

[0103] The radiation efficiency is the ratio of the energy radiated by the antenna to the energy transmitted to the antenna, and the energy that is not radiated is mainly lost by the antenna itself.

[0104] System efficiency, also known as antenna efficiency, refers to the ratio of the antenna's radiated power to the input power provided by the feeder. Part of the energy not radiated by the antenna is reflected back, and part is the loss of the antenna itself.

[0105] The radiation zero point is the frequency point that theoretically neither radiates electromagnetic waves nor receives electromagnetic waves. In practice, the loss at the radiation zero point is relatively large and the efficiency is relatively low. In the efficiency characteristic diagram, the radiation zero point corresponds to the minimum point.

[0106] The structure of the antenna provided by this embodiment will be introduced below.

[0107] The antenna provided in this embodiment mainly increases the resonant modes of the antenna through electromagnetic field coupling between the main antenna and the parasitic antenna, thereby achieving the purpose of widening the antenna bandwidth.

[0108] So, if Figure 1 As shown, the antenna includes a main antenna 1, a parasitic antenna 2 and a mainboard 3, wherein the main antenna 1 and the parasitic antenna 2 are both located on the surface of the mainboard 3, for example, the main antenna 1 and the parasitic antenna 2 are both vertically welded on the surface of the mainboard 3. Figure 1 As shown, the plane where the main antenna 1 is located is parallel to the plane where the parasitic antenna 2 is located, and their positions are opposite.

[0109] In one example, the antenna may also include a dielectric board, which is vertically located on the surface of the main board 3. The main antenna 1 and the parasitic antenna 2 may be printed on two opposite surfaces of the dielectric board. For example, the main antenna 1 is located on the first surface of the dielectric board, and the parasitic antenna 2 is located on the second surface of the dielectric board.

[0110] In another example, the antenna may not include a dielectric plate, and the main antenna 1 and the parasitic antenna 2 are both metal sheets.

[0111] It should be pointed out that the main antenna 1 and the parasitic antenna 2 are arranged on two opposite surfaces of the dielectric plate, which can improve the anti-vibration performance of the antenna. Therefore, when the antenna is used in a car, the degree of shaking of the antenna with the car can be reduced.

[0112] In one example, the main antenna 1 is an active conductive element in the radio antenna, and is connected to the radio frequency circuit through a feeding transmission line (referred to as feeder line), for example, the feeding point of the main antenna 1 is connected to the feeder line on the main board 3. The feeder line is usually a coaxial line, including an inner conductor and an outer conductor, then, the feeding point of the main antenna 1 is connected to the inner conductor of the feeder line, and the outer conductor of the feeder line is connected to the first grounding terminal of the main board 3 to achieve grounding.

[0113] In one example, the parasitic antenna 2 in the radio antenna is a passive conductive element that is not connected to the feeder. The excitation signal of the parasitic antenna 2 is introduced through electric field coupling and magnetic field coupling with the main antenna 1.

[0114] In one example, the parasitic antenna 2 is connected to the second grounding end of the main board 3 to ground the parasitic antenna 2. Grounding the parasitic antenna 2 enables the main board 3 to act as a radiation element of the parasitic antenna 2, radiating electromagnetic waves outward and effectively shortening the size of the parasitic antenna 2.

[0115] As described above, the outer conductor of the feeder connected to the main antenna 1 is connected to the first grounding end of the main board 3 to achieve grounding, and the parasitic antenna 2 is connected to the second grounding end of the main board 3 to achieve grounding. Among them, the main antenna 1 and the parasitic antenna 2 can share the same ground, that is, the reference ground plane is the same.

[0116] The main antenna 1 and the parasitic antenna 2 share the same ground, that is, the first grounding end connected to the outer conductor of the feeder and the second grounding end connected to the parasitic antenna 2 share the same ground.

[0117] For example, as Figure 1 shown, the upper surface of the main board 3 represents the first ground plane 31, and the lower surface represents the second ground plane 32. If both the first grounding end and the second grounding end are located on the upper surface of the main board 3, that is, the outer conductor of the feeder and the parasitic antenna 2 are both connected to the upper surface of the main board 3, then the ground planes referred to by the main antenna 1 and the parasitic antenna 2 are the same, both being the first ground plane 31.

[0118] If both the first grounding end and the second grounding end are located on the lower surface of the main board 3, that is, the outer conductor of the feeder and the parasitic antenna 2 are both connected to the lower surface of the main board 3, then the ground planes referred to by the main antenna 1 and the parasitic antenna 2 are also the same, both being the second ground plane 32.

[0119] If one of the first grounding end and the second grounding end is located on the upper surface of the main board 3 and the other is located on the lower surface of the main board 3, and the upper surface and the lower surface are connected through a metal via of the main board 3, then the first ground plane 31 and the second ground plane 32 represent the same ground plane, and the ground planes referred to by the main antenna 1 and the parasitic antenna 2 are also the same.

[0120] The above is the situation of the main antenna 1 and the parasitic antenna 2 sharing the same ground and the implementation method of sharing the same ground.

[0121] In another example, the main antenna 1 and the parasitic antenna 2 can also not share the same ground, that is, the ground planes they refer to are not the same.

[0122] For example, still taking the upper surface of the main board 3 as the first ground plane 31 and the lower surface as the second ground plane 32 as an example. As an example, the outer conductor of the feeder connected to the main antenna 1 can be connected to the upper surface of the main board 3. Then, the ground plane for reference is the first ground plane 31. The parasitic antenna 2 can be connected to the lower surface of the main board 3. Then, the ground plane for reference is the second ground plane 32. And there is no electrical connection between the first ground plane 31 and the second ground plane 32, so that the main antenna 1 and the parasitic antenna 2 are not grounded together. In order to prevent the parasitic antenna 2 from being connected to the upper surface of the main board 3 when it is connected to the lower surface of the main board 3, the main board 3 can be slotted, and the parasitic antenna 3 passes through the slotted area and is connected to the lower surface of the main board 3.

[0123] Among them, in this embodiment, it is not specifically limited whether the main antenna 1 and the parasitic antenna 2 are grounded together, and it can be flexibly selected according to the design requirements of the antenna and the expected effects achieved. In the following introduction of the resonant mode of the antenna, the effects generated when the main antenna 1 and the parasitic antenna 2 are grounded together will be introduced.

[0124] As described above, through the coupling effect of the main antenna 1 and the parasitic antenna 2, the antenna increases the resonant mode, and further broadens the resonant frequency band of the antenna. Then, the resonant frequency points of the main antenna 1 and the parasitic antenna 2 are close. For example, the difference between the resonant frequency point of the main antenna 1 and the resonant frequency point of the parasitic antenna 2 is less than the target threshold.

[0125] In one example, the difference between the resonant frequency point of the main antenna 1 and the resonant frequency point of the parasitic antenna 2 can be the absolute value of the absolute difference, specifically the absolute value of the difference between the resonant frequency point of the main antenna 1 and the resonant frequency point of the parasitic antenna 2. For example, if the resonant frequency point of the main antenna is f1 and the resonant frequency point of the parasitic antenna is f2, then the difference between the resonant frequency point of the main antenna and the resonant frequency point of the parasitic antenna is |f1 - f2|.

[0126] Or, the difference between the resonant frequency point of the main antenna 1 and the resonant frequency point of the parasitic antenna 2 can also be the absolute value of the relative difference, specifically the absolute value of the difference between the resonant frequency point of the main antenna 1 and the resonant frequency point of the parasitic antenna 2, as a percentage of the intermediate value of the two resonant frequency points. For example, if the resonant frequency point of the main antenna is f1 and the resonant frequency point of the parasitic antenna is f2, then the difference between the resonant frequency point of the main antenna and the resonant frequency point of the parasitic antenna is

[0127] Then, if the difference between the resonant frequency point of the main antenna 1 and the resonant frequency point of the parasitic antenna 2 is the absolute value of the absolute difference, the target threshold is a frequency value. And if the difference between the resonant frequency point of the main antenna 1 and the resonant frequency point of the parasitic antenna 2 is the absolute value of the relative difference, the target threshold is a percentage.

[0128] Whether the target threshold is a frequency value or a percentage, the target threshold is related to the frequency bands where the main antenna 1 and the parasitic antenna 2 are located. That is, if the frequency bands where the main antenna 1 and the parasitic antenna 2 are located are different, the target threshold will be different. And the frequency bands where the main antenna 1 and the parasitic antenna 2 are located are related to the frequency bands to be broadened by the antenna.

[0129] For example, in cellular communication, the operating frequency bands of 4G antennas and 5G antennas are usually divided into low-frequency bands (700 MHz to 960 MHz), mid-high-frequency bands (1710 MHz to 2690 MHz), and high-frequency bands (3300 MHz to 5000 MHz).

[0130] If the antenna broadens the coverage bandwidth of the low-frequency band through the parasitic antenna 2, then the resonance frequencies of both the main antenna 1 and the parasitic antenna 2 are within the low-frequency band, the absolute value of the absolute difference between the resonance frequency of the main antenna 1 and the resonance frequency of the parasitic antenna 2 is less than 350 M, and the absolute value of the relative difference between the resonance frequency of the main antenna 1 and the resonance frequency of the parasitic antenna 2 is less than 42%.

[0131] If the antenna broadens the coverage bandwidth of the mid-high-frequency band through the parasitic antenna 2, then the resonance frequencies of both the main antenna 1 and the parasitic antenna 2 are within the mid-high-frequency band, the absolute value of the absolute difference between the resonance frequency of the main antenna 1 and the resonance frequency of the parasitic antenna 2 is less than 600 M, and the absolute value of the relative difference between the resonance frequency of the main antenna 1 and the resonance frequency of the parasitic antenna 2 is less than 40%.

[0132] If the antenna broadens the coverage bandwidth of the high-frequency band through the parasitic antenna 2, then the resonance frequencies of both the main antenna 1 and the parasitic antenna 2 are within the high-frequency band, the absolute value of the absolute difference between the resonance frequency of the main antenna 1 and the resonance frequency of the parasitic antenna 2 is less than 800 M, and the absolute value of the relative difference between the resonance frequency of the main antenna 1 and the resonance frequency of the parasitic antenna 2 is less than 25%.

[0133] As can be seen from the above, the antenna increases the resonance modes of the antenna through the electromagnetic field coupling between the main antenna 1 and the parasitic antenna 2 to achieve the purpose of broadening the antenna frequency band. Among them, the coupling degree between the main antenna 1 and the parasitic antenna 2 affects the resonance frequency of the antenna. Therefore, adjusting the coupling degree between the main antenna 1 and the parasitic antenna 2 can adjust the resonance frequency of the antenna.

[0134] In one example, the coupling degree between the main antenna 1 and the parasitic antenna 2 can be adjusted by adjusting the positional relationship between the electric field strength point position of the main antenna 1 and the electric field strength point position of the parasitic antenna 2, and the positional relationship between the magnetic field strength point position of the main antenna 1 and the magnetic field strength point position of the parasitic antenna 2.

[0135] Generally, the strong current point corresponds to the strong magnetic field point, and the weak current point corresponds to the strong electric field point.

[0136] Therefore, the key to adjusting the coupling degree between the main antenna 1 and the parasitic antenna 2 lies in adjusting the positional relationship between the strong current point position of the main antenna 1 and the strong current point position of the parasitic antenna 2, and adjusting the positional relationship between the weak current point position of the main antenna 1 and the weak current point position of the parasitic antenna 2.

[0137] Among them, the strong current point position and the weak current point position are related to the type of antenna.

[0138] For example, for a monopole antenna, as Figure 2 shown, in the current distribution exciting the 1 / 4 wavelength line mode, the current is the strongest at the feeding point and the weakest at the open end. Usually, one end of the monopole antenna connected to the main board 3 is denoted as the starting end, serving as the feeding point, and the other end is the open end, denoted as the ending end. Therefore, for a monopole antenna, its starting end is the strong current point position and the ending end is the weak current point position.

[0139] It should be noted that Figure 2 the solid black-filled dots in Figure 2 represent the strong current point positions, and the unfilled dots represent the weak current point positions. This representation method also applies to other drawings.

[0140] Among them, Figure 2 is the schematic diagram of the current distribution at a certain moment when a current is loaded on the monopole antenna as Figure 4 shown.

[0141] Also, for example, for a loop antenna, as Figure 3 shown, in the current distribution exciting the 1 / 2 wavelength loop mode, the current is the weakest at the middle position (i.e., at the 1 / 4 wavelength position), and the strongest at both ends. Therefore, for a loop antenna, its middle position is the weak current point position and both ends are the strong current point positions.

[0142] Among them, Figure 3 is the schematic diagram of the current distribution at a certain moment when a current is loaded on the monopole antenna as Figure 5 shown.

[0143] Based on the above, in one example, the spatial distance between the strong current point position of the main antenna 1 and the strong current point position of the parasitic antenna 2, and the spatial distance between the weak current point position of the main antenna 1 and the weak current point position of the parasitic antenna 2 can be adjusted through simulation software to optimize the electromagnetic field coupling effect between the main antenna 1 and the parasitic antenna 2, so that the operating frequency band of the antenna is relatively wide, meeting the expected bandwidth and achieving broadband coverage of the antenna.

[0144] Regarding the antenna types of the main antenna 1 and the parasitic antenna 2, for example, the main antenna 1 can be a monopole antenna or a loop antenna, and the parasitic antenna 2 can also be a monopole antenna or a loop antenna. Then, there will be the following four scenarios.

[0145] One scenario is that the main antenna 1 is a monopole antenna and the parasitic antenna 2 is a loop antenna. Another scenario is that both the main antenna 1 and the parasitic antenna 2 are loop antennas. Another scenario is that both the main antenna 1 and the parasitic antenna 2 are monopole antennas. Another scenario is that the main antenna 1 is a loop antenna and the parasitic antenna 2 is a monopole antenna.

[0146] The characteristics of the antenna will be introduced below for the case where the main antenna 1 is a monopole antenna and the parasitic antenna 2 is a loop antenna, and also for the case where both the main antenna 1 and the parasitic antenna 2 are monopole antennas.

[0147] Among them, a monopole antenna is an antenna that can excite a specific wavelength linear mode after an excitation signal is input to it. For example, when an excitation signal is input to a monopole antenna, a resonant mode of 1 / 4 wavelength linear mode can be excited.

[0148] A loop antenna, also known as a circular antenna, is a structure in which a metal wire is wound into a certain shape, such as a circle, a square, a triangle, etc., with both ends of the conductor as output terminals. After an excitation signal is input to the loop antenna, a resonant mode of a specific wavelength loop mode can be excited. For example, a resonant mode of 1 / 2 wavelength loop mode can be excited.

[0149] (1) The main antenna 1 is a monopole antenna and the parasitic antenna 2 is a loop antenna.

[0150] As Figure 4 shown, it is a schematic structural diagram of a main antenna 1. One end of the main antenna 1 is fixed on the surface of the main board 3, and the other end is open. The main antenna 1 is a monopole antenna. Then, as described above, the end fixed on the main board 3 is denoted as the starting end, and the open end is denoted as the ending end. The starting end is the feeding point. The position of the strong current point of the main antenna 1 is the starting end, and the position of the weak current point is the ending end.

[0151] As Figure 5 shown, it is a schematic structural diagram of a parasitic antenna 2. Both ends (i.e., the first end and the second end) of the parasitic antenna 2 are fixed on the surface of the main board 3 and are electrically connected to the main board 3 to achieve grounding at both ends. The parasitic antenna 2 is a loop antenna. Then, as described above, the middle position of the parasitic antenna 2 is the position of the weak current point, and the positions of both ends are the positions of the strong current points.

[0152] Therefore, in adjusting the coupling degree between the main antenna 1 and the parasitic antenna 2, the positional relationship between the starting end of the main antenna 1 and the end of the parasitic antenna 2, and the positional relationship between the end of the main antenna 1 and the middle position of the parasitic antenna 2 can be adjusted to meet the antenna after the coupling of the main antenna 1 and the parasitic antenna 2, including multiple resonance modes, so as to broaden the coverage bandwidth of the antenna.

[0153] In one example, the positional relationship between the starting end of the main antenna 1 and the end of the parasitic antenna 2 is adjusted. For example, the distance between the starting end of the main antenna 1 and the end of the parasitic antenna 2 is less than a first value, so that the positions between the starting end of the main antenna 1 and the two ends of the parasitic antenna 2 are relatively close, as shown in Figure 6 For ease of distinguishing the main antenna 1 and the parasitic antenna 2, Figure 6 the solid line in represents the main antenna 1, and the dashed line represents the parasitic antenna 2).

[0154] Similarly, the positional relationship between the end of the main antenna 1 and the middle position of the parasitic antenna 2 is adjusted. For example, the distance between the end of the main antenna 1 and the middle position of the parasitic antenna 2 is less than a second value, so that the end of the main antenna 1 and the middle position of the parasitic antenna 2 are relatively close, as shown in Figure 6 shown.

[0155] Since both the first end and the second end of the parasitic antenna 2 are current strong point positions, the distance between the starting end of the main antenna 1 and the end of the parasitic antenna 2, as shown in Figure 6 can be the distance between the starting end of the main antenna 1 and the first end of the parasitic antenna 2. Of course, it can also be the distance between the starting end of the main antenna 1 and the second end of the parasitic antenna 2, and can also include the distance between the starting end of the main antenna 1 and the first end of the parasitic antenna 2, and the distance between the starting end of the main antenna 1 and the second end of the parasitic antenna 2.

[0156] Among them, the first value and the second value can be determined through simulation results. Moreover, since the resonance frequency bands of the main antenna 1 and the parasitic antenna 2 are different, the values will also be different. For example, if the frequency bands of the resonance frequency points of the main antenna 1 and the parasitic antenna 2 are both low frequency bands (700 MHz to 960 MHz), then the first value can be taken as 8 mm, and the second value can be taken as 35 mm.

[0157] Among them, the above-mentioned distances are all spatial distances in three-dimensional space.

[0158] It should be noted that in order to make the parasitic antenna 2 a loop antenna, the distance between the two ends of the parasitic antenna 2 cannot be too large, usually less than a certain value, for example, less than 25 mm.

[0159] As shown in Figure 6The antenna shown, by adjusting the positional relationship between the starting end of the main antenna 1 and the first end of the parasitic antenna 2, and adjusting the positional relationship between the ending end of the main antenna 1 and the middle position of the parasitic antenna 2, can at least have the current distributions as shown in Figure 2 and as shown in Figure 3 , so as to at least excite the resonant mode of the 1 / 4 wavelength line mode and the resonant mode of the 1 / 2 wavelength loop mode.

[0160] The above is about the layout of the positional relationship between the main antenna 1 and the parasitic antenna 2. Next, the structural characteristics of the main antenna 1, the structural characteristics of the parasitic antenna 2, and the simulation results will be introduced.

[0161] (1) Structural characteristics of the main antenna 1.

[0162] As shown in Figure 4 , the main antenna 1 includes a first radiation arm 11 and a second radiation arm 12. Among them, one end of the first radiation arm 11 is vertically fixed on the surface of the main board 3, and the other end is vertically connected to the second radiation arm 12. That is, the first radiation arm 11 is arranged vertically with respect to the main board 3, while the second radiation arm 12 is arranged horizontally with respect to the main board 3. The main antenna 1 includes a vertical first radiation arm 11 and a horizontal second radiation arm 12, which can compress the vertical dimension of the main antenna 1 to adapt to the height of the shark fin of the vehicle or the height of the roof rack of the vehicle.

[0163] Continuing to refer to Figure 4 , the second radiation arm 12 includes a first inclined branch 121 and a horizontal branch 122. Here, both "inclined" and "horizontal" are with respect to the main board 3. Taking the plane where the main board 3 is located as the horizontal plane, the second radiation arm 12 is designed in this way. On the one hand, it can shorten the horizontal dimension of the main antenna 1 to make the main antenna more compact. On the other hand, it is to adjust the positional relationship between the ending end of the main antenna 1 and the middle position of the parasitic antenna 2 so that the ending end of the main antenna 1 and the middle position of the parasitic antenna 2 are relatively close.

[0164] Continuing to refer to Figure 4 , the first radiation arm 11 includes a first branch 111 and a second branch 112. One end of the first branch 111 is vertically located on the surface of the main board 3, and the other end is connected to one end of the second branch 112. The other end of the second branch 112 is vertically connected to the second radiation arm 12. As shown in Figure 4 , the width of the second branch 112 is greater than the width of the first branch 111.

[0165] As shown in Figure 7As shown, the second branch 112 is relatively wide. Then, there are multiple current paths distributed on the second branch 112. Although the electrical lengths corresponding to these current paths are not very different, there will still be slight differences. Different electrical lengths will excite different resonant frequencies. Then, multiple different electrical lengths will excite multiple resonant frequencies that are close but different, which is conducive to broadening the bandwidth of the antenna.

[0166] Since the second branch 112 is relatively wide, a hollowing design can be carried out on the second branch 112 so that the second branch 112 forms a ring as Figure 8 shown, including a hollow region 1120, and a first branch 1121 and a second branch 1122 located on the left and right sides of the hollow region 1120 respectively.

[0167] As Figure 8 shown, the second branch 112 includes an independent first branch 1121 and a second branch 1122. Then, the current distributed on the first branch 1121 can excite electromagnetic waves of one resonant frequency, and the current distributed on the second branch 1122 can excite electromagnetic waves of another resonant frequency, so that the number of resonant frequencies of the antenna can be increased, and the bandwidth of the antenna can be broadened by increasing the number of resonant frequencies.

[0168] As Figure 9 shown, the main antenna 1 may further include a first matching branch 14. As Figure 9 shown, since the second branch 112 is wider than the first branch 111, there is a certain distance between the second branch 112 and the main board 3. The first matching branch 14 can be located in this distance. For example, the first matching branch 14 is fixed to the main board 3 and is located on one side of the first branch 111, between the second branch 112 and the main board 3.

[0169] In this way, a capacitor can be formed between the mutually close edges of the first matching branch 14 and the first branch 111, and / or between the mutually close edges of the first matching branch 14 and the second branch 112. The formed capacitor can be used to adjust the impedance matching between the antenna and the feeder line, so as to reduce the return loss and improve the radiation efficiency of the antenna.

[0170] For example, this antenna can be a full-frequency antenna, which can receive and transmit electromagnetic waves in the low-frequency band, medium-high frequency band and high-frequency band. The above-mentioned first matching branch 14 can be used to adjust the impedance matching characteristics of the medium-high frequency and reduce the return loss of the medium-high frequency.

[0171] Continue to refer to Figure 9As shown, the main antenna 1 may further include a second matching stub 15. The second matching stub 15 is fixed to the surface of the main board 3, and the second matching stub 15 is located on the side of the first stub 111 opposite to the position of the first matching stub 14. That is, the first stub 111 is located between the first matching stub 14 and the second matching stub 15. As Figure 9 shown, a capacitance can also be formed between the edges of the second matching stub 15 and the first stub 111 that are close to each other. Then, the second matching stub 15 can also be used to adjust the impedance matching characteristics between the main antenna 1 and the feeder.

[0172] In one example, the first matching stub 14 and the second matching stub 15 can be integrally formed. For example, the metal plate where the first matching stub 14 and the second matching stub 15 are located has an opening, and the opening divides the metal plate into the first matching stub 14 and the second matching stub 15. The first stub 111 passes through the opening and is fixed to the surface of the main board 3.

[0173] In another example, the first matching stub 14 and the second matching stub 15 can also be two independent metal plates.

[0174] In one example, the main antenna 1 can adjust the impedance matching characteristics with the feeder through the first matching stub 14, or can adjust the impedance matching characteristics with the feeder through the second matching stub 15, or can also adjust the impedance matching characteristics with the feeder through the first matching stub 14 and the second matching stub 15. This embodiment does not make any limitation in this regard.

[0175] As described above, one end of the first radiation arm 11 is vertically located on the surface of the main board 3, and the other end is vertically connected to one end of the second radiation arm 12. As Figure 10 shown, the main antenna 1 may further include a third radiation arm 13. One end of the third radiation arm 13 is vertically connected to the other end of the second radiation arm 12, and the other end of the third radiation arm 13 is the open end (i.e., the end) of the main antenna 1.

[0176] As Figure 10 shown, the third radiation arm 13 is vertically arranged relative to the main board 3 to further shorten the lateral dimension of the main antenna 1 and further make the main antenna 1 more compact.

[0177] Continuing to refer to Figure 10 shown, the second radiation arm 12 not only includes a first inclined stub 121 and a horizontal stub 122, but may also include a second inclined stub 123, where the first inclined stub 121, the horizontal stub 122, and the second inclined stub 123 are connected in sequence. The structural feature that the second radiation arm 12 includes the first inclined stub 121, the horizontal stub 122, and the second inclined stub 123 connected in sequence can further compress the lateral dimension of the main antenna 1 and further make the structure of the main antenna 1 compact.

[0178] (2) Structural characteristics of parasitic antenna 2.

[0179] As Figure 5 and Figure 11 shown, parasitic antenna 2 is a polygon ring formed by multi-sided connection. Among them, the circular arrangement of parasitic antenna 2 is mainly to adapt to main antenna 1. For example, as Figure 6 and Figure 12 shown, in order to make the width of parasitic antenna 2 equal to or close to the width of main antenna 1, the height of parasitic antenna 2 is equal to or close to the height of main antenna 1. Another example is that in order to make the end of main antenna 1 close to the middle position of parasitic antenna 2. Another example is that in order to make the start end of main antenna 1 close to the first end position of parasitic antenna 2.

[0180] Among them, for the convenience of distinguishing between main antenna 1 and parasitic antenna 2, Figure 12 the solid line in

[0181] In one example, as Figure 11 shown, the width of the second end of parasitic antenna 2 is designed to be widened. The widened design means that the width of the second end is greater than the width at other positions. Such a widened design is similar to loading inductance and can be used to adjust the impedance matching characteristics between the antenna and the feeder and reduce the return loss.

[0182] (3) Figure 12 Simulation results of the antenna shown.

[0183] In one example, the antenna shown in Figure 12 is simulated to obtain the characteristic diagram shown in Figures 13 to 15 shown.

[0184] As Figure 13 shown, it is the return loss characteristic diagram. Figure 13 The ordinate in Figure 13 represents the magnitude of the return loss. 0 dB means the maximum return loss and the worst impedance matching characteristic between the antenna and the feeder. Negative infinity means the minimum return loss and the best impedance matching characteristic between the antenna and the feeder.

[0185] As Figure 13 shown, the return loss of this antenna in the low-frequency bands with band numbers N28, B5, and B8 is less than -5 dB, and the return loss in the mid-high frequency bands with band numbers B3, B34, B39, B40, and B41 is also less than -5 dB. The return loss in the high-frequency band with band number N79 is also less than -5 dB. Therefore, this antenna can achieve 4G and 5G wide-band coverage.

[0186] Among them, the uplink frequency band of N28 is 703 - 748 MHz, and the downlink frequency band is 758 - 803 MHz. The uplink frequency band of B5 is 824 - 849 MHz, and the downlink frequency band is 869 - 894 MHz. The uplink frequency band of B8 is 880 - 915 MHz, and the downlink frequency band is 925 - 960 MHz. The uplink frequency band of B3 is 1710 - 1785 MHz, and the downlink frequency band is 1805 - 1880 MHz. The uplink and downlink frequency bands of B34 are both 2010 - 2025 MHz. The uplink and downlink frequency bands of B39 are both 1880 - 1920 MHz. The uplink and downlink frequency bands of B41 are both 2496 - 2690 MHz. The uplink and downlink frequency bands of N79 are both 4800 - 5000 MHz.

[0187] As Figure 14 shown, it is the antenna radiation efficiency characteristic diagram. Figure 14 The ordinate in it represents the loss situation in radiation efficiency. 0 dB means no loss, corresponding to a radiation efficiency of 1, and -3 dB can correspond to a radiation efficiency of 50%. Negative infinity means the maximum radiation loss and the lowest radiation efficiency. Figure 14 The abscissa in it represents the frequency.

[0188] As Figure 15 shown, it is the system efficiency characteristic diagram. Figure 15 and Figure 14 mean similar things, except that Figure 15 is the efficiency situation of the entire system, including the efficiency caused by echo loss and radiation efficiency. Then, Figure 15 The ordinate in it represents the loss situation in system efficiency. 0 dB means no loss, corresponding to a system efficiency of 1, and -3 dB can correspond to a radiation efficiency of 50%. Negative infinity means the maximum radiation loss and the lowest system efficiency. Figure 15 The abscissa in it represents the frequency.

[0189] As Figure 14 and Figure 15 shown, the in-band radiation efficiency of this antenna in the 5G frequency band is greater than -2 dB.

[0190] Based on, based on Figure 14 and Figure 15 In, the more negative the number on the ordinate, the greater the loss and the lower the efficiency. Then, in the efficiency characteristic diagram, the minimum point corresponds to the radiation zero point. Therefore, as Figure 14 and Figure 15 shown, compared with the traditional antenna without parasitic antennas, the antenna provided in this embodiment has radiation zero points outside the band, and thus has good anti-interference characteristics for different frequencies.

[0191] Among them, the position of the radiation null can be adjusted by adjusting the coupling degree between the main antenna 1 and the parasitic antenna 2. For example, the radiation null can be adjusted to the frequency band of the global navigation satellite system (GNSS) antenna to reduce the interference of the GNSS antenna on the B8 and B3 frequency bands within the 5G frequency band.

[0192] In this way, even if the communication antenna shown in this embodiment is arranged together with the GNSS antenna, the interference of the GNSS antenna on the communication antenna can be reduced.

[0193] Therefore, as Figure 12 shown, the antenna can effectively broaden the frequency band of the antenna and achieve full-band coverage of 4G and 5G. On this basis, the out-of-band suppression ratio can also be improved, and the anti-interference characteristics of different frequencies can be enhanced.

[0194] The above are the structural characteristics and simulation effects of the main antenna 1 being a monopole antenna and the parasitic antenna 2 being a loop antenna. Next, the structural characteristics and simulation effects of the main antenna 1 being a monopole antenna and the parasitic antenna 2 also being a monopole antenna will be introduced.

[0195] (2) The main antenna 1 is a monopole antenna, and the parasitic antenna 2 is also a monopole antenna.

[0196] As Figure 16 shown, it is a schematic structural diagram of a main antenna 1. Referring to the above, the position of the current strong point of the main antenna 1 is the starting end, and the position of the current weak point is the ending end.

[0197] As Figure 17 shown, it is a schematic structural diagram of a parasitic antenna 2. One end of the parasitic antenna 2 is fixed on the surface of the main board 3 and is electrically connected to the main board 3 to be grounded. The other end of the parasitic antenna 2 is open. Since the parasitic antenna 2 is a monopole antenna, then, as described above, the end fixed on the main board 3 is denoted as the starting end, and the open end is denoted as the ending end. The position of the current strong point of the parasitic antenna 2 is the starting end, and the position of the current weak point is the ending end.

[0198] Among them, Figure 16 and Figure 17 the arrows in indicate the distribution of the current on the main antenna 1 at a certain moment. Figure 16 is the current distribution of the main antenna 1 exciting the 1 / 4 wavelength line mode. Figure 17 is the current distribution of the parasitic antenna 2 exciting the 1 / 4 wavelength line mode.

[0199] Therefore, in adjusting the coupling degree between the main antenna 1 and the parasitic antenna 2, the positional relationship between the starting end of the main antenna 1 and the starting end of the parasitic antenna 2 can be adjusted, and the positional relationship between the ending end of the main antenna 1 and the ending end of the parasitic antenna 2 can be adjusted to satisfy that the antenna after the coupling of the main antenna 1 and the parasitic antenna 2 includes multiple resonance modes, so as to broaden the coverage bandwidth of the antenna.

[0200] In one example, the positional relationship between the starting end of the main antenna 1 and the starting end of the parasitic antenna 2 is adjusted. For example, the distance between the starting end of the main antenna 1 and the starting end of the parasitic antenna 2 is less than a third value, so as to make the positions of the starting end of the main antenna 1 and the starting end of the parasitic antenna 2 relatively close, as shown in Figure 18 shown.

[0201] Similarly, the positional relationship between the ending end of the main antenna 1 and the ending end of the parasitic antenna 2 is adjusted. For example, the distance between the ending end of the main antenna 1 and the ending end of the parasitic antenna 2 is less than a fourth value, so as to make the ending end of the main antenna 1 and the ending end of the parasitic antenna 2 relatively close, as shown in Figure 18 shown.

[0202] Among them, the third value and the fourth value can be determined through simulation results. Moreover, since the resonant frequency bands of the main antenna 1 and the parasitic antenna 2 are different, the values of the third value and the fourth value will also be different. For example, if the frequency bands of the resonant frequency points of the main antenna 1 and the parasitic antenna 2 are both in the low-frequency band (700 MHz to 960 MHz), then the third value can be taken as 8 mm and the fourth value can be taken as 25 mm.

[0203] Among them, the above-mentioned distances are all spatial distances in three-dimensional space.

[0204] The above is about the layout of the positional relationship between the main antenna 1 and the parasitic antenna 2. Regarding the structural characteristics of the main antenna 1, since the main antenna 1 described in (2) and the main antenna 1 described in (1) above are both monopole antennas, the structural characteristics of the main antenna 1 described in (2) can refer to those described in (1) above and will not be elaborated here.

[0205] Regarding the structural characteristics of the parasitic antenna 2, as Figure 17 shown, the parasitic antenna 2 also includes a vertical branch and a horizontal branch to match the main antenna 1. The main antenna 1 and the parasitic antenna 2 are matched. For example, as Figure 18 shown, the width of the main antenna 1 is equivalent to the width of the parasitic antenna, the height of the main antenna 1 is equivalent to the height of the parasitic antenna 2, the starting end of the main antenna 1 is close to the starting end of the parasitic antenna, and the ending end of the main antenna 1 is close to the ending end of the parasitic antenna.

[0206] As Figure 18 shown in the antenna, after the main antenna 1 and the parasitic antenna 2 are coupled to each other, it can generate asFigures 19 to 21 The current distribution shown. Among them, Figure 19 (a) in it is the front view, and (b) is the top view. As shown in Figure 19 (b) in it, the current directions on the main antenna 1 and the parasitic antenna 2 are the same, and the two are in a superimposed relationship. As shown in Figure 19 (a) of it, the currents distributed on the first ground plane 31 and the second ground plane 32 of the main board 3 are also in the same direction. Then, Figure 19 The current distribution shown, the excited resonance mode belongs to the effective resonance mode generated by electromagnetic coupling. This resonance mode can be denoted as the resonance mode 1 of the antenna, and the corresponding resonance point is denoted as resonance point 1.

[0207] Among them, Figure 20 (a) in it is the front view, and (b) is the top view. As shown in Figure 20 (b) in it, the current directions on the main antenna 1 and the parasitic antenna 2 are the same, and the two are in a superimposed relationship. As shown in Figure 20 (a) of it, the currents distributed on the first ground plane 31 and the second ground plane 32 of the main board 3 are also in the same direction. Then, Figure 20 The current distribution shown, the excited resonance mode belongs to the effective resonance mode generated by electromagnetic coupling. This resonance mode can be denoted as the resonance mode 2 of the antenna, and the corresponding resonance point is denoted as resonance point 2.

[0208] Among them, Figure 21 (a) in it is the front view, and (b) is the top view. As shown in Figure 21 (b) in it, the current directions on the main antenna 1 and the parasitic antenna 2 are opposite, and the two are in a canceling relationship. As shown in Figure 21 (a) of it, the currents distributed on the first ground plane 31 and the second ground plane 32 of the main board 3 are also in the opposite direction. Then, Figure 21 The current distribution shown, the excited resonance mode has low radiation efficiency and belongs to the ineffective resonance mode generated by electromagnetic coupling. This resonance mode can be denoted as the resonance mode 3 of the antenna, and the corresponding resonance point is denoted as resonance point 3.

[0209] In one example, the resonance mode 3 can be eliminated by grounding the main antenna 1 and the parasitic antenna 2 together. Grounding the main antenna 1 and the parasitic antenna 2 together means that the outer conductor of the feeder connected to the main antenna 1 is grounded together with the parasitic antenna 2. The grounding scheme is as described above and will not be elaborated here.

[0210] In one example, if the resonance point 3 corresponding to the resonance mode 3 is relatively close to the resonance point 2 corresponding to the resonance mode 2, then, after eliminating the invalid resonance mode 3, the decreasing rate of the radiation loss of the resonance mode 2 can still be reduced. This is because the resonance mode 3 is an invalid resonance, and the radiation loss at the resonance point 3 is relatively large. In the radiation efficiency characteristic diagram, the resonance point 3 corresponds to a minimum point. If the resonance mode 3 is not eliminated, then in the radiation efficiency characteristic diagram, the radiation loss rapidly decreases from the resonance point 2 to the resonance point 3. Then, the radiation efficiency of the antenna rapidly decreases from the resonance point 2 to the resonance point 3. However, if the resonance mode 3 is eliminated, then since in the radiation efficiency characteristic diagram, the resonance point 3 does not correspond to the minimum point, then the radiation loss will not rapidly decrease from the resonance point 2 to the resonance point 3. Therefore, eliminating the invalid resonance mode 3 can reduce the decreasing rate of the radiation loss of the resonance mode 2.

[0211] It should be noted that, for the antenna as Figure 12 shown, the current distributions on the main antenna 1 and the parasitic antenna 2 can also excite multiple resonance modes. Among these multiple resonance modes, there will also be invalid resonance modes. Then, the invalid resonance modes can also be eliminated by grounding the main antenna 1 and the parasitic antenna 2 together.

[0212] Next, the simulation results of the antenna as Figure 18 shown will be introduced.

[0213] In one example, the antenna as Figure 18 shown is simulated to obtain the characteristic diagrams as Figure 22 and Figure 23 shown.

[0214] As Figure 22 shown, it is the return loss characteristic diagram. Figure 22 In , the ordinate represents the magnitude of the return loss. 0 dB indicates the maximum return loss and the worst impedance matching characteristic between the antenna and the feeder. Negative infinity indicates the minimum return loss and the best impedance matching characteristic between the antenna and the feeder. Figure 22 The abscissa in represents the frequency.

[0215] According to Figure 22 , the more negative the number on the ordinate, the smaller the return loss. Then, in the return loss characteristic diagram, the minimum point corresponds to a resonance point. Therefore, as Figure 22 shown, compared with the traditional antenna without a parasitic antenna, the antenna provided in this embodiment includes two resonance points. Therefore, the bandwidth of the antenna can be broadened. Among them, the positions of these two resonance points can be adjusted by adjusting the coupling strength between the main antenna 1 and the parasitic antenna 2.

[0216] As Figure 23 shown, it is the efficiency characteristic diagram. Figure 23 ​The vertical coordinate in it represents the loss situation of efficiency. 0 dB means no loss, corresponding to an efficiency of 1, and -3 dB can correspond to an efficiency of 50%. Negative infinity means the maximum loss and the lowest efficiency. Figure 23 The horizontal coordinate in it represents the frequency. Figure 23 The dotted line in it represents the relationship between the radiation efficiency and the frequency, and the solid line represents the relationship between the system efficiency and the frequency.

[0217] According to Figure 23 in it, the more negative the number on the vertical coordinate, the greater the loss and the lower the efficiency. Then, in the efficiency characteristic diagram, the minimum point corresponds to the radiation zero point. Therefore, as Figure 23 shown, compared with the traditional antenna without a parasitic antenna, the antenna provided in this embodiment has a radiation zero point outside the band ( Figure 23 the minimum point in it is the radiation zero point), and thus has good anti-interference characteristics for different frequencies.

[0218] Among them, the antenna including a parasitic antenna, that is, the antenna provided in this embodiment, and the antenna without a parasitic antenna can be a traditional antenna with only a main antenna and no parasitic antenna.

[0219] Among them, the position of the radiation zero point can be adjusted by adjusting the coupling degree between the main antenna 1 and the parasitic antenna 2. For example, the radiation zero point can be adjusted to the frequency band of the global navigation satellite system (GNSS) antenna to reduce the interference of the GNSS antenna on the B8 band and the B3 band within the 5G frequency band.

[0220] In this way, even if the communication antenna shown in this embodiment is arranged together with the GNSS antenna, the interference of the GNSS antenna on the communication antenna can be reduced.

[0221] Therefore, as Figure 18 shown, the antenna can effectively broaden the frequency band of the antenna and achieve full-band coverage of 4G and 5G. On this basis, the out-of-band suppression can also be improved, and the anti-interference characteristics for different frequencies can be enhanced.

[0222] In the embodiment of the present disclosure, the antenna includes a main antenna and a parasitic antenna. The main antenna and the parasitic antenna are arranged relatively. Among them, the excitation signal of the main antenna is introduced by a feeder line, and the excitation signal of the parasitic antenna is introduced by coupling with the electromagnetic field of the main antenna. The main antenna and the parasitic antenna are mutually coupled and can broaden the bandwidth of the antenna. Then, when the antenna is applied in an automobile as a communication antenna of the automobile, such as a 4G communication antenna or a 5G communication antenna, it can achieve 4G or 5G wide-bandwidth coverage, or even full-bandwidth coverage.

[0223] In addition, the antenna can also improve the out-of-band suppression and enhance the anti-interference characteristics of different frequencies. For example, the antenna can improve the out-of-band suppression of the GNSS antenna, so that even if the GNSS antenna and the antenna described in this embodiment are arranged together, such as both arranged in the shark fin or both arranged in the luggage rack, the interference of the GNSS antenna to the antenna described in this embodiment can be reduced.

[0224] The embodiment of the present disclosure also provides an antenna system, which includes a radio frequency circuit and the antenna described above. Among them, the radio frequency circuit is used to enable the antenna to transmit and receive wireless signals.

[0225] The embodiment of the present disclosure also provides a vehicle, which includes the antenna system described above.

[0226] Regarding the arrangement position of the antenna in the antenna system in the vehicle.

[0227] In one example, the antenna of the antenna system can be arranged in the luggage rack of the vehicle. For example, the vehicle includes a left luggage rack on the left side of the vehicle body and a right luggage rack on the right side of the vehicle body. The antenna can be arranged in the left luggage rack, or can be arranged in the right luggage rack, or it can be that both the left luggage rack and the right luggage rack are arranged with antennas.

[0228] For example, as Figure 24 shown, the antenna architecture arranged in the luggage rack is a 4×4 multiple-in multiple-out (MIMO) system, including two 5G full-frequency antennas and two 5G mid-high frequency antennas. These four antennas are respectively denoted as full-frequency antenna A, full-frequency antenna B, mid-high frequency antenna C, and mid-high frequency antenna D. Because the size of the full-frequency antenna is relatively large, so, full-frequency antenna A and full-frequency antenna B are located at a higher position in the cross-section of the luggage rack, and high-frequency antenna C and mid-high frequency antenna D are located at a lower position in the cross-section of the luggage rack.

[0229] Among them, full-frequency antenna A and full-frequency antenna B can adopt the antenna provided by this embodiment. For example, it can adopt the antenna as Figure 12 shown.

[0230] As Figure 25 shown, the main board a of full-frequency antenna A, the main board b of full-frequency antenna B, the main board c of mid-high frequency antenna C, and the main board d of mid-high frequency antenna D are all fixed on the surface of the metal base of the luggage rack.

[0231] In one example, components such as a feeding coplanar waveguide transmission line, series bit matching devices, parallel bit matching devices, and series bit detection resistors are printed on the above-mentioned main board. The excitation signal of the above-mentioned antenna is fed in through a mini-fakra four-in-one connector, then transmitted to the above-mentioned four main boards through the vehicle body wiring harness, and finally the excitation signal is transmitted to the above-mentioned four antennas by the coplanar waveguide transmission lines on each main board, and then the four antennas radiate electromagnetic waves into free space.

[0232] Of course, in another example, the antenna can also be arranged in the shark fin of the car. For example, the above-mentioned four antennas are all arranged in the shark fin.

[0233] Regarding the radio frequency circuit in the antenna system, its layout position in the car.

[0234] In one example, the radio frequency circuit of the antenna system can be arranged in the vehicle's telematics box (T-BOX).

[0235] In order to reduce the path loss of the radio frequency signal on the transmission path, correspondingly, the T-BOX where the radio frequency circuit is located and the antenna position are as close as possible. For example, the T-BOX is located in the back seat of the car and close to the tail of the tire, and the antenna is located in the luggage rack of the car. Then, the luggage rack where the antenna is located and the T-BOX are on the same side of the vehicle body.

[0236] As an example, the antenna is located in the right luggage rack on the right side of the vehicle body, and the T-BOX where the radio frequency circuit is located is in the back seat on the right side of the vehicle body and close to the tail of the tire.

[0237] In this way, when the vehicle supplies power to the T-BOX, the radio frequency signal generated by the radio frequency circuit in the T-BOX is transmitted to the main board on the roof through the signal cable, thereby exciting the antenna and radiating the modulated signal into free space. For the receiving link, vice versa.

[0238] The T-BOX is located in the back seat of the car and close to the tail of the tire, and moreover, the luggage rack where the antenna is located and the T-BOX are on the same side of the vehicle body, making the spatial distance between the antenna and the T-BOX close. Then, the harness of the signal cable is short, which can effectively reduce the link loss caused by the cable, thereby improving the system efficiency of the vehicle antenna.

[0239] In addition, the antenna is hidden in the luggage rack structure. The outer shell of the luggage rack is formed by casting, and a rubber pad with waterproof characteristics is provided between the outer shell and the metal seat at the top of the vehicle body, thus ensuring the concealment and reliability of the vehicle antenna.

[0240] The above is only one embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present disclosure shall be included within the protection scope of the present disclosure.

Claims

1. An antenna, characterized in that, the antenna includes a main antenna (1), a parasitic antenna (2), a main board (3) and a dielectric board; the dielectric board is vertically located on the surface of the main board (3), the main antenna (1) is located on the first surface of the dielectric board, the parasitic antenna (2) is located on the second surface of the dielectric board, the plane where the main antenna (1) is located and the plane where the parasitic antenna (2) is located are parallel, wherein the first surface and the second surface are opposite in position; the main antenna (1) is a monopole antenna, including a first radiation arm (11) perpendicular to the main board (3), the first radiation arm (11) includes a connected first branch (111) and a second branch (112), the width of the second branch (112) is greater than the width of the first branch (111), the end of the first branch (111) serves as a feeding point and is connected to the feeding transmission line of the main board (3); the main antenna (1) further includes a first matching branch (14), the first matching branch (14) is fixed on the surface of the main board (3), and within the area enclosed by the first branch (111), the second branch (112) and the main board (3), between the mutually approaching edges of the first matching branch (14) and the first branch (111), and / or between the mutually approaching edges of the first matching branch (14) and the second branch (112), are all used to form a capacitance; the parasitic antenna (2) is a loop antenna, and both ends of the parasitic antenna (2) are connected to the second grounding end of the main board (3); wherein, the difference between the resonant frequency point of the main antenna (1) and the resonant frequency point of the parasitic antenna (2) is less than a target threshold.

2. The antenna according to claim 1, characterized in that, the feeding point of the main antenna (1) is connected to the inner conductor of the feeding transmission line of the main board (3), the outer conductor of the feeding transmission line is connected to the first grounding end of the main board (3), and the first grounding end and the second grounding end are common ground.

3. The antenna according to claim 1, characterized in that, the starting end of the main antenna (1) is the feeding point, the distance between the starting end of the main antenna (1) and the end of the parasitic antenna (2) is less than a first value, and the distance between the end of the main antenna (1) and the middle position of the parasitic antenna (2) is less than a second value.

4. The antenna according to claim 1, characterized in that, the second branch (112) includes a first branch (1121) and a second branch (1122), and the first branch (1121) and the second branch (1122) are arranged side by side along the width direction of the second branch (112); one end of the first branch (1121) is connected to one end of the second branch (1122), and the other end of the first branch (1121) and the other end of the second branch (1122) are both connected to the first branch (111).

5. The antenna according to any one of claims 1 to 4, characterized in that, The main antenna (1) further includes a second radiation arm (12) and a third radiation arm (13); The first radiation arm (11) is perpendicularly connected to the second radiation arm (12), the second radiation arm (12) is perpendicularly connected to the third radiation arm (13), and the end of the third radiation arm (13) points to the main board (3).

6. The antenna according to any one of claims 1 to 4, characterized in that the total height of the main antenna (1) is equal to the total height of the parasitic antenna (2), and the total width of the main antenna (1) is equal to the total width of the parasitic antenna (2).

7. An antenna system, characterized in that the antenna system includes a radio frequency circuit and the antenna according to any one of claims 1 to 6, and the radio frequency circuit is used to enable the antenna to transmit and receive wireless signals.

8. A vehicle, characterized in that the vehicle includes the antenna system according to claim 7.

9. The vehicle according to claim 8, characterized in that the antenna is located in the luggage rack of the vehicle.

10. The vehicle according to claim 9, characterized in that the radio frequency circuit is arranged in the telematics box (T-BOX) of the vehicle, the T-BOX is located in the back seat of the vehicle and close to the tail of the tire, and the luggage rack where the antenna is located and the T-BOX are on the same side of the vehicle body.

11. The vehicle according to claim 8, characterized in that the antenna is located in the shark fin of the vehicle.

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