CN102195123A - Secondary beamforming high-power circularly polarized base station antenna - Google Patents

Abstract

The invention discloses a high-power circularly polarized base station antenna with secondary beamforming, which includes two sets of base station communication antenna combinations, symmetrically arranged, and the base station communication antennas can work at two required frequencies; each pair of base station communication antennas It includes a millimeter-wave conical horn antenna, a transition device from a square waveguide to a circular waveguide, a shaped reflector and a printed grid. The transition device from a square waveguide to a circular waveguide is located under the millimeter-wave conical horn antenna, and the two are connected to each other; each Each of the millimeter-wave conical horn antennas is provided with a shaped reflector, and the printed grid is arranged on the lower end surface of the shaped reflector, and also includes a shaped lens arranged in front of the shaped reflector, and is connected with the shaped reflector. Forming an angle of 45°±2o, the shaped reflector forms an angle of 45o±2o with the horizontal plane. Therefore, the structure of the high-power circularly polarized base station antenna is simpler and more flexible, the work is stable and reliable, and it can realize the secondary shaping of the electromagnetic wave and meet the requirements of flexible control of the beam shape.

Description

High Power Circularly Polarized Base Station Antenna with Quadratic Beamforming

technical field

The invention relates to a base station antenna, in particular to a secondary beam-forming high-power circularly polarized base station antenna.

Background technique

The vehicle-to-ground communication system of high-speed railway is a large-capacity high-speed communication system proposed in recent years, which is mainly aimed at the short-term large-capacity data transmission of high-speed trains during operation and ground communication. Specific to the communication terminal antenna, the antenna is required to have high efficiency, high power, high gain, and the most important thing is to have a high directivity, especially for the communication system of the maglev train, so that it will not be caused by the maglev train The electromagnetic field itself causes great interference to the communication system. Antenna array is a feasible antenna form to ensure that the antenna has high directivity, but a large number of antenna elements will inevitably lead to an increase in the volume and weight of the antenna array; although a small antenna microstrip array can ensure the size and weight of the antenna array, However, its power and efficiency cannot be effectively improved.

Regarding the above technology, the patent 200710093945.2 "Millimeter-wave communication antenna for base station integrating shaping and variable polarization" proposes the concept of using a reflectarray antenna to shape and polarize the beam emitted from the conical horn, effectively solving the problem of beam polarity. problem of sizing, shaping and requiring high power from the antenna. However, the antenna structure proposed in this patent has limitations on the degree of beam forming. The beam forming mainly comes from two aspects. One is the shaping effect of the reflection array on the reflector on the waveform emitted from the conical horn, and the other is It is the compression effect of the arc shape of the reflector itself on the single direction of the beam. This deficiency in antenna beam forming makes the final beam shape of the outgoing beam fail to fully meet the different requirements of the vertical beam for high-speed train (especially maglev train) communication in different geographical environments.

Contents of the invention

The purpose of the present invention is to provide a high-power circularly polarized base station antenna with secondary beamforming, which can effectively avoid electromagnetic field interference from maglev high-speed trains, has a simpler and more flexible structure, works stably and reliably, and is more precise and flexible in beam width design, enabling flexible control beam shape requirements.

In order to achieve the above object, the present invention is achieved through the following technical solutions:

A high-power circularly polarized base station antenna with secondary beamforming is characterized in that it includes a first group of base station communication antenna combinations and a second group of base station communication antenna combinations, and the two groups of base station communication antenna combinations are arranged symmetrically; the described Each base station communication antenna combination includes several base station communication antennas with the same secondary structure, and each base station communication antenna can work on the two required frequencies;

Each of the base station communication antennas includes a millimeter-wave conical horn antenna, a transition device from a square waveguide to a circular waveguide, a shaped reflector and a printed grid; wherein,

The square waveguide-to-circular waveguide transition device is arranged below the millimeter-wave conical horn antenna, and the square waveguide-to-circular waveguide transition device is connected to the millimeter-wave conical horn antenna;

A shaped reflector is correspondingly provided above the millimeter-wave conical horn antenna;

The printed grid strips are arranged on the lower surface of the shaped reflector;

The base station communication antenna also includes a shaped lens for secondary shaping, which is arranged in front of the shaped reflector, and the electromagnetic wave emitted from the millimeter-wave conical horn antenna is refracted by the shaped reflector and then incident horizontally forward Shaped lenses.

The surface of the shaped lens facing the shaped reflection plate is convex.

The surface of the shaped lens facing the shaped reflection plate is concave.

The shaped reflecting plate has an inclination angle of 45°±2° with the horizontal plane.

The printed grid bars arranged on the shaped reflector in the first group of base station communication antenna combinations are obliquely orthogonal to the printed grid bars in the second group of base station communication antenna combinations.

The shaped lens forms an inclination angle of 45°±2° with the shaped reflector.

Compared with the prior art, the high-power circularly polarized base station antenna with secondary beamforming of the present invention has the following advantages:

Due to the adoption of a shaped lens of a certain specification, the present invention can perform second beam forming on the outgoing wave emitted from the shaped reflector, and the shaped lens and the shaped reflector form an included angle of 45°±2o, opposite poles There is no influence on the polarization, not only can maintain a certain width of the outgoing wave in the horizontal direction, but also realize its extremely narrow beam in the vertical direction, so as to meet the technical requirements of forming a 38GHz base station communication antenna with fan-shaped beam and circular polarization characteristics. This makes the structure of the high-power circularly polarized base station antenna with secondary beamforming of the present invention simpler and more flexible, can effectively avoid the interference of the electromagnetic field of the maglev high-speed train, works stably and reliably, and can meet the requirements of flexible control of the beam shape, making it completely To meet the different requirements of vertical surface beams for communication of high-speed trains (especially maglev trains) in different geographical environments.

Description of drawings

Fig. 1 is the three-dimensional view of the high-power circularly polarized base station antenna of secondary beamforming of the present invention;

Fig. 2 is a schematic front view of the structure of the high-power circularly polarized base station antenna with secondary beamforming of the present invention;

Fig. 3 is a schematic left view of the structure of a high-power circularly polarized base station antenna with secondary beamforming according to the present invention;

Fig. 4 is a right view schematic diagram of the structure of the high-power circularly polarized base station antenna with secondary beamforming according to the present invention;

5 is a schematic structural diagram of a shaped reflector of a high-power circularly polarized base station antenna with secondary beamforming according to the present invention;

Fig. 6 is an antenna pattern in which the lens surface is convex in the high-power circularly polarized base station antenna with secondary beamforming according to the present invention;

Fig. 7 is a diagram of the antenna pattern in which the lens surface is concave in the high-power circularly polarized base station antenna with secondary beamforming according to the present invention.

Detailed ways

The present invention will be further elaborated below in combination with specific embodiments.

Please refer to Figure 1 and Figure 2, according to the requirements of the vehicle-ground wireless communication antenna system, the base station communication antenna (that is, the ground base station antenna) is erected on the antenna poles along the track at an appropriate height, and each antenna pole The communication antenna of the base station should be able to satisfy the communication of A and B communication networks at the same time. Each communication network requires two antennas for transmitting and receiving that work on two frequencies respectively.

Therefore, for the sake of versatility, the high-power circularly polarized base station antenna for secondary beamforming of the present invention includes a first group of base station communication antenna combinations and a second group of base station communication antenna combinations, and the two groups of base station communication antenna combinations are arranged symmetrically; each The base station communication antenna combination includes several base station communication antennas with the same secondary structure, and each base station communication antenna can work on the two required frequencies;

Each base station communication antenna includes a millimeter-wave conical horn antenna 2 , a square waveguide-to-circular waveguide transition device 1 , a shaped reflector 3 , a printed grating 4 and a shaped lens 5 .

Wherein, the transition device 1 from the square waveguide to the circular waveguide is arranged under the millimeter-wave conical horn antenna 2, and is connected to the millimeter-wave conical horn antenna 2; the millimeter-wave conical horn antenna 2 adopts a conical horn antenna with an appropriate opening angle and diameter, Make its primary field pattern wider without cracking.

Each millimeter-wave conical horn antenna 2 is provided with a shaped reflector 3 correspondingly, as shown in Figure 5, the shaped reflector 3 is made of a dielectric material, and it forms an inclination angle of 45°±2° with the ground , which can ensure that the outgoing wave emitted from the shaped reflector 3 maintains a horizontal direction; in order to meet the index requirements of the radiation lobe width of the communication antenna pattern of the base station (that is, the lobe is wide in the azimuth plane and the lobe in the vertical plane is narrow), the given The lower end surface of the shaped reflector 3 is a concave arc surface, and the printed grid bar 4 is arranged on the arc surface. Therefore, when the azimuth plane of the millimeter-wave conical horn antenna 1 is kept constant, the vertical plane The beam is narrowed to complete the first shaping of the beam, and the beam is transformed from linear polarization to circular polarization, which realizes the combination of beam forming and variable polarization, and at the same time changes the direction of beam emission from upward to It shoots forward and horizontally; the advantages of using circularly polarized beams are: (1) The anti-interference ability is stronger than that of linear polarization; (2) Installing circularly polarized antennas on violently swinging or rolling motor vehicles can be used in any state Receive information; (3) The use of circularly polarized antennas in television broadcasting or communications with image transmission can overcome ghosting.

Please refer to Fig. 3 and Fig. 4, combined with Fig. 2, Fig. 3 represents the view of the printed grating 4 of the shaped reflector 3 on the left side in Fig. 2, and Fig. 4 represents the view on the right side in Fig. 2 The view of the printed grid bars 4 of the shaped reflector 3 shows that the printed grid bars 4 of the shaped reflector 3 on the left and right sides are obliquely orthogonal, while the two groups of base station communication antennas have opposite rotations (respectively left-handed circles polarization and right-hand circular polarization), so that the two polarizations are isolated from each other, which can effectively overcome the mutual influence. The direction of rotation of the antenna facing the base station communication antenna and the vehicle communication antenna must be the same.

Please refer to Fig. 1 and Fig. 2, in different environments, the requirements for the beam of the communication antenna are completely different, in order to meet the versatility under different beam requirements, a shaped lens 5 is adopted, the shaped lens 5 is perpendicular to the horizontal plane, and is arranged in front of the shaped reflector 3, and forms an inclination angle of 45°±2o with the shaped reflector 3, and the electromagnetic waves emitted from the millimeter-wave conical horn antenna are refracted by the shaped reflector and projected forward horizontally Into the shaped lens, the height of the center of the shaped lens 5 is equal to the center position of the main lobe of the outgoing beam, and the distance from the center of the millimeter-wave conical horn antenna 1 in the horizontal distance is about 11 times the wavelength λ. Therefore, the The shaped lens 5 can perform secondary shaping on the waves exiting from the shaped reflector 3, so as to realize different beam widths required in the design requirements.

Please refer to Fig. 6 and Fig. 7, the effect of shaping lens 5 on beam shaping depends on different curvatures. If it is a lens with a convex surface, it will have a converging effect on the beam, obtained after the second shaping The fan beam pattern is shown in Figure 6. At this time, the curve of the shaped lens 5 is regulated by the curve equation y ² =-2×p×z, where p is a constant; otherwise, if the lens surface is concave, then For the divergence of the beam, the fan-shaped beam pattern obtained after the second shaping is shown in Figure 7. At this time, the curve of the shaping lens 5 is standardized by the curve equation z ² /2-y ² /2=1 . Different beams have different shaping requirements, so the curvature of the shaping lens 5 will be adjusted accordingly.

The material of the shaped lens 5 is polytetrafluoroethylene, which is a common dielectric material and has the advantages of low loss of transmitted waves and low price. The shaping lens 5 made of this material can realize the shaping requirements of the beam on the one hand, and secondly, because the dielectric constant of the material is small, the loss of the projected wave generated after shaping is also relatively small, which helps to reduce the Minor system loss.

To sum up, the high-power circularly polarized base station antenna with secondary beamforming provided by the present invention can effectively avoid the electromagnetic field interference of maglev high-speed trains, the design of beam width is more accurate and flexible, the structure is simpler and more flexible, and the work is stable and reliable. Fully meet the different requirements of vertical surface beams for communication of high-speed trains (especially maglev trains) in different geographical environments.

Although the content of the present invention has been described in detail through the above preferred embodiments, it should be understood that the above description should not be considered as limiting the present invention. Various modifications and alterations to the present invention will become apparent to those skilled in the art upon reading the above disclosure. Therefore, the protection scope of the present invention should be defined by the appended claims.

Claims (7)

1. A high-power circularly polarized base station antenna with secondary beamforming, characterized in that, It includes a first group of base station communication antenna combinations and a second group of base station communication antenna combinations, and the two groups of base station communication antenna combinations are arranged symmetrically; each group of base station communication antenna combinations includes several base station communication antennas with identical secondary structures, and each base station Both communication antennas can work on the two required frequencies; Each base station communication antenna includes a millimeter-wave conical horn antenna (2), a square waveguide to circular waveguide transition device (1), a shaped reflector (3) and a printed grid (4); wherein, The square waveguide-to-circular waveguide transition device (1) is arranged below the millimeter wave conical horn antenna (2), and the square waveguide to circular waveguide transition device (1) is connected to the millimeter wave conical horn antenna (2); A shaped reflector (3) is correspondingly provided above the millimeter-wave conical horn antenna (2); The printed grid (4) is arranged on the lower end surface of the shaped reflector (3); The base station communication antenna also includes a shaped lens (5) for secondary shaping, which is arranged in front of the shaped reflector (3), and the electromagnetic waves emitted from the millimeter-wave conical horn antenna (2) are shaped After being refracted by the reflective plate, it enters the shaping lens (5) horizontally forward. 2. The secondary beamforming high-power circularly polarized base station antenna according to claim 1, characterized in that the material of the shaped lens (5) is polytetrafluoroethylene. 3. The secondary beamforming high-power circularly polarized base station antenna according to claim 1, characterized in that the surface of the shaped lens (5) facing the shaped reflector (3) is convex . 4. The secondary beamforming high-power circularly polarized base station antenna according to claim 1, characterized in that the surface of the shaped lens (5) facing the shaped reflector (3) is concave. 5. The high-power circularly polarized base station antenna with secondary beamforming according to claim 1, characterized in that, the shaped reflector (3) forms an inclination angle of 45°±2° with the horizontal plane. 6. The high-power circularly polarized base station antenna with secondary beamforming according to claim 1, characterized in that, in the first group of base station communication antenna combinations, the printing plate set on the shaped reflector (3) The printed grid bars (4) are obliquely orthogonal to the printed grid bars (4) in the second group of base station communication antenna combinations. 7. The high-power circularly polarized base station antenna with secondary beamforming according to claim 1, characterized in that the angle between the shaped lens (5) and the shaped reflector (3) is 45°±2° inclination.

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