CN110943292A - Compound low-loss antenna cover - Google Patents

Abstract

The invention discloses a composite low-loss radome, which comprises a radome body and is characterized in that the radome body is formed by splicing a curved surface profile and a plane sheet profile with low dielectric constant and stable shape. According to the invention, a new material and a new process do not need to be developed, a mature processing process is utilized to assemble the basic frame section bar with stable mechanical characteristics and capable of being processed by a curved surface and the filling plate with low dielectric constant and difficult deformation, the advantages are made up for the disadvantages, the limitation of conventional materials and the processing process is broken through, the novel composite antenna housing with excellent mechanical properties, low loss and cost advantage is designed and manufactured, and a low-cost antenna housing solution which is convenient for batch production is provided for the 5G era high-performance base station antenna.

Description

Compound low-loss antenna cover

Technical Field

The invention relates to the field of low wind load antenna housing and plastic section processing, in particular to a composite low-loss antenna housing which is realized by assembling more than two materials by utilizing a conventional processing technology.

Background

For a base station antenna erected outdoors, the radome plays an essential role in providing protection for an antenna radiation unit and a feed network, enhancing electrical isolation, reducing the influence of the external environment on a radiation pattern, standing waves, isolation, passive intermodulation and the like, and has already become an important component of the base station antenna. To achieve the above functions better, generally, the radome needs to have the following characteristics: 1) the antenna has high impact toughness, and provides sufficient protection for the antenna; 2) the sealing performance is good, and the waterproof/anti-seepage capability is strong; 3) the deformation coefficient is low under the ambient temperature (-50 degrees to +70 degrees) and the dry and wet conditions (0-95 percent of humidity); 4) the weather resistance is good, the aging resistance is good, and the service life is long; 5) the curved surface structure meeting the requirement of low wind load can be processed by utilizing common die pressing and pultrusion processes; 6) the antenna has high wave-transmitting rate, low loss and small influence on antenna gain and radiation patterns; 7) the cost is low, the consistency of batch production is good, and the industrial acceptance is high; 8) low density, light weight, and convenient transportation and installation.

However, to date, few radomes exist in the industry that can simultaneously meet the above conditions. Taking the most widely used glass fiber reinforced plastic radome and PVC radome as examples, the former has superior mechanical properties such as high strength, water/leakage resistance, no deformation, aging resistance, good processability, etc., however, the glass fiber reinforced plastic radome has a high dielectric constant (the relative dielectric constant is greater than 3.5), the reflection of electromagnetic waves at the cover body-air interface is large, and the problems of gain reduction and radiation pattern distortion are easily caused for multi-frequency antennas, especially for high-low frequency nested antennas. Although the PVC material can realize lower dielectric constant by adjusting the formula and reduce the influence on gain and a directional diagram, the PVC material is easy to deform and seriously shrinks under a low-temperature environment, thereby limiting the use of the PVC material in cold regions. Some novel composite materials, such as: although the glass fiber/carbon fiber reinforced modified PC and the glass fiber reinforced modified ASA realize basically no deformation and lower dielectric constant and simultaneously meet the requirements of mechanical property and electrical property, the glass fiber/carbon fiber reinforced modified PC and the glass fiber reinforced modified ASA have high cost and are difficult to popularize due to complex processing technology and high technical threshold. The novel foaming material, such as polypropylene microporous foaming Material (MPP), has excellent mechanical properties of high strength, no deformation and aging resistance and a relative dielectric constant close to 1, but has poor plasticity, and can only be used as a planar sheet material and is difficult to process a curved surface required by low wind load. The defects limit the popularization of the new material in the antenna industry.

The arrival of 5G accelerates the miniaturization of the base station antenna and the iteration of a multi-frequency/multi-system integration technology, and the latter provides more urgent requirements for the antenna housing which has the relative dielectric constant close to 1, high transmission/low loss, reliable mechanical performance and low cost; on the other hand, the selection of a radome is severely limited by cost and processability/producibility.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the composite low-loss radome which can be realized by adopting a common die pressing process and common materials, thereby providing a low-cost radome solution which is convenient for batch production for a 5G era high-performance base station antenna.

In order to achieve the purpose, the invention adopts the following technical scheme.

The composite low-loss radome comprises a radome body and is characterized in that the radome body is formed by splicing a curved surface profile and a planar sheet profile with low dielectric constant and stable shape.

More preferably, the curved-surface profile is a glass fiber reinforced plastic profile.

More preferably, the planar sheet-like shape is an MMP foamed plate.

More preferably, an opening is reserved on the curved section bar, an assembly groove is arranged on the opening, and the planar sheet section bar is inserted into the assembly groove and sealed and fixed through an adhesive.

More preferably, the assembly groove and the curved profile are of an integrally formed structure.

More preferably, the adhesive is a resin adhesive or a silicone adhesive.

More preferably, the cover body is formed by splicing a curved section bar and a planar sheet section bar, the curved section bar is in a cuboid shape with two ends and a top opening, four corners of the cuboid are in smooth transition through curved surfaces, and the planar sheet section bar is sealed on the top opening.

More preferably, the cover body is a cuboid structure formed by splicing four curved surface sectional materials and four plane sheet-shaped sectional materials together, the four curved surface sectional materials serve as four edges of the cuboid, and the four plane sheet-shaped sectional materials serve as four side surfaces of the cuboid.

More preferably, the composite low-loss radome is applied to a base station antenna.

More preferably, the base station antenna is a base station antenna of a high-low frequency nested array.

The invention has the beneficial effects that:

with the acceleration of miniaturization and multi-frequency/multi-standard integration technology iteration, the size of the antenna is smaller and smaller, and the number of integrated arrays is increased continuously. The high-low frequency nested and coplanar interpenetration layout enables the space between the radiation units to be reduced to a strong coupling area, the crosstalk between the arrays, the electromagnetic coupling between the radiation units which are mutually bound, secondary radiation and scattering clutter, and the reflection echo from the antenna cover enable the base station antenna in the 5G era to become the most complex antenna feeder system in the history of wireless communication, and the design of the antenna feeder system becomes difficult and serious when the most severe wave beam forming requirement and directional diagram technical index are faced.

According to the antenna housing provided by the invention, the curved surface section bar and the plane sheet-shaped section bar with low dielectric constant and stable shape are spliced and assembled together through a mature processing technology, the advantages and the disadvantages are made up, the limitation of conventional materials and the processing technology is broken through, a novel composite antenna housing with excellent mechanical property, low loss and cost advantage is designed and manufactured, and the requirements of miniaturization and high-integration base station antenna in the 5G era are met; the antenna has the advantages of low wind load, high strength and stability, difficult deformation, ageing resistance, good wave permeability/low loss, and effectively solves the problems of antenna pattern distortion and gain reduction of the compact multi-frequency base station caused by antenna housing reflection.

In addition, the composite low-loss radome disclosed by the invention adopts common glass fiber reinforced plastic and MMP foamed plates as materials, and during actual production, batch production can be realized only by common materials and conventional processing technology, and a new solution is provided for improving the mechanical and electrical properties of the radome, improving the producibility and reducing the cost besides the new material and new technology radome.

Drawings

Fig. 1 is a schematic diagram of a design of a composite low-loss radome provided by the present invention.

Fig. 2 is a schematic structural diagram of a composite low-loss radome provided in embodiment 1 of the present invention.

Fig. 3 is a schematic structural diagram of a composite low-loss radome provided in embodiment 2 of the present invention.

Fig. 4 shows a side view of fig. 3.

Fig. 5 shows a corresponding directional diagram of a conventional glass fiber reinforced plastic radome.

Fig. 6 shows a directional diagram corresponding to the composite low-loss radome of the present invention.

Description of reference numerals:

1: curved surface section bar, 2: planar sheet-like profile, 3: and assembling the groove.

Detailed Description

In the description of the present invention, it should be noted that, for the terms of orientation, such as "central", "lateral", "longitudinal", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., it indicates that the orientation and positional relationship shown in the drawings are based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated without limiting the specific scope of protection of the present invention.

In the present invention, unless otherwise expressly specified or limited, the terms "assembled", "connected", and "connected" are to be construed broadly, e.g., as meaning fixedly connected, detachably connected, or integrally connected; or may be a mechanical connection; the two elements can be directly connected or connected through an intermediate medium, and the two elements can be communicated with each other. The specific meanings of the above terms in the present invention can be understood by those of ordinary skill in the art according to specific situations.

In the present invention, unless otherwise specified and limited, "above" or "below" a first feature may include the first and second features being in direct contact, and may also include the first and second features not being in direct contact but being in contact with each other through another feature therebetween. Also, the first feature being "above," "below," and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply an elevation which indicates a level of the first feature being higher than an elevation of the second feature. The first feature being "above", "below" and "beneath" the second feature includes the first feature being directly below or obliquely below the second feature, or merely means that the first feature is at a lower level than the second feature.

The following describes the embodiments of the present invention with reference to the drawings of the specification, so that the technical solutions and the advantages thereof are more clear and clear. The embodiments described below are exemplary and are intended to be illustrative of the invention, but are not to be construed as limiting the invention.

Additional aspects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention.

The utility model provides a compound low-loss antenna house, the high production efficiency and the low cost advantage of make full use of ripe technology, splice different materials, get the strong point and make up for the weak point, break through conventional material and processing technology limitation, design and manufacture compromise good mechanical properties, low-loss and have the novel compound antenna house of cost advantage, satisfy the demand of miniaturized, the high integration base station antenna of 5G times.

As shown in fig. 1, according to the design concept, the composite low-loss radome of the present invention comprises a curved surface profile 1 meeting the requirement of low wind load and a planar sheet-shaped profile 2 with low relative dielectric constant (≈ 1), high strength and low deformation coefficient. In view of the maturity of the existing process and the easy availability of materials, the invention preferably uses a glass fiber reinforced plastic curved profile as a basic frame of the radome and uses an MMP low-density foam material as a low-dielectric-constant filling plate. With the progress of the process and the materials, other materials meeting the performance requirements can be adopted to replace the glass fiber reinforced plastic curved profile and the MMP low-density foam material in the future.

The glass fiber reinforced plastic is a radome material with high reliability and mature process, has higher structural strength and impact toughness, hardly deforms in natural environment and excellent curved surface processing capacity, and can be processed into a required curved surface section bar by a conventional die pressing process, so the glass fiber reinforced plastic is very suitable for serving as a basic frame of the composite radome disclosed by the invention. In order to overcome the problem of high reflection and poor wave permeability caused by high dielectric constant, as shown in fig. 1, the glass fiber reinforced plastic frame is designed into a non-closed curved surface with a hollow top (main radiation direction) and an open upper part of the cross section, and the open part of the top is filled with a low dielectric constant MMP low-density foam board, so that the reflection of electromagnetic waves in the main radiation direction is eliminated, the wave permeability is improved, and the loss is reduced. Compared with the conventional glass fiber reinforced plastic radome, the composite radome not only retains the advantages of high strength and high reliability, but also effectively reduces the reflection caused by the radome, solves the problems of directional diagram deformation and gain reduction, and is a perfect whole.

Example 1

As shown in fig. 2, the compound low-loss antenna housing for base station antenna that this embodiment provided is formed by the concatenation of a curved surface section bar 1 and a plane sheet section bar 2, curved surface section bar 1 is both ends and open-topped cuboid form, and four corners of cuboid pass through curved surface rounding off, and the open-topped of cuboid is equipped with assembly tray 3, plane sheet section bar 2 is the MMP foaming flat board, pegs graft and be in the assembly tray 3 and through the bonding agent bonding sealing to ensure plane sheet section bar 2 with the bonding strength between the curved surface section bar 1, eliminate the gap, accomplish waterproof antiseep.

In this embodiment, the assembly groove 3 and the curved-surface profile 1 are integrally formed, and can be realized by conventional glass fiber reinforced plastic profile processing technologies such as die pressing, pultrusion and the like. The planar sheet-shaped section bar 2 is a low-density planar sheet-shaped plate which forms a large number of uniformly distributed micron-sized pores in a polypropylene substrate by using a foaming process, and the relative dielectric constant close to 1 can be realized by controlling the foaming ratio and the density of the pores.

Example 2

As shown in fig. 3 and 4, the composite low-loss radome for the base station antenna is a cuboid structure formed by splicing four curved surface profiles 1 and four planar sheet profiles 2. The splicing mode is basically the same as that of the embodiment 1, the two sides of each curved surface section bar 1 are respectively provided with an integrally formed assembling groove 3, and the two sides of the plane sheet-shaped section bar 2 are respectively inserted into the corresponding assembling grooves 3 and are bonded and sealed through resin bonding agents.

This embodiment can be regarded as the enhancement version of embodiment 1, not only the radome top adopts the MMP foaming panel of low dielectric constant, radome bottom and both sides plane part all adopt the MMP foaming panel of low dielectric constant, and only adopt glass steel section bar as the frame member in the place that four corners must be processed into the curved surface that satisfies the low wind load requirement, do so not only eliminated the reflection of main radiation direction electromagnetic wave, also eliminated both sides and reflection behind one's back simultaneously to further reduce the influence of radome to the radiation pattern, make the loss accomplish lower.

The antenna housing that this embodiment provided is particularly suitable for being used for the big and high low frequency nested array's of high and low frequency oscillator height difference base station antenna, and this kind of antenna is because the antenna housing is far away apart from high frequency (short) oscillator radiating surface, and the reflection that comes from the antenna housing side becomes comparatively serious, through the antenna housing that adopts this embodiment to provide, will show the wave permeability that improves cover body both sides to there is great improvement to high frequency directional diagram and gain.

Compared with the existing radome structure, the composite low-loss radome does not need special materials and special processes, and the composite radome with excellent mechanical properties and excellent electrical properties can be obtained only by assembling and splicing two common materials, namely glass fiber reinforced plastics and MMP (metal matrix plastic) foam boards, through a conventional process. In addition, because no new material and new process development are involved, the composite low-loss antenna housing provided by the invention also has the advantages of lower cost and higher production efficiency.

In order to show the practical utility of the composite low-loss radome of the invention in improving the directional diagram of the base station antenna, fig. 5 and 6 respectively show the directional diagrams corresponding to the conventional glass fiber reinforced plastic radome and the composite low-loss radome of the invention. As can be seen more readily: due to the large reflection coefficient, the glass fiber reinforced plastic antenna housing causes serious distortion of the main beam direction of a radiation directional diagram, and the top of the directional diagram is obviously collapsed, thereby seriously affecting gain and signal coverage; after the composite low-loss radome disclosed by the invention is adopted, as shown in fig. 6, the top collapse of a radiation pattern almost disappears, and the gain and the coverage are recovered to be normal.

It should be noted that: the composite low-loss antenna housing is basically characterized in that: 1) the composite antenna housing is assembled by adopting two (or more) conventional materials in a splicing mode; 2) the composite antenna housing comprises a frame piece which meets the requirement of low wind load and comprises a curved surface structure and a filling piece with a low dielectric constant. The above embodiments are merely two representative embodiments of the composite low-loss radome of the present invention, and the composite low-loss radome of the present invention has various embodiments, so that all composite low-loss radomes having the above basic features should be regarded as a specific embodiment of the present invention. In addition, all the basic materials of the composite low-loss radome are not limited to the two glass fiber reinforced plastics and MMP foaming materials adopted in the above embodiments, and other materials and corresponding processing processes can be adopted.

Claims (10)

1. The composite low-loss radome comprises a radome body and is characterized in that the radome body is formed by splicing a curved surface profile and a planar sheet profile with low dielectric constant and stable shape.

2. The composite low-loss radome of claim 1, wherein the curved profile is a glass fiber reinforced plastic profile.

3. The composite low-loss radome of claim 1, wherein the planar sheet-shaped profile is an MMP foam board.

4. The composite low-loss radome of claim 1, wherein an opening is left on the curved section bar, an assembly groove is arranged on the opening, and the planar sheet-shaped section bar is inserted into the assembly groove and sealed and fixed by an adhesive.

5. The composite low-loss radome of claim 4, wherein the assembling groove and the curved profile are of an integrally formed structure.

6. The composite low-loss radome of claim 4, wherein the adhesive is a resin adhesive or a silica gel adhesive.

7. The composite low-loss radome of claim 1, wherein the radome body is formed by splicing a curved surface profile and a planar sheet profile, the curved surface profile is in a cuboid shape with openings at two ends and a top, four corners of the cuboid are in smooth transition through curved surfaces, and the planar sheet profile is sealed on the top opening.

8. The composite low-loss radome of claim 1, wherein the radome body has a rectangular parallelepiped structure formed by jointly splicing four curved surface profiles and four planar sheet profiles, the four curved surface profiles serve as four edges of the rectangular parallelepiped, and the four planar sheet profiles serve as four side surfaces of the rectangular parallelepiped.

9. A composite low-loss radome according to any one of claims 1-8, applied to a base station antenna.

10. The composite low-loss radome of claim 9, wherein the base station antenna is a high-low frequency nested array of base station antennas.

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