Support structure for antenna and preparation method and application thereof

Abstract

The embodiment of the invention provides a supporting structure for an antenna and a preparation method and application of the supporting structure. The supporting structure is connected between a feed source tube and an auxiliary reflecting surface of the antenna and is specifically a hollow supporting joint, the supporting joint is made of a foaming material, and the size shrinkage rate of the supporting joint is smaller than or equal to 1% after the supporting joint is placed for 4 days in an environment with the temperature of 70-100 DEG C and the relative humidity of 50-95%. The supporting joint containing the foaming material is used for supporting the auxiliary reflecting surface, the shielding and loss influence on electromagnetic wave transmission is small, the antenna performance can be ensured to be better, the damp and hot deformation rate is lower, and the antenna performance can be ensured not to be obviously degraded when the antenna is used for a long time.

Description

Technical Field

[0001] The present application relates to the technical field of microwave antennas, and in particular to a support structure for an antenna and a preparation method and application thereof. Background Art

[0002] Microwave antennas are an important part of microwave communication systems. Existing microwave antennas usually use dual-reflector microwave antennas, which have the advantages of short feeder distance, long equivalent focal length, and flexible design. They generally include a main reflector, a feed source, a sub-reflector, and a support structure for supporting the sub-reflector. The support structure is generally directly set on the main reflector or on the feed source tube, and the support structure is usually a metal bracket. However, the structure of the metal bracket is relatively complex and it is easy to block the transmission of electromagnetic waves, reduce the antenna efficiency, and affect the antenna radiation pattern. Summary of the invention

[0003] In view of this, the embodiments of the present application provide a support structure for a sub-reflector, an antenna, etc. that have little impact on the performance of a microwave antenna.

[0004] Specifically, the first aspect of an embodiment of the present application provides a support structure for an antenna, which is used to connect between the feed tube and the sub-reflecting surface of the antenna, wherein the support structure is a hollow support joint, and the support joint is made of foam material, wherein the dimensional shrinkage rate of the support joint after being placed in an environment with a temperature of 70-100°C and a relative humidity of 50-95% for 4 days is less than or equal to 1%.

[0005] The embodiment of the present application uses a hollow support joint made of foam material to support the antenna sub-reflector surface. It has a simple structure and has minimal effect on the obstruction and loss of electromagnetic wave transmission. It also has good moisture and heat resistance and a small dimensional shrinkage rate, thereby ensuring that the antenna's near-axis sidelobe performance is better.

[0006] In the embodiment of the present application, the constant Dk of the foamed material at a frequency of 6-86 GHz is less than or equal to 1.2. With the help of the pore structure of the foamed material, its Dk can be as low as 1.2 or less, which is lower than the homogeneous solid material without foaming, which can ensure that the support joint has little effect on the loss of electromagnetic wave transmission and ensure that the antenna performance is relatively excellent.

[0007] In the embodiment of the present application, the dielectric loss of the foam material at a frequency of 6-86 GHz is less than or equal to 0.005. When the Dk of the foam material is less than or equal to 1.2, controlling the dielectric loss below 0.005 can further ensure that the support joint has little effect on the loss / attenuation of electromagnetic wave transmission, thereby ensuring better antenna performance.

[0008] In the embodiment of the present application, the support joint with a wall thickness of less than 10 mm has a wave transmittance greater than or equal to 90% for vertically incident electromagnetic waves with a frequency range of 6-86 GHz. This reflects that the support joint has good microwave transparency, so that the support joint has less microwave loss, which is conducive to better antenna performance.

[0009] In the implementation manner of the present application, the Shore hardness C of the support joint is greater than or equal to 50. This can reflect to a certain extent that the mechanical strength of the support joint is relatively high, and a good support effect can be achieved.

[0010] In the embodiment of the present application, at least 2 cm on the inner surface or outer surface of the support joint 2 In the region of , the number of exposed cells is less than or equal to 20. This indicates that the number of exposed cells on the inner and outer surfaces of the support joint is small, which helps to make the support joint have excellent resistance to moisture and heat. In some embodiments of the present application, any at least 2 cm on the inner or outer surface of the support joint 2 In the area, the number of exposed cells is less than or equal to 5.

[0011] In the embodiment of the present application, the closed cell ratio of the pores in the support joint is greater than or equal to 90%. A higher closed cell ratio is beneficial to ensure that the support joint has excellent moisture and heat resistance and high structural strength.

[0012] In the embodiment of the present application, the density of the support joint is 0.5g / cm 3 When the density of the support joint using the above foam material is low, it can also take into account the above-mentioned good moisture and heat resistance and high strength and other characteristics, and has excellent comprehensive performance. In some embodiments, the density of the support joint is 0.08-0.15g / cm 3 .

[0013] In the embodiment of the present application, the glass transition temperature of the support joint is greater than or equal to 150° C. This reflects that the support joint has good heat resistance and is particularly suitable for use in high temperature environments. In some embodiments, the glass transition temperature of the support joint is greater than or equal to 190° C.

[0014] In the embodiment of the present application, the foaming material comprises a polymer having an aromatic structure in the main chain. Aromatic polymers have good heat resistance and a low thermal expansion coefficient, and are also conducive to reducing their dimensional shrinkage.

[0015] In the embodiment of the present application, the polymer includes one or more of polyimide, polyethersulfone, polyarylether, and polyarylether sulfide having an aromatic structure in the main chain.

[0016] A second aspect of an embodiment of the present application provides a foam material for use in a support structure of an antenna sub-reflection surface, wherein the dielectric constant of the foam material at a frequency of 6-86 GHz is less than or equal to 1.2.

[0017] In the embodiment of the present application, the dielectric loss of the foam material at a frequency of 6-86 GHz is less than or equal to 0.005.

[0018] In the embodiment of the present application, the Shore hardness C of the foaming material is greater than or equal to 50.

[0019] In the embodiment of the present application, the density of the foaming material is 0.5 g / cm 3 the following.

[0020] A third aspect of an embodiment of the present application provides an antenna assembly, which includes a sub-reflecting surface, a feed tube and a supporting structure as described in the first aspect of the embodiment of the present application, wherein the opposite ends of the supporting structure are respectively connected to the feed tube and the sub-reflecting surface.

[0021] A fourth aspect of the embodiments of the present application provides an antenna, which includes a main reflection surface and the antenna assembly as described in the third aspect of the embodiments of the present application, wherein the feed tube is connected to the main reflection surface.

[0022] The antenna using the above support structure has excellent antenna performance, high polarization gain, good antenna directivity pattern, and little impact on the near-axis sidelobe performance of the antenna.

[0023] A fifth aspect of an embodiment of the present application provides a communication device, which includes the antenna as described in the fourth aspect of the embodiment of the present application, as well as an outdoor unit and an indoor unit.

[0024] The sixth aspect of the embodiment of the present application provides a communication system, wherein the communication system includes at least two communication devices according to the fifth aspect of the embodiment of the present application, and the communication devices can communicate with each other. The communication system can operate stably and efficiently.

[0025] The present application also provides a method for preparing the above-mentioned antenna support structure, including:

[0026] The reaction raw materials for forming the support structure are placed in a mold whose cavity shape corresponds to the shape of the support structure to be prepared and sealed. After heating treatment, the reaction raw materials react with each other and generate gas to obtain a hollow support joint containing a foaming material; wherein the support joint has a dimensional shrinkage rate of less than or equal to 1% after being placed in an environment with a temperature of 70-100°C and a relative humidity of 50-95% for 4 days.

[0027] The preparation method is particularly suitable for in-situ preparation of a support joint with high heat resistance, and giving it a cellular structure, and making the support joint have both good moisture and heat resistance and low dielectric properties.

[0028] The present application also provides another method for preparing the above-mentioned antenna support structure, comprising the following steps:

[0029] The foamed particles are placed in a mold whose cavity shape corresponds to the shape of the support structure to be prepared and sealed, and the foamed particles are melted to form a foamed material through hot steam treatment to obtain a hollow support joint; wherein the support joint has a dimensional shrinkage rate of less than or equal to 1% after being placed in an environment with a temperature of 70-100°C and a relative humidity of 50-95% for 4 days.

[0030] The above preparation method is also suitable for making support joints containing foamed materials, and endowing them with low dielectric properties and good moisture and heat resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The figure is a schematic diagram of an exemplary structure of an existing microwave antenna and its supporting structure.

[0032] Figure 2 A schematic structural diagram of an antenna assembly including a support joint provided in an embodiment of the present application is shown, wherein the right figure is a cross-sectional view of the left figure.

[0033] Figure 3 Shown with Figure 2 A schematic structural diagram of the antenna of the antenna assembly shown.

[0034] Figure 4 A schematic diagram of the structure of a communication device provided in an embodiment of the present application.

[0035] Figure 5 It is a schematic diagram of the structure of the metal bracket for the antenna of comparative example 1, wherein the right figure is a cross-sectional view of the left figure.

[0036] Figure 6 The antenna radiation patterns of the antenna (a) of comparative example 1, the antenna (b) of comparative example 2, and the antenna (c) of embodiment 1 in the horizontal polarization direction measured at a frequency of 78.5 GHz are summarized.

[0037] Figure 7 The antenna radiation pattern of the antenna of Example 1 in the horizontal polarization direction measured at a frequency of 78.5 GHz after the damp heat test is shown.

[0038] Explanation of main figure marks: 200 -antenna assembly; 20 -support structure or support joint of an embodiment of the present application; 201 -first main body; 202 -second main body; 21 -feed tube; 22 -secondary reflector; 23 -primary reflector; 300 -antenna provided in an embodiment of the present application; 24 -radome. DETAILED DESCRIPTION

[0039] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application.

[0040] Figure 1 FIG. 1 is a schematic diagram of an exemplary structure of an existing microwave antenna and its supporting structure. Figure 1 As shown, the microwave antenna 100 includes a main reflector 101, a feed tube 102 connected to the main reflector 101, a sub-reflector 103 and a support bracket 104, wherein the support bracket 104 is used to support the sub-reflector 103 above the feed tube 102, and is connected to the main reflector 101. The support bracket 104 is mostly made of metal material, which is usually a complex structure composed of multiple parts. It is difficult to process / assemble, and will cause obvious shielding and loss to electromagnetic wave transmission, thereby reducing the aperture efficiency and gain of the antenna, affecting its antenna radiation pattern (which can be reflected in the degradation of the antenna near-axis sidelobe performance), etc. There are also some microwave antennas in which the support structure is a plurality of dielectric support rods connected between the sub-reflector and the feed tube (such as CN 105161827 A). The dielectric support rods are usually solid structures with a dielectric constant greater than 2, which will also cause shielding and loss to electromagnetic wave transmission, resulting in deterioration of antenna performance. Therefore, in order to address the problem that the sub-reflector support structure used in existing microwave antennas is prone to deteriorating the antenna performance, an embodiment of the present application provides a sub-reflector support structure that will not deteriorate the microwave antenna performance.

[0041] See also Figure 2 , Figure 2 An antenna assembly including a support structure according to an embodiment of the present application is shown. Figure 2 The middle right figure is a cross-sectional view of the left figure. The antenna assembly 200 includes a feed tube 21, a sub-reflector 22 and a support structure 20, wherein the opposite ends of the support structure 20 are respectively connected to the feed tube 21 and the sub-reflector 22. The support structure 20 is connected between the feed tube 21 and the sub-reflector 22 of the antenna, and the support structure 20 is specifically a hollow support joint 20, which is made of foam material, wherein the size shrinkage rate of the support joint 20 after being placed in an environment with a temperature of 70-100°C and a relative humidity of 50-95% for 4 days is less than or equal to 1%.

[0042] In the present application, the support structure for the antenna sub-reflector is changed from a common complex support bracket to a hollow support joint. The support joint has little shielding and loss on the transmission of electromagnetic waves, and it is a single part and does not need to be assembled. This can simplify the design, processing and assembly of the support structure. While ensuring the basic support function, there is no need to design a separate sealing structure for the feed tube to protect the feed set on the feed tube as when the support bracket is used. After the support joint 20 is connected with the feed tube 21 and the sub-reflector 22, the feed can be sealed and dustproof. More importantly, the support joint uses a foam material with a pore structure. With the help of a suitable pore structure, when the Dk of the foam material is low, its moisture and heat resistance will not be significantly reduced. Therefore, the shrinkage deformation of the support joint under high temperature and high humidity conditions is small, which will not affect the connection reliability between it and the feed tube 21 and the sub-reflector 22, and will not affect the polarization gain and antenna radiation pattern of the antenna too much.

[0043] Therefore, the support joint made of the foam material provided in the embodiment of the present application is used to support the secondary reflector. It has a simple structure and a low dielectric constant, and has minimal effect on the obstruction and loss of electromagnetic wave transmission, thereby ensuring better antenna performance. At the same time, it can also have good moisture and heat resistance, which is conducive to ensuring that it can play a stable supporting / connecting role on the antenna for a long time.

[0044] In the embodiment of the present application, the dimensional shrinkage rate of the support joint 20 after being placed in an environment with a temperature of 70-100° C. and a relative humidity of 50-95% for one week (i.e., 7 days) is less than or equal to 1%, for example, less than or equal to 0.8%, less than or equal to 0.5%, less than or equal to 0.3%, etc. In some embodiments, the dimensional shrinkage rate of the support joint 20 after being placed in an environment with a temperature of 85° C. and a relative humidity of 95% for 4 days is less than or equal to 1%, and the dimensional shrinkage rate after being placed for one week is still less than or equal to 1%.

[0045] In the embodiment of the present application, the dielectric constant Dk of the foamed material at a frequency of 6-86 GHz is less than or equal to 1.2. With the help of a suitable cell structure of the foamed material, the dielectric constant Dk at a frequency of 6-86 GHz can be as low as 1.2 or less, which is lower than that of a homogeneous solid material without foaming. In this way, the support structure of the embodiment of the present application has less influence on the loss of electromagnetic wave transmission and less influence on the degradation of antenna performance.

[0046] In the embodiment of the present application, the dielectric loss Df of the foam material at a frequency of 6-86 GHz is less than or equal to 0.005. The lower end of the support joint 20 (i.e., the end close to the feed tube 21) is generally close to the secondary reflector 22. The above-mentioned low Dk performance of the foam material has helped to reduce the blocking / loss of the support joint 20 to the electromagnetic wave transmission. On this basis, controlling Df below 0.005 can further ensure that the support joint 20 has little effect on the loss / attenuation of the electromagnetic wave transmission, and ensure that the antenna performance is better. Specifically, the Df can be less than or equal to 0.004, further less than or equal to 0.003, less than or equal to 0.002, or less than or equal to 0.001, etc.

[0047] Among them, the above D k and D f The sample of the foam material can be measured according to the resonant cavity method. Specifically, a grid analyzer can be used for testing, and a fixture with a resonant cavity can be used. Among them, the frequency of 6-86GHz is the common frequency range corresponding to microwaves. Common microwave frequency bands include 6-42GHz, 57-64GHz and 71-86GHz. In this application, the dielectric constant Dk of the above-mentioned foam material at a frequency of 6-42GHz is less than or equal to 1.2; the dielectric constant Dk of the foam material at a frequency of 57-64GHz is less than or equal to 1.2; the dielectric constant Dk of the foam material at a frequency of 71-86GHz is less than or equal to 1.2. The Dk values ​​in each frequency band can be found in the description in the previous paragraph. Similarly, the dielectric loss Df of the above foam material at a frequency of 6-42 GHz is less than or equal to 0.005; the dielectric loss Df of the foam material at a frequency of 57-64 GHz is less than or equal to 0.005; the dielectric loss Df of the foam material at a frequency of 71-86 GHz is less than or equal to 0.005. The Df values ​​in each frequency band can be found in the description in the previous paragraph.

[0048] In the embodiment of the present application, the wave transmittance of the support joint 20 with a wall thickness of less than 10 mm to vertically incident electromagnetic waves with a frequency in the range of 6-86 GHz is above 90% (i.e., greater than or equal to 90%). Among them, the wave transmittance can be measured according to the method recorded in the following literature: Sichuan Ordnance Journal Volume 32, Issue 4, "Dielectric Properties and Test Methods of Wave-Transparent Dielectric Materials". The wave transmittance of more than 90% can reflect that the foaming material used in the support joint 20 has good microwave transparency, so that the loss caused by microwaves passing through the support joint 20 is small, which is conducive to ensuring that the antenna performance using the support structure is good. In some embodiments, the wave transmittance is above 92%, and can further be above 95%, for example, 95.5%, 96%, 96.5%, 97%, 98%, or 99%. Electromagnetic waves in the range of 6-86 GHz are generally microwaves. As mentioned above, common microwave frequency bands include 6-42 GHz frequency bands, 57-64 GHz frequency bands, and 71-86 GHz frequency bands. The support joint 20 with a wall thickness of less than 10 mm has a wave transmittance of more than 90% for vertically incident microwaves within the frequency range of 6-42 GHz, 57-64 GHz or 71-86 GHz. For the wave transmittance values ​​within each frequency range, please refer to the description in this paragraph.

[0049] In the implementation manner of the present application, the Shore hardness C of the support joint 20 is greater than or equal to 50. This can reflect to a certain extent that the mechanical strength of the support joint 20 is relatively high, and a good support effect can be achieved. It does not undergo obvious deformation when bearing weight, and is not easy to collapse when impacted, and thus does not cause obvious displacement of the secondary reflective surface 22 supported by it. In some implementation manners, the Shore hardness C of the support joint 20 is greater than or equal to 70.

[0050] In the embodiment of the present application, any one of the inner surface or outer surface of the support joint 20 is at least 2 cm 2 In the region, the number of exposed cells is less than or equal to 20. This indicates that the number of exposed cells on the inner and outer surfaces of the support joint 20 is small, which helps to make the support joint 20 excellent in water absorption resistance and high in structural / shape stability, such as ensuring that the dimensional shrinkage rate after being placed under high humidity and high heat conditions for 4 days is less than 1%. Specifically, the number of exposed cells is less than or equal to 15, less than or equal to 10, less than or equal to 8, etc. In some embodiments of the present application, any at least 2 cm on the inner or outer surface of the support joint 20 2 In the region, the number of exposed cells is less than or equal to 5, and further, there are no exposed cells on the inner surface and the outer surface of the support joint 20. In this case, the support joint 20 has better resistance to moisture and heat.

[0051] In the embodiment of the present application, the closed cell rate of the pores in the support joint 20 is greater than or equal to 90%, for example, greater than 92%, greater than 95%, greater than 96%, greater than 97%, greater than 98%, and greater than 99%. A higher closed cell rate indicates that most of the pores in the support joint 20 are closed cells, which is beneficial to ensure that the foam material has excellent moisture and heat resistance and high structural strength. Among them, the closed cell rate of the foam material can be measured according to the GB / T 10799-2008 standard. In some embodiments, the pores in the support joint 20 are closed cells, that is, its closed cell rate is 100%.

[0052] In the present application, the support joint 20 is a foam material with few pores on the surface layer, many pores inside, and a high pore closed cell rate. These structural features enable the Dk of the foam material to be below 1.2, and its dimensional shrinkage rate is still below 1% after being placed under high temperature and high humidity conditions for a week.

[0053] In the embodiment of the present application, the density of the support joint 20 is 0.5 g / cm 3 The apparent density of the support joint can be tested according to GB / T6343-2009 standard. The density of the support joint using the above foam material is low, which is conducive to ensuring the use of it. Figure 2 The device shown is lightweight and has the above-mentioned good moisture and heat resistance, high strength and other characteristics. In some embodiments of the present application, the density of the support joint 20 is 0.4g / cm 3 Below, or at 0.3g / cm 3 Below, or at 0.2g / cm 3 In some embodiments, the density of the support joint 20 is 0.08 g / cm 3 -0.15g / cm 3 , for example, 0.09, 0.10, 0.12, 0.13, 0.14, 0.145 g / cm 3 In this case, the support joint 20 can achieve a better support effect and better balance low dielectric properties, good moisture and heat resistance, etc.

[0054] In the embodiment of the present application, the glass transition temperature Tg of the support joint 20 is greater than or equal to 150°C. A higher Tg reflects that the support joint has good heat resistance, and its thermal decomposition temperature and cell collapse temperature must be above 150°C, which makes the support joint particularly suitable for use in high temperature environments. In addition, a high Tg can also have high rigidity and good mechanical properties to a certain extent. Generally, due to the limitations of the foaming process (such as supercritical foaming method), the Tg of conventional organic foaming materials generally rarely exceeds 150°C; and organic medium materials with high Tg (such as thermosetting polyimide) are difficult to transform into foaming materials with a cellular structure. The foaming material used in the support joint 20 of the present application is prepared by the preparation method described below in the embodiment of the present application, which can well balance these two contradictions. Specifically, the Tg of the support joint 20 can be 150°C, 160°C, 180°C, 190°C, 195°C, 200°C, or above 220°C, etc. In some embodiments, the glass transition temperature of the support joint 20 is greater than or equal to 190° C., further greater than or equal to 200° C., for example, 200-450° C. In this case, the heat resistance of the support joint is better.

[0055] In the embodiment of the present application, the foaming material includes a polymer with an aromatic structure in the main chain. The main chain of the polymer molecule contains a rigid aromatic structure, which helps to improve the heat resistance of the polymer, reduce the coefficient of thermal expansion (CTE) of the polymer, and also helps to reduce its dimensional shrinkage under high temperature and high humidity conditions. Among them, the polymer includes one or more of polyimide with an aromatic structure in the main chain, polyethersulfone with an aromatic structure in the main chain, polyarylether (such as polyphenylene ether PPO), polyarylether sulfide (such as polyphenylene sulfide PPS), etc., but is not limited thereto.

[0056] In some embodiments of the present application, the above-mentioned polymer is a polymer that can produce reaction gas during the preparation process of the polymer, such as a polyimide containing an aromatic structure in the main chain. In this way, a support joint that meets the requirements of the above-mentioned low dielectric, moisture and heat resistance, etc. can be obtained by the following preparation method provided in the embodiment of the present application, and its thermal stability is relatively high. Among them, the foaming material containing polyimide can be prepared by the in-situ reaction of dianhydride or polyacid and polyisocyanate. The dianhydride or polyacid contains an aromatic ring, or the polyisocyanate contains an aromatic ring, or the dianhydride or polyacid contains an aromatic ring and the polyisocyanate contains an aromatic ring.

[0057] In the present application, the support joint 20 is made of the above foam material, so the characteristics of the support joint 20 and the foam material described above (such as Tg, hardness, density, etc.) can be replaced equivalently. For example, the Tg of the support joint 20 is the glass transition temperature of the foam material.

[0058] In the present application, in the embodiment of the present application, the support joint 20 is a hollow structure so as to be sleeved with the feed tube. Among them, the opening size of the support joint 20 increases gradually from one end to the other end. Specifically, the opening size of the support joint 20 increases gradually from the feed tube 21 to the sub-reflector 22. It can be understood that the opening size of the support joint 20 near the feed tube 21 is larger than the opening size near the sub-reflector 22. This makes it easy to achieve the connection between the feed tube with a small diameter and the sub-reflector 22 with a large lateral size.

[0059] The specific increasing method of "gradient increase" can be: gradually increasing, or first unchanged and then gradually increasing, or first unchanged-then increasing-then unchanged-then increasing, etc. In some embodiments, the specific increasing method of "gradient increase" is first unchanged and then gradually increasing. Figure 2 As shown, the support joint 20 includes a first main body 201 and a second main body 202, wherein the first main body 201 is close to the feed tube 21, and the second main body 202 is close to the sub-reflector 22; wherein the opening size of the first main body 201 remains unchanged, and the opening size of the second main body 202 gradually increases toward the sub-reflector 22. In this way, it can be ensured that the support joint 20 is firmly connected to the feed tube 21 and the sub-reflector 22. To improve the stability of the connection, the end face of the support joint 20 connected to the sub-reflector 22 can have an end face that matches the shape of the sub-reflector 22, and the end face of the support joint 20 connected to the feed tube 21 can have an end face that matches the shape of the feed tube 21.

[0060] In the implementation mode of the present application, the side surface of the support joint 20 is a smooth curved surface. The "side surface" specifically refers to the shaping surface of the support joint, that is, the part of its outer surface excluding the part of the surface perpendicular to the length direction of the feed tube 21. In the present application, the side surface of the support joint 20 is smooth and not stepped, so that when the opening size of the support joint 20 changes, the overall support joint will not have too many edges and corners to interfere with the transmission of electromagnetic waves. In some embodiments, the support joint 20 is a hollow truncated cone structure, and its side surface is a truncated cone side surface.

[0061] In some embodiments of the present application, the side surface of the support joint 20 is symmetrical about the central axis of the feed tube 21. In this way, only one side of the support joint needs to be parameterized, and the other side can use the same parameters, which can reduce the difficulty of process design and production.

[0062] In the embodiment of the present application, the wall thickness of the support joint 20 may be in the range of 7-15 mm, for example, 7.5 mm, 8 mm, 8.5 mm, 9 mm, 9.5 mm, 10 mm, 11 mm, 12 mm, 13 mm, or 14 mm, etc. Controlling the thickness of the support joint within a suitable range can ensure that it has sufficient strength to play a physical supporting role, while not causing loss of electromagnetic waves hitting it and affecting antenna gain due to its excessive thickness.

[0063] The embodiment of the present application also provides a method for preparing the above-mentioned support structure.

[0064] Specifically, in some embodiments, the preparation method may include the following steps:

[0065] The reaction raw materials for forming the support structure are placed in a mold whose cavity shape corresponds to the shape of the support structure to be prepared and sealed. After heating treatment, the reaction raw materials react with each other and generate gas to obtain a hollow support joint containing a foaming material, that is, a support structure is obtained; wherein the dimensional shrinkage rate of the support joint after being placed in an environment with a temperature of 70-100°C and a relative humidity of 50-95% for 4 days is less than or equal to 1%.

[0066] In the embodiment of the present application, the reaction raw materials are also the raw materials required to form the foaming material; the reaction raw materials are generally greater than or equal to two types. The temperature of the heat treatment should be above the starting temperature of the reaction between the reaction raw materials. The gas generated by the reaction between the reaction raw materials has the function of a porogen, and the in-situ preparation of the foaming material can be achieved with the aid of a sealed mold, and there are basically no exposed pores in the place in contact with the mold cavity wall of the mold, and the foaming material is simultaneously given the required shape, that is, a hollow support joint is obtained. In this way, the additional CNC (computer numerical control) processing can be greatly reduced, and the surface of the support joint can be avoided to be covered with exposed pores, thereby ensuring that the dimensional shrinkage rate of the support joint after being placed under the above-mentioned high temperature and high humidity conditions for 4 days is less than 1%.

[0067] It should be noted that for raw materials with high heat resistance (such as aromatic polymers with Tg above 150°C or even above 190°C), it is difficult to transform them into foam materials with a cellular structure through conventional foaming methods such as supercritical foaming or physical foaming with foaming microspheres due to the limitations of conventional foaming processes; when the raw material is a thermosetting raw material, it is even more difficult to transform it into a foam material. The above-mentioned preparation method provided in the embodiment of the present application is particularly suitable for making foam materials with high heat resistance (for example, particularly suitable for foam materials with Tg above 190°C), and gives them good moisture and heat resistance and low dielectric properties.

[0068] In the present application, by controlling parameters including the type of the reaction raw materials and the molar ratio therebetween, the dimensional shrinkage of the support joint after being placed in an environment of 70-100°C and 50-95% relative humidity for 4 days can be less than or equal to 1%, and the dielectric constant of the foaming material at a frequency of 6-86GHz can be less than or equal to 1.2. Wherein, when the cavity volume and the type of the reaction raw materials are fixed, regulating the molar ratio between the reaction raw materials can regulate the amount of gas produced by the reaction, so as to regulate the air pressure environment in the sealed mold, control the foaming ratio of the foaming material to be appropriate, and the pore structure to be appropriate, so as to regulate its dielectric constant Dk to be as low as below 1.2. In addition, the type of each reaction raw material affects the material of the resulting foaming material, and also correspondingly affects the dielectric properties of the foaming material and the dimensional shrinkage under hot and humid conditions.

[0069] In some embodiments, the reaction raw materials react to form a polymer, and the resulting foaming material is an organic foaming material containing the polymer. In some specific embodiments, the polymer is a polyimide with an aromatic structure in the main chain. Accordingly, the above-mentioned reaction raw materials include dianhydride or polyacid, polyisocyanate and catalyst, etc. Among them, if the polymer is prepared by the reaction between dianhydride and polyisocyanate, at least one of the dianhydride and polyisocyanate contains an aromatic ring, for example, the reaction raw materials are specifically aromatic dianhydride and aromatic polyisocyanate; or aromatic dianhydride and aliphatic polyisocyanate, etc.

[0070] In some embodiments of the present application, the reaction raw materials may further include one or more of a cell stabilizer, an auxiliary foaming agent, etc. Among them, the cell stabilizer can be used to stabilize the gas generated during the polymer formation process to ensure the formation of the cell structure. The cell stabilizer is usually a surfactant. The auxiliary foaming agent can be a low-boiling point solvent, such as one or more of furan methanol, formic acid, etc., which also helps the formation of cells during its volatilization process.

[0071] In some other embodiments, the method for preparing the above support structure may include the following steps:

[0072] The foamed particles are placed in a mold whose cavity shape corresponds to the shape of the support structure to be prepared and sealed, and the foamed particles are melted to form a foamed material through hot steam treatment to obtain a hollow support joint; wherein the support joint has a dimensional shrinkage rate of less than or equal to 1% after being placed in an environment with a temperature of 70-100°C and a relative humidity of 50-98% for 4 days.

[0073] In the embodiment of the present application, the foamed particles with a cellular structure are injected into the mold cavity of the sealed mold, and after being treated with hot steam, the surfaces of the foamed particles can be welded together by the thermal effect of the hot steam to obtain a "welded body" with a certain configuration-foaming material, that is, a hollow support joint. Among them, the hot steam treatment can not only weld the foamed particles together, but also facilitate the expansion of the welded foamed particles to obtain a foamed material with a suitable cellular structure and foaming ratio, so that the dielectric constant of the foamed material is low; at the same time, the hot steam treatment is also conducive to the release of internal stress of each foamed particle, the improvement of defects, etc., and is conducive to reducing the size shrinkage of the foamed material in the later stage. In addition, the configuration of the foamed material is the shape of the support structure. The use of the sealed mold can also ensure that there are fewer exposed pores on the inner and outer surfaces of the support joint, and can also reduce the additional CNC processing of the prepared support joint like the above method, so as to avoid the surface of the support joint being covered with exposed pores, thereby ensuring that the size shrinkage rate of the support joint after being placed under the above-mentioned high humidity and high heat conditions for 4 days is less than 1%.

[0074] Therefore, the above preparation method provided in the embodiment of the present application is also suitable for making a support structure containing a foam material, and giving it low dielectric properties and good moisture and heat resistance. In particular, the preparation method is more suitable for making a foam material with a glass transition temperature above 150°C. In the embodiment of the present application, the dielectric constant Dk of the foam material at a frequency of 6-86GHz can be as low as below 1.2.

[0075] Wherein, the hot steam can be water vapor, flue gas, etc., but is not limited thereto. The foamed particles contain a material corresponding to the support structure. For example, when the obtained foamed material contains a polymer, the foamed particles also contain the polymer. The material of the foamed particles also affects the dielectric constant of the foamed material. Therefore, by controlling parameters including the material of the foamed particles, the dielectric constant of the obtained foamed material can also be regulated. In order to facilitate the fusion of the foamed particles and reduce the temperature of the hot steam, the surface of the foamed particles can be subjected to certain surface treatments, such as coating a flux (such as polystyrene) that can reduce its softening temperature.

[0076] In addition, the particle size of the expanded particles can also affect the void ratio of particle welding and the dielectric loss of the obtained foamed material. In order to reduce the dielectric loss, in the embodiment of the present application, the particle size of the expanded particles used is controlled to be less than 1 mm.

[0077] The embodiment of the present application also provides a foam material for use in a support structure of an antenna sub-reflector, wherein the dielectric constant of the foam material at a frequency of 6-86 GHz is less than or equal to 1.2. In other words, the present application provides an application of a foam material in a support structure for an antenna sub-reflector.

[0078] The foam material with a pore structure is used for the supporting structure of the antenna sub-reflector. With its suitable pore structure, the dielectric constant Dk of the foam material at a frequency of 6-86GHz can be reduced to below 1.2, which is lower than that of the homogeneous solid material without foaming. In this way, the supporting structure has less effect on the degradation of the antenna's electrical performance and less effect on the loss of electromagnetic wave (specifically microwave) transmission.

[0079] The foam material with a pore structure provided in the present application has a relatively low Dk, while its mechanical hardness and density will not be significantly reduced, and can meet the support requirements; at the same time, it has good moisture and heat resistance, etc. As described in the previous text of the present application, since the support joint 20 is made of the above-mentioned foam material, the characteristic description of the support joint 20 in the present application is also applicable to the foam material. Specifically, in the embodiment of the present application, the Shore hardness C of the foam material is greater than or equal to 50. The density of the foam material is 0.5g / cm 3 Below, further 0.08-0.15g / cm 3 The dielectric loss Df of the foam material at a frequency of 6-86 GHz is less than or equal to 0.005. The glass transition temperature of the foam material is greater than or equal to 150°C, and further greater than or equal to 190°C. 2 In the region, the number of exposed cells is less than or equal to 20, and further less than or equal to 5. The closed cell ratio of the cells in the foam material is greater than or equal to 90%. These help to ensure that the foam material has good resistance to moisture and heat. Among them, the specific values ​​of each parameter, further narrowing of the range, etc. can all be referred to the previous description of this application.

[0080] The embodiment of the present application further provides an antenna, which includes an antenna assembly 200 of the above-mentioned supporting structure of the embodiment of the present application.

[0081] Please also refer to the above Figure 2 and Figure 3 , Figure 3 A schematic diagram of the structure of an antenna provided in an embodiment of the present application is shown. Figure 3 The antenna in the Figure 2 The antenna assembly shown. The antenna 300 includes a main reflector 23, a sub-reflector 22, a feed tube 21 and a support structure 20 (i.e., the above-mentioned support joint 20), wherein the feed tube 21 is connected to the main reflector 23, and the opposite ends of the support structure 20 are respectively connected to the feed tube 21 and the sub-reflector 22. In this way, the support joint 20 is arranged between the feed tube 21 and the sub-reflector 22, connecting the two and fixing them on the same central axis. In some embodiments, Figure 2 The structure shown includes a sub-reflecting surface 22, a supporting joint 20 and a feed tube 21 which are sequentially connected from top to bottom and have the same central axis. Figure 3The antenna shown is generally used for receiving / transmitting electromagnetic waves in the microwave frequency band, so the antenna can be called a "microwave antenna", and can further be called a "double-reflector microwave antenna", or a Cassegrain antenna.

[0082] In some embodiments of the present application, one end of the support joint 20 is sleeved on the outside of the feed tube 21, and the other end is connected to the secondary reflector 22. In this way, one end of the feed tube 21 is located in the space enclosed by them, so as to achieve sealing and dustproof of the feed on the feed tube 21. The support joint 20 can be sleeved on the outside of the feed tube 21 by threaded connection or bonding.

[0083] In some embodiments of the present application, the two opposite ends of the support joint 20 are respectively bonded to the feed tube 21 and the secondary reflector 22. Compared with the threaded connection, the bonding method does not require machining threads on the inner surface of the support joint 20 by mechanical processing, which reduces the difficulty of manufacturing the support joint 20 and helps to ensure that the number of exposed pores on its surface is small.

[0084] In the present application, the antenna 300 may also include a feed source ( Figure 2 , Figure 3 The feed source is arranged at one end of the feed source tube 21 close to the sub-reflection surface 22. The feed source is the primary radiator of the reflector microwave antenna, and its function includes converting the radio frequency signal in the feed line into a spatial electromagnetic wave and radiating it onto the sub-reflection surface 22. The feed source can be specifically a horn feed source, a dipole feed source, or a double-slot feed source, etc. The Cassegrain antenna usually adopts a horn feed source.

[0085] When the antenna transmits a signal, the feed source can be used to generate electromagnetic waves, and the sub-reflector 22 can be used to reflect the electromagnetic waves generated by the feed source to the main reflector 23. The main reflector 23 can further reflect the electromagnetic waves reflected by the sub-reflector 22 to complete the signal radiation function of the antenna 300. When the antenna receives a signal, the signal is reflected from the main reflector 23 to the sub-reflector 22 and finally enters the feed source, and is transmitted through the feed source tube into the back-end receiving system of the antenna.

[0086] In the present application, the main reflector 23 and the sub-reflector 22 are generally made of metal, such as aluminum. The main reflector 23 is generally a rotating parabola. In the embodiment of the present application, the tail of the feed tube 21 (i.e., the end away from the sub-reflector 22) can also be provided with a base ( Figure 3 With the help of the base, the feed tube 21 can be installed on the main reflection surface 23.

[0087] In addition, the antenna 300 may further include a radome ( Figure 3The radome is generally arranged on the main reflector 23 to cover the feed tube 21, the support structure 20 and the sub-reflector 22 in the space formed by the radome and the main reflector 23. The radome is used to protect the feed tube 21, the support structure 20 and the sub-reflector 22 from being disturbed by the outdoor bad weather.

[0088] An embodiment of the present application also provides a communication device, which includes the above-mentioned antenna of the embodiment of the present application.

[0089] Figure 4 This is an exemplary structure of a communication device provided in an embodiment of the present application. Figure 4 As shown, the communication device 400 includes the above-mentioned antenna 300 ( Figure 4 400 ), an outdoor unit (Out Door Unit, ODU) 401 and an indoor unit (In Door Unit, IDU) 402. The outdoor unit 401 is connected to the antenna 300, and the indoor unit 402 and the outdoor unit 401 can be connected through an intermediate frequency cable 403.

[0090] The outdoor unit 401 can be directly connected to the antenna 300, or connected through a flexible waveguide. This helps to reduce feeder losses. The antenna 300 can be installed on a pole 404 or a tower by adjusting the bracket to receive or transmit antenna signals.

[0091] Figure 4 The antenna 300 shown in the figure also has a radome 24, which is arranged on the main reflective surface 23 of the antenna, so as to cover the feed tube 21, the support structure 20 and the sub-reflective surface 22 in the space formed by the radome 24 and the main reflective surface 23. In this way, the feed tube 21, the support structure 20 and the sub-reflective surface 22 are all located on the inner side of the main reflective surface 23. Among them, the radome 24 has good electromagnetic wave penetration characteristics in electrical performance, and can withstand the influence of external harsh environment in mechanical performance, so as to protect the core components of the antenna from the influence of the external environment.

[0092] Specifically, the indoor unit 402 can be used to process the baseband signal and convert it into an intermediate frequency signal, and transmit the intermediate frequency signal to the outdoor unit 401. The outdoor unit 401 can realize the frequency conversion and amplification of the intermediate frequency signal and the radio frequency signal, and transmit the processed radio frequency signal to the antenna 300. The antenna 300 is responsible for converting the radio frequency signal into a spatial electromagnetic wave and radiating it. The process of the antenna receiving the radio frequency signal is the opposite. The outdoor unit 401 can select the frequency, amplify and convert the radio frequency signal received by the antenna, and convert it into an intermediate frequency signal and send it to the indoor unit 402. The indoor unit 402 then processes the intermediate frequency signal and converts it into a baseband signal.

[0093] In an embodiment of the present application, the above-mentioned communication device may be a device for microwave frequency band communication, that is, a microwave device. The communication frequency band of the microwave device is in the range of 6-86 GHz. In some embodiments, the communication frequency band of the microwave device includes the 6-42 GHz frequency band, the 57-64 GHz frequency band, and the 71-86 GHz frequency band.

[0094] The embodiment of the present application also provides a communication system, which includes at least two of the above communication devices, and the communication devices can communicate with each other. As mentioned above, the communication device can be a microwave device with a communication frequency band in the range of 6-86 GHz.

[0095] The following is a further description of the embodiments of the present application in terms of a number of specific embodiments, wherein the embodiments of the present application are not limited to the following specific embodiments.

[0096] Example 1

[0097] A support structure for a sub-reflecting surface of a microwave antenna, used to connect between a feed tube and a sub-reflecting surface of the antenna, the support structure is a hollow support joint (such as Figure 2 As shown in the reference numeral 20 in the figure), one end is sleeved on the outside of the feed tube and bonded to the feed tube, and the other end is bonded to the secondary reflector; the wall thickness of the support joint is about 8 mm.

[0098] Among them, the supporting joint is made of foam material, which contains polyimide (PI) with an aromatic structure in the main chain. The dielectric constant Dk of the foam material at a frequency of 6-86GHz is about 1.17-1.18. The dimensional shrinkage rate of the supporting joint after being placed in an environment of temperature 85°C and relative humidity 85% for one week is 0.2%.

[0099] The inner and outer surfaces of the support joint have no exposed pores, and the closed cell rate of the pores in the support joint is above 97%. The density of the support joint is 0.128 g / cm 3 , Shore hardness C is about 70; the glass transition temperature Tg of the support joint is 315°C, and the thermal expansion coefficient CTE of the above-mentioned PI is 48ppm / °C; the dielectric loss Df of the foam material at a frequency of 6-86GHz is about 0.004; the support joint with a wall thickness of 8mm has a transmittance of 90% for vertically incident electromagnetic waves in the range of 6-86GHz.

[0100] The foaming material is formed by reacting aromatic dianhydride (specifically phthalic anhydride) and aromatic isocyanate (specifically polymethylene polyphenyl isocyanate) in a molar ratio of 0.9:1, a catalyst (specifically a composite catalyst composed of triethanolamine and dibutyltin dilaurate), anhydrous methanol as a foaming aid, and a foam stabilizer in a sealed mold under heating conditions. Specifically, PI is formed by in-situ reaction of aromatic dianhydride and aromatic isocyanate, and CO generated synchronously by the reaction is used to generate the foaming material. 2 To give the cell structure, a small amount of water can be added to adjust the reaction rate and the amount of bubbles produced. The foaming ratio of the foaming material is 7 times (the foaming ratio is the volume ratio of the foaming material to the reaction raw materials used to form PI).

[0101] Example 2

[0102] A support structure for a sub-reflecting surface of a microwave antenna, used to connect between a feed tube and a sub-reflecting surface of the antenna, the support structure is a hollow support joint (such as Figure 2 As shown in the reference numeral 20 in the figure), one end is sleeved on the outside of the feed tube and bonded to the feed tube, and the other end is bonded to the secondary reflector; the wall thickness of the support joint is about 8 mm.

[0103] Among them, the supporting joint is made of foam material, which contains polyphenylene ether (PPO) with an aromatic structure in the main chain. The dielectric constant Dk of the foam material at a frequency of 6-86GHz is about 1.15-1.16. The dimensional shrinkage rate of the supporting joint after being placed in an environment of temperature 85°C and relative humidity 85% for one week is 0.3%.

[0104] The inner and outer surfaces of the support joint have no exposed pores, and the closed cell rate of the pores in the support joint is 100%; the density of the support joint is 0.135 g / cm 3 , Shore hardness C is about 78; the glass transition temperature Tg of the support joint is 211°C, and the thermal expansion coefficient CTE of the above-mentioned PPO is 60ppm / °C; the dielectric loss Df of the foam material at a frequency of 6-86GHz is about 0.001-0.003; the support joint with a wall thickness of 8mm has a transmittance of 90% for vertically incident electromagnetic waves with a frequency in the range of 6-86GHz.

[0105] The preparation process of the above-mentioned supporting joint may include: subjecting surface-modified polyphenylene ether (PPO) plastic particles (surface coated with a low-melting point polymer (such as polystyrene)) to supercritical foaming using nitrogen or carbon dioxide in an extruder above its glass transition temperature to obtain foamed particles with a predetermined foaming ratio; then injecting the foamed particles into a mold cavity, and passing high-temperature water vapor into the mold cavity to weld the foamed particles to form a foamed material to obtain a hollow supporting joint.

[0106] In order to highlight the effects of the embodiments of the present application, the following comparative examples 1 and 2 are provided.

[0107] Comparative Example 1

[0108] A support structure for a microwave antenna, used to be connected to the main reflector of the antenna to support the secondary reflector; the support structure is a metal bracket (structure diagram as shown in Figure 5 shown).

[0109] Comparative Example 2

[0110] A supporting structure for a secondary reflector of a microwave antenna is a hollow supporting joint, and its structure is the same as that of Example 1, except that: the supporting joint is made by a foamed plate containing a blend of polyphenylene ether (PPO) and polystyrene (PS) through a mechanical processing method. The dielectric constant Dk of the foamed material at a frequency of 6-86 GHz is about 1.15-1.16, but the size shrinkage rate of the supporting joint after being placed in an environment of a temperature of 85°C and a relative humidity of 85% for one week is 3%, which cannot meet the requirements of moisture and heat aging resistance.

[0111] In order to further demonstrate the beneficial effects of the present application, the support structures of Example 1 and Comparative Examples 1-2 were assembled into double-reflecting-surface microwave antennas, and the polarization gain and radiation pattern of each antenna were tested.

[0112] Table 1 below summarizes the vertical polarization gain and horizontal polarization gain of the antennas of Example 1 and Comparative Examples 1-2 at different frequencies. Wherein, VV and HH represent that the amplitude direction of the electric field radiated by the antenna is vertical and horizontal, respectively. The antenna gain test adopts the comparison method, and measures the received power of the standard antenna (whose gain is known) and the received power of the antenna to be tested respectively under the same environment. The difference between the two is calculated and added to the gain value of the standard antenna, which is the gain value of the antenna to be tested.

[0113] Table 1

[0114]

[0115]

[0116] It can be seen from Table 1 that the polarization gain of the antenna in Comparative Example 1, which uses a metal bracket as a sub-reflector support structure, in both vertical and horizontal directions is lower than that of Example 1 and Comparative Example 2. However, the antennas in Example 1 and Comparative Example 2, which use a support joint containing a foam material as a sub-reflector support structure, have basically the same gain, and the polarization gain in the vertical and horizontal directions is improved by about 0.5 dB compared with Comparative Example 1.

[0117] Figure 6The antenna radiation patterns of the horizontal polarization direction measured at a frequency of 78.5 GHz for the antenna of comparative example 1 (a), the antenna of comparative example 2 (b), and the antenna of embodiment 1 (c) are summarized. The broken line in the figure is the ETSI Class 3 standard template, and the antenna radiation pattern needs to be below the broken line to meet the standard requirements. Figure 6 It can be known that Figure 6 As shown in (a), the radiation pattern of the antenna in Comparative Example 1 performs poorly within the range of ±15°, which indicates that the metal bracket has a greater impact on the near side lobes of the antenna radiation pattern, with almost no margin compared to the standard requirements, and even slightly exceeding the standard at some positions. The radiation patterns of the antennas in Example 1 and Comparative Example 2 have improved a lot within the range of ±15°, both with a margin of about 5dB, meeting the margin of ETSI C3.

[0118] Next, the antenna performance of the antenna of Example 1 is compared before and after the damp heat test, wherein the antenna polarization gain before and after the damp heat test is summarized in the following Table 2: Figure 7 The antenna radiation pattern of the horizontal polarization direction measured at a frequency of 78.5 GHz after the damp heat test of the antenna of Example 1 is illustrated. The damp heat test is performed in an environment of 85° C. and 85% relative humidity for one week.

[0119] Table 2

[0120]

[0121] Note: In Table 2, after being placed under damp heat conditions for one week, the support joint 20 of the embodiment of the present application has a small amount of size shrinkage. "Pull up 1-2mm" means that in the antenna after the damp heat test, Figure 2 The sub-reflecting surface 22 in the support joint is moved 1-2 mm in the direction away from the feed tube 21 so that the sub-reflecting surface 22 is accommodated in the upper end opening of the support joint again.

[0122] It can be seen from Table 2 that after one week of the damp heat test, the vertical polarization gain of the antenna in Example 1 at high frequency has only deteriorated by about 0.1-0.2 dB, which has little impact. After focusing, the gain at each frequency can basically reach the same level as before the damp heat test, or even better.

[0123] from Figure 7 With the above Figure 6 From the comparison in (c), it can be seen that the antenna radiation pattern of the antenna in the horizontal polarization direction of Example 1 measured before and after the wet heat test has a high degree of consistency, and there is no obvious difference before and after the test, indicating that the sub-reflector support material used in the antenna has good weather resistance and will not be affected by the use environment and cause performance deterioration.

[0124] The above only expresses several exemplary embodiments of the present application, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present application. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present application, which all belong to the protection scope of the present application. Therefore, the protection scope of the patent of the present application shall be based on the attached claims.

[0125] It should be understood that the words "first", "second", etc. in this application are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. In addition, in this document, directional terms such as "upper" and "lower" are defined relative to the orientation of the structure schematically placed in the drawings. It should be understood that these directional terms are relative concepts. They are used for relative description and clarification, and they can change accordingly according to the change of the orientation of the structure.

[0126] In the description of this application, unless otherwise specified, "multiple" means greater than or equal to two. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple.

[0127] In this application, "and / or" describes the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects are in an "or" relationship.

Claims

1. A support structure for an antenna, used to connect between a feed tube and a sub-reflecting surface of the antenna, characterized in that: The support structure is a hollow support joint, and the support joint is made of foam material. The size shrinkage rate of the support joint after being placed in an environment with a temperature of 70-100° C. and a relative humidity of 50-95% for 4 days is less than or equal to 1%.

2. The support structure according to claim 1, characterized in that The dielectric constant of the foaming material at a frequency of 6-86 GHz is less than or equal to 1.

2.

3. The support structure according to claim 1 or 2, characterized in that: The dielectric loss of the foaming material at a frequency of 6-86 GHz is less than or equal to 0.

005.

4. The support structure according to any one of claims 1 to 3, characterized in that: The support joint has a Shore C hardness greater than or equal to 50.

5. The support structure according to any one of claims 1 to 4, characterized in that: At least 2 cm on either the inner or outer surface of the support joint 2 In the area, the number of exposed cells is less than or equal to 20.

6. The support structure according to claim 5, characterized in that At least 2 cm on either the inner or outer surface of the support joint 2 In the area, the number of exposed cells is less than or equal to 5.

7. The support structure according to any one of claims 1 to 6, characterized in that: The closed cell ratio of the cells in the supporting joint is greater than or equal to 90%.

8. The support structure according to any one of claims 1 to 7, wherein the density of the support joint is 0.5 g / cm 3 the following.

9. The support structure according to claim 8, characterized in that The density of the support joint is 0.08-0.15 g / cm 3 .

10. The support structure according to any one of claims 1 to 9, characterized in that: The support joint with a wall thickness of less than 10 mm has a wave transmittance greater than or equal to 90% for vertically incident microwaves with a frequency in the range of 6-86 GHz.

11. The support structure according to any one of claims 1 to 10, characterized in that: The glass transition temperature of the supporting joint is greater than or equal to 150°C.

12. The support structure according to any one of claims 1 to 11, characterized in that: The glass transition temperature of the supporting joint is greater than or equal to 190°C.

13. The support structure according to any one of claims 1 to 12, characterized in that: The foaming material comprises a polymer having an aromatic structure in the main chain.

14. The support structure according to claim 13, characterized in that The polymer includes one or more of polyimide, polyethersulfone, polyarylether, and polyarylether sulfide, the main chain of which contains an aromatic structure.

15. The support structure according to any one of claims 1 to 14, characterized in that: The opening size of the support joint increases gradually from one end to the opposite end, and the side surface of the support joint is a smooth curved surface.

16. The support structure according to any one of claims 1 to 15, characterized in that: The wall thickness of the support joint is in the range of 8-15 mm.

17. A foaming material used for the supporting structure of the antenna sub-reflection surface, characterized in that: The dielectric constant of the foaming material at a frequency of 6-86 GHz is less than or equal to 1.

2.

18. The foam material according to claim 17, characterized in that The dielectric loss of the foaming material at a frequency of 6-86 GHz is less than or equal to 0.

005.

19. The foam material according to claim 17 or 18, characterized in that: The Shore hardness C of the foaming material is greater than or equal to 50.

20. The foaming material according to any one of claims 17 to 19, characterized in that: The density of the foaming material is 0.5 g / cm 3 the following.

21. An antenna assembly, characterized in that: The antenna assembly includes a sub-reflecting surface, a feed tube, and a supporting structure as described in any one of claims 1 to 16, wherein opposite ends of the supporting structure are respectively connected to the feed tube and the sub-reflecting surface.

22. The antenna assembly according to claim 21, wherein: One end of the support structure is sleeved on the outside of the feed tube, and the other end is connected to the secondary reflector.

23. The antenna assembly according to claim 21 or 22, characterized in that: The opposite ends of the support structure are bonded to the feed tube and the secondary reflector respectively.

24. The antenna assembly according to any one of claims 21 to 23, characterized in that: The support structure includes a first main body and a second main body, wherein the first main body is close to the feed tube; wherein the opening size of the first main body remains unchanged, and the opening size of the second main body gradually increases toward the secondary reflector.

25. An antenna, characterized in that: The antenna comprises a main reflecting surface and an antenna assembly as described in any one of claims 21 to 24, wherein the feed tube is connected to the main reflecting surface.

26. A communication device, characterized in that: The communication device includes the antenna as claimed in claim 25, and an outdoor unit and an indoor unit.

27. A communication system, characterized in that: The communication system comprises at least two communication devices according to claim 26, and the communication devices can communicate with each other.

28. A method for preparing a supporting structure for an antenna, characterized in that: The following steps are involved: The reaction raw materials for forming the support structure are placed in a mold whose cavity shape corresponds to the shape of the support structure to be prepared and sealed. After heating treatment, the reaction raw materials react with each other and generate gas to obtain a hollow support joint containing a foaming material; wherein the support joint has a dimensional shrinkage rate of less than or equal to 1% after being placed in an environment with a temperature of 70-100°C and a relative humidity of 50-95% for 4 days.

29. A method for preparing a supporting structure for an antenna, characterized in that: The following steps are involved: The foamed particles are placed in a mold whose cavity shape corresponds to the shape of the support structure to be prepared and sealed, and the foamed particles are melted to form a foamed material through hot steam treatment to obtain a hollow support joint; wherein the support joint has a dimensional shrinkage rate of less than or equal to 1% after being placed in an environment with a temperature of 70-100°C and a relative humidity of 50-95% for 4 days.

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