Frequency selection surface antenna housing

Abstract

The utility model provides a frequency selection surface radome, which belongs to the design field of multifunctional radomes and comprises 15 dielectric layers including four layers of wide-strip dielectric circuit boards, two layers of narrow-strip dielectric circuit boards, four layers of glass fiber reinforced plastics and five layers of low-density foam boards. The two layers of narrow-strip dielectric circuit boards comprise an upper narrow-strip dielectric circuit board and a lower narrow-strip dielectric circuit board; an upper low-density foam board I, upper glass fiber reinforced plastic I and an upper wide-strip dielectric circuit board I are sequentially arranged above the upper narrow-strip dielectric circuit board; an upper low-density foam board II, an upper glass fiber reinforced plastic II and an upper wide-strip dielectric circuit board II are sequentially arranged below the upper narrow-strip dielectric circuit board; according to the utility model, the platform mold and the positioning pin are used for positioning, so that the actual transmission characteristic of the dielectric layer can be closer to an electrical performance simulation result, and the frequency selection characteristics that the dielectric layer can pass in a certain frequency band range, the insertion loss is less than 1.5 dB, the dielectric layer is isolated in a certain stop band range, and the isolation degree is greater than 10dB are realized.

Description

Technical Field

[0001] This utility model belongs to the field of multifunctional radome design, specifically relating to a frequency selective surface radome. Background Technology

[0002] A frequency-selective radome is a type of radome with specific frequency selectivity characteristics. In modern wireless communication and radar systems, radomes play a crucial role, protecting antennas from external environmental influences such as wind, rain, dust, and temperature changes without affecting antenna performance. Traditional radomes are typically made of wave-transparent materials, allowing virtually indiscriminate transmission of electromagnetic waves of all frequencies.

[0003] In some applications, radomes are required to selectively allow electromagnetic waves of specific frequencies to pass through while reflecting or absorbing electromagnetic waves of other frequencies. In multi-band communication systems, to avoid interference between different frequency bands, radomes need to selectively allow specific frequency bands to pass through while isolating certain frequency bands.

[0004] Publication No. CN108767488B discloses a frequency selective surface, a frequency selective surface structure, and an radome. The frequency selective surface is composed of periodically arranged slot-type units. Each slot-type unit is composed of a regular polygonal ring and a regular polygonal patch located inside the regular polygonal ring, both of which are concentric and have the same number of sides. The inner side of any edge of the regular polygonal ring is provided with the same mesh structure. The mesh structure includes multiple "V" patterns spaced apart on the inner side of the ring edge, with their openings not facing the ring edge. The arms of each "V" pattern do not intersect with those of its adjacent "V" patterns. One arm of the "V" patterns on the inner side of the two ring edges, located near the intersection of the two ring edges, intersects at a single point, and the structure formed by the intersecting arm of the "V" patterns on the inner side of the two ring edges and the two ring edges is a solid metal structure. This invention can achieve continuous transmission characteristics in a wide frequency band of X, Ku, K, Ka, and U bands.

[0005] To address the issue of radomes being able to transmit in a specific frequency band and isolate in another, high-precision manufacturing and positioning processes can be used to achieve frequency selectivity characteristics that meet the required specifications. Summary of the Invention

[0006] To overcome the problem that existing radomes cannot selectively transmit electromagnetic waves of a specific frequency while reflecting or absorbing electromagnetic waves of other frequencies, this invention provides a frequency-selective radome. This invention has frequency selectivity characteristics, including transmission within a certain frequency band with insertion loss of less than 1.5dB, and isolation within a certain stopband with an isolation degree greater than 10dB.

[0007] The technical solution adopted in this utility model is as follows:

[0008] A frequency selective radome includes 15 dielectric layers, comprising four wide-strip dielectric circuit boards, two narrow-strip dielectric circuit boards, four layers of fiberglass and five layers of low-density foam board, wherein the two narrow-strip dielectric circuit boards comprise an upper narrow-strip dielectric circuit board and a lower narrow-strip dielectric circuit board.

[0009] Above the upper narrow strip dielectric circuit board, there are sequentially arranged upper low-density foam board one, upper fiberglass one, and upper wide strip dielectric circuit board one; below the upper narrow strip dielectric circuit board, there are sequentially arranged upper low-density foam board two, upper fiberglass two, and upper wide strip dielectric circuit board two.

[0010] Above the lower narrow strip dielectric circuit board, there are sequentially arranged a lower low-density foam board, a lower fiberglass board, and a lower wide strip dielectric circuit board; below the lower narrow strip dielectric circuit board, there are sequentially arranged a lower low-density foam board, a lower fiberglass board, and a lower wide strip dielectric circuit board.

[0011] A middle low-density foam board is provided between the upper wide strip dielectric circuit board two and the lower wide strip dielectric circuit board one.

[0012] The four-layer wide strip dielectric circuit board has metal lines placed horizontally on each layer, with a line width of 4mm, and the metal lines are periodically arranged horizontally at a spacing of 4.4mm.

[0013] The two-layer narrow strip dielectric circuit board has metal lines placed vertically on each layer, with a line width of 0.2mm, and the metal lines are periodically arranged vertically at a spacing of 4.4mm.

[0014] The total thickness of the 15 dielectric layers is 10.1 mm.

[0015] The five-layer low-density foam board includes a middle low-density foam board with a thickness of 0.7 mm and upper low-density foam board one, upper low-density foam board two, lower low-density foam board one, and lower low-density foam board two, each with a thickness of 1.3 mm.

[0016] The thickness of both the upper narrow strip dielectric circuit board and the lower narrow strip dielectric circuit board is 0.5 mm.

[0017] The four-layer fiberglass includes upper fiberglass I, upper fiberglass II, lower fiberglass I, and lower fiberglass II, each with a thickness of 0.3mm.

[0018] The four-layer wide stripe dielectric circuit board includes an upper wide stripe dielectric circuit board one, an upper wide stripe dielectric circuit board two, a lower wide stripe dielectric circuit board one, and a lower wide stripe dielectric circuit board two, all with a thickness of 0.5mm.

[0019] The four-layer wide-strip dielectric circuit board and the two-layer narrow-strip dielectric circuit board are both polytetrafluoroethylene (PTFE) circuit boards. The surface coating of the PTFE circuit board is a copper layer with a thickness of 0.035 mm.

[0020] The 15 dielectric layers are bonded together with epoxy adhesive film.

[0021] The beneficial effects of this utility model are:

[0022] In this invention, the metal line width accuracy of the wide strip dielectric circuit board and the narrow strip dielectric circuit board is required to be ±0.05mm, and the metal line spacing accuracy is required to be ±0.05mm; secondly, the positioning pin hole accuracy between the copper-clad boards is ±0.05mm, and the metal line and the positioning pin hole are completed by clamping the copper-clad board in one operation during processing to ensure the position accuracy of the positioning pin hole and the metal line; ensuring the high-precision manufacturing of the frequency selective radome.

[0023] In this invention, the 15-layer dielectric layer is positioned by platform molds and tooling, so that the upper and lower metal lines of the wide strip dielectric circuit board and the narrow strip dielectric circuit board can be precisely aligned. In this way, the actual transmission characteristics of the dielectric layer are closer to the electrical performance simulation results.

[0024] The radome provided by this utility model has frequency selectivity characteristics, which allows it to pass through a certain frequency band with an insertion loss of less than 1.5dB, and provides isolation within a certain stopband with an isolation degree of greater than 10dB. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the dielectric layer structure of a frequency selective radome.

[0026] Figure 2 This is a schematic diagram of the dielectric structure after 15 dielectric layers are combined.

[0027] Figure 3 This is a schematic diagram of a narrow strip dielectric circuit board structure.

[0028] Figure 4 yes Figure 3 Enlarged diagram of point A in the middle.

[0029] Figure 5 This is a schematic diagram of a wide stripe dielectric circuit board structure.

[0030] Figure 6 yes Figure 5 Enlarged diagram of point A in the middle.

[0031] Figure 7 This is a schematic diagram of the positioning method for composite molding of dielectric layers.

[0032] The present invention will be further described in detail below with reference to the accompanying drawings.

[0033] In the figure, the attached figures are labeled as follows:

[0034] 1. Lower wide strip medium circuit board one; 2. Lower fiberglass one; 3. Lower low-density foam board one; 4. Lower narrow strip medium circuit board; 5. Lower low-density foam two; 6. Lower fiberglass two; 7. Lower wide strip medium circuit board two; 8. Middle low-density foam board; 9. Upper wide strip medium circuit board one; 10. Upper fiberglass one; 11. Upper low-density foam board one; 12. Upper narrow strip medium circuit board; 13. Upper low-density foam board two; 14. Upper fiberglass two; 15. Upper wide strip medium circuit board two; 16. Platform mold; 17. Positioning pin. Detailed Implementation

[0035] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0036] The accompanying drawings show various structural schematic diagrams according to embodiments of the present invention. These drawings are not to scale, and some details have been enlarged and may have been omitted for clarity. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0037] Example 1:

[0038] To overcome the problem that existing radomes cannot selectively transmit electromagnetic waves of specific frequencies while reflecting or absorbing electromagnetic waves of other frequencies, this invention provides... Figures 1-7 The present invention provides a frequency selective radome that has the characteristics of passing through a certain frequency band with an insertion loss of less than 1.5dB, and isolating within a certain stopband with an isolation degree of greater than 10dB.

[0039] A frequency selective radome includes 15 dielectric layers, comprising four wide stripe dielectric circuit boards, two narrow stripe dielectric circuit boards, four fiberglass layers, and five low-density foam boards. The two narrow stripe dielectric circuit boards include an upper narrow stripe dielectric circuit board 4 and a lower narrow stripe dielectric circuit board 12.

[0040] Above the upper narrow strip dielectric circuit board 4, there are sequentially arranged upper low-density foam board 3, upper fiberglass 2, and upper wide strip dielectric circuit board 1; below the upper narrow strip dielectric circuit board 4, there are sequentially arranged upper low-density foam board 2 5, upper fiberglass 2 6, and upper wide strip dielectric circuit board 2 7.

[0041] Above the lower narrow strip dielectric circuit board 12, there are sequentially arranged a lower low-density foam board 11, a lower fiberglass 10, and a lower wide strip dielectric circuit board 9; below the lower narrow strip dielectric circuit board 12, there are sequentially arranged a lower low-density foam board 2 13, a lower fiberglass 2 14, and a lower wide strip dielectric circuit board 2 15.

[0042] A middle low-density foam board 8 is provided between the upper wide strip dielectric circuit board 2 7 and the lower wide strip dielectric circuit board 1 9.

[0043] The frequency selective radome provided by this utility model is manufactured using a dielectric layer composite structure, which combines 15 layers of dielectric material according to... Figure 1 The order shown is used to lay the layers one by one. Figure 7 On the platform mold 16 shown, the dielectric layers are bonded together with epoxy film. The upper and lower wide strip dielectric circuit boards, narrow strip dielectric circuit boards, fiberglass plates, and PMI low-density foam boards are precisely positioned using the platform mold 16 and positioning pins 17. The positioning accuracy between the upper and lower dielectric circuit boards is less than 0.05mm. The 15 layers of dielectric material are bonded together in an autoclave under high temperature and pressure to form a composite material dielectric structure with frequency selectivity. Figure 2 The total thickness shown is 10.1 mm.

[0044] like Figure 2 As shown, this application uses a low-density foam board 8 as the central layer, with symmetrical sides on both sides based on this. In this utility model, there are 5 layers of low-density foam board, 4 layers of fiberglass board, and 6 layers of dielectric circuit board. The substrate of the dielectric circuit board is made of polytetrafluoroethylene (PTFE), with a surface coating of a copper layer. The copper layer has a thickness of 0.035 mm, a dielectric constant of 2.55, and a loss tangent of 0.0001. The fiberglass board has a thickness of 0.3 mm, a dielectric constant of 4, and a loss tangent of 0.02. The PMI foam has a dielectric constant of 1.08 and a loss tangent of 0.008. Through electrical performance simulation, it can meet the following requirements: for a certain passband range, vertical polarization allows passage with an insertion loss of less than 1.5 dB; for a certain stopband range, horizontal polarization provides isolation with an isolation greater than 10 dB.

[0045] Example 2:

[0046] Based on Embodiment 1, in this embodiment, preferably, the metal lines on each layer of the four-layer wide strip dielectric circuit board are placed horizontally, with a line width of 4mm, and the metal lines are periodically arranged horizontally at a spacing of 4.4mm.

[0047] Preferably, the four-layer wide stripe dielectric circuit board includes an upper wide stripe dielectric circuit board 1, an upper wide stripe dielectric circuit board 7, a lower wide stripe dielectric circuit board 9, and a lower wide stripe dielectric circuit board 15, all with a thickness of 0.5mm.

[0048] In this invention, the circuit board substrate of the four-layer wide strip dielectric circuit board is made of polytetrafluoroethylene material, and the surface coating is a copper layer with a thickness of 0.035mm, a dielectric constant of 2.55, and a loss tangent of 0.0001.

[0049] In this invention, a wide strip dielectric circuit board is used, with metal lines placed horizontally, each 4mm wide, and the metal lines arranged periodically at 4.4mm intervals. The dielectric circuit board layout is shown in the diagram below. Figure 3 and Figure 4 As shown, the dielectric circuit board uses Taizhou Wangling products with a thickness of 0.5mm.

[0050] like Figure 3 As shown, the wide strip dielectric circuit board is symmetrically arranged on both sides with a vertical processing reference line as the reference.

[0051] like Figure 4 As shown, the wide strip dielectric circuit board has a single-sided copper clad plate with a thickness of δ0.5. The shaded area is the copper clad area with a copper thickness of 0.035mm. The metal lines are placed horizontally. During processing, the horizontal processing reference line is used to make the two sides symmetrical.

[0052] Preferably, in the two-layer narrow strip dielectric circuit board, the metal lines on each narrow strip dielectric circuit board are placed vertically, with a line width of 0.2mm, and the metal lines are periodically arranged vertically at a spacing of 4.4mm.

[0053] Preferably, the thickness of both the upper narrow strip dielectric circuit board 4 and the lower narrow strip dielectric circuit board 12 is 0.5 mm.

[0054] In this utility model, the two-layer narrow strip dielectric circuit board adopts Taizhou Wangling products with a thickness of 0.5mm. The substrate of the narrow strip dielectric circuit board is made of polytetrafluoroethylene material, and the surface coating is a copper layer with a thickness of 0.035mm, a dielectric constant of 2.55, and a loss tangent of 0.0001.

[0055] In this invention, a narrow strip dielectric circuit board is used, with metal lines placed vertically, each line being 0.2 mm wide. The metal lines are periodically arranged vertically at 4.4 mm intervals. The dielectric circuit board layout diagram is shown below. Figure 5 and Figure 6 As shown, its error range is ±0.005.

[0056] like Figure 5As shown, the narrow strip dielectric circuit board has a vertical processing reference line, which is used as a reference for symmetry on both sides; the narrow strip dielectric circuit board also has a horizontal processing reference line, which is used as a reference for symmetry on both sides.

[0057] like Figure 6 As shown, the shaded area is the copper-clad area with a copper thickness of 0.035mm; the single-sided copper-clad board has a δ of 0.5, and the vertical processing reference line is symmetrical on both sides.

[0058] Preferably, the four-layer wide strip dielectric circuit board and the two-layer narrow strip dielectric circuit board are both polytetrafluoroethylene (PTFE) circuit boards, and the surface coating of the PTFE circuit board is a copper layer with a thickness of 0.035 mm.

[0059] In this invention, the metal line width accuracy of the wide strip copper clad laminate (wide strip dielectric circuit board) and the narrow strip copper clad laminate (narrow strip dielectric circuit board) is required to be ±0.05mm, and the metal line spacing accuracy is required to be ±0.05mm. Secondly, the positioning pin hole accuracy between the copper clad laminates is ±0.05mm, and the metal line and the positioning pin hole are completed by clamping the copper clad laminate in one operation during processing to ensure the positional accuracy of the positioning pin hole and the metal line.

[0060] Preferably, the total thickness of the 15 dielectric layers is 10.1 mm.

[0061] Preferably, the five-layer low-density foam board includes a middle low-density foam board 8 with a thickness of 0.7 mm and upper low-density foam board 3, upper low-density foam board 5, lower low-density foam board 11, and lower low-density foam board 13, each with a thickness of 1.3 mm.

[0062] In this invention, all five layers of low-density foam boards are preferably PMI low-density foam boards. The thickness of the upper low-density foam board 3, the upper low-density foam board 5, the lower low-density foam board 11, and the lower low-density foam board 213 is 1.3 mm, the dielectric constant is 1.08, and the loss tangent is 0.008.

[0063] In this invention, the low-density foam is divided into two types: one is 0.7mm thick and has one layer; the other is 1.3mm thick and has four layers, which are customized by the foam processing plant according to the thickness.

[0064] Preferably, the four-layer fiberglass includes upper fiberglass 12, upper fiberglass 26, lower fiberglass 10, and lower fiberglass 214, all with a thickness of 0.3mm.

[0065] In this invention, all four layers of fiberglass are 0.3mm thick, with a dielectric constant of 4 and a loss tangent of 0.02. The fiberglass is 0.3mm thick, consisting of four layers, and is made using epoxy fiberglass cloth. It is cured in an autoclave and its external dimensions and positioning holes are CNC cut.

[0066] Preferably, the 15 dielectric layers are bonded together with epoxy adhesive film.

[0067] In this utility model, during the manufacturing of multilayer dielectric boards, such as Figure 7 As shown, a platform mold 16 is prepared, and positioning pin holes with a positioning accuracy of ±0.025mm are designed on the platform mold 16. Figure 1 The laying sequence shown involves laying the above 15 layers of medium material layer by layer. Figure 5 On the mold shown, the layers of dielectric materials are bonded together with epoxy film. The upper and lower wide strip dielectric circuit boards, narrow strip dielectric circuit boards, fiberglass plates, and PMI low-density foam boards are precisely positioned by positioning pin holes and positioning pins 17 on the platform mold 16. The positioning accuracy between the upper and lower dielectric circuit boards is less than 0.05mm. The 15 layers of dielectric materials are bonded together under high temperature and high pressure to form a composite material dielectric structure with frequency selection function.

[0068] In this invention, the 15-layer dielectric material is positioned by the platform mold 16 and tooling, so that the upper and lower metal lines of the wide strip copper clad laminate and the narrow strip copper clad laminate can be precisely aligned. In this way, the actual transmission characteristics of the dielectric layer are closer to the electrical performance simulation results.

[0069] This invention can achieve the following polarization characteristics and frequency selection functions:

[0070] (1) A certain passband; the passband insertion loss is no more than 1.5dB.

[0071] (2) A certain stopband range; stopband isolation: greater than 10dB.

[0072] (3) Vertical polarization passes through, horizontal polarization is isolated, and the horizontal polarization isolation is 10 dB.

[0073] (4) Incident angle range ±55°.

[0074] This invention provides a solution for manufacturing a radome with specific frequency selectivity characteristics and its dielectric layer composite structure. The single-slot FSS (Frequency Selective Surface) is characterized by a high transmission coefficient for vertically polarized incident waves at 10 GHz at 0° incidence, while exhibiting very low transmission coefficient for horizontally polarized incident waves at 10 GHz, almost isolating them. The single-slot FSS demonstrates polarization selectivity and high transmittance for vertically polarized plane waves, making it suitable for TE mode operation. Utilizing these characteristics, a single-slot frequency selective surface is inserted into a multilayer dielectric material. By adjusting the shape and material of the FSS structure and employing high-precision composite manufacturing of the multilayer materials, more precise control over electromagnetic waves can be achieved. CST simulation results show that the radome provided by this invention exhibits frequency selectivity characteristics: transmission within a certain frequency band with insertion loss less than 1.5 dB, and isolation within a certain stopband with an isolation degree greater than 10 dB.

[0075] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0076] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the scope of the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0077] The examples above are merely illustrative of this utility model and do not constitute a limitation on the scope of protection of this utility model. All designs that are identical or similar to this utility model fall within the scope of protection of this utility model. Device structures and method steps not described in detail in this utility model are existing technologies and will not be further described in this utility model.

Claims

1. A frequency selective radome, characterized in that: It includes 15 dielectric layers, which include four wide strip dielectric circuit boards, two narrow strip dielectric circuit boards, four fiberglass and five low-density foam boards. The two narrow strip dielectric circuit boards include an upper narrow strip dielectric circuit board (4) and a lower narrow strip dielectric circuit board (12). Above the upper narrow strip dielectric circuit board (4) are arranged an upper low-density foam board (3), an upper fiberglass board (2), and an upper wide strip dielectric circuit board (1); below the upper narrow strip dielectric circuit board (4) are arranged an upper low-density foam board (5), an upper fiberglass board (6), and an upper wide strip dielectric circuit board (7). Above the lower narrow strip dielectric circuit board (12), there are successively arranged a lower low-density foam board (11), a lower fiberglass board (10), and a lower wide strip dielectric circuit board (9); below the lower narrow strip dielectric circuit board (12), there are successively arranged a lower low-density foam board (13), a lower fiberglass board (14), and a lower wide strip dielectric circuit board (15). A middle low-density foam board (8) is provided between the upper wide strip dielectric circuit board 2 (7) and the lower wide strip dielectric circuit board 1 (9).

2. The frequency selective radome according to claim 1, characterized in that: The four-layer wide strip dielectric circuit board has metal lines placed horizontally on each layer, with a line width of 4mm, and the metal lines are periodically arranged horizontally at a spacing of 4.4mm.

3. The frequency selective radome according to claim 1, characterized in that: The two-layer narrow strip dielectric circuit board has metal lines placed vertically on each layer, with a line width of 0.2mm, and the metal lines are periodically arranged vertically at a spacing of 4.4mm.

4. A frequency selective surface radome according to claim 1, characterized in that: The total thickness of the 15 dielectric layers is 10.1 mm.

5. A frequency selective surface radome according to claim 1, characterized in that: The five-layer low-density foam board includes a middle low-density foam board (8) with a thickness of 0.7 mm and upper low-density foam board one (3), upper low-density foam board two (5), lower low-density foam board one (11) and lower low-density foam board two (13), each with a thickness of 1.3 mm.

6. A frequency selective surface radome according to claim 1, characterized in that: The thickness of both the upper narrow strip dielectric circuit board (4) and the lower narrow strip dielectric circuit board (12) is 0.5 mm.

7. A frequency selective radome according to claim 1, characterized in that: The four-layer fiberglass includes upper fiberglass one (2), upper fiberglass two (6), lower fiberglass one (10), and lower fiberglass two (14), all with a thickness of 0.3mm.

8. A frequency selective surface radome according to claim 1, characterized in that: The four-layer wide strip dielectric circuit board includes an upper wide strip dielectric circuit board one (1), an upper wide strip dielectric circuit board two (7), a lower wide strip dielectric circuit board one (9), and a lower wide strip dielectric circuit board two (15), all with a thickness of 0.5mm.

9. A frequency selective surface radome according to claim 1, characterized in that: The four-layer wide-strip dielectric circuit board and the two-layer narrow-strip dielectric circuit board are both polytetrafluoroethylene (PTFE) circuit boards. The surface coating of the PTFE circuit board is a copper layer with a thickness of 0.035 mm.

10. A frequency selective surface radome according to claim 1, characterized in that: The 15 dielectric layers are bonded together with epoxy adhesive film.

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