A low-frequency wave-transparent and high-frequency wave-reflecting device based on a frequency-selective surface and a satellite antenna cover

Abstract

The application belongs to the technical field of frequency selective surface radomes, and particularly relates to a low-frequency wave-transparent and high-frequency wave-reflecting device based on a frequency selective surface and a satellite radome, which comprises, from top to bottom, a first low-pass layer, a first dielectric isolation layer, a first band-stop layer, a second dielectric isolation layer and a second low-pass layer; the first low-pass layer and the second low-pass layer have the same structure and each comprises a first metal patch pattern arranged periodically; each first metal patch pattern is composed of four square ring patterns and a cross pattern, and the four ends of the cross pattern are connected with the four square ring patterns respectively; and the first band-stop layer comprises a second metal patch pattern arranged periodically. The application achieves the effect of low-frequency wave-transparency and high-frequency wave-reflection in the super wide band by constructing a novel low-pass layer / band-stop layer pattern multilayer structure under the condition of sacrificing the thickness, effectively solves the problem that the existing frequency selection cannot simultaneously consider the in-band super wide band wave-transparency and the out-of-band super wide band wave-reflection, and further ensures the normal work of the satellite radome.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of satellite frequency selective surface radome, and particularly relates to a low-frequency wave-transmitting and high-frequency wave-reflecting device based on a frequency selective surface and a satellite radome. BACKGROUND

[0002] Radar cross section is an important index for evaluating target stealth performance, which reflects the strength of radar detection echo. For satellites, aircrafts and other large platforms, the strong scattering of radar antenna systems is the main contributor to the overall radar cross section. Traditional shape stealth technology and material stealth technology will have a very fatal impact on the radiation performance of the antenna, which is difficult to meet the development needs of existing equipment.

[0003] Structural materials have advantages in realizing wideband wave transmission and reflection performance while having bearing capacity in the field of satellite radome stealth. Frequency selective surface (FSS) is a periodic structure, which has selective transmission, reflection and absorption performance for incident waves after loading loss devices, so the design is more flexible.

[0004] Generally, for the FSS design loaded on the satellite radome, the single-layer FSS structure design will result in narrow bandwidth of the overall structure in terms of wave transmission and reflection, which cannot meet the application of high-frequency satellite radomes. Therefore, it is necessary to provide an improved low-frequency wave-transmitting and high-frequency wave-reflecting device based on a frequency selective surface to solve the above problems. SUMMARY

[0005] The application aims to provide a low-frequency wave-transmitting and high-frequency wave-reflecting device based on a frequency selective surface and a satellite radome, which utilizes the coupling effect between the band-stop layer and the low-pass layer to realize the generation of transmission poles and ensure the rapid transition between ultra-wide bands.

[0006] To achieve the above purpose, the application provides a low-frequency wave-transmitting and high-frequency wave-reflecting device based on a frequency selective surface, which comprises, from top to bottom, a first low-pass layer, a first dielectric isolation layer, a first band-stop layer, a second dielectric isolation layer and a second low-pass layer; the first low-pass layer and the second low-pass layer have the same structure and each comprise a periodic arrangement of first metal patch patterns; each first metal patch pattern is composed of four square ring patterns and a cross pattern, and the four square ring patterns are respectively connected to one end of the cross pattern.

[0007] The first band-stop layer comprises a periodic arrangement of second metal patch patterns.

[0008] Further, the four square ring patterns are located at four right angles of a square respectively, and the cross pattern coincides with the diagonal line of the square; the end of each cross pattern is connected with the top corner of the corresponding square ring pattern, and the extension line of the cross pattern passes through the center of the square ring pattern connected therewith.

[0009] Further, the width of each intersection line of the cross pattern is times of the width of each side length of the square ring pattern, and the length of each intersection line is wherein, W3 represents the width of each side length of the square ring pattern, and S represents the interval of adjacent two square ring patterns.

[0010] Further, the outer side length of each square ring pattern is 2.3-3.3 mm, the width W3 of each side length of the square ring pattern is 0.2-0.4 mm, and the interval S of adjacent two square ring patterns in each first metal patch pattern is 0.7-1 mm; the distance between adjacent two first metal patch patterns is 0.3-0.5 mm.

[0011] Further, the second metal patch pattern is a cross pattern, the length of each intersection line of the cross pattern is 5.5-7.6 mm, the width is 0.2-0.4 mm, and the distance between adjacent two second metal patch patterns is 0.2-0.4 mm.

[0012] Further, the arrangement periods of the first layer low-pass layer, the second layer low-pass layer and the first layer band-stop layer are the same.

[0013] Further, the first layer low-pass layer, the first layer band-stop layer and the second layer low-pass layer further respectively comprise a dielectric substrate, the first metal patch pattern and the second metal patch pattern are periodically arranged on the dielectric substrate, and the dielectric substrate of the first layer low-pass layer is adjacent to the first dielectric isolation layer, the first metal patch pattern of the second layer low-pass layer is adjacent to the second dielectric isolation layer;

[0014] the dielectric substrate of the first layer band-stop layer is adjacent to the second dielectric isolation layer.

[0015] Further, the material of the dielectric substrate is glass fiber reinforced epoxy resin material, and the thickness is 0.15-0.25 mm; the first metal patch pattern and the second metal patch pattern are formed of metal copper.

[0016] Further, the material of the first dielectric isolation layer and the second dielectric isolation layer is aramid paper honeycomb material, and the thickness is 1.8-2.2 mm.

[0017] The application further provides an antenna cover, which is a frequency selective surface antenna cover provided with the low-frequency wave-transparent and high-frequency wave-reflecting device.

[0018] Overall, compared with the prior art, the above technical solutions conceived by the application mainly have the following technical advantages:

[0019] 1. The application can solve the problems of narrow bandwidth of the existing FSS structure and the inability to simultaneously consider low-frequency wave transmission and high-frequency wave reflection by constructing a low-pass layer and a band-stop layer composite structure and reasonably arranging the space. The application uses the selectivity of the FSS to the incident electromagnetic wave, makes a specific frequency selective surface layer act on the corresponding frequency band, uses interlayer coupling to realize rapid transition from the low-frequency band to the high-frequency band, ensures the in-band ultra-wideband wave transmission frequency and the out-of-band ultra-wideband wave reflection frequency, and has the characteristics of high selectivity.

[0020] 2. The wave transmission frequency band of the application is mainly for the S wave band, and the wave reflection frequency band is mainly for the Ka wave band. The design mode is simple, easy to assemble, light in quality, low in cost, and wide in wave transmission frequency band and wave reflection frequency band. Through the design of the metal patch pattern, the first low-pass layer and the second low-pass layer have the transmission characteristics of wave transmission-wave reflection at high frequencies; the first band-stop layer has the transmission characteristics of wave transmission-wave reflection-wave transmission. Therefore, the first low-pass layer, the first band-stop layer, and the second low-pass layer mainly realize low-frequency wideband wave transmission and high-frequency wideband wave reflection through the action of interlayer coupling; the first low-pass layer and the second low-pass layer reflect at high frequencies of 22.93-40GHz and transmit at 1-4.33GHz, and the second band-stop layer transmits at 1-18GHz.

[0021] 3. The application can independently design a wave transmission and reflection device with low-frequency wave transmission and high-frequency wave reflection performance according to the stealth requirements of the low-frequency band and the high-frequency band. Through the optimization design of the shape and size of the frequency selective surface metal patch pattern, the resonance point can be changed, so as to accurately control the wave transmission and reflection frequencies. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 is a structure diagram of a unit pattern in the low-frequency wave transmission and high-frequency wave reflection device based on a frequency selective surface provided by the embodiment of the application;

[0023] Figure 2 is a structure diagram of a low-pass layer and a band-stop layer in the low-frequency wave transmission and high-frequency wave reflection device based on a frequency selective surface provided by the embodiment of the application; (a) corresponds to the first metal patch pattern of the first low-pass layer and the second low-pass layer, and (b) corresponds to the second metal patch pattern of the first band-stop layer;

[0024] Figure 3This is a first metal patch pattern in the low-frequency transmission and high-frequency reflection device based on a frequency-selective surface provided in the embodiments of the present invention, wherein the first low-pass layer and the second low-pass layer are periodically arranged.

[0025] Figure 4 This is the second metal patch pattern of the first layer of the resistive layer periodically arranged in the low-frequency transmission and high-frequency reflection device based on the frequency selective surface provided in the embodiments of the present invention.

[0026] Figure 5 This is a schematic diagram of the layer structure of a low-frequency wave transmission and high-frequency reflection device based on a frequency-selective surface provided in an embodiment of the present invention;

[0027] Figure 6 This refers to the transmission and reflection characteristics of this invention.

[0028] In all the accompanying drawings, the same reference numerals are used to denote the same elements or structures, wherein:

[0029] 1-First low-pass layer; 11-First metal patch pattern A; 12-First dielectric substrate; 2-Cross pattern A; 3-Square ring pattern A; 4-First dielectric isolation layer; 5-First bandstop layer; 51-Second metal patch pattern; 52-Second dielectric substrate; 6-Cross pattern; 7-Second dielectric isolation layer; 8-Second low-pass layer; 81-First metal patch pattern B; 82-Third dielectric substrate; 9-Cross pattern B; 10-Square ring pattern B. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of this invention described below can be combined with each other as long as they do not conflict with each other.

[0031] like Figures 1-6 As shown, this invention provides a wave-transmitting and reflecting device loaded onto a satellite radome, specifically a low-frequency wave-transmitting and high-frequency reflecting device based on a frequency-selective surface. From top to bottom, it comprises a first low-pass layer 1, a first dielectric isolation layer 4, a first band-stop layer 5, a second dielectric isolation layer 7, and a second low-pass layer 8. The first low-pass layer 1 and the second low-pass layer 8 have the same structure and both include a periodically arranged pattern of first metal patches. Figure 5 The first metal patch patterns A11 and B81); each first metal patch pattern consists of four square ring patterns ( Figure 1 Chinese ring pattern A3 and B10) and a cross pattern ( Figure 1The structure consists of cross patterns A2 and B9), with each of the four ends of the cross pattern connected to a square ring pattern. The first bandstop layer 5 includes periodically arranged second metal patch patterns 51. In this invention, the low frequency of low-frequency transmission generally refers to frequencies below 20 GHz (excluding 20 GHz), preferably 1-20 GHz, and the high frequency of high-frequency reflection generally refers to frequencies above 20 GHz (including 20 GHz), preferably 20-45 GHz.

[0032] This configuration utilizes the coupling between the bandstop layer and the low-pass layer to generate transmission poles, thereby ensuring low-frequency ultra-wideband transmission and high-frequency ultra-wideband reflection.

[0033] like Figure 2 As shown in (a) (the yellow part represents metallic copper), the first low-pass layer 1 and the second low-pass layer 8 have the same structure and dimensions. Taking the first low-pass layer 1 as an example, the first low-pass layer 1 is a single-sided copper-clad laminate, on which a first metal patch pattern A 11 is processed in a periodic row and column arrangement, as shown in Figure 1. Figure 3 Each first metal patch pattern A11 includes four square ring patterns A3 and one cross pattern A2. For any four square ring cross pattern (first metal patch pattern A11) in the array, there is a gap P-2*DS between two adjacent first metal patch patterns A11 (the existence of the resonant point can be changed by changing the gap width). The four square ring patterns A3 are connected by rotating the cross pattern A2 by 45° (that is, the four square ring patterns A3 are located at the four corners of a square, and the cross pattern A2 coincides with the diagonal of the square; the ends of the cross pattern A2 are connected to the top corners of the four square ring patterns A3, and the extension line of the cross pattern A2 passes through the center of the square ring pattern A3 connected to it). This constitutes the first low-pass layer FSS unit. The array period P of the first low-pass layer FSS unit is 6-8mm (one period consists of the first metal patch pattern A11 and the gap width of the edge, and the gap width between two adjacent first metal patch patterns A11 is 6-8mm). The gap between 11 is P-2*DS, which is the width of two gaps.

[0034] like Figure 2 In (a), the width of each intersecting line of the cross pattern A2 is the width W3 of each side of the square ring pattern A3. The length of each intersecting line is times that of the previous one. S, where W3 represents the width of each side of the square ring pattern, and S represents the spacing between two adjacent square ring patterns.

[0035] The outer side length D of each square ring pattern A 3 is 2.3-3.3 mm, the width W3 of each side length of the square ring pattern A 3 is 0.2-0.4 mm, and the distance S between adjacent two square ring patterns in each first metal patch pattern is 0.7-1 mm; the distance between adjacent two first metal patch patterns is 0.3-0.5 mm.

[0036] As Figure 2 (b) and Figure 4 The first layer band-stop layer 5 is a single-sided copper-clad plate, and a second metal patch pattern 51 periodically arranged in rows and columns is processed on the copper foil, each second metal patch pattern 51 comprising a cross-shaped pattern 6; adjacent two cross-shaped patterns 6 in the array are not directly connected, but have a gap, thereby forming a first layer band-stop layer FSS unit, and the array period P of the first layer band-stop layer FSS unit is 6-8 mm (one period consists of one second metal patch pattern 51 and the gap width W2 of the edge).

[0037] The second metal patch pattern is a cross-shaped pattern, the length of each cross line of the cross-shaped pattern is P-W2=5.5-7.6 mm, the width W1 is 0.2-0.4 mm, and the distance 2W2 between adjacent two second metal patch patterns is 0.2-0.4 mm.

[0038] In particular, the dielectric substrate adopted by the first layer low-pass layer 1, the first layer band-stop layer 5, and the second layer low-pass layer 8 is a glass fiber reinforced epoxy resin material with a thickness of 0.2 mm; the first dielectric isolation layer 4 and the second dielectric isolation layer 7 are both aramid paper honeycomb materials with a thickness of 2 mm; the cross-shaped pattern A 2, the four square ring patterns 3, the cross-shaped pattern 6, the cross-shaped pattern 9, and the four square ring patterns B 10 are all copper sheets. Through printed circuit board (PCB) processing technology, the first layer low-pass layer 1, the first layer band-stop layer 5, and the second layer low-pass layer 8 are made on a single-sided copper-clad plate to form corresponding FSS unit arrays, and the corresponding patterns are placed on the upper surfaces of the corresponding dielectric isolation layers with the patterns facing down, as shown in Figure 5 , of course, as shown in Figure 1 , the second layer low-pass layer 8 is also placed on the lower surfaces of the corresponding dielectric isolation layers with the dielectric substrate facing up and the pattern facing down); through overall structure simulation optimization, a special device with good wave transmission / reflection characteristics is realized.

[0039] The application realizes the transmission and reflection of electromagnetic waves in the microwave frequency band 1-8GHz and the reflection of electromagnetic waves in the microwave frequency band 26-40GHz by the overall cooperation of the layers in the device.

[0040] The application realizes the transmission and reflection of electromagnetic waves in the microwave frequency band 1-8GHz and the reflection of electromagnetic waves in the microwave frequency band 26-40GHz by the overall cooperation of the layers in the device.

[0041] Embodiment 1

[0042] The first metal patch pattern A11 of the first low-pass layer 1 is a single-sided copper-clad plate, four square ring patterns A3 and cross-shaped patterns A2 arrays are processed on the copper foil in a periodic arrangement, the array period P is 6mm, the outer side length D of the square ring pattern is 2.5mm, the line width W3 of the square ring is 0.3mm, the line width of the cross-shaped pattern rotated by 45° in the middle is that is the length is that is The gap width S between the square rings is 0.6mm, and the single-sided edge gap width is (P-2*D-S) / 2, that is, 0.2mm.

[0043] The first dielectric isolation layer 4 is made of aramid paper honeycomb material, the thickness is 2mm, the relative dielectric constant is 1.07, and the dielectric loss tangent is 0.0017.

[0044] The second metal patch pattern 51 of the first layer band-stop layer 5 is a single-sided copper-clad plate, cross-shaped pattern 6 arrays are processed on the copper foil in a periodic arrangement, the array period P is 6mm, the length P-W2 of the cross-shaped pattern is 5.7mm, and the line width W1 is 0.3mm.

[0045] The second dielectric isolation layer 7 is made of aramid paper honeycomb material, the thickness is 2mm, the relative dielectric constant is 1.07, and the dielectric loss tangent is 0.0017.

[0046] The first metal patch pattern B 81 of the second layer low-pass layer 8 is a single-sided copper-clad plate, and four square ring patterns B 10 and cross-shaped pattern B 9 arrays are arranged periodically in rows and columns on the copper foil. The array period P is 6 mm, the outer side length D of the square ring pattern B 10 is 2.5 mm, the square ring line width W 3 is 0.3 mm, and the line width of the cross-shaped pattern B 9 rotated by 45° in the middle is That is The length is That is The gap width S between the square rings is 0.6 mm, and the edge gap width is (P-2*D-S) / 2, that is, 0.2 mm.

[0047] In a microwave darkroom, the transmission and reflection characteristics of the embodiment are measured, and the parameter characteristics are as shown in the figure. Figure 6 The horizontal axis is frequency, and the vertical axis is reflectivity. S 11 represents the reflectivity of electromagnetic waves, and S 21 represents the wave permeability of electromagnetic waves. The multilayer structure FSS realizes wave permeability in 1-12 GHz and has good reflection effect in 26-40 GHz.

[0048] The first layer low-pass layer 1 and the second layer low-pass layer 8 have transmission characteristics of wave permeability-reflection at high frequencies. The first layer band-stop layer 5 has transmission characteristics of wave permeability-reflection-wave permeability. Therefore, the first layer low-pass layer 1, the first layer band-stop layer 5, and the second layer low-pass layer 8 mainly realize low-frequency broadband wave permeability and high-frequency broadband reflection through the effect of interlayer coupling. The first layer low-pass layer 1 and the second layer low-pass layer 8 reflect at high frequencies of 22.93-40 GHz and permeate at low frequencies of 1-4.33 GHz. The second band-stop layer 5 permeates at low frequencies of 1-18 GHz. In general, the present application is a wave permeability / reflection device of a multilayer structure of a low-pass type and a band-stop type composite structure. According to the stealth requirements of low-frequency bands and high-frequency bands, a wave permeability / reflection device with low-frequency wave permeability and high-frequency reflection performance can be independently designed.

[0049] The wave permeability and reflection performance of the low-frequency wave permeability / high-frequency reflection device based on the frequency selective surface (wave permeability / reflection device loaded on a satellite antenna cover) can be adjusted according to actual requirements. For example, the first layer band-stop layer 5 is calculated by the equivalent circuit principle and the wave permeability resonance point formula The wave permeability performance is determined by the product of the metal length (equivalent inductance L) and the gap size (equivalent capacitance C). Correspondingly, the method for adjusting the wave permeability frequency point is, for example, ① the size of the gap, that is, the equivalent capacitance C, is kept unchanged, and the size of the metal length, that is, the equivalent inductance L, is changed; ② the width of the gap, that is, the equivalent capacitance C, is changed, and the same effect can be achieved; among them, method ① is the most convenient; the first layer low-pass layer is also similar.

[0050] The present application uses the selectivity of FSS to incident electromagnetic wave, makes the specific frequency selective surface layer act on the corresponding frequency band, uses the interlayer coupling, realizes the fast transition from low frequency band to high frequency band, ensures the in-band ultra-wide band wave-transparent frequency and the out-of-band ultra-wide band reflection frequency, and has the characteristics of high selectivity. The steep degree of the transition bandwidth is represented by relative transition bandwidth K in the present application wherein f -10dB represents the frequency where -10dB is located, f -1dB represents the frequency where -1dB is located, that is, the relative bandwidth K=0.035 of the transition of the wave-transparent frequency band to the reflection frequency band, has the characteristics of high selectivity, and has good advantages in the high-selectivity stealth of radar antenna.

[0051] The cross-shaped pattern A2, the four square ring patterns A3, the cross-shaped patch pattern 6, the cross-shaped pattern B 9 and the four square ring patterns B10 in the present application are all thin sheets made of metal copper. The various materials used in the present application, such as glass fiber reinforced epoxy resin material, aramid paper honeycomb material, etc., can all use commercially available materials. In addition to the above-mentioned embodiments, the present application can also use other dielectric materials with little change in relative dielectric constant, dielectric loss angle, relative magnetic permeability, magnetic loss angle as the substrate; the period of each layer structure can also be other values in the range of 6-8mm, and the change of the period value will also change the overall performance of the whole structure. In addition, the periods of the two selected FSS structures can also be different from each other.

[0052] Those skilled in the art can easily understand that the above-mentioned only the preferred embodiments of the present application, and does not limit the present application, any modification, equivalent replacement and improvement made within the spirit and principles of the present application, should be included in the protection scope of the present application.

Claims

1. A low-frequency transmission and high-frequency reflection device based on a frequency-selective surface, characterized in that, From top to bottom, it includes a first low-pass layer, a first dielectric isolation layer, a first band-stop layer, a second dielectric isolation layer, and a second low-pass layer. The first low-pass layer and the second low-pass layer have the same structure and both include periodically arranged first metal patch patterns. Each first metal patch pattern consists of four square ring patterns and one cross pattern, and the four square ring patterns are respectively connected to one end of the cross pattern. The first bandgap layer includes a periodically arranged cross-shaped pattern of second metal patches; The four square ring patterns are located at the four right angles of a square, and the cross pattern coincides with the diagonal of the square; the end of each cross pattern is connected to the apex of the corresponding square ring pattern, and the extension line of the cross pattern passes through the center of the square ring pattern it is connected to.

2. The low-frequency transmission and high-frequency reflection device according to claim 1, characterized in that, The width of each intersecting line of the cross pattern is equal to the width of each side of the square ring pattern. The length of each intersecting line is times that of the previous one. ,in, This represents the width of each side of the square ring pattern. S This indicates the spacing between two adjacent square ring patterns.

3. The low-frequency transmission and high-frequency reflection device according to claim 2, characterized in that, The outer side length of each of the square ring patterns is 2.3-3.3 mm, and the width of each side of the square ring pattern is... The spacing between two adjacent square ring patterns in each first metal patch pattern is 0.2-0.4 mm. S The distance is 0.7-1 mm; the distance between two adjacent first metal patch patterns is 0.3-0.5 mm.

4. The low-frequency transmission and high-frequency reflection device according to any one of claims 1-3, characterized in that, The length of each intersecting line of the cross-shaped pattern of the second metal patch is 5.5-7.6 mm, the width is 0.2-0.4 mm, and the distance between two adjacent second metal patch patterns is 0.2-0.4 mm.

5. The low-frequency transmission and high-frequency reflection device according to claim 4, characterized in that, The metal patch patterns of the first low-pass layer, the second low-pass layer, and the first resistive layer have the same period.

6. The low-frequency transmission and high-frequency reflection device according to claim 4, characterized in that, The first low-pass layer, the first band-stop layer, and the second low-pass layer each include a dielectric substrate. The first metal patch pattern and the second metal patch pattern are periodically arranged on the dielectric substrate. The dielectric substrate of the first low-pass layer is adjacent to the first dielectric isolation layer, and the first metal patch pattern of the second low-pass layer is adjacent to the second dielectric isolation layer. The first dielectric substrate with a resistive layer is adjacent to the second dielectric isolation layer.

7. The low-frequency transmission and high-frequency reflection device according to claim 6, characterized in that, The substrate is made of glass fiber reinforced epoxy resin with a thickness of 0.15-0.25 mm; the first and second metal patch patterns are formed of copper.

8. The low-frequency transmission and high-frequency reflection device according to claim 1, characterized in that, The first and second dielectric isolation layers are made of aramid paper honeycomb material with a thickness of 1.8-2.2 mm.

9. An antenna radome, characterized in that, The radome is a frequency selective surface radome equipped with the low-frequency transmission and high-frequency reflection device as described in any one of claims 1-8.

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