A metasurface array antenna cover for a sky-through antenna

Abstract

The application discloses a metasurface array antenna cover for a sky-through antenna, and relates to the fields of artificial electromagnetic structures and microwave technologies.The application comprises a plurality of periodically arranged metasurface structure units, any of the metasurface structure units comprising first, second, third and fourth metal layers arranged in sequence, coaxially and in parallel and at intervals, the first, second and fourth metal layers being frequency selective surfaces, and the third metal layer being an energy selective surface; the metasurface structure unit allows electromagnetic waves in a preset wave-transparent frequency band to pass through and intercepts electromagnetic waves outside the wave-transparent frequency band when the power of incident electromagnetic waves is less than a preset power threshold, and excites the third metal layer when the power is greater than the preset power threshold, and intercepts and absorbs the incident electromagnetic waves.The application realizes the integration of energy selection protection function and wideband high-efficiency wave-absorption function, so that an electronic information system can be stably transmitted and protected without complex rectification, the system design difficulty is reduced, and the system integration is improved.

Description

Technical Field

[0001] This invention relates to the fields of artificial electromagnetic structures and microwave technology, and in particular to a metasurface array radome for a Tiantong antenna. Background Technology

[0002] In the context of modern electronic information systems increasingly pursuing multifunctional integration and adaptability to complex electromagnetic environments, achieving integrated stealth and protection has become a key challenge in radome and electromagnetic window design. Especially in military stealth platforms and high-reliability communication systems, electronic devices not only need to efficiently transmit communication signals in specific frequency bands, but also suppress external electromagnetic waves over a wide bandwidth (such as the X-band) to reduce radar cross section (RCS), and be able to quickly activate protection mechanisms when encountering high-power microwave (HPM) threats to ensure the safety of sensitive back-end circuits. How to ensure the safe and reliable operation of electronic information systems in complex electromagnetic environments has become a core issue that urgently needs to be addressed.

[0003] Currently, protection strategies against strong electromagnetic pulses mainly fall into two technical routes: "backdoor" hardening and "frontdoor" defense. Regarding "backdoor" protection, traditional methods such as shielding and grounding are commonly used. Although these technologies are theoretically mature, in practical applications, achieving ideal isolation often requires complex electromagnetic compatibility modifications to the entire system structure, significantly increasing system design complexity and introducing signal integrity issues, leading to decreased system integration.

[0004] For the "front door" channel where electromagnetic energy is directly coupled, on the one hand, traditional limiters or attenuators can effectively reduce high power peaks, but they will severely degrade the signal-to-noise ratio of the receiver, causing normal signals to be submerged or distorted; on the other hand, although frequency selective surfaces (FSS) provide the possibility of frequency domain filtering, they are usually unable to cope with strong electromagnetic pulse threats within the passband because their operating frequency band is fixed and they lack adaptive capabilities.

[0005] Energy-selective surfaces (ESS), as a cutting-edge technology in electromagnetic protection, are based on the principle of field-induced nonlinear impedance transformation. Through the field-induced response characteristics of nonlinear components, they achieve adaptive dynamic control of surface impedance: under low-power incident conditions, the ESS exhibits low-loss transmission, ensuring normal transmission of communication signals; when encountering strong electromagnetic excitation, its surface impedance can switch to a high-resistivity state, achieving rapid protection against high-power threats. Despite the advantage of power-adaptive response, existing technologies still suffer from limitations such as functional simplification and difficulty in achieving multi-band composite protection.

[0006] A search of publicly available literature revealed no existing radome design schemes that combine frequency-selective and energy-selective surfaces. Therefore, this paper proposes a radome for Tiantong antennas that combines frequency-selective and energy-selective surfaces to improve system integration. This achieves compatibility between high wave transmission in the 1.98-2.01GHz and 2.17-2.20GHz bands and broadband absorption in the X-band at low power, and provides adaptive protection in the L-band against high-power excitation. This is a direction for research in the field. Summary of the Invention

[0007] In view of this, the present invention provides a metasurface array radome for Tiantong antennas, which has both low-frequency adaptive wave transmission and protection performance, as well as good X-band wave absorption performance and compact structure.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A metasurface array radome for a Tiantong antenna includes: multiple periodically arranged metasurface structure units; Each metasurface structural unit includes a first metal layer, a second metal layer, a third metal layer, and a fourth metal layer, which are arranged coaxially and parallel to each other in sequence; the first metal layer, the second metal layer, and the fourth metal layer are frequency-selective surfaces, and the third metal layer is an energy-selective surface; The metasurface structure unit is used to be in a wave-transmitting state when the power of the incident electromagnetic wave is less than a preset power threshold, allowing electromagnetic waves in the preset wave-transmitting frequency band to pass through and intercepting electromagnetic waves outside the preset wave-transmitting frequency band; when the power of the incident electromagnetic wave is greater than the preset power threshold, it is in an interception state, and under the action of the incident electromagnetic wave, the third metal layer is excited to intercept and absorb the incident electromagnetic wave.

[0009] In the above-mentioned metasurface radome structure, optionally, the first metal layer includes a first substrate dielectric substrate and a first metal circuit structure printed on the upper surface of the first substrate dielectric substrate; the second metal layer includes a second substrate dielectric substrate and a second metal circuit structure printed on the upper surface of the second substrate dielectric substrate; the third metal layer includes a third substrate dielectric substrate and a third metal circuit structure printed on the upper surface of the third substrate dielectric substrate; and the fourth metal layer includes a fourth substrate dielectric substrate and a fourth metal circuit structure printed on the upper surface of the fourth substrate dielectric substrate.

[0010] In the above-mentioned metasurface radome structure, optionally, the first metal circuit structure is a symmetrical structure, including multiple straight metal strip groups, each straight metal strip group including a first straight metal strip and a second straight metal strip with the same bandwidth, and a third straight metal strip and a fourth straight metal strip with the same bandwidth; The first straight metal strip and the second straight metal strip are connected perpendicularly and symmetrically to form an outer symmetrical metal zigzag structure; the third straight metal strip and the fourth straight metal strip are connected perpendicularly and symmetrically to form an inner symmetrical metal zigzag structure. There are gaps between the outer symmetrical metal zigzag structure of any straight metal strip group and the outer metal zigzag structure of the adjacent straight metal strip groups, and between the inner symmetrical metal zigzag structure and the inner metal zigzag structure of the adjacent straight metal strip groups.

[0011] In the above metasurface radome structure, optionally, the second metal layer and the fourth metal layer have the same structure; The second metal circuit structure has a hollowed-out hexagonal slotted structure in the center, and each side of the hexagonal slotted structure is connected to the inner and outer edges of the slot by the first capacitor.

[0012] In the above-mentioned metasurface radome structure, optionally, the third metal circuit structure includes a square metal resonant ring composed of seven metal microstrips connected end to end; the square metal resonant ring is a C-shaped structure with an opening, and is connected across the two ends of the opening by diodes and a second capacitor to form a closed loop.

[0013] In the above metasurface radome structure, optionally, the first substrate dielectric substrate, the second substrate dielectric substrate, the third substrate dielectric substrate and the fourth substrate dielectric substrate are all RogersRT 5880 dielectric substrates with a dielectric constant of 2.2 and a loss tangent of 0.0009.

[0014] In the above-mentioned metasurface radome structure, optionally, for any straight metal strip group, the resistance value of the gap connecting its outer symmetrical metal folded structure and the outer symmetrical metal folded structure of the adjacent straight metal strip groups is 300Ω, and the resistance value of the gap connecting its inner symmetrical metal folded structure and the inner symmetrical metal folded structure of the adjacent straight metal strip groups is 400Ω.

[0015] In the above metasurface radome structure, the diode model is optionally SMP1330-040LF.

[0016] In the above-mentioned metasurface radome structure, optionally, the first metal circuit structure, the second metal circuit structure, the third metal circuit structure and the fourth metal circuit structure are all made of copper material, and the thickness is 0.035mm.

[0017] Optionally, in any of the above-described metasurface radome structures, multiple metasurface structural units are arranged in a two-dimensional array of M rows × N columns, where M≥2, N≥2, and M and N are both positive integers; any metasurface structural unit is a square structure with a side length p satisfying: 8mm≤p≤12mm.

[0018] As can be seen from the above technical solution, compared with the prior art, the present invention provides a metasurface array radome for antennas, which has the following beneficial effects: (1) By combining FSS and ESS in a structure, this invention can achieve compatibility between dual-band high wave transmission and X-band broadband absorption at low power (1.98-2.01GHz and 2.17-2.20GHz) and high power excitation (L-band). (2) Within the 1.75GHz-1.82GHz operating frequency band of relevant electronic equipment, the metasurface radome structure designed in this invention has excellent protection performance, which can reach more than 40dB. It can effectively restrain the attack of high-energy electromagnetic waves, prevent damage to electromagnetic equipment, ensure the safe and stable operation of electronic equipment, and ensure the safe conduct of electronic communication. (3) The metasurface radome structure of the present invention can achieve a transmission of not less than -1dB in the dual bands of 1.98-2.01GHz and 2.17-2.20GHz in low power operation mode, and achieves an absorption performance of more than 99% average absorption rate in the X band, thus achieving effective reduction of RCS. (4) The present invention also reduces the design difficulty of electronic information systems by structurally combining FSS and ESS, eliminating the need for complex electromagnetic compatibility rectification and ensuring high integration of electronic information systems. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0020] Figure 1 This is a perspective view of any metasurface structure unit of a metasurface array radome for a Tiantong antenna disclosed in this invention. Figure 2 This is a schematic diagram of the first metal layer of the metasurface radome structure unit disclosed in an embodiment of the present invention; Figure 3 This is a schematic diagram of the second and fourth metal layers of the metasurface radome structure unit disclosed in an embodiment of the present invention; Figure 4 This is a schematic diagram of the third metal layer of the metasurface radome structure unit disclosed in an embodiment of the present invention; Figure 5 This is a schematic diagram of the third metal layer of a special structure of the metasurface radome structure unit disclosed in an embodiment of the present invention. Figure 6 This is a simulation result diagram of electromagnetic wave incident at a power less than a preset threshold for a metasurface array radome for a Tiantong antenna, as disclosed in an embodiment of the present invention. Figure 7 This is a simulation result diagram of electromagnetic wave incident with a power greater than a preset threshold for a metasurface array radome for a Tiantong antenna, as disclosed in an embodiment of the present invention. Wherein, 1-first metal layer, 2-second metal layer, 3-third metal layer, 4-fourth metal layer, 1-1-first substrate dielectric substrate, 1-2-first metal circuit structure, 2-1-second substrate dielectric substrate, 2-2-second metal circuit structure, 3-1-third substrate dielectric substrate, 3-2-third metal circuit structure, 4-1-fourth substrate dielectric substrate, 4-2-fourth metal circuit structure, 1-2-1-first straight metal strip, 1-2-2-second straight metal strip The components are: 1-2-3-Third straight metal strip, 1-2-4-Fourth straight metal strip, 1-2-5-Gap, 2-2-1-First capacitor, 3-2-1-First metal microstrip, 3-2-2-Second metal microstrip, 3-2-3-Third metal microstrip, 3-2-4-Fourth metal microstrip, 3-2-5-Fifth metal microstrip, 3-2-6-Sixth metal microstrip, 3-2-7-Seventh metal microstrip, 3-2-8-Diode, 3-2-9-Second capacitor. Detailed Implementation

[0021] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0022] In this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. The terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0023] See Figure 1 As shown, this invention discloses a metasurface array radome for antennas, which is suitable for electronic devices or antennas that need to achieve specific frequency band communication and broadband stealth at low power, while achieving electromagnetic protection at high power. The metasurface radome structure disclosed in this invention includes: multiple periodically arranged metasurface structure units.

[0024] Each metasurface structural unit includes a first metal layer 1, a second metal layer 2, a third metal layer 3, and a fourth metal layer 4, which are arranged sequentially, coaxially, and parallelly spaced. The first metal layer 1, second metal layer 2, and fourth metal layer 4 are frequency-selective surfaces, and the third metal layer 3 is an energy-selective surface. The metasurface structural unit is used to be in a wave-transmitting state when the power of the incident electromagnetic wave is less than a preset power threshold, allowing electromagnetic waves in the preset wave-transmitting frequency band to pass through while intercepting electromagnetic waves outside the preset wave-transmitting frequency band. When the power of the incident electromagnetic wave is greater than the preset power threshold, it is in an interception state, where the third metal layer 3 is excited under the action of the incident electromagnetic wave to intercept and absorb the incident electromagnetic wave.

[0025] Optionally, the first metal layer 1 includes a first substrate dielectric substrate 1-1 and a first metal circuit structure 1-2 printed on the upper surface of the first substrate dielectric substrate 1-1; the second metal layer 2 includes a second substrate dielectric substrate 2-1 and a second metal circuit structure 2-2 printed on the upper surface of the second substrate dielectric substrate 2-1; the third metal layer 3 includes a third substrate dielectric substrate 3-1 and a third metal circuit structure 3-2 printed on the upper surface of the third substrate dielectric substrate 3-1; and the fourth metal layer 4 includes a fourth substrate dielectric substrate 4-1 and a fourth metal circuit structure 4-2 printed on the upper surface of the fourth substrate dielectric substrate 4-1.

[0026] In order to meet the operation and communication requirements of precision electromagnetic devices such as electronic equipment and antennas, the first metal circuit structure 1-2, the second metal circuit structure 2-2, the third metal circuit structure 3-2 and the fourth metal circuit structure 4-2 of this invention are all made of copper material with good conductivity and excellent ductility, and the thickness is 0.035mm.

[0027] Optional, refer to Figure 2 The first metal circuit structure 1-2 is a symmetrical structure, including multiple straight metal strip groups. Each straight metal strip group includes a first straight metal strip 1-2-1 and a second straight metal strip 1-2-2 with the same bandwidth, and a third straight metal strip 1-2-3 and a fourth straight metal strip 1-2-4 with the same bandwidth. The first straight metal strip 1-2-1 and the second straight metal strip 1-2-2 are vertically connected and symmetrically processed to form an outer symmetrical metal zigzag structure; the third straight metal strip 1-2-3 and the fourth straight metal strip 1-2-4 are vertically connected and symmetrically processed to form an inner symmetrical metal zigzag structure. A gap of 1-2-5 is provided between the outer symmetrical metal zigzag structure of any straight metal strip group and the outer metal zigzag structure of the adjacent straight metal strip groups on both sides, and between the inner symmetrical metal zigzag structure and the inner metal zigzag structure of the adjacent straight metal strip groups on both sides.

[0028] Furthermore, for any straight metal strip group, the resistance value of the gap 1-2-5 connecting its outer symmetrical metal broken line structure and the outer symmetrical metal broken line structure of the adjacent straight metal strip groups is 300Ω, and the resistance value of the gap 1-2-5 connecting its inner symmetrical metal broken line structure and the inner symmetrical metal broken line structure of the adjacent straight metal strip groups is 400Ω.

[0029] Reference Figure 2 In the first metal circuit structure 1-2, the composite right-angle metal strip structure (i.e., the outer symmetrical metal zigzag structure) formed by the first straight metal strip 1-2-1 and the second straight metal strip 1-2-2 is arranged at equal intervals along the outer square ring. The composite right-angle metal strip (i.e., the inner symmetrical metal zigzag structure) formed by the adjacent third straight metal strip 1-2-3 and the fourth straight metal strip 1-2-4 is arranged at equal intervals along the inner square ring. A gap 1-2-5 is left between any two adjacent outer symmetrical metal zigzag structures and between any two adjacent inner symmetrical metal zigzag structures to place resistors, so as to realize the wave absorption function of the first metal layer 1.

[0030] Optionally, the first metal circuit structure 1-2 can be printed on the first substrate dielectric substrate 1-1 using PCB printed circuit board technology.

[0031] Because devices used for electromagnetic wave transmission and interception are mostly high-precision and small-sized structures, in order to adapt to existing electromagnetic wave equipment, it is necessary to combine... Figure 2 In the first metal circuit structure 1-2, the width w1 of the first straight metal strip 1-2-1 and the second straight metal strip 1-2-2 in each straight metal strip group satisfies 0.1mm≤w1≤0.5mm, the outer edge length l1 of the first straight metal strip 1-2-1 satisfies 3mm≤l1≤4mm, and the outer edge length l2 of the second straight metal strip 1-2-2 satisfies 3mm≤l2≤4mm; the width w2 of the third straight metal strip 1-2-3 and the fourth straight metal strip 1-2-4 in each straight metal strip group satisfies 0.1mm≤w2≤0.5mm, the outer edge length l3 of the third straight metal strip 1-2-3 satisfies 1.5mm≤l3≤2.5mm; and the outer edge length l4 of the fourth straight metal strip 1-2-4 satisfies 1.5mm≤l4≤2.5mm.

[0032] The vertical distance between the center of the first metal circuit structure 1-2 and the inner edge of the third straight metal strip 1-2-3 is 1.5mm≤d1≤2.5mm; in the first metal circuit structure 1-2, a gap 1-2-5 is provided between adjacent inner and outer symmetrical metal zigzag structures, and the length g1 of the gap 1-2-5 satisfies 0.5mm≤g1≤1mm.

[0033] As a feasible implementation method, combined with Figure 2 The present invention further discloses the following specific embodiments: In the first metal circuit structure 1-2, the width w1 of the first straight metal strip 1-2-1 and the width w2 of the third straight metal strip 1-2-3 and the fourth straight metal strip 1-2-4 are all 0.5mm; the outer edge length l1 of the first straight metal strip 1-2-1 is 3.5mm; the outer edge length l2 of the second straight metal strip 1-2-2 is 3.5mm; and the outer edge length l3 of the third straight metal strip 1-2-3 is... The length of the fourth straight metal strip 1-2-4 is 2mm, the length of the gap 1-2-5 is 1mm, the distance from the center of the first metal circuit structure 1-2 to the inner edge of the third straight metal strip 1-2-3 is 2mm, the resistance of the resistor R1 used for welding the gap 1-2-5 between any two adjacent outer symmetrical metal broken line structures is 300Ω, and the resistance of the resistor R2 used for welding the gap 1-2-5 between any two adjacent inner symmetrical metal broken line structures is 400Ω.

[0034] Optionally, the second metal layer 2 and the fourth metal layer 4 have the same structure and printing process; the structure of the fourth metal layer 4 can be referred to the following disclosure regarding the second metal layer 2.

[0035] Reference Figure 3The second metal circuit structure 2-2 has a hollowed-out hexagonal slotted structure in the center, and the first capacitor 2-2-1 is used to bridge the inner and outer edges of the slot on any side of the hexagonal slotted structure.

[0036] Furthermore, in the central hexagonal ring slotted structure of the second metal circuit structure 2-2, the slot width g2 satisfies 0.5mm≤g2≤1mm; the diagonal length w3 of the central hexagonal structure of the second metal circuit structure 2-2 satisfies 7mm≤w3≤9mm; and the side length l5 of the central hexagonal structure of the second metal circuit structure satisfies l5 = w3.

[0037] Optionally, the capacitance of the first capacitor 2-2-1 connected between the inner and outer edges of each side of the hexagon is 1.8pF.

[0038] Optionally, the second metal circuit structure 2-2 can be printed on the second substrate dielectric substrate 2-1 using an etching process.

[0039] As one possible implementation method, refer to Figure 3 In this embodiment of the invention, the hexagonal slotted structure in the second metal circuit structure 2-2 of the second metal layer 2 has a slot width g2 of 0.5 mm, a diagonal length w3 of the central hexagonal structure of 8.6 mm, and a side length l5 of 0.5 mm. w3, approximately 7.45mm, has a hexagonal slotted structure in which the capacitance value C1 of each of the first capacitors 2-2-1 used for bridging the outer edge is 1.8pF.

[0040] Optionally, the third metal circuit structure 3-2 can be printed on the third substrate dielectric substrate 3-1 using an etching process.

[0041] Optional, refer to Figure 4 The third metal circuit structure 3-2 includes a square metal resonant ring composed of seven metal microstrips connected end to end; the square metal resonant ring is a C-shaped structure with an opening, and is connected across the two ends of the opening by diodes 3-2-8 and the second capacitor 3-2-9 to form a closed loop. Diodes 3-2-8 and the second capacitor 3-2-9 are connected in parallel.

[0042] Furthermore, in combination Figure 4 In the third metal circuit structure 3-2: The length l6 of the first metal microstrip length 3-2-1 satisfies l6 = p, where p is the side length of the metasurface structure unit of the square structure, and is also the side length of the first metal layer 1, the second metal layer 2, the third metal layer 3 and the fourth metal layer 4 arranged in sequence, coaxially and parallelly, and the width w4 satisfies 0.1mm≤w4≤0.4mm. The length l7 of the second metal microstrip 3-2-2 satisfies 2.5mm≤l7≤3mm, and the width w5 satisfies 0.1mm≤w5≤0.4mm; The length l8 of the third metallic microstrip 3-2-3 satisfies l6–l8. 2≥0.4mm, and the width w6 satisfies 0.5mm≤w6≤1mm; The length l9 of the fourth metal microstrip 3-2-4 satisfies 2.5mm≤l9≤3mm, and the width w7 satisfies 0.5mm≤w7≤1mm; the opening gap length g3 satisfies g3 = l6–(l8+l9). 2; The fifth metal microstrip 3-2-5 has the same dimensions as the fourth metal microstrip 3-2-4; The sixth metal microstrip 3-2-6 has the same dimensions as the third metal microstrip 3-2-3; The seventh metal microstrip 3-2-7 has the same dimensions as the second metal microstrip 3-2-2; The diode 3-2-8 connected across the two ends of the opening is model SMP1330-040LF; The second capacitor 3-2-9 connected across the two ends of the opening has a capacitance of 0.27pF.

[0043] Combination Figure 4 The second metal microstrip 3-2-2 and the seventh metal microstrip 3-2-7 are placed in parallel. The first metal microstrip 3-2-1 is perpendicularly connected to the same end of the second metal microstrip 3-2-2 and the seventh metal microstrip 3-2-7. The third metal microstrip 3-2-3 is perpendicularly connected to the second metal microstrip 3-2-2. The fourth metal microstrip 3-2-4 is perpendicularly connected to the third metal microstrip 3-2-3. The fifth metal microstrip 3-2-5 is perpendicularly connected to the sixth metal microstrip 3-2-6. The sixth metal microstrip 3-2-6 is perpendicularly connected to the seventh metal microstrip 3-2-7. The fourth metal microstrip 3-2-4 and the fifth metal microstrip 3-2-5 are connected by a diode 3-2-8 and a second capacitor 3-2-9 to form a closed loop between the microstrips.

[0044] According to one embodiment of the present invention, combined with Figure 4 In the third metal circuit structure 3-2, the first metal microstrip 3-2-1 of the square metal resonant ring structure has a length l6 of 10 mm and a width w4 of 0.1 mm; the second metal microstrip 3-2-2 has a length l7 of 2.89 mm and a width w5 of 0.2 mm; the third metal microstrip 3-2-3 has a length l8 of 4.8 mm and a width w6 of 0.91 mm; and the fourth metal microstrip 3-2-4 has a length l9 of 2.91 mm and a width w7 of 0.9 mm. The opening gap length g3 satisfies g3 = l6 – l8. 2 = 0.4 mm. The fifth metal microstrip 3-2-5 has the same dimensions as the fourth metal microstrip 3-2-4, the sixth metal microstrip 3-2-6 has the same dimensions as the third metal microstrip 3-2-3, and the seventh metal microstrip 3-2-7 has the same dimensions as the second metal microstrip 3-2-2. Optionally, the first substrate dielectric substrate 1-1, the second substrate dielectric substrate 2-1, the third substrate dielectric substrate 3-1, and the fourth substrate dielectric substrate 4-1 are all Rogers RT 5880 dielectric substrates with a dielectric constant of 2.2 and a loss tangent of 0.0009.

[0045] Furthermore, refer to Figure 5 The present invention also discloses a metal pattern layer 3 with a special structure. In the third metal circuit structure 3-2 of the current special structure metal pattern 3: The length l6 of the first metal microstrip length 3-2-1 satisfies l6 = p, where p is the side length of the composite electromagnetic structure unit of the square structure, and is also the side length of the first metal layer 1, the second metal layer 2, the third metal layer 3 and the fourth metal layer 4 arranged in sequence, coaxially and parallelly, and the width w4 satisfies 0.1mm≤w4≤0.4mm. The length l7 of the second metal microstrip 3-2-2 satisfies 0.5mm≤l7≤0.8mm, and the width w5 satisfies 0.1mm≤w5≤0.4mm; The length l8 of the third metallic microstrip 3-2-3 satisfies l6–l8. 2≥0.4mm, width w6 satisfies 3mm≤w6≤5mm; opening gap length g3 satisfies g3 = l6–l8 2; The fourth metal microstrip 3-2-4 and the fifth metal microstrip 3-2-5 are no longer set, or in other words, the fourth metal microstrip 3-2-4 and the fifth metal microstrip 3-2-5 are respectively integrated with the third metal microstrip 3-2-3 and the sixth metal microstrip 3-2-6 into a single metal microstrip.

[0046] The sixth metal microstrip 3-2-4 has the same dimensions as the third metal microstrip 3-2-3; The seventh metal microstrip 3-2-5 has the same dimensions as the second metal microstrip 3-2-2; The diode 3-2-8 remains unchanged, while the second capacitor 3-2-9 is now a surface-mount capacitor with a capacitance of 0.3pF.

[0047] It should be noted that when using the third metal circuit structure 3-2 of the current special metal pattern 3, the inner and outer strip gap resistors of the first metal circuit structure 1-2 need to be changed accordingly. The outer strip gap resistor R1 is 350Ω and the inner strip gap resistor R2 is 1000Ω.

[0048] As a special structure, combined Figure 5 In the third metal circuit structure 3-2, the first metal microstrip 3-2-1 of the square metal resonant ring structure has a length l6 of 10 mm and a width w4 of 0.2 mm; the second metal microstrip 3-2-2 has a length l7 of 0.75 mm and a width w5 of 0.2 mm; and the third metal microstrip 3-2-3 has a length l8 of 4.8 mm and a width w6 of 3 mm. The opening gap length g3 satisfies g3 = l6 – l8. 2 = 0.4mm. The sixth metal microstrip 3-2-6 has the same size as the third metal microstrip 3-2-3, and the seventh metal microstrip 3-2-7 has the same size as the second metal microstrip 3-2-2.

[0049] Due to structural changes, this invention is based on... Figure 5 The metasurface array radome obtained by the metal patterned layer 3 shown is based on... Figure 4 The metasurface array radome obtained from the metal patterned layer 3 shown in the diagram achieves the same function: enabling the metasurface structure unit to intercept electromagnetic waves outside a preset transmission frequency band in a transparent state. Because both use the same type of diode, their power thresholds are essentially the same. Furthermore, the metasurface array radome with its special structural design has a narrower transmission frequency band, approaching single-frequency transmission, thus resulting in a difference in their preset transmission frequency bands. Therefore, the metasurface structure unit with the special structure has a narrower preset transmission frequency band range, but it also achieves superior performance in X-band absorption and L-band protection under high-power protection conditions.

[0050] Optionally, for any of the above embodiments disclosed in this invention, multiple metasurface structure units can be arranged in a two-dimensional array of M rows × N columns, where M≥2, N≥2, and M and N are both positive integers; any metasurface structure unit is a square structure with a side length p satisfying: 8mm≤p≤12mm.

[0051] Based on the specification requirements of the metasurface structure unit, each metal layer should also meet the corresponding structural requirements. Optionally, the thickness h1 of the first substrate dielectric substrate 1-1, the second substrate dielectric substrate 2-1 and the fourth substrate dielectric substrate 4-1 should satisfy: 0.5mm≤h1≤1mm; the thickness h2 of the third substrate dielectric substrate 3-1 should satisfy: 1mm≤h2≤2mm.

[0052] According to one embodiment of the present invention, the thickness of the metal structure on the upper surface of all substrates is 0.035 mm. The diode 3-2-8 used is model SMP1330-040LF. The resistor R1 has a resistance of 300 Ω and the resistor R2 has a resistance of 400 Ω. The first capacitor 2-2-1 is a capacitor with a capacitance of 1.8 pF and the second capacitor 3-2-9 is a capacitor with a capacitance of 0.27 pF. The width p of the first substrate dielectric substrate 1-1, the second substrate dielectric substrate 2-1 and the fourth substrate dielectric substrate 4-1 is 10 mm, and they are made of Rogers RT5880 material with a thickness of 0.5 mm. The width p of the third substrate dielectric substrate 3-1 is 10 mm, and it is made of Rogers RT 5880 material with a thickness of 1 mm.

[0053] Reference Figure 6 According to any of the above embodiments of the present invention, a multilayer metasurface structure is obtained, which is based on the utilization of the energy selective surface (i.e., the third metal layer 3). Each metasurface structure unit performs electromagnetic tests on incident low-power signals and high-energy electromagnetic waves to obtain the expected S11 and S21 curves.

[0054] For example, when a low-power electromagnetic wave signal passes through a multilayer metasurface structure composed of multiple metasurface structure units arranged periodically, its incident power is insufficient to excite the diodes 3-2-8 on the multilayer metasurface structure. At this time, the energy selective surface where the third metal layer 3 is located is in an unexcited state, and a low-power electromagnetic wave signal of a specific frequency can pass through the metal layer of the multilayer frequency selective surface with low loss. When a high-energy electromagnetic wave signal passes through the multilayer metasurface structure, its incident power can excite the diodes 3-2-8 on the energy selective surface composed of the third metal layer 3 of each metasurface structure unit in the multilayer metasurface structure of the present invention. At this time, the energy selective surface is in an excited state, and the high-energy electromagnetic wave will be intercepted when it passes through the multilayer metasurface structure of the present invention. The X-band electromagnetic wave will be absorbed by the multilayer metasurface structure disclosed in the present invention. After processing by the signal transmitting end and receiving end, the S11 and S21 curves of the multilayer metasurface structure under different incident conditions can be obtained.

[0055] Furthermore, referring to Figure 6 and Figure 7 When low-power electromagnetic wave signals are incident, the M-row × N-column arrangement of the multilayer metasurface structure units exhibits low insertion loss transmission peaks in both the 1.98-2.01 GHz and 2.17-2.20 GHz bands, and the average absorption rate in the X-band is greater than 99%. When high-energy electromagnetic wave signals are incident, the protection effectiveness of the multilayer metasurface structure units in the 1.75 GHz-1.82 GHz range is greater than 40 dB. Figure 6 and Figure 7It can be seen that in the multilayer metasurface structure disclosed in this invention, when each metasurface structure unit is in the wave-transmitting state and the protective state, the difference in the transmission curve is at least 20dB, which can effectively control the intensity of the transmitted signal.

[0056] In summary, the metasurface array radome provided by this invention exhibits a transmission curve difference of at least 20 dB between the transparent and protected states of each metasurface structural unit, effectively controlling the strength of the transmitted signal. It innovatively integrates the frequency selectivity of FSS and the power adaptability of ESS, not only optimizing the transmission performance under low power conditions but also expanding its application potential in complex scenarios such as multi-band compatibility and strong electromagnetic countermeasures through multi-layer cascade design.

[0057] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A metasurface array radome for a Tiantong antenna, characterized in that, include: Multiple periodically arranged metasurface structural units; Each metasurface structural unit includes a first metal layer, a second metal layer, a third metal layer, and a fourth metal layer, which are arranged coaxially and parallel to each other in sequence; the first metal layer, the second metal layer, and the fourth metal layer are frequency-selective surfaces, and the third metal layer is an energy-selective surface; The metasurface structure unit is used to be in a wave-transparent state when the power of the incident electromagnetic wave is less than a preset power threshold, allowing electromagnetic waves in the preset wave-transparent frequency band to pass through and blocking electromagnetic waves outside the preset wave-transparent frequency band. When the power of the incident electromagnetic wave is greater than the preset power threshold, it is in the interception state. Under the action of the incident electromagnetic wave, the third metal layer is excited to intercept and absorb the incident electromagnetic wave. The first metal layer includes a first substrate dielectric substrate and a first metal circuit structure printed on the upper surface of the first substrate dielectric substrate; the second metal layer includes a second substrate dielectric substrate and a second metal circuit structure printed on the upper surface of the second substrate dielectric substrate; the third metal layer includes a third substrate dielectric substrate and a third metal circuit structure printed on the upper surface of the third substrate dielectric substrate; and the fourth metal layer includes a fourth substrate dielectric substrate and a fourth metal circuit structure printed on the upper surface of the fourth substrate dielectric substrate. The first metal circuit structure is a symmetrical structure, including multiple straight metal strip groups. Each straight metal strip group includes a first straight metal strip and a second straight metal strip with the same bandwidth, and a third straight metal strip and a fourth straight metal strip with the same bandwidth. The first straight metal strip and the second straight metal strip are connected perpendicularly and symmetrically to form an outer symmetrical metal zigzag structure; the third straight metal strip and the fourth straight metal strip are connected perpendicularly and symmetrically to form an inner symmetrical metal zigzag structure. There are gaps between the outer symmetrical metal zigzag structure of any straight metal strip group and the outer metal zigzag structure of the adjacent straight metal strip groups, and between the inner symmetrical metal zigzag structure and the inner metal zigzag structure of the adjacent straight metal strip groups. The second metal layer has the same structure as the fourth metal layer; the center of the second metal circuit structure has a slotted structure in the shape of a regular hexagon, and each side of the regular hexagonal slotted structure is connected to the inner and outer edges of the slot by the first capacitor. The third metal circuit structure includes a square metal resonant ring consisting of seven metal microstrips connected end to end; the square metal resonant ring is a C-shaped structure with an opening, and a closed loop is formed by connecting the two ends of the opening through diodes and a second capacitor.

2. The metasurface array radome for a Tiantong antenna according to claim 1, characterized in that, The first, second, third, and fourth substrates are all Rogers RT 5880 dielectric substrates with a dielectric constant of 2.2 and a loss tangent of 0.0009.

3. A metasurface array radome for a Tiantong antenna according to claim 1, characterized in that, For any straight metal strip group, the resistance value of the gap connecting its outer symmetrical metal broken line structure and the outer symmetrical metal broken line structure of the adjacent straight metal strip groups is 300Ω, and the resistance value of the gap connecting its inner symmetrical metal broken line structure and the inner symmetrical metal broken line structure of the adjacent straight metal strip groups is 400Ω.

4. A metasurface array radome for a Tiantong antenna according to claim 1, characterized in that, The diode model is SMP1330-040LF.

5. A metasurface array radome for a Tiantong antenna according to claim 1, characterized in that, The first, second, third, and fourth metal circuit structures are all made of copper and have a thickness of 0.035 mm.

6. A metasurface array radome for a skycombing antenna according to any one of claims 1-5, characterized in that, Multiple metasurface structural units are arranged in a two-dimensional array of M rows × N columns, where M≥2, N≥2, and M and N are both positive integers; any metasurface structural unit is a square structure with a side length p satisfying: 8mm≤p≤12mm.

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