A dual-band wave-transparent wave-absorbing frequency-selective radome structure design method, device and equipment

Abstract

This invention relates to a design method, apparatus, and device for a dual-band transparent absorbing frequency-selective radome structure. The method includes designing a dual-passband transparent absorbing frequency-selective surface using bending, composite, and multi-layer cascading techniques, and a regular array composed of absorbing frequency-selective surface units. The apparatus includes an absorbing module and a dual-band transparent module, and the device includes a protective layer, an absorbing layer, a support layer, and a bandpass layer. This invention achieves an absorbing frequency-selective surface structure with two passband responses, which not only absorbs electromagnetic waves from the upper and lower frequency bands of the two passbands, suppresses electromagnetic wave reflection, reduces the risk of radar detection, but also ensures the dual-band communication requirements of the system. The two passbands operate in the C-band and X-band, respectively. This invention exhibits good polarization stability and angular stability for electromagnetic waves incident at different angles.

Description

Technical Field

[0001] This invention relates to the field of frequency selective radomes, and more particularly to a dual-band transparent absorbing frequency selective radome. Background Technology

[0002] Currently, radar counter-detection technology primarily reduces the radar cross-section (RCS) by decreasing or eliminating the detection echo emitted by enemy radar, thus avoiding detection and achieving stealth. Radar stealth technology is widely used in aircraft, with its core focus on reducing the RCS scattering of the target aircraft's nose. The main method is to attach a stealth material to the aircraft's nose. This stealth material absorbs the electromagnetic waves detected by the enemy, reduces reflected waves, or scatters incident waves in other directions, making it impossible for enemy radar to pinpoint the aircraft's exact location, thereby achieving stealth. Based on the current state of stealth technology in aircraft, research has been conducted on stealth radomes. In the early stages of design, radomes were primarily designed based on frequency selective surfaces (FSS). Within the operating frequency band of the radar antenna, electromagnetic signals can be transmitted normally, reflecting electromagnetic waves outside the passband to other directions. Since the reflected waves still exist outside the passband, they are still easily received by other radars, which can then pinpoint the location of the electromagnetic wave source, making it easy for friendly targets to be exposed during communication. Therefore, traditional radar radomes do not have comprehensive stealth capabilities and cannot meet the needs of modern complex electromagnetic countermeasures.

[0003] To address the shortcomings of traditional radomes and better adapt to complex electromagnetic environments and dual-station or multi-station radar applications, while ensuring uninterrupted communication and radar detection operations, a Frequency Selective Absorbent Surface (FSAS) has been proposed. This structure not only transmits electromagnetic waves within the passband but also demonstrates a significant advantage in absorbing electromagnetic energy outside the passband, reducing the radar cross-section (RCS) of friendly targets. Absorbing signals outside the communication band greatly reduces reflection, resulting in a low reflectivity. Simultaneously, this structure does not interfere with the normal communication performance of the radar, allowing signals within the passband to be transmitted with near-lossless, low-loss transmission. The application of frequency selective absorbing surfaces in radar radomes has significant strategic importance and research value for aircraft, ships, and other weaponry in military combat and for ensuring more covert communication.

[0004] Current frequency-selective absorbing surfaces, such as those in [Reference 1], achieve broadband low-frequency absorption and high-frequency transmission, while [Reference 2] proposes a dual-frequency selective surface with angular stability. However, they still have shortcomings in two aspects: 1. The transmission bandwidth is narrow, making it difficult to meet the needs of broadband or multi-frequency communication; 2. Existing frequency-selective absorbing radomes are affected by the impedance surface, which to some extent affects the transmission effect, increases the insertion loss of the transmission, and makes the insertion loss of the transmission band relatively high. To address the shortcomings of current frequency-selective absorbing radomes, this patent proposes a dual-band transmission frequency-selective absorbing radome that has almost lossless transmission in both the C-band and X-band, and achieves absorption outside of these two frequency bands, effectively reducing the reflection of the protected target.

[0005] [Document 1] Chen Q, Yang S, Bai J, et al. Design of Absorptive / TransmissiveFrequency-Selective Surface Bas ed on Parallel Resonance[J]. IEEE Transactionson Antennas and Propagation, 2017.

[0006] Z.Chen,Y.Xu,X.Wang,R.Wang and L.Hao,"Design of a Dual-Band FrequencySelective Surface with Angular Stability,"2019International AppliedComputational Electrification Society Symposium-China(ACES), 2019, pp.1-2, doi:10.23919 / ACES48530.2019.9060595. Summary of the Invention

[0007] Technical problems to be solved

[0008] This invention addresses the problem of multi-band communication in frequency-selective radomes, as well as the issues of reducing the target's RCS and decreasing the probability of radar detection.

[0009] Technical solution

[0010] To address the aforementioned problems, this invention provides a design method, apparatus, and device for a dual-band transparent, wave-absorbing, frequency-selective radome structure.

[0011] As a further explanation of the present invention, preferably, the first aspect of the present invention provides a design method for a dual-band transparent absorbing frequency-selective radome structure, including designing a dual-passband absorbing frequency-selective surface unit using bending technology, composite technology, and multi-layer cascading technology, including a regular array composed of absorbing frequency-selective surface units.

[0012] As a further explanation of the design method, preferably, the frequency-selective absorbing surface unit includes two cascaded structures, with an absorbing layer on top and a bandpass layer on the bottom.

[0013] As a further explanation of the design method, preferably, the basic unit of the absorbing layer is formed by bending a long metal strip with a loaded resistor; the absorbing layer is composed of a rotating arrangement of basic units, with the included angle between the basic units being 120°. The dimensions of the basic unit are M1 = 3.8 mm, L1 = 4.7 mm, and M2 = 1 mm.

[0014] As a further explanation of the design method, preferably, a lumped resistor is applied at a position 0.7 mm away from the center of the metal strip in the absorbing layer, wherein the resistance of the lumped unit is 120 ohms.

[0015] As a further explanation of the design method, preferably, the dielectric material of the absorbing layer is Rogers RO4350b, with a dielectric constant of 3.48, a dielectric loss of 0.004, and a thickness h of 1 mm.

[0016] As a further explanation of the design method, preferably, the design of the bandpass layer is a two-ring structure, where a square ring can excite a resonance, and adding another square ring can excite another resonance.

[0017] As a further explanation of the design method, preferably, the upper layer of the dielectric substrate with a through layer is a square ring, and the lower layer is a concentric square ring.

[0018] As a further explanation of the design method, preferably, the bandpass dielectric material is low-loss Rogers RT 5880 with a dielectric constant of 2.2, a loss tangent of 0.0009, and a thickness of 1 mm.

[0019] As a further explanation of the present invention, preferably, the second aspect of the present invention provides a dual-band transparent absorbing frequency-selective radome structure device, including an absorbing module for realizing out-of-band absorbing function.

[0020] As a further explanation of the device, preferably, it includes a dual-frequency transmission module to achieve dual-frequency transmission function within the frequency band of its own communication.

[0021] As a further explanation of the present invention, preferably, the third aspect of the present invention provides a dual-band transparent absorbing frequency-selective radome structure device, including a protective layer, an absorbing layer, a support layer, and a bandpass layer.

[0022] As a further explanation of the equipment, preferably, the protective layer serves to protect the equipment from wind and rain erosion and impact from external objects.

[0023] As a further explanation of the device, preferably, the absorbing layer is used for out-of-band wave absorption.

[0024] As a further explanation of the device, preferably, the support layer is used to fix and support the positions of the absorbing layer and the bandpass layer.

[0025] As a further explanation of the device, preferably, the bandpass layer is used to achieve dual-band wave transmission within the frequency band of its own communication.

[0026] Beneficial effects

[0027] The present invention has the following beneficial effects: the present invention has good wave absorption characteristics, which reduces the radar detection probability, and also ensures the requirements of multi-frequency communication. The structural model has symmetry, so it has good polarization stability. Attached Figure Description

[0028] Figure 1 This is a diagram of the absorbing frequency-selective antenna radome structure of the present invention;

[0029] Figure 2 This is a device diagram of the frequency-selective absorbing antenna radome structure of the present invention;

[0030] Figure 3 This is a basic unit diagram of the absorbing layer of the present invention;

[0031] Figure 4 This is an overall structural diagram of the absorbing layer of the present invention;

[0032] Figure 5 This is a basic unit diagram of the bandpass layer of the present invention;

[0033] Figure 6 This is an overall structural diagram of the bandpass layer of the present invention;

[0034] Figure 7 These are the S-parameter simulation results of the frequency-selective absorbing surface;

[0035] Figure 8 These are the S-parameter simulation results for incident under different polarization modes;

[0036] Figure 9 These are the S-parameter simulation results for different incident angles of electromagnetic waves.

[0037] In the diagram: 0, protective layer; 1, absorbing module; 2, dual-frequency transparent module; 3, support layer; 4, resistor; 5, frequency-selective absorbing surface; 11, absorbing layer; 21, bandpass layer; 11-1, 11-2, basic units of loss layer; 21-1, structure above dielectric layer; 21-2, structure below dielectric layer. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0039] Exemplary methods

[0040] This application proposes a design method for a dual-band transparent absorbing frequency-selective radome structure. The method includes: designing a dual-passband absorbing frequency-selective surface using bending technology, composite technology, and multi-layer cascading technology, and forming a regular array composed of absorbing frequency-selective surface units.

[0041] Specifically, the absorbing frequency-selective antenna radome, such as Figure 1 As shown, it includes a regular array structure composed of frequency-selective absorbing surface units 5.

[0042] Specifically, the frequency-selective absorbing surface unit 5 is a dual-passband FSS structure designed using bending technology, composite technology, and multi-layer cascading technology. It includes two cascaded structures: an absorbing layer 11 on top and a bandpass layer 21 on the bottom.

[0043] Specifically, in combination Figure 3 and Figure 4 The basic unit 11-1 of the absorbing layer 11 is formed by bending a long metal strip 11-2 with a loaded resistor 4. The absorbing layer 11 is composed of the rotating arrangement of the basic units 11-1, with an included angle of 120° between the basic units. The dimensions of the basic unit 11-1 are M1 = 3.8 mm, L1 = 4.7 mm, and M2 = 1 mm. The dielectric material of the absorbing layer is Rogers RO4350b, with a dielectric constant of 3.48, a dielectric loss of 0.004, and a thickness h of 1 mm. A lumped resistor 4 is loaded at a position 0.7 mm from the center of the metal strip in the absorbing layer, where the resistance of the lumped unit 4 is 120 ohms.

[0044] Specifically, in combination Figure 5 and 6The bandpass layer 21 of this invention is designed as a double-ring structure, with a square ring 21-1 on the upper layer of the dielectric substrate and a concentric square ring 21-2 on the lower layer. The square ring 21-1 and the concentric square ring 21-2 are combined to form the structure of the bandpass layer. The dielectric substrate material used for the bandpass layer is low-loss Rogers RT 5880, with a dielectric constant of 2.2, a loss tangent of 0.0009, and a thickness of 1 mm.

[0045] Specifically, observe Figure 7 The curves showing the transmission coefficient and reflection coefficient of the absorption frequency selection surface as a function of frequency are presented. The transmission coefficient curve shows that the structure has two transmission frequency bands, ranging from 5.3GHz to 7.7GHz and from 10.2GHz to 10.7GHz, with maximum losses of 0.8dB and 2.4dB respectively. The reflection curve shows that the structure exhibits low electromagnetic reflection characteristics over a wide frequency range, with a reflection coefficient less than -10dB in the 5.9GHz-12GHz band, indicating a relatively large bandwidth.

[0046] Specifically, observe Figure 8 and Figure 9 The results under different TE / TM modes show polarization stability; the results under different angles show good angular stability, which can reach 0 to 30 degrees, keeping the overall absorption effect below -10dB. In the first transmission frequency band, the transmission effect is almost unaffected, and the insertion loss is relatively low.

[0047] Exemplary device

[0048] Accordingly, this application also provides a dual-band transparent absorbing frequency-selective radome structure device, see [link to relevant documentation]. Figure 1 As shown, the device includes:

[0049] Absorption module 1 is used to achieve out-of-band absorption.

[0050] Dual-band wave transmission module 2 is used to realize the function of dual-band wave transmission within the frequency band of one's own communication.

[0051] Exemplary device

[0052] Accordingly, this application also provides a dual-band transparent absorbing frequency-selective radome structure device, see [link to relevant documentation]. Figure 2 As shown, the device includes:

[0053] Protective layer 0 is used to protect the equipment from wind and rain erosion and impact from external objects.

[0054] The absorbing layer 11 is used to achieve out-of-band absorption.

[0055] Support layer 3, with a height of h = 7.6 mm, is located between the absorbing layer and the bandpass layer. It is used to fix and support the positions of the absorbing layer 11 and the bandpass layer 21.

[0056] Bandpass layer 21 is used to achieve dual-band wave transmission.

[0057] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A design method for a dual-band transparent, wave-absorbing, frequency-selective radome structure, characterized in that: A frequency-selective absorbing surface is designed using bending technology, composite technology, and multi-layer cascading technology, and then a regular array of frequency-selective absorbing surface units is formed. The frequency-selective absorbing surface unit 5 includes two cascaded structures: an absorbing layer 11 on top and a bandpass layer 21 on the bottom. The basic unit 11-1 of the absorbing layer 11 is formed by bending a long metal strip 11-2 with a loaded resistor 4; the absorbing layer 11 is composed of the basic units 11-1 arranged in a rotating manner, and the included angle between the basic units inside is 120°. The design of the bandpass layer 21 is a double-ring structure. The upper layer of the dielectric substrate is a square ring 21-1, and the lower layer is a concentric square ring 21-2. The square ring 21-1 and the concentric square ring 21-2 are combined together to form the structure of the bandpass layer 21.

2. The method according to claim 1, characterized in that: A resistor 4 is applied to the absorbing layer 11 at a position 0.7 mm from the center of the metal strip. The resistor 4 has a resistance of 120 ohms. The dielectric material of the absorbing layer is Rogers RO4350b with a dielectric constant of 3.48, a dielectric loss of 0.004, and a thickness h of 1 mm.

3. The method according to claim 1, characterized in that: The dielectric substrate material of the bandpass layer 21 is Rogers RT 5880 with low loss, a dielectric constant of 2.2, a loss tangent of 0.0009, and a thickness of 1 mm.

4. A dual-band transparent, wave-absorbing, frequency-selective radome structure device, characterized in that: The device is manufactured according to the method described in claim 1, and includes a wave-absorbing module 1 and a dual-frequency wave-transmitting module 2, with the outer layer being the wave-absorbing module 1 and the inner layer being the dual-frequency wave-transmitting module 2.

5. A dual-band transparent, wave-absorbing, frequency-selective radome structure device, characterized in that: The device is manufactured according to the method described in claim 1, and includes a protective layer 0, an absorbing layer 11, a support layer 3, and a bandpass layer 21. The protective layer 0 protects the device from wind and rain erosion and impact from foreign objects. The support layer 3 fixes and supports the positions of the absorbing layer 11 and the bandpass layer 21. The absorbing layer 11 and the bandpass layer 21 enable the device to absorb waves outside the band and transmit waves in both frequency bands.

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