Broadband wide-angle absorbing-transmitting-reflection integrated reconfigurable skin

Abstract

The application discloses a broadband and wide-angle domain absorption-transmission-reflection integrated reconfigurable skin, and relates to the fields of electromagnetic stealth, radome design and artificial electromagnetic materials. The reconfigurable skin is composed of a resistive film absorption layer, a multilayer double-sided copper-clad PCB board and an active device, miniaturization of units is realized by introducing interlayer coupling capacitors, and a transmission band is switched and reconfigured by using a feeding design of a metal structure itself. When the active device is in an off state, the skin presents an excellent low-insertion-loss wave-transmitting state in a band, and does not affect the receiving and transmitting performance of an antenna inside an aperture; when the active device is in an on state, a transmission window in the band is closed and switched to a shielding and reflecting state; and in a high-frequency band outside the band, the super surface presents wide-band high-cut-off reflection and high-efficiency absorption characteristics. In particular, the skin can still maintain good out-of-band stealth and shielding performance under wide-angle oblique incidence. The application does not need to introduce an additional feeding network, and has the advantages of polarization insensitivity, high angle stability and strong functional integration while taking into account the integration of radio frequency aperture detection and stealth.

Description

Technical Field

[0001] This invention relates to artificial electromagnetic metasurfaces, radome design, and electromagnetic compatibility and stealth, and particularly to a wide-bandwidth angular domain integrated reconfigurable skin that absorbs, transmits, and reflects light. Background Technology

[0002] With the rapid development of radar detection and radio frequency antenna technology, the application of multi-frequency, broadband antennas in modern radar stealth platforms is becoming increasingly mature. As a strong scattering source on stealth platforms, the integrated design of radio frequency apertures for detection and stealth has become crucial for modern aerospace stealth technology. Traditional electromagnetic metasurfaces or radome structures often suffer from limitations such as narrow operating bandwidth, poor angular stability, and non-reconfigurability. Furthermore, since stealth applications such as airborne radomes need to be tightly integrated with low-scattering, low-attitude platforms, if the metasurface unit period is too large, it is highly susceptible to grating lobe effects and strong backscattering during tilted or large-angle grazing incidence, thereby worsening the platform's monostatic radar cross section (RCS). Therefore, how to introduce energy loss mechanisms and active reconfigurable mechanisms while ensuring the miniaturization and high angular stability of metasurface units, and to achieve independently adjustable in-band communication windows and efficient out-of-band broadband absorption and reflection integration, is a critical technical challenge that urgently needs to be addressed in the field of stealth materials. Summary of the Invention

[0003] The purpose of this invention is to provide a wide-bandwidth, angle-domain, integrated reconfigurable skin that combines detection-stealth integration with multi-functional integration requirements for airborne radar systems. This invention, through spatial layered geometric topology and interlayer coupling design, achieves unit miniaturization without introducing complex additional power supply networks, enabling active switching reconfiguration of the in-band communication transmission band, while also providing wideband, high-shield, and efficient wave absorption characteristics at out-of-band high frequencies.

[0004] To achieve the above objectives, the present invention provides the following solution:

[0005] The present invention provides a wide bandwidth and angle domain integrated reconfigurable skin for absorption, penetration and reflection. The wide bandwidth and angle domain integrated reconfigurable skin for absorption, penetration and reflection includes multiple periodically arranged metasurface units. The metasurface units include: a resistive film absorption layer, a first double-sided copper clad PCB, a second double-sided copper clad PCB, a third double-sided copper clad PCB, and active devices surface-mounted on the third double-sided copper clad PCB.

[0006] The upper surface of the resistive film absorption layer is a carbon paste square resistive film array fabricated by screen printing, with a sheet resistance of 130 Ω / sq, which is used to introduce an energy loss mechanism at out-of-band high frequencies.

[0007] The first double-sided copper-clad PCB includes an upper metal structure and a lower metal structure, the second double-sided copper-clad PCB includes an upper metal structure and a lower metal structure, and the third double-sided copper-clad PCB includes an upper metal structure and a lower metal structure. The upper metal structure and the lower metal structure, as well as the upper metal structure and the lower metal structure, form interlayer coupling capacitance in the vertical direction through their overlapping areas.

[0008] The upper and lower metal structures are identical cross-shaped mesh metal structures.

[0009] The resistive film absorption layer, the first double-sided copper clad PCB board, the second double-sided copper clad PCB board and the third double-sided copper clad PCB board are laminated sequentially from top to bottom, and adjacent layers are tightly bonded and filled with cyanate ester prepreg with a thickness of 1.7 mm (relative permittivity 3.28, loss tangent 0.0067).

[0010] The dielectric substrates of the resistive film absorption layer, the first double-sided copper clad PCB, the second double-sided copper clad PCB, and the third double-sided copper clad PCB are all F4B265 dielectric substrates with a thickness of 0.127 mm (relative permittivity 2.65, loss tangent 0.001).

[0011] The upper metal structure 1 and the lower metal structure 2, as well as the upper metal structure 5 and the lower metal structure 6, each have a specific overlapping cross-sectional area in the vertical direction. Under the influence of the potential difference between the two ends of the dielectric substrate, strong interlayer local electric fields are excited inside the dielectric of the first double-sided copper-clad PCB and the third double-sided copper-clad PCB, respectively, and a large interlayer coupling capacitance is constructed, thereby significantly reducing the intrinsic resonant frequency of the metasurface as a whole and realizing miniaturized design.

[0012] The active device is a Schottky diode, with its two leads surface-mount soldered to the narrow gaps between adjacent units of the lower metal structure 6. The wide-bandwidth, wide-angle, penetration-reflection integrated reconfigurable skin full array is arranged by rotating the metal structure by 45°, directly utilizing the series-parallel metal chains of the lower metal structure 6 as a DC bias bus, achieving full-array active state switching reconfiguration without introducing any additional external power supply network.

[0013] Optionally, the wide bandwidth angle domain absorber-permeable-reflector integrated reconfigurable skin has polarization insensitivity.

[0014] Optionally, the wide bandwidth angle domain absorber-transmitter-reflector integrated reconfigurable skin has excellent angular stability and can maintain good out-of-band shielding effectiveness at large angles or even grazing incidence.

[0015] Optionally, the wide bandwidth angular domain absorber-transmitter-reflector integrated reconfigurable skin has broadband characteristics.

[0016] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects:

[0017] This invention achieves a large interlayer coupling capacitance by designing specific geometric overlaps between adjacent metal layers, thereby generating a strong interlayer local electric field within the dielectric. This allows the cell to achieve a capacitance of 0.052λ without relying on a large horizontal period. L × 0.052λ L × 0.06λ L The miniaturized topology maintains extremely stable electromagnetic response even under large-angle oblique incidence of up to 60°, effectively avoiding the grating lobe effect caused by traditional structures under grazing incidence. Simultaneously, a Schottky diode is loaded into the narrow gap of the lower metal structure 6. In the off state, its junction capacitance and gap capacitance are superimposed in parallel to optimize impedance matching, ensuring the transmission band is precisely located in the 2.8 ~ 3.5 GHz band with an in-band insertion loss of less than 1 dB, guaranteeing efficient detection of the antenna aperture. When conducting, a low-impedance short circuit completely destroys the resonance condition, completely closing the communication window and reducing the transmission coefficient to below -19 dB, achieving independent reconfiguration of the in-band transmission and reflection function. Furthermore, a square carbon paste resistive film with a sheet resistance of 130 Ω / sq is introduced at the top layer, providing an excellent loss attenuation mechanism for out-of-band high frequencies, resulting in an electromagnetic wave absorption rate greater than 90% in the 13.3 ~ 18 GHz band. The full array is powered by rotating the metal structure by 45° and directly using the series-parallel metal structure to build a DC bias bus for active power supply. There is no need to introduce any additional external power supply wires or backplane power supply columns. This not only greatly simplifies the manufacturing process and reduces the profile, but also completely avoids parasitic scattering and beam distortion caused by additional bias networks in the high-frequency band, significantly improving the stealth function integration of the full array. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 Main view of the wide bandwidth and angle domain integrated reconfigurable skin unit structure;

[0020] Figure 2 Side view of a wide-bandwidth, wide-angle domain, absorbent, reflective, and reconfigurable skin unit structure;

[0021] Figure 3 Schematic diagram of a wide-bandwidth angle-domain integrated reconfigurable skin power supply network;

[0022] Figure 4 The normal incidence S21 parameters for the wide bandwidth and angle domain integrated reconfigurable skin in two states;

[0023] Figure 5 The normal incidence S11 parameters for the wide bandwidth and angle domain integrated reconfigurable skin in two states;

[0024] Figure 6 TE polarization oblique incidence S21 parameters for two states of wide bandwidth and wide angle domain integrated reconfigurable skin;

[0025] Figure 7 The TM polarization oblique incidence S21 parameters for a wide bandwidth and angle-range integrated reconfigurable skin in two states;

[0026] Figure 8 TE polarization oblique incidence S11 parameters for two states of wide bandwidth and wide angle domain integrated reconfigurable skin;

[0027] Figure 9 The TM polarization oblique incidence S11 parameters for a wide bandwidth and angle-domain integrated reconfigurable skin in two states.

[0028] Symbol explanation:

[0029] ①: Resistive film absorption layer; ②: First double-sided copper-clad PCB board; ③: Cross-shaped grid metal layer; ④: Second double-sided copper-clad PCB board. Detailed Implementation

[0030] 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.

[0031] The purpose of this invention is to provide a wide-bandwidth, wide-angle, and integrated reconfigurable skin that combines wave absorption and wave reflection. Its features include wide bandwidth, wide angle range, and high functional integration. It can dynamically switch between in-band wave transmission and strong shielding states according to the applied bias voltage, and achieve efficient wave absorption at high out-of-band frequencies.

[0032] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] Figure 1 and Figure 2The images show a front view and a deteriorated side view of the wide-bandwidth, wide-angle, penetration-reflection integrated reconfigurable skin unit structure provided by this invention. The wide-bandwidth, wide-angle, penetration-reflection integrated reconfigurable skin unit consists of layer ① a resistive film absorption layer, layer ② a first double-sided copper-clad PCB board, layer ③ a second double-sided copper-clad PCB board, layer ④ a third double-sided copper-clad PCB board, and a Schottky diode surface-mounted to the third double-sided copper-clad PCB board. The dielectric substrate material used in the wide-bandwidth, wide-angle, penetration-reflection integrated reconfigurable skin is F4B265 (relative permittivity 2.65, loss tangent 0.001), and the thickness of each of the four dielectric substrate layers is 0.127 mm. The functional structural layers are bonded and filled with cyanate ester prepreg (relative permittivity 3.28, loss tangent 0.0067), which has excellent mechanical properties and bendability. The thickness of the cyanate ester prepreg filler material is 1.7 mm. The wide bandwidth and angle domain reversible skin is formed by periodically arranged metasurface units with a period of 5.6 mm. To achieve polarization insensitivity, the metal geometry of all layers of the wide bandwidth and angle domain reversible skin has fourfold rotational symmetry with respect to the unit center.

[0034] Figure 3 This is a schematic diagram of a wide-bandwidth, angle-domain, penetration-reverse integrated reconfigurable skin power supply network. The wide-bandwidth, angle-domain, penetration-reverse integrated reconfigurable skin full array is arranged by rotating the metal structure horizontally by 45°. In this topology, the metal patches of the third double-sided copper-clad PCB spontaneously interconnect in space to form multiple interlaced series-parallel metal power supply paths. The Schottky diodes are directly soldered across the narrow gaps between adjacent unit patches, and the structure itself serves as a DC bias bus. Only DC feed lines (V0 and V1) need to be added at the top and bottom boundaries of the full array. + and V - By providing welding positions, the DC voltage drop across each diode can be made the same, and all devices on the entire array can be controlled simultaneously without the need for a complex additional power supply network.

[0035] The simulation results of the normal incidence S21 parameters of the wide bandwidth angular domain penetrating and anti-reconstructive reconfigurable skin under two states are as follows: Figure 4 As shown in the figure, the curves indicate that when the diode is off, the reconfigurable skin forms a low-loss broadband transmission window in the frequency range of 2.8 to 3.5 GHz, with an in-band insertion loss of less than 1 dB and a relative bandwidth of 22.2%. When the diode is on, the original transmission window is completely closed and switched to a reflection shielding state. The transmission coefficient S21 in the frequency range of 2 to 18 GHz is less than -19 dB, effectively preventing electromagnetic waves in the band from passing through the structure.

[0036] The simulation results of the normal incidence S11 parameters of the wide bandwidth angular domain penetrating and anti-reconstructive reconfigurable skin under two states are as follows: Figure 5 As shown in the figure, the curves indicate that the reconfigurable skin exhibits efficient absorption of incident electromagnetic waves in the frequency range of 3.3 to 18 GHz, with an absorption rate greater than 90%.

[0037] The wide-angle domain reconfigurable skin exhibits excellent wide-angle domain angular stability, with its S21 values ​​under TE polarization and TM polarization oblique incidence being as follows: Figure 6 and Figure 7 As shown in the figure, under a large-angle oblique incidence of 60°, the shielding response outside the transmission band of the reconfigurable skin remains basically stable regardless of whether it is TE-polarized or TM-polarized, and still has a strong shielding effectiveness of more than 20 dB in the frequency range of 2~18 GHz; the oblique incidence S11 of the wide bandwidth angle-domain integrated absorber-transmitter-reflector reconfigurable skin under TE-polarized and TM-polarized conditions are respectively as follows: Figure 8 and Figure 9 As shown in the figure, the angular stability of the absorption performance of the wide bandwidth angular domain absorber-permeable-reflective integrated reconfigurable skin can reach 60°.

[0038] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0039] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A wide-bandwidth, wide-angle domain absorbent-transparent, reconfigurable skin, characterized in that, include: The resistive film absorption layer, the first double-sided copper-clad PCB, the cross-shaped grid metal layer, the second double-sided copper-clad PCB, and the active devices surface-mounted on the second double-sided copper-clad PCB. The resistive film absorption layer, the first double-sided copper-clad PCB board, the second double-sided copper-clad PCB board and the third double-sided copper-clad PCB board are arranged sequentially from top to bottom, and adjacent layers are bonded and filled with cyanate ester prepreg. The first double-sided copper-clad PCB includes an upper metal structure and a lower metal structure, the second double-sided copper-clad PCB includes an upper metal structure and a lower metal structure, and the third double-sided copper-clad PCB includes an upper metal structure and a lower metal structure, wherein the upper metal structure and the lower metal structure form interlayer coupling capacitance in the vertical direction through their overlapping areas. The lower metal structure of the third double-sided copper-clad PCB has a narrow gap, and the active device is connected across the narrow gap. The entire skin of the array is fed by the series-parallel combination of the metal structure itself without introducing an additional external power supply network.

2. The wide bandwidth and angle domain absorbent-reflective integrated reconfigurable skin according to claim 1, characterized in that, The resistive film absorption layer consists of a square carbon paste resistive film screen-printed on an F4B265 dielectric substrate, and the sheet resistance of the carbon paste resistive film is 130 Ω / sq.

3. The wide bandwidth and angular domain absorbent-transparent integrated reconfigurable skin according to claim 1, characterized in that, The dielectric substrate material used in the first, second, and third double-sided copper-clad PCB boards is F4B265, and the thickness of each dielectric substrate layer is 0.127 mm.

4. The wide bandwidth and angular domain absorbent-transparent integrated reconfigurable skin according to claim 1, characterized in that, The upper and lower metal structures in the second double-sided copper-clad PCB are identical cross-shaped mesh metal structures.

5. The wide bandwidth and angular domain absorbent-transparent integrated reconfigurable skin according to claim 1, characterized in that, All layers of the reconfigurable skin's metallic geometry have fourfold rotational symmetry relative to the unit center, achieving polarization insensitivity to incident electromagnetic waves.

6. The wide bandwidth and angular domain absorbent-transparent integrated reconfigurable skin according to claim 1, characterized in that, The active device is a Schottky diode, which is welded between adjacent unit metal structures. DC feed lines are loaded on the top and bottom of the skin, and the independent switching control of the entire array of Schottky diodes can be achieved by changing the bias voltage.

7. The wide bandwidth angular domain absorbent-reflective integrated reconfigurable skin according to any one of claims 1-6, characterized in that, When the applied bias voltage is zero or there is no applied voltage, the active device is in the off state, and the reconfigurable skin is in a low insertion loss transmission state in the 2.8 ~ 3.5 GHz operating frequency band, with an in-band insertion loss of less than 1 dB; when the frequency increases to the out-of-band high frequency band, the reconfigurable skin switches to a shielding and absorption state, with an electromagnetic wave absorption rate of more than 90% in the 13.3 ~ 18 GHz frequency band.

8. The wide bandwidth angular domain absorbent-reflective integrated reconfigurable skin according to any one of claims 1-6, characterized in that, When the applied bias voltage is greater than the sum of the on-state voltage drops of all active devices in the same branch, the active device is in the on state, the in-band transmission window is closed, and the reconfigurable skin exhibits strong shielding reflection or absorption in the entire frequency band from 2 to 18 GHz, with an in-band transmission coefficient of less than -19 dB.

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