CN111725626A - A radome that absorbs and can be reconfigured to achieve asymmetric transmission of electromagnetic waves and energy isolation - Google Patents

Abstract

The embodiment of the invention discloses a radome that can absorb and reconfigure to realize asymmetric transmission and energy isolation of electromagnetic waves, relates to the technical field of electromagnetic compatibility, and can meet the requirements of asymmetric transmission and energy isolation for small signals and high-energy electromagnetic waves, respectively. The invention includes: the broadband polarization rotating body is composed of three layers, including: the front and the rear layers are mutually perpendicular grating structures to form a Fabry-Perot cavity; the middle layer of the broadband polarization rotating body is inclined at 45° Elliptical resonance structure; the FSR with switchable absorption and penetration is also composed of a 3-layer structure, including: front and rear lossy layers with the same structure, and the front and rear lossy layers are spatially symmetric with respect to the middle layer; The layer is a lossless layer; and each layer of the switchable FSR is embedded with a PIN tube, a resistor, and a capacitor lumped element. The invention is suitable for a non-reciprocal radome against electromagnetic interference.

Description

A radome that absorbs and can be reconfigured to achieve asymmetric transmission of electromagnetic waves and energy isolation

technical field

The invention relates to the technical field of electromagnetic compatibility, in particular to a radome capable of absorbing and reconfiguring to realize asymmetric transmission of electromagnetic waves and energy isolation.

Background technique

Electromagnetic waves are the carrier of information generation, transmission, reception, processing and storage. In a complex electromagnetic environment, in addition to being able to withstand certain external electromagnetic interference, any electronic and electrical product must also ensure that it can work normally. Usually, radiated interference occurs in the media surrounding the product. Generally speaking, electromagnetic interference emitted through the enclosure, or interference intruded through the enclosure is radiated interference. Conventional protective measures (such as radar absorbing material technology, etc.) cannot simply be applied in antenna protection. In fact, the radar antenna system is required to only radiate its own radar waves and suppress external electromagnetic interference signals to form non-reciprocal electromagnetic wave transmission, which is actually a pair of contradictions that are difficult to solve.

At present, there is no perfect theory and systematic design method for how to suppress external interference signals while ensuring the antenna radiation performance remains unchanged or even improved. In practical engineering applications, many anti-interference protections require the help of non-reciprocal electromagnetic materials, such as large-scale ferrite materials to work under the condition of static magnetic field bias, but these materials are difficult to apply to integrated microwave devices, Difficulty working with antenna. In addition, the working frequency band of active electronic information equipment is getting wider and wider, the sensitivity is getting stronger and stronger, and the integration level is getting higher and higher, which puts forward higher requirements for the design of non-reciprocal radomes against electromagnetic interference.

SUMMARY OF THE INVENTION

Embodiments of the present invention provide a radome that can absorb and reconfigure to achieve asymmetric transmission and energy isolation of electromagnetic waves, specifically, a radome that is sensitive to incident electromagnetic wave energy. The sensitivity of the PIN tube to the field strength can be used to realize adaptive switching, which can meet the requirements of asymmetric transmission and energy isolation for small signals and high-energy electromagnetic waves, respectively.

To achieve the above object, the embodiments of the present invention adopt the following technical solutions:

The radome is a composite structure, and the composite structure includes two parts: a broadband polarized rotating body (1) and an FSR (2) that can be switched between absorption and penetration.

The broadband polarization rotating body (1) is composed of a three-layer structure, including: the front and the rear layers are mutually perpendicular grating structures, forming a Fabry-Pérot cavity, which can realize the expansion of the bandwidth. The middle layer of the broadband polarization rotating body (1) is an elliptical resonance structure with an oblique angle of 45°, which realizes the function of polarization rotation.

The FSR(2), which can be switched between absorption and penetration, is also composed of a 3-layer structure, including: front and rear lossy layers with the same structure, and the front and rear lossy layers are spatially symmetric with respect to the middle layer. The transmission characteristics are the same in the direction of transmission. The interlayer, which absorbs through the switchable FSR (2), is a lossless layer and serves to provide a transmission band. And each layer of the frequency selective radar absorber (Frequency Selective Surface, FSR) ((2), which can be absorbed and switched, is embedded with PIN tubes, resistors, and capacitor lumped elements. Under the first working condition, all the The asymmetric transmission of electromagnetic waves can be realized when the PIN tube is disconnected.

In the second working condition, all the PIN tubes are turned on, the whole structure realizes the wave absorption function and the wave absorption rate is greater than 90%.

The embodiment of the present invention provides a radome that can realize energy isolation and asymmetric transmission through absorption and reconfiguration, and belongs to the field of electromagnetic compatibility. It includes a broadband polarized rotating body (1) and a PIN tube-embedded body (FSR) (2) that realizes absorption and permeability switching, and the broadband polarized rotating body is composed of a three-layer composite structure: an upper and lower orthogonal grating structure layer, the middle inclined elliptical layer; and the absorption and reconfigurable FSR is also composed of a three-layer structure: the middle lossless layer, the upper and lower layers of the lossy layer with the same structure and space symmetry about the middle lossless layer, the purpose is to make the electromagnetic wave from the positive The transmission coefficient is the same for directional incidence and reverse incidence. Asymmetric transmission of electromagnetic waves can be achieved by using this characteristic in combination with a polarized rotating body. The two parts (1) and (2) have the same physical dimensions and working frequency bands, and are combined to form an intelligent radome (3). By combining a broadband polarized rotating body and a switchable FSR, the invention realizes the asymmetric transmission of electromagnetic waves and isolation of high-energy electromagnetic waves by relying on the change of the state of the PIN tube, and realizes impedance matching and small passband insertion loss indicators. Require. The radome is designed with composite structural metamaterials, and the broadband polarized rotating body is skillfully combined with the switchable FSR of absorption and penetration. When low-power electromagnetic waves are incident, the PIN tube is not excited and is in a disconnected state. The radome is an FSR, which can transmit the signal emitted by its own antenna in the transmission band and suppress the external electromagnetic waves with the same polarization as the antenna. signal, forming asymmetric transmission. And there is an absorbing band in front of the transmission band, which can reduce the out-of-band RCS, which is more conducive to the stealth protection of the antenna; and when an external high-power electromagnetic wave with interference is incident, the PIN tube is excited and turned on. The radome is a broadband wave absorber with a wave absorption rate greater than 90%, which can effectively isolate the energy and reduce the RCS (Radar Cross Section) in the entire working bandwidth.

Description of drawings

In order to illustrate the technical solutions in the embodiments of the present invention more clearly, the following briefly introduces the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can also be obtained from these drawings without any creative effort.

1 is a three-dimensional schematic diagram of a cell structure provided by an embodiment of the present invention;

2 is a schematic structural diagram of a broadband polarization rotor part in a unit structure provided by an embodiment of the present invention;

3 is a schematic structural diagram of a switchable FSR part in a unit structure provided by an embodiment of the present invention;

FIG. 4 is an S-parameter curve when asymmetric transmission is realized when a small signal is incident according to an embodiment of the present invention;

FIG. 5 is an S-parameter curve when a wave-absorbing and shielding high-energy interference electromagnetic wave according to an embodiment of the present invention is provided.

Detailed ways

In order to make those skilled in the art better understand the technical solutions of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Hereinafter, embodiments of the present invention will be described in detail, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals refer to the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, but not to be construed as a limitation of the present invention. It will be understood by those skilled in the art that the singular forms "a", "an", "the" and "the" as used herein can include the plural forms as well, unless expressly stated otherwise. It should be further understood that the word "comprising" used in the description of the present invention refers to the presence of stated features, integers, steps, operations, elements and/or components, but does not exclude the presence or addition of one or more other features, Integers, steps, operations, elements, components and/or groups thereof. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items. It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It should also be understood that terms such as those defined in the general dictionary should be understood to have meanings consistent with their meanings in the context of the prior art and, unless defined as herein, are not to be taken in an idealized or overly formal sense. explain.

The embodiment of the present invention provides a radome that can be reconfigured to achieve asymmetric transmission of electromagnetic waves and energy isolation. The radome is a composite structure, and the composite structure includes two parts: a broadband polarized rotating body (1) and an absorption Transparent switchable FSR(2).

The broadband polarization rotating body (1) is composed of a three-layer structure, including: the front and the rear layers are mutually perpendicular grating structures, forming a Fabry-Pérot cavity, which can realize the expansion of the bandwidth. The middle layer of the broadband polarization rotating body (1) is an elliptical resonance structure with an oblique angle of 45°, which realizes the function of polarization rotation.

The FSR(2), which can be switched between absorption and penetration, is also composed of a 3-layer structure, including: front and rear lossy layers with the same structure, and the front and rear lossy layers are spatially symmetric with respect to the middle layer. The transmission characteristics are the same in the direction of transmission. The interlayer, which absorbs through the switchable FSR (2), is a lossless layer and serves to provide a transmission band. And each layer of the switchable FSR (2) is embedded with a PIN tube, a resistor, and a capacitor lumped element. In the first working condition, all PIN tubes are disconnected to realize asymmetrical transmission of electromagnetic waves.

In the second working condition, all the PIN tubes are turned on, the whole structure realizes the wave absorption function and the wave absorption rate is greater than 90%.

In practical applications, the solution described in this embodiment may have two working conditions: under the first working condition when a small signal of normal communication power (less than or equal to about 50 watts) is incident, a high-power interference electromagnetic wave signal (greater than or equal to 100 watts) watts) the second working condition when incident.

Since the state of the PIN tube can be controlled by the external field strength, when a small signal of normal communication power is incident, the PIN tube is in the disconnected state to achieve asymmetric transmission of electromagnetic waves. When the high-power electromagnetic wave is incident, the induced voltage makes the PIN tube conduct, and the whole structure realizes the wave-absorbing function and the wave-absorbing rate is greater than 90%, which can effectively isolate the interference of the high-energy electromagnetic wave to the communication antenna. The composite structure radome can perform state switching adaptively, which is in line with the application prospect of "intelligence". The described structure utilizes the polarization rotation structure to realize the torsion of the polarization form of the transmission electromagnetic wave, and then combines the polarization-sensitive absorber to realize the screening of the transmission electromagnetic wave, so as to achieve the index requirements of asymmetric transmission, absorption and shielding of high-energy interference signals, so that Meet the actual requirements of the electrical performance of the radome window and the suppression of interference signals. The overall structure can achieve switchable wave absorption/transmission in the S-band (2GHz-4GHz), so that asymmetric transmission of electromagnetic waves and shielding of high-energy electromagnetic waves can be achieved at the same time, with good impedance matching and low insertion loss in the transmission band.

In the preferred solution of this embodiment, the perimeter of each periodic unit structure of the radome is 38mm, and the thickness is 8.25cm. All dielectric substrates use F4B dielectric material with relative permittivity of 2.65 and loss tangent of 0.001. All dielectric substrates use Rogers 5880 dielectric material or low relative permittivity dielectric. The width of the mutually perpendicular grating structures is 2.25mm, and the interval is 5.25mm. The radius of the major axis of the elliptical resonance structure inclined at 45° is 24 mm, and the radius of the minor axis is 5.25 mm. The thickness of each layer of the dielectric substrate of the broadband polarized rotating body (1) is 2 mm, and the interlayer spacing is 12.25 mm.

For example, as shown in FIG. 1 , the structure designed by the present invention consists of a broadband polarized rotating body (1) and a FSR (2) that can be switched between absorption and penetration, and the distance is D. The perimeter of the entire unit structure is 38mm, and the overall thickness is about 8.25cm. All the dielectric substrates are made of F4B dielectric materials with a relative dielectric constant of 2.65 and a loss tangent of 0.001.

As shown in Figure 2, the width of the vertical grating structure of the front and rear layers of the broadband polarized rotating body is 2.25mm, and the interval is 5.25mm. The thickness is 2mm, and the spacing between layers is 12.25mm. The polarization rotator can realize cross-polarization rotation between 1.8GHz-6.2GHz and the conversion rate is about 1.

In the preferred solution of this embodiment, the thicknesses of the front and rear lossy layers are both 0.5 mm. The widths of the metal strips in the most middle position are w ₁ =2.5 mm and w ₂ =2.8 mm, respectively. The width of the metal strip adjacent to the middlemost position is w ₀ =5 mm, and the interval between the metal strips is 2 mm. The resistance values of the resistors are respectively R1=80Ω, R2=30Ω, and the distance between R2 is 24.7mm. The capacitor value is 1.4x10 ^-12 F and the capacitors are separated by 36.2mm. The thickness of the lossless layer is 0.5mm, the interval between the two metal blocks is 1.6mm, and the capacitance value of the lossless layer is 5x10 ^-9 F. The interlayer spacing of the switchable FSR (2) was 20 mm. All PIN tubes use SMP1345-079LF.

For example, as shown in Figure 3, the front and rear layers of the FSR are lossy layers with a thickness of 0.5mm, the widths of the most adjacent metal strips in the middle are w ₁ =2.5mm, w ₂ =2.8mm, and the width of the adjacent metal strips w ₀ =5mm, the interval between the metal strips is 2mm, the resistance values of the selected resistors are R1=80Ω, R2=30Ω, and the distance between R2 is 24.7mm, the capacitance value is ^1.4x10-12 F and the The distance between them is 36.2mm.

The middle layer is a lossless layer with a thickness of 0.5mm. The interval between the two metal blocks is 1.6mm. The capacitance value of this layer is 5x10 ^-9 F. All PIN tubes use SMP1345-079LF. The interval is 20mm. The FSR is switchable between transmitting and absorbing. Combining the two parts of Fig. 2 and Fig. 3 with an interval of 20mm can design a radome to achieve energy isolation and asymmetric transmission. When the PIN tube is disconnected, the asymmetrical transmission of electromagnetic waves can be achieved, and the insertion loss through the band is only 0.72dB at 3.52GHz. When the PIN is turned on, the radome can absorb waves between 1.8GHz and 4.4GHz, and the wave absorption rate can reach more than 90%, which has the effect of good energy isolation for high-power interference signals.

The elliptical resonance unit structure in the broadband polarized rotating body used in the present invention can be designed as an open ring structure, and the same effect can be achieved. All dielectric substrates can use Rogers 5880 with lower loss or low relative dielectric constant dielectric, which can further reduce the passband insertion loss, as long as the relative dielectric constant, loss and thickness of the material meet good impedance matching.

The design purpose of this scheme is: in view of the problems of the prior art, the present invention aims to provide a novel radome with excellent electromagnetic performance, which can absorb and reconfigure to realize asymmetric transmission of electromagnetic waves and energy isolation, and overcome the above-mentioned prior art. problems in . Specifically design a radome that can be reconfigured to achieve asymmetric transmission and energy isolation of electromagnetic waves. The unit structure includes two parts: a broadband polarized rotating body (1) and a switchable FSR (2) that can be absorbed and penetrated. The physical size of the part is consistent with the operating frequency band, and each part contains a 3-layer structure.

The general design idea is: for the electronic information system to achieve in-band stealth when the external detection radar transmits signals from its own radar antenna, and to achieve shielding and isolation from external high-power interference signals, PIN diodes are important lumped components that can This makes the design adaptively change and switch between asymmetric transmission and energy isolation. Breaking through the characteristics of the existing frequency selective radome, which cannot transmit electromagnetic waves in one direction, the electromagnetic characteristics are not rich, and the engineering realization is relatively weak, the electromagnetic metamaterial polarized rotating structure, high resistance surface, and lumped parameter elements are introduced into the radome. designing. The invention utilizes the polarized rotating surface and the wave absorbing surface, combined with the design of the PIN tube, to achieve the index requirements of non-reciprocal transmission, absorption and shielding of interference signals, so as to meet the actual requirements of the electrical performance of the radome window and clutter suppression.

The embodiment of the invention discloses a radome that can absorb and reconfigure to realize energy isolation and asymmetric transmission, and belongs to the field of electromagnetic compatibility. It includes a broadband polarized rotating body (1) and a PIN tube-embedded body (FSR) (2) that realizes absorption and permeability switching, and the broadband polarized rotating body is composed of a three-layer composite structure: an upper and lower orthogonal grating structure layer, the middle inclined elliptical layer; and the absorption and reconfigurable FSR is also composed of a three-layer structure: the middle lossless layer, the upper and lower layers of the lossy layer with the same structure and space symmetry about the middle lossless layer, the purpose is to make the electromagnetic wave from the positive The transmission coefficient is the same for directional incidence and reverse incidence. Asymmetric transmission of electromagnetic waves can be achieved by combining this characteristic with a polarized rotating body. The two parts (1) and (2) have the same physical dimensions and working frequency bands, and are combined to form an intelligent radome (3). By combining a broadband polarized rotating body and a switchable FSR, the invention realizes the asymmetric transmission of electromagnetic waves and isolation of high-energy electromagnetic waves by relying on the change of the state of the PIN tube, and realizes impedance matching and small passband insertion loss indicators. Require.

The radome with switchable absorption and penetration in the present invention is designed by using composite structure metamaterials, and the broadband polarized rotating body is skillfully combined with the FSR which can be switched between absorption and penetration. When low-power electromagnetic waves are incident, the PIN tube is not excited and is in a disconnected state. The radome is an FSR, which can transmit the signal emitted by its own antenna in the transmission band and suppress the external electromagnetic waves with the same polarization as the antenna. signal, forming asymmetric transmission. And there is an absorbing band in front of the transmission band, which can reduce the out-of-band RCS, which is more conducive to the stealth protection of the antenna; and when an external high-power electromagnetic wave with interference is incident, the PIN tube is excited and turned on. The radome is a broadband wave absorber with a wave absorption rate greater than 90%, which can effectively isolate the energy and reduce the RCS (Radar Cross Section) in the entire working bandwidth.

To sum up, it can have the following advantages:

(1), the present invention can not realize one-way transmission for the existing frequency selective radome, and realizes the asymmetric propagation of electromagnetic waves by using the cascading mode of the polarization rotating body and the polarization-sensitive wave absorber for the first time, and the present invention has a novel viewpoint, The invention is very innovative and simple in structure, and the preparation is more convenient.

(2) The present invention uses the voltage-controlled conductive structure to participate in the design of the polarization-sensitive wave absorber, so that the wave absorber can switch between the two states of wave transmission and wave absorption, so that the asymmetric transmission and energy isolation can be achieved. Adaptive switching between.

(3) The present invention realizes the switching between wave transmission and wave absorption by loading the lumped element PIN tube and controlling the state of the PIN tube, which is more suitable for "intelligent" when the communication environment is complex. application prospects.

Each embodiment in this specification is described in a progressive manner, and the same and similar parts between the various embodiments may be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, as for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and for related parts, please refer to the partial descriptions of the method embodiments. The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical scope disclosed by the present invention can easily think of changes or substitutions. All should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (9)

1. a kind of radome that can be reconfigured to realize electromagnetic wave asymmetric transmission and energy isolation, it is characterized in that, described radome is a composite structure, and this composite structure comprises two parts: broadband polarized rotating body (1) and Suction through switchable FSR(2); The broadband polarization rotator (1) is composed of a three-layer structure, including: the front and rear layers are mutually perpendicular grating structures to form a Fabry-Pérot cavity; The middle layer is an elliptical resonance structure with an oblique 45°; The switchable FSR(2) of absorption and penetration is also composed of a 3-layer structure, including: front and rear lossy layers with the same structure, and the front and rear lossy layers are spatially symmetric with respect to the middle layer; The middle layer is a lossless layer; and PIN tubes, resistors and capacitors are embedded on each layer of the switchable FSR (2); In the first working condition, all PIN tubes are in a disconnected working state; In the second working condition, all the PIN tubes are in a conducting working state. 2 . The radome of claim 1 , characterized in that the perimeter of each periodic unit structure of the radome is 38mm and the thickness is 8.25cm. 3. The radome of claim 1, characterized in that, all dielectric substrates are F4B dielectrics with a relative permittivity of 2.65 and a loss tangent of 0.001 Material. 4 . The radome capable of absorbing and reconfiguring to realize asymmetric transmission of electromagnetic waves and energy isolation according to claim 1 , wherein all dielectric substrates are made of Rogers 5880 dielectric material. 5 . 5. The radome of claim 1, characterized in that the width of the mutually perpendicular grating structures is 2.25mm, and the interval is 5.25mm; The radius of the long axis of the elliptical resonance structure inclined at 45° is 24mm, and the radius of the short axis is 5.25mm; The thickness of each layer of the dielectric substrate of the broadband polarized rotating body (1) is 2 mm, and the interlayer spacing is 12.25 mm. 6. The radome of claim 1, characterized in that the thicknesses of the front and rear lossy layers are both 0.5mm; The widths of the metal strips at the middlemost position are w ₁ =2.5mm, w ₂ =2.8mm; The width of the metal strip adjacent to the middlemost position is w ₀ =5 mm, and the interval between the metal strips is 2 mm. 7. The radome of claim 6, characterized in that the resistance values of the resistors are respectively R1=80Ω, R2=30Ω, and the distance between R2 is 24.7mm; The capacitor value is 1.4x10 ^-12 F and the capacitors are separated by 36.2mm. 8. The radome of claim 1, characterized in that the thickness of the lossless layer is 0.5mm, and the interval between the two metal blocks is 1.6mm, The capacitance value of the lossless layer is 5x10 ^{- 9} F. The interlayer spacing of the switchable FSR (2) was 20 mm. 9 . The radome that absorbs and can be reconfigured to realize asymmetric transmission of electromagnetic waves and energy isolation according to claim 1 , wherein all PIN tubes adopt SMP1345-079LF. 10 .

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