Design method of integrated reflective array compatible with protection, stealth and radiation functions

Abstract

The invention provides an integrated reflective array design method compatible with protection, stealth and radiation functions, and the method comprises the steps: constructing a reflective array equivalent circuit model covering a plurality of different scenes, and calculating a transfer matrix and a scattering matrix of a dual-port network according to the equivalent circuit model; according to the mapping relation between the equivalent circuit model and an energy selection surface unit ESS physical model, fast optimization of frequency response is carried out in an advanced design system ADS; according to the mapping relation in the second step, rapid optimization is completed through a model in the auxiliary computer simulation technology CST, and design of the energy selection surface unit with the phase modulation capacity is achieved. According to the invention, a universal circuit model capable of covering various scenes of different incident powers, polarizations and working bands inside / outside is constructed based on a nonlinear device, a decoupling strategy of protection, stealth and radiation is provided, and theoretical guidance is provided for the establishment of a structure and function integrated model.

Description

Technical Field

[0001] The present application relates to the technical field of metasurface reflector array antennas, and more specifically, to an integrated reflector array design method having compatible protection, stealth, and radiation functions. Background Art

[0002] The competition for information control has become the core content and key link for gaining the initiative in future wars. High power microwave (HPM) weapons are considered to be new concept weapons that can change the rules of war. They are directed energy weapons with an operating frequency of 300MHz to 300GHz. High-gain antennas emit high-power, concentrated and directional microwave beams, which enter enemy electronic systems through front and rear door coupling, instantly interfering with or destroying sophisticated and advanced large-scale integrated circuits, causing communication interruptions, command failures and equipment paralysis.

[0003] Where there is a spear, there must be a shield. HPM weapon countermeasure technology is also about to usher in a climax of development. The biggest challenge it faces is how to ensure that various electronic instruments on major equipment are not affected by HPM and can work normally. One of the future equipment development trends is the integrated design of radar and HPM weapons to meet the integrated requirements of detection and attack. The radar implements low-power detection, intercepts and tracks the target, and then switches to the HPM weapon state to interfere with, destroy or implement hard kill and destruction of the target electronic equipment. Therefore, while studying HPM weapon countermeasure technology, it is also urgent to develop anti-radar detection stealth technology.

[0004] At present, the fuselage can achieve stealth characteristics through relatively mature technical means such as appearance design and coating with absorbing materials, so the RF aperture / antenna array becomes an important interference source that causes the performance of the stealth platform to deteriorate. In other words, the RF aperture mounted on the stealth platform also needs to be designed for stealth. Advanced RF apertures should ensure that they have stealth functions while not affecting radiation performance. At this stage, HPM protection and RF aperture stealth technologies are developed separately. Therefore, in actual applications, electromagnetic coupling or interference problems may be inevitable due to limited installation size, which may cause equipment performance instability and inability to adapt to complex electromagnetic environments. Summary of the invention

[0005] In view of this, the present application provides an integrated reflective array design method that is compatible with protection, stealth, and radiation functions to overcome the defects in the above-mentioned prior art and achieve the integration of stealth, protection, and radiation functions.

[0006] To achieve the above objectives, the technical solutions adopted in this application are as follows:

[0007] An integrated reflective array design method with compatible protection, stealth and radiation functions, comprising:

[0008] Step 1: construct an equivalent circuit model of a reflective array energy selective surface (ESS) unit covering a variety of different scenarios, and calculate the transfer matrix and scattering matrix of a two-port network based on the equivalent circuit model;

[0009] Step 2: According to the mapping relationship between the equivalent circuit model and the physical model of the energy selective surface ESS unit, the frequency response of the equivalent circuit model is quickly optimized in the advanced design system ADS;

[0010] Step 3: According to the mapping relationship in step 2, by adjusting the electrical parameters in ADS, the rapid optimization of the ESS physical model in CST is assisted to realize the design of the energy selective surface unit with phase modulation capability;

[0011] Step 4: Calculate the compensation phase of each unit of the energy selective surface ESS according to the reflected beam pointing direction and determine the array coding, and arrange the units rotated by 0° and 90° according to coding 0 and 1 respectively;

[0012] Step 5: Use three-dimensional electromagnetic simulation software to simulate low-power incident and high-power incident on the integrated reflectarray antenna.

[0013] Optionally, the energy selective surface unit is composed of a lossy layer, a phase-modulation layer and a metal floor from top to bottom, wherein the lossy layer is a layer loaded with lossy element absorbing resistors, the phase-modulation layer has a 1-bit phase regulation function, nonlinear device PIN diodes are embedded in the lossy layer and the phase-modulation layer, four resistors with equal resistance are embedded in the metal square ring of the lossy layer, and the lossy layer is surrounded by a feather-shaped metal patch structure.

[0014] Optionally, in step five, the component model of the PIN diode under low-power incident light is equivalent to a capacitor, and the component model under high-power incident light is equivalent to a resistor.

[0015] Optionally, the scattering matrix |S 11 |Calculated by the following formula:

[0016] The transfer matrix of the lossy layer can be expressed as:

[0017]

[0018] Where Z P1 is the equivalent impedance of the upper surface of the lossy layer, Z SUB1 is the impedance of the first equivalent transmission line between the upper surface of the lossy layer and the upper surface of the phase modulation layer, δ SUB1refers to the electrical length corresponding to the first equivalent transmission line, β refers to the phase constant, l1 refers to the physical length between the upper surface of the lossy layer and the upper surface of the phase modulation layer, R1 is the equivalent resistance of the lossy layer, L1, L2 and L3 respectively represent the equivalent inductance of the lossy layer, C1 represents the equivalent capacitance of the lossy layer, and Z PIN1 Represents the equivalent impedance of a diode loaded in a lossy layer:

[0019]

[0020] δ SUB1 =βl1 (3)

[0021] The transfer matrix of the phase modulation layer can be expressed as:

[0022]

[0023] Where Z P2 is the equivalent impedance of the upper surface of the phase modulation layer, Z SUB2 is the second equivalent transmission line impedance of the medium between the upper surface of the phase modulation layer and the metal floor, δ SUB2 refers to the electrical length corresponding to the second equivalent transmission line, β refers to the phase constant, l2 refers to the physical length between the upper surface of the phase modulation layer and the metal floor, L x1(y1) and L x2(y2) represents the equivalent inductance of the phase modulation layer under x and y polarization, C x1(y1) represents the equivalent capacitance of the phase modulation layer under x and y polarization, Z PIN1 Represents the equivalent impedance of the diode loaded in the phase modulation layer:

[0024]

[0025] δ SUB2 =βl2 (6)

[0026] The transfer matrix of the metal floor can be expressed as:

[0027]

[0028] Where Z P3 is the equivalent impedance of the metal floor:

[0029] Z P3 =jωL4 (8)

[0030] Cascading A1, A2, and A3 gives the transfer matrix A of the integrated structure:

[0031]

[0032] It is known that when the ESS is regarded as a two-port network, both ports are connected to free space, Z0 is the characteristic impedance of free space 377Ω, and the normalized transfer matrix a can be obtained by normalizing A:

[0033]

[0034] The scattering matrix S is obtained based on the normalized transfer matrix a and the relationship between the normalized transfer matrix a and the scattering matrix S:

[0035]

[0036] Through the above transformation relationship, we can get |S 11 |As follows:

[0037]

[0038] Optionally, the phase compensation of each unit in step 4 is calculated by the formula:

[0039]

[0040] in is the initialization phase of each unit, is the beam pointing phase, is the array phase constant, k is the wave number, x mn ,y mn 、z mn are the coordinates of the (m, n)th unit, θ0 and They are the beam deflection angles in the azimuth plane (horizontal plane) and the elevation plane (vertical plane), respectively.

[0041] Optionally, the energy selective surface ESS unit is an energy selective surface ESS unit with a 1-bit phase modulation function, and the 1-bit phase modulation function is implemented by the following formula:

[0042] When the electromagnetic wave emitted by the feed source irradiates the 1-bit integrated ESS array, the phase of the electromagnetic wave received by each unit (m, n) It is expressed as: When the electromagnetic wave emitted by the feed source irradiates the 1-bit integrated ESS array, the phase of the electromagnetic wave received by each unit (m, n) is It is expressed as:

[0043]

[0044] Different location units Subtract the phase generated by the electromagnetic wave irradiated by the feed source reaching the center of the array, and the initialization phase of each unit after normalization It is expressed as:

[0045]

[0046] Since 1-bit unit design is adopted, the quantization rule is expressed as:

[0047]

[0048] Optionally, the reflectarray array is composed of 14×14 energy selective surface units, and the integrated reflectarray antenna structure has a size of 210 mm×210 mm×7 mm.

[0049] Compared with the prior art, the beneficial effects of this application are:

[0050] 1. This application builds a universal circuit model based on nonlinear devices that can cover multiple scenarios with different incident powers, polarizations, and in-band / out-of-band working conditions, proposes a decoupling strategy for protection, stealth, and radiation, and provides theoretical guidance for the establishment of a structural and functional integration model;

[0051] 2. This application establishes a physical mapping relationship between the geometric topological structure and the equivalent circuit model. Based on the Floquet theorem, it develops an AR / AA (absorption-reflection / absorption-absorption) type ESS unit that can sense the incident power and adaptively switch the electromagnetic response, avoiding multiple full-wave simulations and realizing the rapid solution of the optimization model, providing an effective solution for the efficient design of low-scattering electromagnetic protection structures;

[0052] 3. The integrated reflector array of the present application has a broadband out-of-band radar cross section (RCS) reduction, a low-power ±45° wide-angle beam scanning capability within the band, and a high-power adaptive switching wave absorption protection capability, which greatly enhances the protection and stealth capability of the RF aperture (RF aperture refers to the antenna aperture of the RF sensor on a fighter jet) in a complex electromagnetic environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0054] Figure 1 A flow chart of a design method for an integrated reflective array with compatible protection, stealth and radiation functions provided in this application;

[0055] Figure 2 A schematic diagram of an equivalent circuit model of the integrated stealth radiation protection unit provided in an embodiment of the present application;

[0056] Figure 3 A schematic diagram of mapping the equivalent circuit model of the AR / AA type ESS unit provided in an embodiment of the present application to the physical structure;

[0057] Figure 4 (a) is a graph showing theoretical calculation results of an ESS unit in ADS under different powers and polarization incidences provided in an embodiment of the present application;

[0058] Figure 4 (b) is a graph showing full-wave simulation results of an ESS unit in a CST under different powers and polarization incidences provided in an embodiment of the present application;

[0059] Figure 5 (a) is a comparison diagram of theoretical calculation and full-wave simulation when adjusting the notch point according to the mapping relationship under different incident powers provided in the embodiment of the present application;

[0060] Figure 5 (b) is a comparison diagram of theoretical calculation and full-wave simulation when adjusting the absorption bandwidth according to the mapping relationship under different power incidents provided in the embodiment of the present application;

[0061] Figure 6 The equivalent circuit model and physical structure diagram of the ESS unit with 1-bit phase modulation function provided in the embodiment of the present application;

[0062] Figure 7 (a) is a reflection amplitude curve diagram of a 1-bit phase modulation function ESS unit calculated by an equivalent circuit model theory according to an embodiment of the present application;

[0063] Figure 7 (b) is a reflection phase curve diagram of a 1-bit phase modulation function ESS unit calculated by an equivalent circuit model theory according to an embodiment of the present application;

[0064] Figure 8 (a) is a schematic diagram of the physical model and equivalent circuit mapping of the cross-shaped metal strip provided in the embodiment of the present application;

[0065] Figure 8 (b) is a graph showing the reflection amplitude under x-polarization and y-polarization when a cross-shaped metal strip is introduced into an ESS as a phase modulation layer according to an embodiment of the present application and low power is incident;

[0066] Figure 8 (c) A cross-shaped metal strip is introduced into the ESS as a phase modulation layer according to an embodiment of the present application, and a reflection phase curve diagram under x-polarization and y-polarization when low power is incident;

[0067] Figure 8(d) is a graph showing the reflection amplitude under x-polarization and y-polarization when a cross-shaped metal strip is introduced into an ESS as a phase modulation layer according to an embodiment of the present application and high power is incident;

[0068] Fig. 9 (a) is a physical model and equivalent circuit mapping diagram of the asymmetric arrow structure provided in an embodiment of the present application;

[0069] Fig. 9 (b) is a graph showing the reflection amplitude under x-polarization and y-polarization when the asymmetric arrow structure provided in an embodiment of the present application is introduced into the ESS as a phase modulation layer and low power is incident;

[0070] Fig. 9 (c) is a graph showing the reflection phase curves under x-polarization and y-polarization when the asymmetric arrow structure is introduced into the ESS as a phase modulation layer according to an embodiment of the present application and low power is incident;

[0071] Fig. 9 (d) is a graph showing the reflection amplitude under x-polarization and y-polarization when an asymmetric arrow structure is introduced into an ESS as a phase modulation layer according to an embodiment of the present application and high power is incident;

[0072] Fig.10 (a) is a graph showing the reflection amplitude of an integrated 1-bit ESS unit based on a cross-shaped metal strip phase modulation layer provided in an embodiment of the present application at low power vertical incidence and 30° oblique incidence;

[0073] Fig.10 (b) is a graph showing the absorption rate of an integrated 1-bit ESS unit based on a cross-shaped metal strip phase modulation layer provided in an embodiment of the present application at low power vertical incidence and 30° oblique incidence;

[0074] Fig.10 (c) is a graph showing the reflection amplitude of an integrated 1-bit ESS unit based on a cross-shaped metal strip phase modulation layer provided in an embodiment of the present application, at vertical incidence and 30° oblique incidence of the HPM;

[0075] Fig.10 (d) is a graph showing the wave absorption rate of an integrated 1-bit ESS unit based on a cross-shaped metal strip phase modulation layer provided in an embodiment of the present application, at HPM vertical incidence and 30° oblique incidence;

[0076] Fig.11 A schematic diagram of a 14×14 integrated 1-bit reflective array 3D model provided in an embodiment of the present application;

[0077] Fig.12 (a) is a schematic diagram of the array coding required for the phase modulation layer when the radiation beam is pointed at 0° provided in an embodiment of the present application;

[0078] Fig.12 (b) is a schematic diagram of the array coding required for the phase modulation layer when the radiation beam is pointed at 30° provided in an embodiment of the present application;

[0079] Fig.12 (c) is a schematic diagram of the array coding required for the phase modulation layer when the radiation beam is pointed at 45° provided in an embodiment of the present application;

[0080] Fig.13 (a) is the radiation pattern of the xoz plane at 8.64 GHz provided by the embodiment of the present application;

[0081] Fig.13 (b) The radiation pattern of the yoz plane at 8.64 GHz provided by the embodiment of the present application;

[0082] Fig.14 (a) is a graph showing RCS reduction of a 14×14 integrated 1-bit reflective array in coding state 1 under low power incidence provided by an embodiment of the present application;

[0083] Fig.14 (b) is a graph showing RCS reduction of a 14×14 integrated 1-bit reflective array in coding state 2 under low power incidence provided by an embodiment of the present application;

[0084] Fig.15 A dual-station RCS result diagram of a 14×14 integrated 1-bit reflective array in coding state 2 under low power incidence provided in an embodiment of the present application and a large metal plate such as the array at an out-of-band absorption frequency of 7 GHz and a notch frequency of 8.64 GHz;

[0085] Fig.16 (a) is an RCS reduction curve diagram of a 14×14 integrated 1-bit reflective array in coding state 1 under HPM incidence provided by an embodiment of the present application;

[0086] Fig.16 (b) is an RCS reduction curve diagram of the 14×14 integrated 1-bit reflective array in coding state 2 under HPM incidence provided in an embodiment of the present application. DETAILED DESCRIPTION

[0087] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments.

[0088] like Figure 1 As shown, a design method for an integrated reflective array having protection, stealth and radiation functions includes:

[0089] S101: constructing an equivalent circuit model of a reflective array energy selective surface (ESS) unit covering a variety of different scenarios, and calculating a transfer matrix and a scattering matrix of a two-port network according to the equivalent circuit model;

[0090] like Figure 2 As shown in FIG. 1 , the equivalent circuit model consists of a lossy layer (Layer 1), a phase modulation layer (Layer 2), and a metal floor (Layer 3). Both the lossy layer and the phase modulation layer are embedded with PIN diodes, which together realize the energy selection characteristics of the reflect array.

[0091] In one embodiment of the present invention, Figure 3 As shown, without considering the phase modulation layer, a mapping relationship from the equivalent circuit model of an AR / AA (absorption-reflection / absorption-absorption) type ESS (energy selective surface) unit to the physical structure is proposed.

[0092] In the equivalent circuit models of various scenarios with different incident powers, polarizations, and in-band / out-of-band working conditions, the component model of the PIN diode under low-power incident power is equivalent to a capacitor, and the component model under high-power incident power is equivalent to a resistor. The values ​​of the equivalent inductance components and circuit components of the phase modulation layer under different polarizations are defined according to the sizes of the patch structure and the gap structure.

[0093] Optionally, the scattering matrix of the two-port network |S 11 |It can be calculated by the following formula:

[0094] The transfer matrix of the lossy layer can be expressed as:

[0095]

[0096] Where Z P1 is the equivalent impedance of the upper surface of the lossy layer, Z SUB1 is the impedance of the first equivalent transmission line between the upper surface of the lossy layer and the upper surface of the phase modulation layer, δ SUB1 refers to the electrical length corresponding to the first equivalent transmission line, β refers to the phase constant, l1 refers to the physical length between the upper surface of the lossy layer and the upper surface of the phase modulation layer, R1 is the equivalent resistance of the lossy layer, L1, L2 and L3 respectively represent the equivalent inductance of the lossy layer, C1 represents the equivalent capacitance of the lossy layer, and Z PIN1 Represents the equivalent impedance of a diode loaded in a lossy layer:

[0097]

[0098] δ SUB1 =βl1 (3)

[0099] The transfer matrix of the phase modulation layer can be expressed as:

[0100]

[0101] Where Z P2 is the equivalent impedance of the upper surface of the phase modulation layer, Z SUB2 is the second equivalent transmission line impedance of the medium between the upper surface of the phase modulation layer and the metal floor, δ SUB2 refers to the electrical length corresponding to the second equivalent transmission line, β refers to the phase constant, l2 refers to the physical length between the upper surface of the phase modulation layer and the metal floor, L x1(y1) and L x2(y2) represents the equivalent inductance of the phase modulation layer under x and y polarization, C x1(y1) represents the equivalent capacitance of the phase modulation layer under x and y polarization, Z PIN1 Represents the equivalent impedance of the diode loaded in the phase modulation layer:

[0102]

[0103] δ SUB2 =βl2 (6)

[0104] The transfer matrix of the metal floor can be expressed as:

[0105]

[0106] Where Z P3 is the equivalent impedance of the metal floor:

[0107] Z P3 =jωL4 (8)

[0108] Cascading A1, A2, and A3 gives the transfer matrix A of the integrated structure:

[0109]

[0110] It is known that when the ESS is regarded as a two-port network, both ports are connected to free space, Z0 is the characteristic impedance of free space 377Ω, and the normalized transfer matrix a can be obtained by normalizing A:

[0111]

[0112] The scattering matrix S is obtained based on the normalized transfer matrix a and the relationship between the normalized transfer matrix a and the scattering matrix S:

[0113]

[0114] Through the above transformation relationship, we can get |S 11 |As follows:

[0115]

[0116] Therefore, by adjusting the electrical parameters in the equivalent circuit, the reflection coefficient of the integrated reflectarray under different incident powers and polarizations can be theoretically calculated.

[0117] Under low power incident conditions, the PIN diodes in the lossy layer and the phase modulation layer can be equivalent to capacitors C when they are disconnected. PIN1 and C PIN2 The equivalent circuits of the lossy layer are the same under different polarizations. The equivalent circuits of the phase-modulation layer are the same under x and y polarizations, but the specific values ​​of the electrical parameters are different. Therefore, new notches of different frequencies can be introduced on both sides of the notch generated by the lossy layer, thereby achieving a specific phase difference within the overlapping notch bands of the two polarizations. Under HPM incidence, the PIN adaptive triggering in the lossy layer and the phase-modulation layer can be equivalent to a small resistor R PIN1 and R PIN2 . Figure 3 Middle Z Layer1 is the lossy layer impedance, Z Layer2 is the impedance of the phase modulation layer, Z Layer3 is the metal floor impedance, and Z0 is the free space characteristic impedance of 377Ω.

[0118] S102, according to the mapping relationship between the equivalent circuit model and the physical model of the energy selective surface ESS unit, quickly optimize the frequency response of the equivalent circuit model in the advanced design system ADS;

[0119] The constructed mapping relationship can be used to observe the change trend of the frequency response by adjusting the values ​​of R1, L1, C1, L2, and L3 in the reflective array equivalent circuit model. Through the rapid calculation of the circuit, the change trend of the corresponding topological structure when adjusted can be equivalently analyzed, thereby realizing the rapid optimization of the physical model.

[0120] The energy selective surface ESS unit is composed of a lossy layer, a phase modulation layer and a metal floor from top to bottom. The lossy layer and the phase modulation layer are both embedded with nonlinear device PIN diodes, and the metal square ring of the lossy layer is embedded with four resistors with equal resistance values, so as to achieve out-of-band wave absorption stealth. In a preferred embodiment, the resistance value of the four resistors with equal resistance values ​​is 130Ω, but the resistance value is not limited to this, and it can be set differently according to the wave absorption bandwidth and wave absorption amplitude; the lossy layer is surrounded by a gap-type arrow feather-shaped metal patch structure (i.e., a metal patch structure similar to the shape of a bow and arrow feather), such as Figure 3 and 6 As shown, a notch point is provided in the absorption band. The physical size of the phase modulation layer is different under the two polarizations, so that two additional notch points are introduced on the left and right of the notch point generated by the absorption layer. In one embodiment, the reflection phase difference of the energy selective surface in the overlapping notch bands of the two polarizations is within the range of 180±37°, realizing a 1-bit phase modulation function.

[0121] S103, according to the mapping relationship in step 2, the ESS model in the auxiliary computer simulation technology CST is used to complete the rapid optimization, so as to realize the design of the energy selective surface unit with phase modulation capability;

[0122] S104, calculating the compensation phase of each unit of the energy selective surface ESS according to the reflected beam pointing direction and determining the array coding, and arranging the units rotated by 0° and 90° according to the coding 0 and 1 respectively;

[0123] Optionally, the phase compensation of each unit in step S104 is calculated by the following formula:

[0124]

[0125] in is the initialization phase of each unit, is the beam pointing phase, is the array phase constant.

[0126] S105, using three-dimensional electromagnetic simulation software to simulate low-power incident and high-power incident on the integrated reflective array antenna.

[0127] The verification of the low-power incident performance in step S105 includes scattering characteristics and radiation characteristics. The scattering characteristics require setting a plane wave excitation above the integrated ESS array, and setting an RCS far-field probe in the mirror direction for reception. The radiation characteristics calculate the array encoding according to the beam pointing, call matlab for array modeling, and use a horn antenna for space feeding. Since the notch point disappears under high-power incidence and does not have the reflective array characteristics, only the scattering characteristics need to be verified, and the simulation settings are consistent with the low-power incidence case.

[0128] Optionally, the energy selective surface ESS unit is an energy selective surface ESS unit with a 1-bit phase shift function, and the 1-bit phase shift function is implemented by the following formula:

[0129] When the electromagnetic wave emitted by the feed source irradiates the 1-bit integrated ESS array, the coordinates of the (m, n)th unit are x mn ,y mn 、z mn , θ0 and are the beam deflection angles in the azimuth plane (horizontal plane) and the pitch plane (vertical plane), f is the focal length, and the phase of the electromagnetic wave received by each unit (m, n) is It is expressed as:

[0130]

[0131] Different location units Subtract the phase generated by the electromagnetic wave irradiated by the feed source reaching the center of the array, and the initialization phase of each unit after normalization It is expressed as:

[0132]

[0133] Since 1-bit unit design is adopted, the quantization rule is expressed as:

[0134]

[0135] According to the above theory, once the radiation direction of the beam is determined, the electromagnetic wave reflection phase of each unit of the phase modulation layer can be theoretically calculated. In this application, the reflection phase of the phase modulation layer unit can be independently adjusted, so the array encoding can be reasonably controlled to achieve beam scanning in the required direction.

[0136] Optionally, the reflectarray array is composed of 14×14 energy selective surface units, and the integrated reflectarray antenna structure has a size of 210 mm×210 mm×7 mm.

[0137] This application combines radar stealth, high-power microwave protection and metasurface reflector arrays, mines the phase information of the notch band, constructs a power-dependent 1-bit reflector array based on the nonlinear element PIN diode, and integrates stealth, protection and radiation functions. The integrated reflector array of this application can achieve power-independent broadband out-of-band RCS reduction, and can achieve ±45° wide-angle beam scanning through reasonable array face coding and external low-power spatial feeding, and can achieve broadband stealth protection under high-power incidence.

[0138] In one embodiment of the present invention, Figure 4 (a)- Figure 4 (b) shows the theoretical calculation and full-wave simulation results of the ESS unit in ADS and CST under different powers and polarization incident conditions.

[0139] ESS has full reflection characteristics in the target radiation frequency band, which is also called the notch band, so that the subsequent array can form a reflection array; it has broadband wave-absorbing characteristics on both sides of the notch band to achieve electromagnetic stealth. Under HPM incidence, ESS should have wave-absorbing characteristics on both sides inside and outside the notch band to achieve wide-band electromagnetic protection.

[0140] In one embodiment of the present application, Figure 5 (a)- Figure 5As shown in (b), a comparison chart of theoretical calculation and full-wave simulation is given when the notch point and the absorption bandwidth are adjusted according to the mapping relationship under different incident powers. The ADS theoretical calculation results fit well with the CST full-wave simulation results, proving that the mapping relationship between the equivalent circuit model and the physical topology can achieve rapid optimization of electrical parameters to corresponding physical dimensions.

[0141] In one embodiment of the present application, Figure 6 As shown in the figure, the equivalent circuit model and physical structure diagram of the ESS unit with 1-bit phase shift function are given. An asymmetric phase modulation structure is introduced based on the above-mentioned centrally symmetrical AR / AA type ESS unit, so that it can generate overlapping notch bands (|S 11 | should be greater than -3dB), and the reflection phase difference between the two notch bands is within the range of 180±37°. In this way, the ESS integrates 1-bit phase control capability in addition to protection and stealth.

[0142] In one embodiment of the present invention, Figure 7 (a)- Figure 7 As shown in (b), the reflection amplitude and reflection phase curves of the ESS unit with 1-bit phase shift function calculated by the equivalent circuit model theory are given. When low power is incident, there is an overlapping notch band at around 8.5GHz under x and y polarizations, and the reflection phase difference between the two notch bands is within the range of 180±37°, so it has the potential for 1-bit phase regulation, and has absorbing and stealth characteristics on both sides outside the notch band. When HPM is incident, broadband absorbing protection can be achieved under both x and y polarizations.

[0143] In one embodiment of the present application, Figure 8 (a)- Figure 8 As shown in (d), the reflection amplitude and phase curves under x-polarization and y-polarization at different incident powers are given when a cross-shaped metal strip is introduced into the ESS as a phase modulation layer. The cross-shaped metal strip structure mapped by the RL series circuit is loaded into the AR / AA type ESS and electromagnetic simulation is performed. Under low-power incidence, two notch points are generated at 8.58 and 8.88 GHz under x and y polarizations, respectively, thereby realizing an overlapping notch band, and the reflection phase difference between the two notch bands in the overlapping frequency band is in the range of 180±37°, which can realize 1-bit phase control function. Under HPM incidence, broadband wave absorption protection can be achieved under both x and y polarizations. The full-wave simulation results under different incident powers are well matched with the theoretical calculation results.

[0144] In one embodiment of the present application, Figure 8 (a)- Figure 8As shown in (d), the reflection amplitude and phase curves under x-polarization and y-polarization at different incident powers are given when a cross-shaped metal strip is introduced into the ESS as a phase modulation layer. The cross-shaped metal strip structure mapped by the RL series circuit is loaded into the AR / AA type ESS and electromagnetic simulation is performed. Under low-power incidence, two notch points are generated at 8.58 and 8.88 GHz under x and y polarizations, respectively, thereby realizing an overlapping notch band, and the reflection phase difference between the two notch bands in the overlapping frequency band is in the range of 180±37°, which can realize 1-bit phase control function. Under HPM incidence, broadband wave absorption protection can be achieved under both x and y polarizations. The full-wave simulation results under different incident powers are well matched with the theoretical calculation results.

[0145] In one embodiment of the present application, Fig. 9 (a)- Fig. 9 As shown in (d), the reflection amplitude and phase curves under x-polarization and y-polarization at different power incident conditions are given when the asymmetric arrow structure is introduced into the ESS as a phase modulation layer. The asymmetric arrow structure mapped by the LC series circuit is also loaded into the AR / AA type ESS and electromagnetic simulation is performed. However, when HPM is incident, the two notch points introduced by the asymmetric arrow structure are not eliminated under HPM incidence, so wide-band wave absorption protection cannot be achieved. Therefore, a cross-shaped metal strip in the form of RL series should be selected as the phase modulation layer to integrate the 1-bit phase modulation function without affecting the protection and wave absorption characteristics of the ESS.

[0146] In one embodiment of the present application, Fig.10 (a)- Fig.10 As shown in (d), the reflection amplitude and absorptivity curves of the integrated 1-bit ESS unit based on the cross-shaped metal strip phase modulation layer at low power, HPM incidence, vertical incidence and 30° oblique incidence are given. The designed AR / AA type 1-bit ESS unit has angular stability.

[0147] In one embodiment of the present application, Fig.11 As shown in the figure, a schematic diagram of the 14×14 integrated 1-bit reflectarray 3D model is given, with an overall size of 210mm×210mm×7mm. In order to achieve beam scanning, the phase modulation layer of each ESS unit needs to be encoded and a spatial feed source needs to be placed at its focus.

[0148] In one embodiment of the present application, Fig.12 (a)- Fig.12 As shown in (c), a schematic diagram of the array coding required for the phase modulation layer when the radiation beam points to 0°, 30°, and 45° is given. Once the radiation direction of the beam is determined, the electromagnetic wave reflection phase of each unit in the phase modulation layer can be theoretically calculated.

[0149] In one embodiment of the present application, Fig.13 (a)- Fig.13 As shown in (b), the radiation patterns of the xoz and yoz planes at 8.64 GHz are given. The maximum gain of the designed 14×14 1-bit integrated reflectarray is 17.3 dBi when the beam points to 0°. The beam scanning range of 45° can be achieved in both planes, and the reflectarray designed at multiple angles has lower side lobes.

[0150] In one embodiment of the present application, Fig.14 (a)- Fig.14 As shown in (b), the RCS reduction curves of the 14×14 integrated 1-bit reflectarray under low-power incidence in coding state 1 (radiation beam pointing to 30°) and coding state 2 (radiation beam pointing to 45°) are given.

[0151] The integrated reflective array can not only achieve broadband RCS reduction on both sides of the out-of-band, but also produce phase cancellation effect on the back-reflected energy in the notch band due to the alternating arrangement of the array units, thereby achieving RCS reduction in the band. Therefore, the designed integrated reflective array can achieve low scattering characteristics on both sides of the band and out-of-band.

[0152] In one embodiment of the present application, Fig.15 As shown in the figure, the dual-station RCS result diagram of the 14×14 integrated 1-bit reflectarray in coding state 2 and the same large metal plate at the out-of-band absorption frequency of 7 GHz and the notch frequency of 8.64 GHz is given, proving that the coded integrated reflectarray has the RCS reduction capability under low-power plane wave incidence, further verifying the independent adjustability of radiation and stealth.

[0153] In one embodiment of the present application, Fig.16 (a)- Fig.16 As shown in (b), the RCS reduction curves of the 14×14 integrated 1-bit reflective array under HPM incidence in coding state 1 and coding state 2 are given.

[0154] When HPM is incident, all PIN diodes of the ESS are turned on. Under different coding states, the 14×14 integrated 1-bit reflector array can achieve wave absorbing protection characteristics in the entire target frequency band, which is in good agreement with the simulation results of the above integrated ESS unit.

[0155] The above is only a specific implementation of the present application, but the protection scope of the present application is not limited thereto. Any technician familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed in the present application, which should be included in the protection scope of the present application. Therefore, the protection scope of the present application should be based on the protection scope of the claims.

Claims

1. A method for designing an integrated reflective array with compatible protection, stealth and radiation functions, characterized in that: include: Step 1: construct an equivalent circuit model of a reflective array energy selective surface (ESS) unit covering a variety of different scenarios, and calculate the transfer matrix and scattering matrix of a two-port network based on the equivalent circuit model; Step 2: According to the mapping relationship between the equivalent circuit model and the physical model of the energy selective surface ESS unit, the frequency response of the equivalent circuit model is quickly optimized in the Advanced Design System (ADS); Step 3: According to the mapping relationship in step 2, by adjusting the electrical parameters in ADS, the physical model of the ESS unit in CST is quickly optimized to realize the design of the energy selective surface unit with phase modulation capability; Step 4: Calculate the compensation phase of each unit of the energy selective surface ESS according to the reflected beam pointing direction and determine the array coding, and arrange the units rotated by 0° and 90° according to coding 0 and 1 respectively; Step 5: Use three-dimensional electromagnetic simulation software to simulate low-power incident and high-power incident on the integrated reflectarray antenna.

2. The integrated reflective array design method with compatible protection, stealth and radiation functions as claimed in claim 1, characterized in that: The energy selective surface ESS unit is composed of a lossy layer, a phase modulation layer and a metal floor from top to bottom, wherein the lossy layer is a layer loaded with a lossy element absorbing resistor, and the phase modulation layer has a 1-bit phase modulation effect, wherein the lossy layer and the phase modulation layer are both embedded with a nonlinear device PIN diode, and the metal square ring of the lossy layer is embedded with four resistors with equal resistance values, and the lossy layer is surrounded by a feather-shaped metal patch structure.

3. The integrated reflective array design method with compatible protection, stealth and radiation functions as claimed in claim 1 or 2, characterized in that: In the step five, the component model of the PIN diode under low-power incident light is equivalent to a capacitor, and the component model under high-power incident light is equivalent to a resistor.

4. The integrated reflective array design method with compatible protection, stealth and radiation functions as claimed in claim 3, characterized in that: The scattering matrix |S 11 |Calculated by the following formula: The transfer matrix of the lossy layer can be expressed as: Where Z P1 is the equivalent impedance of the upper surface of the lossy layer, Z SUB1 is the impedance of the first equivalent transmission line between the upper surface of the lossy layer and the upper surface of the phase modulation layer, δ SUB1 refers to the electrical length corresponding to the first equivalent transmission line, β refers to the phase constant, l1 refers to the physical length between the upper surface of the lossy layer and the upper surface of the phase modulation layer, R1 is the equivalent resistance of the lossy layer, L1, L2 and L3 respectively represent the equivalent inductance of the lossy layer, C1 represents the equivalent capacitance of the lossy layer, and Z PIN1 Represents the equivalent impedance of a diode loaded in a lossy layer: d SUB1 =βl1 (3) The transfer matrix of the phase modulation layer can be expressed as: Where Z P2 is the equivalent impedance of the upper surface of the phase modulation layer, Z SUB2 is the second equivalent transmission line impedance of the medium between the upper surface of the phase modulation layer and the metal floor, δ SUB2 refers to the electrical length corresponding to the second equivalent transmission line, β refers to the phase constant, l2 refers to the physical length between the upper surface of the phase modulation layer and the metal floor, L x1(y1) and L x2(y2) represents the equivalent inductance of the phase modulation layer under x and y polarization, C x1(y1) represents the equivalent capacitance of the phase modulation layer under x and y polarization, Z PIN1 It represents the equivalent impedance of the diode loaded in the phase modulation layer: d SUB2 =βl2 (6) The transfer matrix of the metal floor can be expressed as: Where Z P3 is the equivalent impedance of the metal floor: WITH P3 =jωL4 (8) Cascading A1, A2, and A3 gives the transfer matrix A of the integrated structure: It is known that when the ESS is regarded as a two-port network, both ports are connected to free space, Z0 is the characteristic impedance of free space 377Ω, and the normalized transfer matrix a can be obtained by normalizing A: The scattering matrix S is obtained based on the normalized transfer matrix a and the relationship between the normalized transfer matrix a and the scattering matrix S: Through the above transformation relationship, we can get |S 11 |As follows:

5. The integrated reflective array design method with compatible protection, stealth and radiation functions as claimed in claim 4, characterized in that: The phase compensation of each unit in step 4 is calculated by the formula: in is the initialization phase of each unit, is the beam pointing phase, is the array phase constant, k is the wave number, x mn ,y mn 、z mn are the coordinates of the (m, n)th unit, θ0 and They are the beam deflection angles in the azimuth plane (horizontal plane) and the elevation plane (vertical plane), respectively.

6. The integrated reflective array design method with compatible protection, stealth and radiation functions as claimed in claim 5, characterized in that: The energy selective surface ESS unit is an energy selective surface ESS unit with a 1-bit phase modulation function, and the 1-bit phase modulation function is implemented by the following formula: When the electromagnetic wave emitted by the feed source irradiates the 1-bit integrated ESS array, the phase of the electromagnetic wave received by each unit (m, n) It is expressed as: Different location units Subtract the phase generated by the electromagnetic wave irradiated by the feed source reaching the center of the array, and the initialization phase of each unit after normalization It is expressed as: Since 1-bit unit design is adopted, the quantization rule is expressed as:

7. The integrated reflective array design method with compatible protection, stealth and radiation functions as claimed in claim 6, characterized in that: The reflective array is composed of 14×14 energy selective surface units, and the structural dimensions of the integrated reflective array antenna are 210 mm×210 mm×7 mm.

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