A design method of integrated reflectarray compatible with shielding, stealth and radiation functions

Abstract

The application provides a design method of an integrated reflectarray compatible with protection, stealth and radiation functions, comprising: constructing a reflectarray equivalent circuit model covering multiple different scenes, and calculating a transfer matrix and a scattering matrix of a two-port network according to the equivalent circuit model; according to a mapping relationship between the equivalent circuit model and an energy selective surface unit (ESS) physical model, performing fast optimization of frequency response in an advanced design system (ADS); according to the mapping relationship of step two, completing fast optimization by using a model in a computer simulation technology (CST), and realizing design of an energy selective surface unit with phase modulation capability. The application constructs a universal circuit model covering multiple scenes such as different incident power, polarization and in-band / out-of-band based on a nonlinear device, proposes a decoupling strategy for protection, stealth and radiation, and provides theoretical guidance for establishment of a structure-function integrated model.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of metasurface reflectarray antennas, in particular to a design method of an integrated reflectarray compatible with protection, stealth and radiation functions. BACKGROUND

[0002] The competition for information rights becomes the core content and key link of gaining the initiative in future wars. High power microwave (HPM) weapons are considered to be new concept weapons that can change the rules of the war, and belong to directional energy weapons. The working frequency is 300 MHz-300 GHz. A high-power microwave beam with high gain antenna is emitted, which is directional and has high energy concentration. It enters the enemy's electronic system through the front and back doors, and instantaneously interferes or destroys precision advanced large-scale integrated circuits, causing communication interruption, command malfunction and equipment paralysis.

[0003] There is a shield for every spear, and the HPM weapon countermeasure technology is 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, switches to the HPM weapon state after intercepting and tracking the target, and interferes with, destroys or implements hard-kill destruction on the target electronic equipment. Therefore, while researching HPM weapon countermeasure technology, it is also urgent to develop stealth technology against radar detection.

[0004] At present, the fuselage can achieve stealth characteristics through mature technical means such as shape design and coating of wave-absorbing materials. Therefore, the radio frequency aperture / antenna array becomes an important interference source that deteriorates the performance of the stealth platform. In other words, the radio frequency aperture loaded on the stealth platform also needs to be designed for stealth. Advanced radio frequency apertures should ensure that their radiation performance is not affected while having stealth function. At the present stage, HPM protection and radio frequency aperture stealth technology are developed separately. Therefore, in actual application, electromagnetic coupling or interference problems may inevitably occur due to limited installation size, thereby causing instability of equipment performance and failing to adapt to complex electromagnetic environments. SUMMARY

[0005] Therefore, the application provides a design method of an integrated reflectarray compatible with protection, stealth and radiation functions to overcome the defects in the prior art and realize the integration of stealth, protection and radiation functions.

[0006] To achieve the above-mentioned purpose, the technical solution adopted by the application is as follows:

[0007] A design method of an integrated reflectarray compatible with protection, stealth and radiation functions, comprising:

[0008] Step one, constructing an equivalent circuit model of the energy selective surface (ESS) unit covering a variety of different scenarios, and calculating the transfer matrix and scattering matrix of the two-port network according to the equivalent circuit model;

[0009] Step two, according to the mapping relationship between the equivalent circuit model and the physical model of the energy selective surface (ESS) unit, performing fast optimization of the frequency response of the equivalent circuit model in the advanced design system (ADS);

[0010] Step three, according to the mapping relationship of step two, adjusting the electrical parameters in ADS to assist in the fast optimization of the ESS physical model in CST, and realizing the design of the energy selective surface unit with phase modulation capability;

[0011] Step four, according to the reflection beam pointing, calculating the compensation phase of each unit of the energy selective surface (ESS) and determining the array coding, and arranging the units rotated by 0° and the units rotated by 90° according to the coding 0 and 1 respectively;

[0012] Step five, using three-dimensional electromagnetic simulation software to simulate low-power incidence and high-power incidence of 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 wave-absorbing resistance, the phase modulation layer has a 1-bit phase control function, the lossy layer and the phase modulation layer are embedded with nonlinear devices PIN diodes, the metal square ring of the lossy layer is embedded with four resistors with equal resistance, and the lossy layer is surrounded by arrow feather type metal patch structure.

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

[0015] Optionally, the scattering matrix is calculated by the following formula:

[0016] The transfer matrix of the lossy layer can be represented as: (1);

[0017] wherein 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 of the medium sandwiched between the upper surface of the lossy layer and the upper surface of the phase modulation layer, and δ SUB1The first equivalent transmission line refers to the electrical length, 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-tuning layer, R1 is the equivalent resistance of the lossy layer, L1, L2 and L3 represent the equivalent inductances of the lossy layer, C1 represents the equivalent capacitance of the lossy layer, and Z represents the equivalent capacitance of the lossy layer. PIN1 This represents the equivalent impedance of the diode loaded in the lossy layer: (2);

[0018] (3);

[0019] The transfer matrix of the phase modulation layer can be expressed as: (4);

[0020] Z P2 Z is the equivalent impedance of the upper surface of the phase modulation layer. SUB2 δ is the second equivalent transmission line impedance of the dielectric sandwiched between the upper surface of the phase-tuning layer and the metal ground plane. SUB2 The second equivalent transmission line refers to the electrical length, β refers to the phase constant, l2 refers to the physical length between the upper surface of the phase-tuning layer and the metal ground plane, and L... x1（y1） and L x2（y2） C represents the equivalent inductance of the phase layer under x, y polarization. x1（y1） This represents the equivalent capacitance of the phase layer under x and y polarization. This represents the equivalent impedance of the diode loaded in the phase modulation layer: (5);

[0021] (6);

[0022] The transition matrix of the metal floor can be represented as: (7);

[0023] Z P3 The equivalent impedance of the metal ground plane: (8);

[0024] Concatenating A1, A2, and A3 yields the transition matrix of the integrated structure. : (9);

[0025] It is known that when the ESS is considered as a whole as a two-port network, both ports are connected to free space, and Z0 is the characteristic impedance of free space, which is 377Ω. After normalization, the normalized transition matrix a can be obtained: (10);

[0026] The scattering matrix S is obtained from the normalized transfer matrix a and the relationship between the normalized transfer matrix a and the scattering matrix S: (11);

[0027] |S 11 |S (12);

[0028] Optionally, the phase compensation of each unit in step four is calculated by the formula: (13);

[0029] wherein is the initialization phase of each unit, is the beam pointing phase, is the array phase constant, k is the wave number, f is the focal length, x mn , y mn , z mn is the coordinate of the (m, n)th unit, θ 0 and φ 0 are the beam deflection angles in the azimuth plane (horizontal plane) and the elevation plane (vertical plane), respectively.

[0030] Optionally, the energy selection surface (ESS) unit is a 1-bit phase modulation energy selection surface (ESS) unit, and the 1-bit phase modulation function is realized by the following formula:

[0031] When the electromagnetic wave emitted by the feed source irradiates the 1-bit integrated ESS array, the electromagnetic wave phase received by each unit (m, n) is represented as: when the electromagnetic wave emitted by the feed source irradiates the 1-bit integrated ESS array, the electromagnetic wave phase received by each unit (m, n) is represented as: (14);

[0032] The of different position units is subtracted from the phase generated by the electromagnetic wave irradiated by the feed source to the array center, and the initialization phase of each unit after normalization is represented as: (15);

[0033] Since the 1-bit unit design is adopted, the quantization rule is represented as: (16).

[0034] Optionally, the array of the reflective array is composed of 14×14 energy selection surface units, and the structure size of the integrated reflective array antenna is 210 mm×210 mm×7 mm.

[0035] Compared with the prior art, the application has the beneficial effects that:

[0036] 1. The application is based on a nonlinear device to build a universal circuit model that can cover different incident power, polarization, and in-band / out-of-band scenarios. It proposes a decoupling strategy for protection, stealth, and radiation, providing theoretical guidance for the establishment of a structure-function integrated model.

[0037] 2. The application establishes a physical mapping relationship between geometric topological structure and equivalent circuit model. Based on Floquet theorem, it develops A-R / A-A (absorption-reflection / absorption-absorption) type ESS unit that can perceive incident power and adaptively switch electromagnetic response, avoiding multiple full-wave simulations and realizing fast solution of optimized model, providing an effective solution for efficient design of low-scattering electromagnetic protection structure.

[0038] 3. The integrated reflectarray of the application has wideband out-of-band Radar Cross Section (RCS) reduction, in-band low-power ±45° wide-angle beam scanning capability, and high-power adaptive switching absorption protection capability, greatly enhancing the protection and stealth capability of radio frequency aperture in complex electromagnetic environment. BRIEF DESCRIPTION OF DRAWINGS

[0039] To more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be considered as limiting the scope. For those skilled in the art, other related drawings can also be obtained without creative labor.

[0040] Figure 1 A flow chart of the integrated reflectarray design method provided by the application, which is compatible with protection, stealth, and radiation functions;

[0041] Figure 2 Equivalent circuit model schematic diagram of the protection, stealth, and radiation integrated unit provided by the embodiment of the application;

[0042] Figure 3 Mapping schematic diagram of the equivalent circuit model of the A-R / A-A type ESS unit to the physical structure provided by the embodiment of the application;

[0043] Figure 4 (a) Theoretical calculation result curve of the ESS unit in ADS under different power and polarization incidence provided by the embodiment of the application;

[0044] Figure 4 (b) Full-wave simulation result curve of the ESS unit in CST under different power and polarization incidence provided by the embodiment of the application;

[0045] Figure 5 (a) Theoretical calculation and full-wave simulation comparison chart when adjusting the notch point according to the mapping relationship under different power incidence provided by the embodiment of the application;

[0046] Figure 5 (b) Theoretical calculation and full-wave simulation comparison chart when adjusting the wave absorption bandwidth according to the mapping relationship under different power incidence provided by the embodiment of the application;

[0047] Figure 6 The equivalent circuit model and physical structure schematic diagram of the ESS unit fused with 1-bit phase modulation function provided by the embodiment of the application;

[0048] Figure 7 (a) The reflection amplitude curve diagram of the 1-bit phase modulation function ESS unit calculated by the equivalent circuit model provided by the embodiment of the application;

[0049] Figure 7 (b) The reflection phase curve diagram of the 1-bit phase modulation function ESS unit calculated by the equivalent circuit model provided by the embodiment of the application;

[0050] Figure 8 (a) The physical model and equivalent circuit mapping schematic diagram of the cross-shaped metal strip provided by the embodiment of the application;

[0051] Figure 8 (b) The reflection amplitude curve diagram of the cross-shaped metal strip as a phase modulation layer introduced into the ESS under x polarization and y polarization under low power incidence provided by the embodiment of the application;

[0052] Figure 8 (c) The reflection phase curve diagram of the cross-shaped metal strip as a phase modulation layer introduced into the ESS under x polarization and y polarization under low power incidence provided by the embodiment of the application;

[0053] Figure 8 (d) The reflection amplitude curve diagram of the cross-shaped metal strip as a phase modulation layer introduced into the ESS under x polarization and y polarization under high power incidence provided by the embodiment of the application;

[0054] Figure 9 (a) The physical model and equivalent circuit mapping schematic diagram of the asymmetric arrow structure provided by the embodiment of the application;

[0055] Figure 9 (b) The reflection amplitude curve diagram of the asymmetric arrow structure as a phase modulation layer introduced into the ESS under x polarization and y polarization under low power incidence provided by the embodiment of the application;

[0056] Figure 9(c) Reflection phase curves of x-polarization and y-polarization under low power incidence when the asymmetric arrowhead structure is introduced into the ESS as the phase modulation layer provided in the embodiments of the present application;

[0057] Figure 9 (d) Reflection amplitude curves of x-polarization and y-polarization under high power incidence when the asymmetric arrowhead structure is introduced into the ESS as the phase modulation layer provided in the embodiments of the present application;

[0058] Figure 10 (a) Reflection amplitude curves of low power normal incidence and 30° oblique incidence of the integrated 1-bit ESS unit based on the cross-shaped metal strip phase modulation layer provided in the embodiments of the present application;

[0059] Figure 10 (b) Absorption rate curves of low power normal incidence and 30° oblique incidence of the integrated 1-bit ESS unit based on the cross-shaped metal strip phase modulation layer provided in the embodiments of the present application;

[0060] Figure 10 (c) Reflection amplitude curves of HPM normal incidence and 30° oblique incidence of the integrated 1-bit ESS unit based on the cross-shaped metal strip phase modulation layer provided in the embodiments of the present application;

[0061] Figure 10 (d) Absorption rate curves of HPM normal incidence and 30° oblique incidence of the integrated 1-bit ESS unit based on the cross-shaped metal strip phase modulation layer provided in the embodiments of the present application;

[0062] Figure 11 A 14x14 integrated 1-bit reflective array 3D model schematic diagram provided in the embodiments of the present application;

[0063] Figure 12 (a) An array surface coding schematic diagram required for the phase modulation layer when the radiated beam is directed at 0° provided in the embodiments of the present application;

[0064] Figure 12 (b) An array surface coding schematic diagram required for the phase modulation layer when the radiated beam is directed at 30° provided in the embodiments of the present application;

[0065] Figure 12 (c) An array surface coding schematic diagram required for the phase modulation layer when the radiated beam is directed at 45° provided in the embodiments of the present application;

[0066] Figure 13 (a) A planar radiation pattern at 8.64 GHz provided in the embodiments of the present application; xoz

[0067] Figure 13 ​(b) RCS reduction curves of a 14x14 integrated 1-bit reflectarray in encoding state 2 under low power incidence provided by an embodiment of the present application; yoz a planar radiation pattern;

[0068] Figure 14 (a) RCS reduction curves of a 14x14 integrated 1-bit reflectarray in encoding state 1 under HPM incidence provided by an embodiment of the present application;

[0069] Figure 14 (b) RCS reduction curves of a 14x14 integrated 1-bit reflectarray in encoding state 2 under HPM incidence provided by an embodiment of the present application.

[0070] Figure 15 RCS results of a 14x14 integrated 1-bit reflectarray in encoding state 2 and a large metal plate of the same size as the array under out-of-band wave absorption frequency point 7 GHz and wave trap frequency point 8.64 GHz provided by an embodiment of the present application;

[0071] Figure 16 (a) RCS reduction curves of a 14x14 integrated 1-bit reflectarray in encoding state 1 under low power incidence provided by an embodiment of the present application;

[0072] Figure 16 (b) RCS reduction curves of a 14x14 integrated 1-bit reflectarray in encoding state 2 under low power incidence provided by an embodiment of the present application. DETAILED DESCRIPTION

[0073] In order to make the objects, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application.

[0074] As shown in Figure 1 , a design method of an integrated reflectarray compatible with protection, stealth and radiation functions comprises:

[0075] S101: An equivalent circuit model of a reflectarray energy selection surface (ESS) unit covering multiple different scenarios is constructed, and a transfer matrix and a scattering matrix of a two-port network are calculated according to the equivalent circuit model;

[0076] As shown in Figure 2 , the equivalent circuit model is composed of a lossy layer (Layer 1), a phase modulation layer (Layer 2) and a metal ground plate (Layer 3). The lossy layer and the phase modulation layer both embed PIN diodes to jointly realize the energy selection characteristics of the reflectarray.

[0077] In one embodiment of the present application, as shown in Figure 3 An equivalent circuit model to physical structure mapping relationship of A-R / A-A (absorption-reflectance / absorption-absorption) type ESS (energy selective surface) unit is proposed without considering the phase modulation layer.

[0078] In the equivalent circuit model of different incident power, polarization, in-band / out-of-band scenarios, the element model of PIN diode under low power incident is equivalent to a capacitor, and the element model under high power incident is equivalent to a resistor, and the values of equivalent inductance elements and circuit elements of the phase modulation layer under different polarizations are defined according to the size of the patch structure and the slot structure.

[0079] Optionally, the scattering matrix of the two-port network The scattering matrix of the two-port network can be calculated by the following formula:

[0080] The transfer matrix of the lossy layer can be expressed as: (1);

[0081] Wherein 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 sandwiched 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 refers to 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, Z PIN1 represents the equivalent impedance of the diode loaded in the lossy layer: (2);

[0082] (3);

[0083] The transfer matrix of the phase modulation layer can be expressed as: (4);

[0084] Wherein Z P2 is the equivalent impedance of the upper surface of the phase modulation layer, Z SUB2 is the impedance of the second equivalent transmission line sandwiched 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） represent the equivalent inductance of the phase modulation layer under x, y polarization, C x1（y1） represents the equivalent capacitance of the phase modulation layer under x, y polarization, The equivalent impedance of the diode loaded in the phase modulation layer is represented as: (5);

[0085] (6);

[0086] The transfer matrix of the metal floor can be represented as: (7);

[0087] wherein Z P3 is the equivalent impedance of the metal floor: (8);

[0088] The transfer matrix of the integrated structure can be obtained by cascading A1, A2 and A3: : (9);

[0089] When the ESS is regarded as a two-port network, both ports are connected to the free space, Z0 is the characteristic impedance of the free space 377 Ω, and after normalization, the normalized transfer matrix a can be obtained: (10);

[0090] According to the normalized transfer matrix a and the relationship between the normalized transfer matrix a and the scattering matrix S, the scattering matrix S can be obtained: (11);

[0091] Through the above transformation relationship, |S 11 | can be obtained as follows: (12);

[0092] Therefore, by adjusting the electrical parameters in the equivalent circuit, the reflection coefficient of the integrated reflection array under different incident powers and different polarizations can be theoretically calculated.

[0093] Under low-power incidence, the PIN diodes in the lossy layer and the phase modulation layer are disconnected, which can be respectively equivalent to capacitors C PIN1 and C PIN2 . The equivalent circuit of the lossy layer under different polarizations is the same. The equivalent circuit of the phase modulation layer under x and y polarizations is the same, but the specific values of the electrical parameters are different, so that new notch points of different frequencies can be introduced on both sides of the notch points generated by the lossy layer, thereby realizing a specific phase difference in the overlapping notch band of the two polarizations. Under HPM incidence, the PIN in the lossy layer and the phase modulation layer is adaptively triggered, which can be respectively equivalent to small resistances R PIN1 and R PIN2 . Figure 3 Z Layer1 is the impedance of the lossy layer, Z Layer2 is the impedance of the phase modulation layer, Z Layer3 is the impedance of the metal floor, and Z0 is the characteristic impedance of the free space 377 Ω. ​

[0094] S102, according to the mapping relationship between the equivalent circuit model and the energy selective surface ESS unit physical model, the frequency response of the equivalent circuit model is quickly optimized in the advanced design system ADS;

[0095] The constructed mapping relationship can observe the change trend of the frequency response by adjusting the values of R1, L1, C1, L2 and L3 in the reflection array equivalent circuit model. Through the quick calculation of the circuit, the change trend of the corresponding topology structure adjustment is analyzed, so that the physical model is quickly optimized.

[0096] 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 nonlinear device PIN diode is embedded in the lossy layer and the phase modulation layer. The metal square ring of the lossy layer is embedded in four resistors with equal resistance, so as to realize out-of-band wave absorption and invisibility. In the preferred embodiment, the resistance of the four resistors with equal resistance is 130Ω, but the resistance is not limited to this, and it can be set differently according to the wave absorption bandwidth and the wave absorption amplitude. The four resistors with equal resistance are surrounded by a gap-type arrowhead-shaped metal patch structure (i.e. a metal patch structure similar to the shape of an arrow feather), as shown in Figure 3 and 6 The phase modulation layer has different physical sizes under two polarizations, thereby introducing two additional wave traps on the left and right of the wave absorption layer. In one embodiment, the reflection phase difference of the energy selective surface in the overlapping wave trap band under two polarizations is within the range of 180° ± 37°, realizing 1-bit phase modulation function.

[0097] S103, according to the mapping relationship of step two, the ESS model in the auxiliary computer simulation technology CST is used to complete the quick optimization, and the design of the energy selective surface unit with phase modulation capability is realized.

[0098] S104, according to the reflection beam pointing, the compensation phase of each unit of the energy selective surface ESS is calculated and the array coding is determined, and the units rotated by 0° and 90° are arranged according to the coding 0 and 1 respectively.

[0099] Optionally, the phase compensation of each unit in the step S104 is calculated by the following formula: (13);

[0100] Wherein is the initial phase of each unit, is the beam pointing phase, is the array phase constant.

[0101] S105, the three-dimensional electromagnetic simulation software is used to simulate the low-power incidence and high-power incidence of the integrated reflectarray antenna.

[0102] The verification of the low-power incident performance in the step S105 includes scattering characteristics and radiation characteristics. The scattering characteristics need to be set on the plane wave excitation above the integrated ESS array, and the RCS far-field probe is set in the mirror direction to receive. The radiation characteristics are calculated according to the beam pointing array coding, the matlab is called for array modeling, and the horn antenna is used for spatial feeding. Since the nulls disappear under high-power incidence, it does not have the characteristics of a reflective array, so only the scattering characteristics need to be verified, and the simulation settings are consistent with the low-power incident case.

[0103] 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 realized by the following formula:

[0104] When the electromagnetic wave emitted by the feed source irradiates the 1-bit integrated ESS array, the coordinates of the (m, n) unit are x mn , y mn , and z mn , θ 0 and φ 0 are the beam deflection angles in the azimuth plane (horizontal plane) and the elevation plane (vertical plane), respectively, f is the focal length, and the phase of the electromagnetic wave received by each unit (m, n) at this time is represented as: (14);

[0105] The of the units at different positions is subtracted from the phase generated by the electromagnetic wave irradiated by the feed source to the array center, and the normalized initial phase of each unit is represented as: (15);

[0106] Since a 1-bit unit design is adopted, the quantization rule is represented as: (16).

[0107] According to the above theory, when 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. The reflection phase of the unit of the phase modulation layer in the application can be independently controlled, so that reasonable control of the array coding can realize the required direction of beam scanning.

[0108] Optionally, the array of the reflective array is composed of 14×14 energy selective surface units, and the size of the integrated reflective array antenna structure is 210 mm×210 mm×7 mm.

[0109] The application combines radar stealth, high-power microwave protection and metasurface reflection array, excavates the phase information of the trap band, constructs a power-dependent 1-bit reflection array based on a nonlinear element PIN diode, and simultaneously integrates stealth, protection and radiation functions. The integrated reflection array of the application can realize power-independent wideband out-of-band RCS reduction. Through reasonable array coding and additional low-power spatial feeding, the wide-angle beam scanning of ±45° can be realized, and the wideband stealth protection can be realized under high-power incidence.

[0110] In an embodiment of the application, as shown in Figure 4 (a) Figure 4 (b) shows the theoretical calculation and full-wave simulation result curves of the ESS unit under different power and polarization incidence.

[0111] The ESS presents full reflection characteristics in the target radiation frequency band, which is also called the trap band, so as to form a reflection array by subsequent arraying; and has wideband wave absorption characteristics on both sides of the trap band, so as to realize electromagnetic stealth. Under HPM incidence, the ESS should have wave absorption characteristics in the trap band and on both sides of the trap band, so as to realize wideband electromagnetic protection.

[0112] In an embodiment of the application, as shown in Figure 5 (a) Figure 5 (b) shows the comparison chart of theoretical calculation and full-wave simulation when the trap point and wave absorption bandwidth are adjusted according to the mapping relationship under different power incidence. The ADS theoretical calculation result and the CST full-wave simulation result are well fitted, which proves that the mapping relationship based on the equivalent circuit model and the physical topology can realize the rapid optimization of the electrical parameters to the corresponding physical size.

[0113] In an embodiment of the application, as shown in Figure 6 (b) shows the equivalent circuit model and physical structure diagram of the ESS unit integrating 1-bit phase shift function. The asymmetric phase modulation structure is introduced on the basis of the above-mentioned center-symmetric A-R / A-A type ESS unit, so that it can produce overlapping trap bands under x and y polarization S 11 should be greater than -3 dB), and the reflection phase difference of the two trap bands is within 180°±37°. In this way, the ESS integrates the 1-bit phase control capability in addition to protection and stealth.

[0114] In an embodiment of the application, as shown in Figure 7 (a) Figure 7(b) shows the reflection amplitude and reflection phase curves of the 1-bit phase shift function ESS unit calculated by the equivalent circuit model theory. At low power incidence, there is an overlapping stop band at about 8.5 GHz under x and y polarizations, and the reflection phase difference of the two stop bands is within 180°± 37°, thus having the potential of 1-bit phase control, and having the wave-absorbing stealth characteristics on both sides of the stop band. Under HPM incidence, broadband wave-absorbing protection can be achieved under both x and y polarizations.

[0115] In an embodiment of the present application, as shown in Figure 8 (a) Figure 8 (d) shows the reflection amplitude and phase curves of the ESS with the cross-shaped metal strip as the phase modulation layer under different power incidences. The cross-shaped metal strip structure mapped by the RL series circuit is loaded into the A-R / A-A type ESS and subjected to electromagnetic simulation. At low power incidence, two stop bands are generated at 8.58 and 8.88 GHz under x and y polarizations, respectively, thus achieving an overlapping stop band, and the reflection phase difference of the two stop bands within the overlapping frequency range is within 180°± 37°, which can achieve 1-bit phase control function. Under HPM incidence, broadband wave-absorbing protection can be achieved under both x and y polarizations. The full-wave simulation results under different incident powers are well fitted with the theoretical calculation results.

[0116] In an embodiment of the present application, as shown in Figure 9 (a) Figure 9 (d) shows the reflection amplitude and phase curves of the ESS with the asymmetric arrow structure as the phase modulation layer under different power incidences. The asymmetric arrow structure mapped by the LC series circuit is also loaded into the A-R / A-A type ESS and subjected to electromagnetic simulation. However, the two stop bands introduced by the asymmetric arrow structure are not eliminated under HPM incidence, so broadband wave-absorbing protection cannot be achieved. Therefore, the cross-shaped metal strip in the form of RL series should be selected as the phase modulation layer, which integrates the 1-bit phase modulation function while not affecting the protection and wave-absorbing characteristics of the ESS.

[0117] In an embodiment of the present application, as shown in Figure 10 (a) Figure 10 (d) shows the reflection amplitude and phase curves of the ESS with the asymmetric arrow structure as the phase modulation layer under different power incidences. The asymmetric arrow structure mapped by the LC series circuit is also loaded into the A-R / A-A type ESS and subjected to electromagnetic simulation. However, the two stop bands introduced by the asymmetric arrow structure are not eliminated under HPM incidence, so broadband wave-absorbing protection cannot be achieved. Therefore, the cross-shaped metal strip in the form of RL series should be selected as the phase modulation layer, which integrates the 1-bit phase modulation function while not affecting the protection and wave-absorbing characteristics of the ESS.

[0118] In an embodiment of the present application, as shown in Figure 11As shown in FIG. 1, a 14x14 integrated 1-bit reflective array 3D model is shown, with a total size of 210 mm x 210 mm x 7 mm. In order to achieve beam scanning, the phase modulation layer of each ESS unit needs to be encoded, and a spatial feed source is placed at its focal point.

[0119] In an embodiment of the present application, as shown in FIG. 2, Figure 12 (a) Figure 12 As shown in FIG. 3, the required array surface encoding of the phase modulation layer when the radiation beam is directed at 0°, 30°, and 45° is shown. When 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.

[0120] In an embodiment of the present application, as shown in FIG. 4, Figure 13 (a) Figure 13 As shown in FIG. 5, the radiation pattern of the 8.64 GHz plane is shown. xoz 、 yoz The maximum gain of the designed 14x14 1-bit integrated reflective array is 17.3 dBi when the beam is directed at 0°, and a beam scanning range of 45° can be achieved in both planes. The designed reflective array has low sidelobes at multiple angles.

[0121] In an embodiment of the present application, as shown in FIG. 6, Figure 14 (a) Figure 14 (b) shows the RCS reduction curves of the 14x14 integrated 1-bit reflective array under low-power incidence in encoding state 1 (radiation beam directed at 30°) and encoding state 2 (radiation beam directed at 45°).

[0122] The integrated reflective array not only achieves wideband RCS reduction on both sides of the band, but also produces phase cancellation for backward reflected energy in the wave-trapping band due to the alternating arrangement of array units, thereby achieving in-band RCS reduction. Therefore, the designed integrated reflective array can simultaneously achieve low scattering characteristics in the band and on both sides of the band.

[0123] In an embodiment of the present application, as shown in FIG. 7, Figure 15 shows the bistatic RCS results of the 14x14 integrated 1-bit reflective array in encoding state 2 and the same-size metal plate at the out-of-band wave-absorbing frequency point 7 GHz and the wave-trapping frequency point 8.64 GHz, proving that the integrated reflective array after encoding has RCS reduction capability under low-power plane wave incidence, and further verifying the independent adjustability of radiation and stealth.

[0124] In an embodiment of the present application, as shown in FIG. 8, Figure 16 (a) Figure 16(b) is shown, which gives the RCS reduction curves of the 14x14 integrated 1-bit reflectarray under HPM incidence in the encoding state 1 and the encoding state 2.

[0125] When the HPM is incident, all the PIN diodes of the ESS are turned on, and the 14x14 integrated 1-bit reflectarray can achieve wave absorption and protection characteristics in the entire target frequency band under different encoding states, which is consistent with the simulation results of the integrated ESS unit described above.

[0126] The above merely provides specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which shall be encompassed in the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A design method of an integrated reflectarray compatible with shielding, cloaking, and radiating functions, characterized in that, The application relates to a method for designing an integrated reflectarray antenna. Step one, constructing an equivalent circuit model of an energy selective surface (ESS) unit covering multiple different scenes, and calculating a transfer matrix and a scattering matrix of a two-port network according to the equivalent circuit model; Step two, according to a mapping relationship between the equivalent circuit model and a physical model of the ESS unit, performing fast optimization of frequency response of the equivalent circuit model in an advanced design system (ADS); Step three, according to the mapping relationship of step two, the fast optimization of the physical model of the ESS unit in CST is assisted by adjusting the electrical parameters in the ADS, and the design of the energy selective surface unit with a phase modulation function is realized; Step four, according to the calculation of a reflected beam direction, the compensation phase of each unit of the energy selective surface (ESS) is calculated, and the array coding is determined, and the units rotating by 0 DEG and the units rotating by 90 DEG are arranged according to the coding 0 and 1 respectively; Step five, using three-dimensional electromagnetic simulation software to simulate low-power incidence and high-power incidence of the integrated reflectarray antenna.

2. The design method of an integrated reflectarray with the functions of shielding, cloaking and radiating according to 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, the lossy layer is a layer loaded with lossy element wave-absorbing resistors, the phase modulation layer has a 1-bit phase modulation function, the nonlinear device PIN diode is embedded in the lossy layer and the phase modulation layer, the metal square ring of the lossy layer is embedded with four resistors with equal resistance, and the periphery of the lossy layer is an arrow feather type metal patch structure.

3. A design method of an integrated reflectarray with the functions of shielding, cloaking and radiating according to claim 1 or 2, characterized in that, In step five, the element model of the PIN diode under low-power incidence is equivalent to a capacitor, and the element model of the PIN diode under high-power incidence is equivalent to a resistor.

4. The design method of an integrated reflectarray with shielding, cloaking and radiating functions according to claim 3, characterized in that, the scattering matrix is calculated by the formula: The transfer matrix of the lossy layer can be expressed as: (1); 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 of the medium sandwiched between the upper surface of the lossy layer and the upper surface of the phase-modulating layer, δ SUB1 denotes the electrical length corresponding to said first equivalent transmission line, β denotes the phase constant, l1 denotes the physical length between the upper surface of the lossy layer and the upper surface of the phase-modulating layer, R1 is the equivalent resistance of the lossy layer, L1, L2 and L3 represent the respective equivalent inductances of the lossy layer, C1 represents the equivalent capacitance of the lossy layer, Z PIN1 represents the equivalent impedance of the diode loaded in the lossy layer: (2); （3）； The transfer matrix of the phase modulation layer can be expressed as: (4); where Z P2 is the equivalent impedance of the upper surface of the phase-adjusting layer, Z SUB2 is the second equivalent transmission line impedance of the medium sandwiched between the upper surface of the phase-adjusting 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-adjusting layer and the metal floor, L x1（y1） and L x2（y2） represent the equivalent inductance of the phase-adjusting layer under x, y polarization, C x1（y1） represent the equivalent capacitance of the phase-adjusting layer under x, y polarization, Z PIN2 represents the equivalent impedance of the diode loaded in the phase-adjusting layer: (5); （6）； The transfer matrix of the metallic floor can be expressed as: (7); where Z P3 is the equivalent impedance of the metallic floor: (8); A1, A2, A3 concatenated to obtain a transfer matrix of the integrated structure : (9); It is known that when the ESS is considered as a whole as a two-port network, both ports are connected to free space, Z0is the characteristic impedance of free space 377 Ω, and The normalized transfer matrix a is obtained after normalization: (10); The scattering matrix S is calculated from the normalized transition matrix a and the relationship between the normalized transition matrix a and the scattering matrix S: (11); By the above transformation, |S 11 As follows: (12).

5. The design method of an integrated reflectarray with shielding, cloaking and radiating functions according to claim 4, wherein, The phase compensation of each unit in the fourth step is calculated by the formula: (13); wherein is an initialization phase for each element, is a beam pointing phase, is an array phase constant, k is a wave number, f is a focal length, x mn , y mn , z mn is the coordinate of the (m, n)th element, 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 realized through the following formula: 0 and The array of the reflectarray is composed of 14*14 energy selective surface units, and the structure size of the integrated reflectarray antenna is 210 mm*210 mm*7 mm. 0 are the beam deflection angles in the azimuth and elevation planes, respectively.

6. The design method of an integrated reflectarray with shielding, cloaking and radiating functions according to claim 5, characterized in that, ​ When the electromagnetic wave emitted from the feed source is irradiated to the 1-bit integrated ESS array, the electromagnetic wave phase received by each cell (m, n) is represented as: (14); The initial phase of each element is subtracted from the phase produced by the feed illuminating the electromagnetic wave to the center of the array, and is normalized The initial phase of each element is subtracted from the phase produced by the feed illuminating the electromagnetic wave to the center of the array, and is normalized is represented as: (15); Due to the 1-bit cell design, the quantization rule is expressed as: (16).

7. The design method of an integrated reflectarray with shielding, cloaking and radiating functions according to claim 6, characterized in that, ​

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