Scattering characteristic reconfigurable Van Atta array based on feed network design

Abstract

The invention discloses a scattering characteristic reconfigurable Van Atta array based on feed network design. The scattering characteristic reconfigurable Van Atta array comprises a top-layer metal covering surface and a bottom-layer metal covering surface, the top metal covering surface is composed of N linear antenna arrays, and each linear antenna array is composed of four antenna patches; the bottom layer metal covering face is composed of N adjusting units, and each adjusting unit comprises two first metal strips, two second metal strips and two signal path adjuster structures. Each signal path regulator structure is provided with two orthogonal couplers, the two orthogonal couplers of one signal path regulator structure are connected with the two first metal strips respectively, and the two orthogonal couplers of the other signal path regulator structure are connected with the two second metal strips respectively. The four antenna patches in the same linear antenna array are respectively connected with the two first metal strips and the two second metal strips. The device has the advantages of reconfigurable scattering characteristics, simple structure, easy miniaturization and coplanar design, and can be used for flexible electromagnetic scattering characteristic reconstruction.

Description

Technical Field

[0001] The present invention belongs to the fields of communication, electromagnetic field and microwave technology, and relates to the regulation of electromagnetic scattering characteristics. In particular, it relates to a reconfigurable Van Atta array with scattering characteristics based on the design of a feeding network. Background Art

[0002] With the increasingly complex electromagnetic environment, the regulation of electromagnetic scattering characteristics through miniaturization design has important application value in the communication field. At present, the research on the regulation of electromagnetic scattering characteristics mainly focuses on aspects such as scattering enhancement, scattering suppression, and polarization conversion of scattered waves. In practical applications, it is necessary to flexibly regulate electromagnetic scattering enhancement and scattering states for different scenarios. However, there is a natural contradiction between these two different requirements for scattering characteristics. In recent years, reconfigurable metasurfaces and intelligent metasurfaces have provided feasible solutions for the dynamic control of electromagnetic scattered waves. However, this method requires loading sensors, intelligent beam control systems, and control algorithms to sense spatial electromagnetic waves, resulting in response delays and unable to truly achieve adaptive real-time control of scattered waves.

[0003] Based on the phase conjugation principle, a Van Atta array can achieve a reverse beam pointing in the direction of the incident wave, thereby realizing scattering enhancement within a wide range of incident angles. There are mainly three methods to achieve scattering control using a Van Atta array: The first method is to use active amplification or attenuation to control the power of the scattered signal, which requires additional coaxial cables to connect the antenna with the power amplification or attenuation devices, increasing the complexity of system design and making it difficult to achieve miniaturization. The second method is to use PIN diodes to control the amplitude or phase of the signal transmission path to achieve reconfigurable scattering characteristics. However, in the scattering suppression state, it will transfer the scattering peak to other angular domains, thereby increasing the bistatic radar cross-section in a specific angular domain. The third method is to load a reconfigurable metasurface coating on the Van Atta array. By using a switchable metasurface as the covering layer of the array, scattering characteristic reconstruction is achieved. However, loading the coating inevitably increases the profile of the array and the complexity of system design.

[0004] Therefore, it is still an unsolved problem to flexibly control between scattering enhancement and suppression using a compact structure. The research on reconfigurable Van Atta arrays with scattering characteristics has great significance in the application of communication technology. Summary of the Invention

[0005] In order to overcome the above-mentioned disadvantages of the prior art and fill the gap in the communication field of reconfigurable Van Atta arrays with flexible scattering characteristics, the purpose of the present invention is to provide a reconfigurable Van Atta array with scattering characteristics based on the design of a feeding network, aiming to adjust the working state of the Van Atta array using the feeding network to achieve flexible regulation of electromagnetic scattering characteristics.

[0006] The specific idea to achieve the object of the present invention is: by regulating the conduction and blocking of the PIN diodes in the signal path transmission regulator structure in the feeding network to control the working state of the Van Atta array. Based on the phase conjugation principle, when linearly polarized plane waves with different angles in the yoz plane are incident, the array has the characteristic of direction backtracking, and compared with an equal-sized metal flat plate, it can achieve the scattering enhancement effect for plane waves incident at different angles.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A Van Atta array with reconfigurable scattering characteristics based on feeding network design, comprising a top metal cladding and a bottom metal cladding; the top metal cladding is composed of N linear antenna arrays, and each linear antenna array is composed of 4 antenna patches;

[0009] The bottom metal cladding is composed of N adjusting units, and each adjusting unit includes two first metal strips, two second metal strips and two signal path regulator structures; each signal path regulator structure has two orthogonal couplers, the two orthogonal couplers of one signal path regulator structure are respectively connected to the two first metal strips, the two orthogonal couplers of the other signal path regulator structure are respectively connected to the two second metal strips, and the 4 antenna patches in the same linear antenna array are respectively connected to the two first metal strips and the two second metal strips.

[0010] In an embodiment of the present invention, in each signal path regulator structure, the coupling ends of the two orthogonal couplers are directly connected, and the through ends are respectively connected to a first metal arm. The two first metal arms and a second metal arm are connected in a loop by a first PIN diode, a second PIN diode and a third PIN diode, and the cathode and anode directions of each PIN diode on the loop are the same; the two first metal arms are respectively connected to a metal bias line A and a metal bias line B. The Van Atta array works under the incidence of plane electromagnetic waves. By applying voltages to the metal bias line A and the metal bias line B to switch the working states of the PIN diodes, the reconfigurability of electromagnetic scattering characteristics is realized.

[0011] In an embodiment of the present invention, the through ends of the two orthogonal couplers are respectively connected to a first metal arm through a first capacitor.

[0012] In an embodiment of the present invention, the two first metal arms are respectively connected to the metal bias line A and the metal bias line B through an inductor; the metal bias line A and the metal bias line B are respectively grounded through a second capacitor.

[0013] In one embodiment of the present invention, the quadrature coupler is a branch-line coupler formed by enclosing two longitudinal metal strips and two transverse metal strips.

[0014] In one embodiment of the present invention, the lengths of each of the first metal strips and each of the second metal strips are the same.

[0015] In one embodiment of the present invention, the third PIN diode is connected to the two first metal arms, and the first metal arm connected to the cathode thereof is connected to the metal bias line A, and the first metal arm connected to the anode thereof is connected to the metal bias line B. Then:

[0016] When a positive bias voltage is applied at the metal bias line A, the third PIN diode is in the cut-off state, the first PIN diode and the second PIN diode are in the conducting state, and the Van Atta array is in the scattering suppression state;

[0017] When a positive bias voltage is applied at the metal bias line B, the third PIN diode is in the conducting state, the first PIN diode and the second PIN diode are in the cut-off state, and the Van Atta array is in the scattering enhancement state.

[0018] Thus, when the first PIN diode and the second PIN diode connected in series in the upper branch are in the conducting state and the third PIN diode in the lower branch is in the cut-off state, the signal path transmission regulator structure behaves as a transmission line with a 180° phase difference at both ends. In this way, the cross-polarization ports of the upper paired antenna patches are connected to each other. Under the incidence of a linearly polarized plane wave, the array has polarization conversion and phase cancellation characteristics and can achieve the scattering suppression effect for a vertically incident plane wave; when the first PIN diode and the second PIN diode connected in series in the upper branch are in the cut-off state and the third PIN diode in the lower branch is in the conducting state, the signal path transmission regulator structure behaves as a cross, and in this way, the same polarization ports of the upper paired antenna patches are connected to each other.

[0019] In one embodiment of the present invention, each of the first metal strips is divided into two segments, and each of the second metal strips is divided into two segments;

[0020] One end of each of the two segments of each first metal strip is respectively used to connect to the same antenna patch, and the other end is respectively connected to the input end and the isolation end of the same quadrature coupler of a signal path regulator structure;

[0021] One end of each of the two segments of each second metal strip is respectively used to connect to the same antenna patch, and the other end is respectively connected to the input end and the isolation end of the same quadrature coupler of another signal path regulator structure;

[0022] The two first metal strips and the two second metal strips are connected to a total of 4 antenna patches.

[0023] In one embodiment of the present invention, a third metal strip is loaded at a position where the distance between the metal wires of the first metal strip is less than 3 mm and / or at a position where the distance between the metal wires of the second metal strip is less than 3 mm, and the third metal strip is grounded.

[0024] One embodiment of the present invention further includes: an upper dielectric substrate, a middle metal ground plane, and a lower dielectric substrate arranged in sequence;

[0025] The top metal cladding is printed on the upper surface of the upper dielectric substrate, the bottom metal cladding is printed on the lower surface of the lower dielectric substrate, and the first metal strip and the second metal strip are connected to the antenna patch through metal posts penetrating each substrate. This embodiment realizes a specific structural design of the present invention.

[0026] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0027] First, since the present invention adopts a reconfigurable feeding network design, it overcomes the problem of difficult co-planar design for electromagnetic scattering characteristic regulation, enabling the array to flexibly regulate scattering enhancement and scattering suppression within one antenna aperture without adding an additional cladding or increasing the array profile or aperture area.

[0028] Second, since the present invention utilizes the principles of phase conjugation and phase cancellation, through the design of a signal path phase reconfigurable structure, electromagnetic scattering enhancement and suppression are achieved without the need to use additional amplification and attenuation devices, greatly simplifying the system structure.

[0029] Third, since the present invention combines the design concept of a Van Atta array, polarization conversion and phase cancellation can be achieved without additional design of cancellation sub-arrays, and at the same time, significant suppression of co-polarization scattering peaks and cross-polarization scattering peaks is achieved. Description of the Drawings

[0030] Figure 1 is a side view of the overall structure of the present invention.

[0031] Figure 2 is an exploded side view of the overall structure of the present invention.

[0032] Figure 3 is a structural diagram of the adjustment unit of the present invention.

[0033] Figure 4 is a structural diagram of the signal path phase reconfigurable structure in the adjustment unit of the present invention.

[0034] Figure 5 is a schematic diagram of the distribution of metallized vias in one adjustment unit of the present invention.

[0035] Figure 6It is the curve graph of the monostatic RCS of the array in the scattering enhancement state under the incidence of plane waves at different angles in the yoz plane in the simulation experiment of the present invention.

[0036] Figure 7 It is the curve graph of the monostatic RCS varying with frequency of the array in the scattering suppression state and a metal flat plate of the same size under the perpendicular incidence of x-polarized plane waves in the simulation experiment of the present invention.

[0037] Figure 8 It is the curve graph of the monostatic RCS varying with frequency of the array in the scattering suppression state and a metal flat plate of the same size under the perpendicular incidence of y-polarized plane waves in the simulation experiment of the present invention. Specific implementation manners

[0038] The implementation manners of the present invention will be described in detail below with reference to the drawings and embodiments.

[0039] Refer to Figure 1 、 Figure 2 、 Figure 3 and Figure 4 to further describe in detail the overall structure of the Van Atta array with reconfigurable scattering characteristics of the present invention.

[0040] The functional part of the present invention mainly includes a top metal cladding 2 and a bottom metal cladding 5. The top metal cladding 2 is composed of N linear antenna arrays, and each linear antenna array is composed of 4 antenna patches 6. The bottom metal cladding 5 is composed of N adjusting units, and each adjusting unit corresponds to a linear antenna array.

[0041] Each adjusting unit includes two first metal strips 9, two second metal strips 10 and two signal path regulator structures 12. Each signal path regulator structure 12 has two quadrature couplers. For the convenience of description, in one adjusting unit, the present invention defines the two quadrature couplers of one signal path regulator structure 12 as quadrature coupler A and quadrature coupler B, and defines the two quadrature couplers of the other signal path regulator structure 12 as quadrature coupler C and quadrature coupler D.

[0042] In one adjusting unit, the two quadrature couplers of one signal path regulator structure 12 are respectively connected to the two first metal strips 9, and the two quadrature couplers of the other signal path regulator structure 12 are respectively connected to the two second metal strips 10. The four antenna patches 6 in the same linear antenna array are respectively connected to the two first metal strips 9 and the two second metal strips 10. The first metal strip 9 and the second metal strip 10 serve as transmission line structures and are responsible for signal transmission, and their widths are both W2 = 0.6 mm.

[0043] According to the above structure, the present invention changes the scattering characteristics of the array by switching the operating state of the signal path transmission regulator structure 12.

[0044] For a specific device design implementation, in the embodiments of the present invention, it further includes: an upper dielectric substrate 1, a middle metal ground plane 4, and a lower dielectric substrate 3 arranged in sequence. The long sides and short sides of the upper dielectric substrate 1, the lower dielectric substrate 3, and the middle metal ground plane 4 are preferably equal respectively, that is, as shown in the figure, W1 = 84 mm and L1 = 42 mm. Among them, the top metal cladding 2 is printed on the upper surface of the upper dielectric substrate 1, and the bottom metal cladding 5 is printed on the lower surface of the lower dielectric substrate 3. The first metal strip 9 and the second metal strip 10 are connected to the antenna patch 6 through metal posts 8 and metallized vias that penetrate each substrate. Obviously, the number of metal posts 8 and metallized vias is multiple. Among them, a circular hole 7 is etched at the position of the middle metal ground plane 4 corresponding to the antenna patch 6 to prevent the metal post 8 from contacting the middle metal ground plane 4. The relative dielectric constant of the upper dielectric substrate 1 of the present invention is between 2 and 4, and the thickness is between 1 and 3 mm. The relative dielectric constant of the lower dielectric substrate 3 is between 6 and 10.5, and the thickness is between 0.2 and 1.5 mm. In the embodiments of the present invention, the relative dielectric constant ε r = 2.2, and the thickness H1 = 1.5 mm. The dielectric constant range of the lower dielectric substrate 3 is ε r = 10.2, and the thickness H2 = 0.635 mm.

[0045] In the present invention Figure 1 and Figure 2 In the shown embodiments, the top metal cladding 2 is composed of 8 antenna patches 6. 4 antenna patches 6 along the y - direction of the coordinate system in the figure form 1 linear antenna array, and a total of 8 antenna patches 6 form 2 linear antenna arrays. Among them, the antenna patch 6 can be a circular or rectangular metal sheet. In this embodiment, a circular shape is adopted, and its diameter D1 = 11.6 mm.

[0046] The signal path regulator structure 12 is one of the key parts of the present invention. Refer to Figure 3 、 Figure 4 and Figure 5As shown, in a signal path regulator structure 12, the coupling ends of the quadrature coupler A and the quadrature coupler B are directly connected. The through end of the quadrature coupler A is connected to the first metal arm A, and the through end of the quadrature coupler B is connected to the first metal arm B. The first metal arm A, the first metal arm B, and the second metal arm are connected into a loop by the first PIN diode 15, the second PIN diode 16, and the third PIN diode 17, and the anode-cathode directions of the PIN diodes on the loop are the same. In this embodiment, the second metal arm is in an inverted U shape and is respectively connected to the cathode of the first PIN diode 15 and the anode of the second PIN diode 16 at both ends. The cathode of the second PIN diode 16 and the anode of the third PIN diode 17 are connected to the first metal arm B, and the anode of the first PIN diode 15 and the cathode of the third PIN diode 17 are connected to the first metal arm A. The first metal arm A is connected to the metal bias line A13, and the first metal arm B is connected to the metal bias line B14 to form a feeding network structure. The Van Atta array of the present invention operates under the incidence of plane electromagnetic waves. By applying voltages to the metal bias line A13 and the metal bias line B14 to switch the operating states of the PIN diodes, the electromagnetic scattering characteristics can be reconfigured.

[0047] Preferably, the placement layouts of the components on all the signal path transmission regulator structures 12 are the same.

[0048] Specifically, according to the above structure, when a positive bias voltage is applied at the metal bias line A13, the third PIN diode 17 in the lower branch is in the cut-off state, and the first PIN diode 15 and the second PIN diode 16 in the upper branch are in the conducting state. At this time, the signal path transmission regulator structure 12 behaves as a transmission line with a 180° phase difference at both ends. The cross-polarization ports of the upper paired antenna patches are connected to each other. Under the incidence of a linearly polarized plane wave, the array has polarization conversion and phase cancellation characteristics and can achieve the scattering suppression effect for a vertically incident plane wave. The Van Atta array is in a scattering suppression state.

[0049] When a positive bias voltage is applied at the metal bias line B14, the third PIN diode 17 in the lower branch is in the conducting state, and the first PIN diode 15 and the second PIN diode 16 in the upper branch are in the cut-off state. At this time, the signal path transmission regulator structure 12 behaves as a crossover, and the same polarization ports of the upper paired antenna patches are connected to each other. The Van Atta array is in a scattering enhancement state.

[0050] Based on the principle of phase conjugation, when linearly polarized plane waves at different angles in the yoz plane are incident, the array has the characteristic of direction backtracking. Compared with an equal-sized metal plate, it can achieve the effect of enhanced scattering for plane waves incident at different angles. Specifically, when the array is in the state of enhanced scattering, under the incidence of plane waves at different angles in the yoz plane, compared with an equal-sized metal plate, the monostatic radar cross-section has obvious enhancement characteristics, and the -6dB monostatic radar cross-section beamwidth is greater than 70°. When the array is in the state of scattering suppression, under the incidence of dual-polarized vertically incident waves, compared with an equal-sized metal plate, it has the characteristic of suppressing the monostatic radar cross-section by more than 6dB within the operating frequency range.

[0051] In another signal path regulator structure 12 of the adjustment unit, the arrangement forms of its quadrature coupler C and quadrature coupler D are exactly the same as those of quadrature coupler A and quadrature coupler B, and the only difference is that different antenna patches 6 are connected.

[0052] In a further embodiment of the present invention, the through end of the quadrature coupler A is connected to the first metal arm A through a first capacitor 18. Correspondingly, the through end of the quadrature coupler B is connected to the first metal arm B through another first capacitor 18. The function of the first capacitor 18 is to prevent DC signals from being transmitted to the external sides and is only used to control the on / off of the diode.

[0053] In a further embodiment of the present invention, the first metal arm A is connected to the metal bias line A13 through an inductor 20, and the first metal arm B is connected to the metal bias line B14 through another inductor 20. The function of the inductor 20 is to prevent AC signals from crosstalking to the DC feeding point.

[0054] In a further embodiment of the present invention, the metal bias line A13 is grounded through a second capacitor 19, and the metal bias line B14 is grounded through another second capacitor 19. The function of the second capacitor 19 is to ground and export the AC signals that crosstalk into the DC feed line. Further, referring to Figure 5 , the metal bias line A13 is connected to a metallized via structure eleven 31 through a second capacitor 19, and the metal bias line B14 is connected to a metallized via structure twelve 32 through another second capacitor 19 and is connected to the middle-layer metal ground plane 4 through metal posts located in the embedded lower dielectric substrate 3 to achieve grounding. Correspondingly, the metal bias line A13 and the metal bias line B14 in another signal path regulator structure 12 are grounded through the metallized via structure nine 29 and the metallized via structure ten 30 and the corresponding metal posts respectively.

[0055] In a further embodiment of the present invention, each quadrature coupler is a branch-line coupler formed by enclosing two longitudinal metal strips and two transverse metal strips. The width W4 of the transverse metal strip is 1.15 mm, which forms a quadrature coupler with the longitudinal metal strips. The distance L2 between the two longitudinal metal strips is 2.2 mm, and the width W5 of the longitudinal metal strip is 0.6 mm. The distance L3 between the two quadrature couplers is 5.3 mm, and the distance between the two parallel metal strips therebetween, that is, the distance L4 between the first metal arm and the connection line of the coupling end, is 1.8 mm. The length of the upper metal part of the third PIN diode 17, that is, the distance L5 between the second metal arm and the connection of the third PIN diode 17, is 2.96 mm. The width W6 of the feeding point on the metal bias line is 2 mm, which is convenient for soldering the DC feeding wire.

[0056] In a further embodiment of the present invention, the first PIN diode 15, the second PIN diode 16, and the third PIN diode 17 are all MADP-000907-14020P type diodes manufactured by MACOM. When the PIN diode is turned on, it can be equivalent to a series connection of a 5.2 Ω resistor and a 30 pH inductor; when the PIN diode is turned off, it can be equivalent to a series connection of a 25 fF capacitor and a 30 pH inductor.

[0057] In a further embodiment of the present invention, each first metal strip 9 is divided into two segments. One end of each of these two segments is respectively connected to the same antenna patch 6, and the other end is respectively connected to the input end and the isolation end of the same quadrature coupler of a signal path regulator structure 12. For example, the other ends of the two segments are respectively connected to the input end and the isolation end of quadrature coupler A. Further, as Figure 5 , at one end of the two segments of a first metal strip 9, a metallized via structure one 21 and a metallized via structure two 22 are respectively provided to be connected to the same antenna patch 6 through metal posts 8. At one end of the two segments of another first metal strip 9, a metallized via structure seven 27 and a metallized via structure eight 28 are respectively provided to be connected to another antenna patch 6 through metal posts 8.

[0058] Correspondingly, each second metal strip 10 is also divided into two segments. One end of each of these two segments is respectively connected to the same antenna patch 6, and the other end is respectively connected to the input end and the isolation end of the same quadrature coupler of another signal path regulator structure 12. For example, the other ends of the two segments are respectively connected to the input end and the isolation end of quadrature coupler B. Further, as Figure 5, at one end of two segments of a second metal strip 10, a metallized via structure three 23 and a metallized via structure four 24 are respectively arranged to be connected to the same antenna patch 6 through metal posts 8. At one end of two segments of another second metal strip 10, a metallized via structure five 25 and a metallized via structure six 26 are respectively arranged to be connected to another antenna patch 6 through metal posts 8.

[0059] Obviously, in one antenna unit and one adjustment unit, the two first metal strips 9 are not connected to the same antenna patch 6, the two second metal strips 10 are not connected to the same antenna patch 6, and the first metal strip 9 and the second metal strip 10 are not connected to the same antenna patch 6 either. That is, the two first metal strips 9 and the two second metal strips 10 in one adjustment unit are respectively connected to 4 antenna patches 6 of one antenna unit.

[0060] In a further embodiment of the present invention, a third metal strip 11 is loaded at a position where the distance between metal wires of the first metal strip 9 is less than 3 mm and / or at a position where the distance between metal wires of the second metal strip 10 is less than 3 mm, and this position is further preferably less than 2.5 mm. The width W3 of the third metal strip 11 is 0.6 mm, and it is grounded. Specifically, it can be grounded by uniformly arranging and embedding metallized vias on the third metal strip 11 and connecting the metal posts in the lower dielectric substrate 3 to the metal ground plane 4, which is used to suppress the coupling between adjacent transmission lines.

[0061] In a further embodiment of the present invention, the lengths of the first metal strips 9 and the second metal strips 10 connected to the signal path transmission regulator structure 12 in the bottom metal cladding 5 are the same, meeting the requirement of the feed network for equal electrical lengths of metal connection lines.

[0062] The technical effects of the present invention are further described below in combination with simulation experiments:

[0063] By using the commercial simulation software HFSS to model and simulate the present invention, when the two series PIN diodes on the upper branch are in the cut-off state and one PIN diode on the lower branch is in the conducting state, the signal path transmission regulator structure is equivalent to a crossover. At this time, the same polarization ports of the upper paired antenna patches are connected to each other. Based on the phase conjugate principle, under the incidence of linearly polarized plane waves at different angles in the yoz plane, the array has the characteristic of direction backtracking. When the Van Atta array with reconfigurable scattering characteristics and an equal-sized metal plate are under the incidence of linearly polarized plane waves at different angles in the yoz plane polarized plane waves, the normalized monostatic RCS is as Figure 6 shown. Figure 6 The abscissa in [[ ]] is the angle value, the unit is deg, and the ordinate is the normalized monostatic RCS, the unit is dB. Figure 6The solid line in [Figure] is the normalized monostatic RCS curve of the scattering-enhanced state array, and the dashed line is the normalized monostatic RCS curve of the metal plate of the same size. It can be seen that in the case of oblique incidence, the scattering value of the scattering-enhanced state array is more than 10 dB higher than that of the metal plate of the same size, and the -6 dB monostatic RCS beamwidth is 74°, showing good retro-directivity characteristics.

[0064] It is obtained by modeling and simulating the present invention using the commercial simulation software HFSS that when the two series-connected PIN diodes in the upper branch are in the on state and one PIN diode in the lower branch is in the off state, the signal path transmission regulator structure is equivalent to a transmission line with a 180° phase difference at both ends. At this time, the cross-polarization ports of the upper paired antenna patches are connected to each other. Under the incidence of a linearly polarized plane wave, the array has polarization conversion and phase cancellation characteristics. The monostatic RCS of the reconfigurable Van Atta array with scattering characteristics and the metal plate of the same size under the incidence of an x-polarized plane wave is as Figure 7 shown. Figure 7 In [Figure], the abscissa is the frequency value in GHz, and the ordinate is the monostatic RCS in dBsm. Figure 7 The solid line in [Figure] is the monostatic RCS curve of the scattering-suppressed state array, and the dashed line is the monostatic RCS curve of the metal plate of the same size. It can be seen that under the x-polarized vertical incident wave, the reconfigurable Van Atta array with scattering characteristics has an RCS reduction of more than 6 dB compared with the metal plate of the same size in the range of 9.15 - 9.86 GHz. The monostatic RCS of the reconfigurable Van Atta array with scattering characteristics and the metal plate of the same size under the incidence of a y-polarized plane wave is as Figure 8 shown. Figure 8 In [Figure], the abscissa is the frequency value in GHz, and the ordinate is the monostatic RCS in dBsm. Figure 8 The solid line in [Figure] is the monostatic RCS curve of the scattering-suppressed state array, and the dashed line is the monostatic RCS curve of the metal plate of the same size. It can be seen that under the y-polarized vertical incident wave, the reconfigurable Van Atta array with scattering characteristics has an RCS reduction of more than 6 dB compared with the metal plate of the same size in the range of 9.13 - 9.87 GHz. The array exhibits good dual-polarization scattering suppression characteristics.

[0065] The above simulation results show that, compared with the prior art, the present invention adopts a reconfigurable feeding network design, overcomes the problem of difficult coplanar design for electromagnetic scattering characteristic regulation, and enables flexible regulation of scattering enhancement and scattering suppression within one antenna aperture without adding an additional cladding or increasing the array profile or aperture area. Through the design of the signal path phase reconfigurable structure, electromagnetic scattering enhancement is achieved without the need to use an additional amplification device. Combining the design concept of the Van Atta array, polarization conversion and phase cancellation can be achieved without the need to additionally design a cancellation sub-array, and at the same time, significant suppression of the co-polarization scattering peak and the cross-polarization scattering peak is realized. By controlling the on-off of the PIN diode, the working state of the present invention can be arbitrarily changed to obtain different electromagnetic scattering characteristics. The present invention has the advantages of reconfigurable scattering characteristics, simple structure, easy miniaturization and coplanar design, and can be used for flexible electromagnetic scattering characteristic reconstruction.

Claims

1. A reconfigurable Van Atta array with scattering characteristics based on the design of a feeding network, characterized in that It includes a top metal cladding (2) and a bottom metal cladding (5); the top metal cladding (2) is composed of N linear antenna arrays, and each linear antenna array is composed of 4 antenna patches (6). The bottom metal cladding (5) is composed of N adjustment units, and each adjustment unit includes two first metal strips (9), two second metal strips (10), and two signal path regulator structures (12); each signal path regulator structure (12) has two quadrature couplers. The two quadrature couplers of one signal path regulator structure (12) are respectively connected to the two first metal strips (9), and the two quadrature couplers of the other signal path regulator structure (12) are respectively connected to the two second metal strips (10). The 4 antenna patches (6) in the same linear antenna array are respectively connected to the two first metal strips (9) and the two second metal strips (10).

2. The reconfigurable Van Atta array with scatter characteristics designed based on the feeding network according to claim 1, wherein In each signal path regulator structure (12), the coupling ends of the two quadrature couplers are directly connected, and the through ends are respectively connected to a first metal arm. The two first metal arms and a second metal arm are connected into a loop by a first PIN diode (15), a second PIN diode (16), and a third PIN diode (17), and the anode-cathode directions of the PIN diodes on the loop are the same; the two first metal arms are respectively connected to a metal bias line A (13) and a metal bias line B (14). The Van Atta array operates under the incidence of plane electromagnetic waves. By applying voltages to the metal bias line A (13) and the metal bias line B (14) to switch the working states of the PIN diodes, the electromagnetic scattering characteristics can be reconfigured.

3. The reconfigurable Van Atta array with scattering characteristics designed based on the feeding network according to claim 2, wherein The through ends of the two quadrature couplers are respectively connected to a first metal arm through a first capacitor (18).

4. The reconfigurable Van Atta array based on the design of the feeding network according to claim 2, characterized in that, The two first metal arms are respectively connected to the metal bias line A (13) and the metal bias line B (14) through an inductor (20); the metal bias line A (13) and the metal bias line B (14) are respectively grounded through a second capacitor (19).

5. The reconfigurable Van Atta array with scattering characteristics designed based on the feeding network according to claim 2, characterized in that, The quadrature coupler is a branch-line coupler formed by enclosing two longitudinal metal strips and two transverse metal strips.

6. The reconfigurable Van Atta array with scattering characteristics designed based on the feeding network according to claim 1, characterized in that The lengths of the first metal strips (9) and the second metal strips (10) are the same.

7. The reconfigurable Van Atta array with scattering characteristics designed based on the feeding network according to claim 2, wherein The third PIN diode (17) is connected to the two first metal arms, and the first metal arm connected to its cathode is connected to the metal bias line A (13), and the first metal arm connected to its anode is connected to the metal bias line B (14). Then: When a positive bias voltage is applied at the metal bias line A (13), the third PIN diode (17) is in the cut-off state, the first PIN diode (15) and the second PIN diode (16) are in the conduction state, and the Van Atta array is in the scattering suppression state. When a positive bias voltage is applied at the metal bias line B (14), the third PIN diode (17) is in the conduction state, the first PIN diode (15) and the second PIN diode (16) are in the cut-off state, and the Van Atta array is in the scattering enhancement state.

8. The reconfigurable Van Atta array with scattering characteristics designed based on a feeding network according to any one of claims 1 to 7, characterized in that, Each of the first metal strips (9) is divided into two segments, and each of the second metal strips (10) is divided into two segments; One end of each of the two segments of each first metal strip (9) is respectively used for connection with the same antenna patch (6), and the other end is respectively connected to the input end and the isolation end of the same quadrature coupler of a signal path regulator structure (12); One end of each of the two segments of each second metal strip (10) is respectively used for connection with the same antenna patch (6), and the other end is respectively connected to the input end and the isolation end of the same quadrature coupler of another signal path regulator structure (12); Two first metal strips (9) and two second metal strips (10) are connected to a total of 4 antenna patches (6).

9. The reconfigurable Van Atta array with scattering characteristics designed based on the feeding network according to claim 1, characterized in that A third metal strip (11) is loaded at a position where the distance between the metal wires of the first metal strip (9) is less than 3 mm and / or at a position where the distance between the metal wires of the second metal strip (10) is less than 3 mm, and the third metal strip (11) is grounded.

10. The reconfigurable Van Atta array with reconfigurable scattering characteristics designed based on the feeding network according to claim 1, characterized in that, It further includes: an upper dielectric substrate (1), a middle metal ground plane (4), and a lower dielectric substrate (3) arranged in sequence; The top metal cladding (2) is printed on the upper surface of the upper dielectric substrate (1), the bottom metal cladding (5) is printed on the lower surface of the lower dielectric substrate (3), and the first metal strip (9) and the second metal strip (10) are connected to the antenna patch (6) through metal posts (8) penetrating through each substrate.

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