Low-RCS planar array antenna with reconfigurable broadband scattering beam

Abstract

The invention discloses a broadband scattering beam reconfigurable low RCS planar array antenna. The antenna array structurally comprises a metal radiation oscillator structure, a dielectric substrate, an offset line structure, a rectangular metal floor, a pin header, a slotted metal aluminum plate and a feed structure from top to bottom, the pin header penetrates through the dielectric substrate; the metal radiation array structure realizes phase regulation of the antenna unit on reflected electromagnetic waves and regulates the beam direction of scattered electromagnetic waves; the antenna array is composed of N * N antenna units, and N is greater than or equal to 2 and is a positive integer. According to the invention, broadband scattering phase reconstruction is realized, and the wide radiation characteristic of the antenna is realized by using the tight coupling design.

Description

Technical Field

[0001] The invention belongs to the technical field of antennas, and in particular relates to a low RCS planar array antenna with a broadband scattering beam and reconfigurable characteristics. Background Art

[0002] The main function of the antenna in the wireless communication system is to transmit and receive electromagnetic wave signals. The performance of the antenna will directly affect the quality of the entire communication system, so the antenna is one of the key components in the wireless communication system. On the one hand, the antenna array carried by many low-visibility platforms is one of the main scattering sources of the entire platform; on the other hand, the demand for low scattering of the platform is getting higher and higher, so how to reduce the scattering of the antenna has become an issue that needs to be solved urgently.

[0003] Antenna is a special scatterer, and its scattering can be divided into two parts: one part is the structural mode scattering field, which is only related to the physical structure of the antenna itself and has nothing to do with the antenna load; the other part is the antenna mode scattering field, which is generated by secondary radiation caused by the mismatch between the load impedance and the antenna impedance, so it changes with the change of the antenna load impedance. This is a scattering field unique to the antenna as a scatterer. The key to reducing the scattering of the antenna is to reduce the radar cross section. The radar cross section is a physical quantity that characterizes the scattering strength of the target for the incident radar wave.

[0004] The antenna radar cross section reduction scheme can be divided into the following types according to the reduction principle. The first is to use the principle of wave absorption to directly absorb electromagnetic waves to reduce the radar cross section, but this method often deteriorates the antenna radiation performance. The other is to use the principle of cancellation to scatter the electromagnetic wave energy to the non-threatening angle area, thereby achieving a single station radar cross section reduction. Common specific measures include loading polarization rotation surface, phase gradient surface and other periodic structure metasurfaces, but this method usually requires loading a large-sized metasurface, which will increase the overall size of the antenna and is not conducive to the miniaturization of the antenna.

[0005] The patent application document with application number 201911236876.5 discloses a low RCS microstrip array antenna with reconfigurable scattered beam. The scattered phase is adjusted by changing the state of the diode in the rectangular ring outside the microstrip antenna, thereby achieving control of the scattered beam. Under the premise of maintaining stable and good radiation performance of the antenna, the radar cross section is reduced when the electromagnetic wave is vertically incident and obliquely incident.

[0006] The patent application document with application number 202311046038.8 discloses a low RCS circularly polarized antenna array with reconfigurable scattering beam. The scattering characteristics are reconstructed by adjusting the state of the switching diodes in the array unit, thereby realizing active adjustment of the scattering beam.

[0007] However, the adjustable scattering bandwidth of the above-mentioned patent is relatively limited, and when the scattering state of the unit is changed, the far-field radiation phase of the unit changes significantly, so additional phase compensation is required to maintain a stable radiation beam. In addition, the number of diodes used in each antenna unit is large, and the antenna structure is complex, which will be greatly restricted in processing and manufacturing as well as large-scale applications. Summary of the invention

[0008] In order to overcome the shortcomings of the above-mentioned prior art, the purpose of the present invention is to provide a low RCS planar array antenna with a broadband scattering beam reconfigurable. Firstly, the radiation (y-polarized radiation wave) and scattering (for x-polarized electromagnetic wave incidence) of the antenna are designed independently through polarization isolation. Secondly, through the asymmetric radiation array arm design, the on-off state of the two switching diodes in the unit is changed at the same time to realize broadband scattering phase reconstruction, and the tight coupling design is used to realize the wider radiation characteristics of the antenna.

[0009] In order to achieve the above object, the technical solution adopted by the present invention is:

[0010] A broadband scattering beam reconfigurable low RCS planar array antenna, the antenna array structure from top to bottom includes: a metal radiation array structure 1, a dielectric substrate 2, a bias line structure and a rectangular metal floor 3, a pin row 4, a slotted metal aluminum plate and a feeding structure 5; the pin row 4 runs through the dielectric substrate 2; the antenna array is composed of N×N antenna units, wherein N≥2, and N is a positive integer;

[0011] The metal radiation array structure 1 realizes the phase control of the reflected electromagnetic wave by the antenna unit and controls the beam direction of the scattered electromagnetic wave.

[0012] The metal radiation array structure 1 includes a pair of asymmetric array arms, which are divided into a left arm and a right arm;

[0013] The left arm includes two symmetrically designed metal patches 1.1 and one metal patch 1.2. The metal patch 1.2 is located between the two metal patches 1.1 and is connected to the two metal patches 1.1 respectively through a switching diode 1.3. The switching diode 1.3 is placed in a mirror image along the y-axis.

[0014] A square gap ring is etched inside the metal patch 1.1, and a 4.7nH inductor 1.4 is used to connect the patch inside the square gap ring with the patch outside the square ring.

[0015] The right arm is a metal patch 1.2, which is mirror-symmetrical with the metal patch 1.2 of the left arm along the x-axis; the middle of the two metal patches 1.1 has a metal disk, both located at the center of the square gap ring, and the two metal patches 1.1 are symmetrically placed along the y-axis, and the geometric center of the metal patch 1.2 of the left arm is located at the center of the gap formed by the two metal patches 1.1;

[0016] The metal patch 1.1 is a trapezoidal patch, and the metal patch 2 1.2 is a polygonal patch. The bases of the two trapezoidal patches are arranged opposite to each other, the bases of the polygonal patch and the trapezoidal patch 1.1 are of equal length, and the hypotenuse of the metal patch 2 1.2 is on the same oblique line as the waist of the metal patch 1 1.1.

[0017] Metal pillars are installed between the metal radiation array structure 1 and the dielectric substrate 2, and the metal pillars include a metal pillar 1 2.1, a metal pillar 2.2 and a metal pillar 3 2.3;

[0018] Among them, a pair of metal pillars 2.1 penetrate the dielectric substrate 2, one end of which is connected to the patch inside the square gap ring, that is, connected to the geometric center of the metal patch 1.1, and the other end is connected to the DC bias line at the bottom of the dielectric plate 2, that is, the bias line structure and the center position of the metal disc of the rectangular metal floor 3;

[0019] A pair of metal pillars 2.2 are respectively located at the center of the opposite edges of the polygonal patch structure on the left and right arms of the metal radiation array 1, and vertically connect the bias line structure and the rectangular metal floor 3;

[0020] The metal column 3 2.3 is located at the lower geometric center of the right arm of the metal radiation array 1, and is connected to the rectangular metal floor 3. Metal patch 1 1.1 Metal patch 2 1.2 The bias line structure and the rectangular metal floor 3 are both located at the bottom of the dielectric substrate 2, including the bias line structure arranged on the left side and the rectangular metal floor on the right side;

[0021] The bias line structure includes an h-shaped bias line structure 3.1 and two 4.3nH inductors 3.2;

[0022] The h-shaped bias line structure 3.1 has circular metal sheet structures printed on both ends, and the center position of the circle coincides with the center position of the metal column 2.1; the two inductors 3.2 are symmetrically placed along the y-axis, and are located at the midpoint between the geometric center of the h-shaped bias line structure 3.1 and the center of the circular metal sheet;

[0023] Wherein, the right bias line of the h-shaped bias line structure 3.1 is extended along the x-axis to the bottom of the antenna unit;

[0024] A circular ring 3.4 is arranged on the surface of the rectangular metal floor 3.3; the center position of the circular ring 3.4 coincides with the center position of the metal column 2.2 on the left arm.

[0025] The bottom position of the right extension line of the DC bias line 3.1 along the x-axis is connected to V1, and the bottom position of the rectangular metal floor 3.3 along the x-axis is connected to V2;

[0026] V1 and V2 are DC voltages.

[0027] The slotted metal aluminum plate and feeding structure 5 include a slotted aluminum plate 5.1, which is located directly below the dielectric substrate 2. The slot of the slotted aluminum plate 5.1 is along the x-direction, the slot depth h2=1mm, and the slot position coincides with the projection of the complete aluminum plate structure minus the rectangular metal floor 3.4 on the z-axis. The feeding structure 5.2 is an SMP RF connector, which is installed at the geometric center of the slotted aluminum plate 5.1.

[0028] The antenna unit period is p=13 mm, the array size is 138 mm×103 mm×6 mm, the pin header 4 has a specification of 2×8, and is a double-row pin header, each row has eight pins, and the number is N×N / 16.

[0029] N×N antenna units are printed on the surface of the dielectric substrate 2 by a printed circuit board manufacturing process.

[0030] The pins 4 are evenly installed along the edges of both sides of the y-axis of the array antenna, and the number of the pins 4 on each side is N×N / 32.

[0031] A control method for a broadband scattering beam reconfigurable low RCS array antenna, wherein the broadband scattering beam reconfigurable antenna array has two control states, named state 1 and state 2, the reflection phase difference between the two states is 180°, and the impedance matching, gain and radiation pattern of the two states are basically the same;

[0032] The specific implementation method of the two states includes the following steps:

[0033] When the bias voltage V1 is not connected to the DC voltage source and V2 is grounded, the antenna unit is in state 1;

[0034] When the bias voltage V1 is connected to a 5.0V DC voltage source and V2 is grounded, the antenna unit is in state 2. By changing the state of the units in the array, the phase of the scattering field on the array surface is changed, thereby achieving active control of the scattering beam. At the same time, the antenna array ensures stable radiation capability.

[0035] Beneficial effects of the present invention:

[0036] 1. The asymmetric radiation array arm used in the present invention is composed of a metal array and a switch diode and an inductor installed on the left array arm; by printing an asymmetric radiation unit on a single-layer dielectric substrate and loading a switch diode and an inductor, the on-off state of the switch diode on the antenna unit is actively regulated, so that the antenna unit can control the phase of the reflected electromagnetic wave in the 6.6-13.9GHz (71.2%) broadband and control the beam direction of the scattered electromagnetic wave. In addition, the radiation bandwidth of the antenna covers 8-12GHz (40%) and has the ability to scan the radiation beam at ±45°. For the case of vertical incidence of electromagnetic waves, adjusting the state of the array unit can achieve a single-station radar cross-section reduction in the broadband; for oblique incidence, selecting any frequency point in the working frequency band of the antenna broadband can achieve targeted oblique incidence single-station radar cross-section peak reduction, which overcomes the technical problem of the narrow scattering control bandwidth in the prior art. When the electromagnetic wave is vertically incident and 10° obliquely incident, the antenna radar scattering cross-section reduction peak reaches 30dBsm and 24dBsm or more reduction respectively.

[0037] 2. The asymmetric radiation array arm used in the present invention is composed of a metal array and a switching diode and an inductor installed on the left array arm; when the on-off state of the switching diode on the antenna unit is adjusted, the far-field radiation phase and radiation gain of the antenna unit remain basically unchanged, and the radiation performance remains stable. The antenna array can achieve the reconstruction of the scattered beam without changing the radiation characteristics, and isolate the antenna radiation and scattering design statistical polarization in an orthogonal manner, so that independent radiation beams and scattered beams can be actively controlled without additional phase compensation. In addition, the entire antenna is integrated in a single-layer dielectric substrate, and only two switching diodes are used in each unit, which overcomes the problem that the structure of the scattering adjustable antenna in the prior art is relatively complex and not easy to process. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic diagram of the overall structure of the antenna array of the present invention.

[0039] Figure 2 It is a schematic diagram of the overall structure of the antenna unit of the present invention.

[0040] Figure 3 It is a schematic diagram of the top and bottom structures of the antenna unit of the present invention.

[0041] Figure 4 It is a schematic diagram of the side structure of the antenna unit of the present invention.

[0042] Figure 5 It is the reflection characteristic of the antenna unit of the present invention in different states.

[0043] Figure 6 It is a schematic diagram of the active standing wave ratio of the antenna unit of the present invention in different states.

[0044] Figure 7 It is a schematic diagram of the far-field gain and phase of the antenna unit of the present invention in different states.

[0045] Figure 8 It is a single-station radar cross-section diagram of the array antenna of the present invention in different states.

[0046] Fig. 9 These are the radiation patterns of different surfaces of the array antenna of the present invention. DETAILED DESCRIPTION

[0047] The present invention will be further described in detail below in conjunction with the accompanying drawings.

[0048] like Figure 1 , Figure 2 As shown;

[0049] A broadband scattering beam reconfigurable low RCS planar array antenna comprises, from top to bottom, a metal radiation array structure 1, a dielectric substrate 2, a bias line structure and a rectangular metal patch 3, a pin row 4, a slotted metal aluminum plate and a feeding structure 5.

[0050] The metal radiation array structure 1 is printed on the upper surface of the dielectric substrate 2, the slotted metal floor and the bias line structure 3 are printed on the lower surface of the dielectric substrate 2, the pin header 4 penetrates the dielectric substrate 2, and the aluminum plate and the feeding structure 5 are below the bias line structure and the rectangular metal patch 3.

[0051] The broadband scattering reconfigurable antenna array of the present invention is composed of N×N scale Figure 2 The antenna unit consists of N≥2, where N is a positive integer. Figure 1 The dielectric substrate 2 in the antenna array is made of F4B with a dielectric constant of 2.2 and a loss tangent of 0.001. The antenna unit period is p=13mm, and the array size is 138mm×103mm×6mm. The pin header 3 is a double-row 16pin with a specification of 2×8.

[0052] Next, the metal pillars penetrating the dielectric substrate 2 are further described. One end of the metal pillar 1 2.1 is connected to the left arm of the metal radiation array 1, and the other end is connected to the DC bias line structure 3. A pair of metal pillars 2.2 respectively connect the left and right arms of the metal radiation array 1 and the rectangular metal floor 3. The metal pillar 3 2.3 is located at the right arm of the metal radiation array 1, connecting the array and the metal floor 3.

[0053] Reference Figure 3 The metal radiation array structure 1, the bias line structure and the rectangular metal floor 3 of the present invention are further described.

[0054] The metal radiation array is composed of a pair of asymmetric array arms, wherein the left arm is composed of two symmetrically placed metal patches 1.1 and 1.2, two switch diodes 1.3 placed along the y-axis mirror image connect the three patches of the left arm, a square ring is etched inside the metal patch 1.1, and a 4.7nH inductor 1.4 connects the inner and outer patches of the square ring; the right arm is composed of the metal patch 1.2. Among them, the upper base of the metal patch 1.1 is w1=2.9mm, the length of the left arm is l1=12mm, the length of the metal patch 1.2 is l2=5.7mm, and the width is w2=4.9mm.

[0055] On the left side of the rectangular metal floor and bias line structure 3 is an H-shaped bias line structure 3.1, in which two inductors 3.2 with an inductance of 4.3nH are located, and on the right side is a rectangular metal floor 3.3 with a length of l3=13mm and a width of w3=7.9mm. There is a ring 3.4 with a diameter of d1=2.1mm in the rectangular metal floor 3.3; V1 and V2 are DC voltages connected to the DC bias line 3.1 and the rectangular metal floor 3.3 respectively.

[0056] Reference Figure 4 The slotted aluminum plate and the feeding structure 5 of the present invention are further described. The slotted aluminum plate 5.1 is located directly below the dielectric substrate 2 with a thickness of h2 = 3.4 mm, the slot of the slotted aluminum plate 5.1 is along the x direction, the slot depth h2 = 1 mm, the slot position coincides with the projection position of the bias line structure 3.1 on the z axis, and the feeding structure SMP RF connector 5.2 is installed at the geometric center of the slotted aluminum plate.

[0057] The asymmetric array arm, metal patch 1.1, metal patch 2.2, switch diode 1.3 and the like in the metal radiating array in the broadband scattering reconfigurable antenna array of the present invention work together to realize the broadband scattering reconfigurable function. Among them, for the incident x-polarized electromagnetic wave, the asymmetric array arm can be equivalent to a resonant circuit with different resonant frequencies, respectively, acting on low frequency and high frequency, and the switch diode 1.3 mainly realizes the function of electrically controlled adjustable. In addition, the metal radiating arrays of adjacent units in the array are tightly coupled, and through the joint action of metal column 2.2 and metal column 3.3, good broadband impedance matching is achieved for antenna unit feeding and impedance matching, wherein the design of metal patch 2.2 ensures the tight coupling of adjacent units, and metal column 2.2 realizes the unbalanced planar feeding design, ensuring the low complexity and low profile advantages of the antenna unit, and metal column 3.3 is mainly used to improve the impedance matching of the antenna unit during scanning, ensuring that the antenna unit has good beam scanning capability. In addition, the 4.7nH inductor 1.4, the metal pillar 2.1, and the h-shaped DC bias line 3.1 work together to realize the on-off control of the switching diode in the unit, thereby realizing the control of the unit scattering phase. Among them, the inductor 1.4 mainly functions to isolate the RF current, and the metal pillar 2.1 transmits the DC voltage from the bias line to the metal radiation array structure on the surface.

[0058] The present invention will be further described below in conjunction with the accompanying drawings.

[0059] 1. Simulation content and conditions

[0060] The present invention uses the commercial simulation software Ansoft HFSS to calculate and analyze the reflection characteristics of the broadband scattering reconfigurable antenna in different states under periodic boundary conditions in the above embodiment. The results are as follows: Figure 5 As shown. When V1 and V2 are not connected to a DC voltage source, the antenna unit is in state 1. At this time, the switching diode is equivalent to a series circuit of inductance L = 30pH and capacitance C = 0.025pF in the simulation; when V1 is connected to a 5V voltage source and V2 is connected to a reference voltage of 0V, the antenna unit is in state 2. At this time, the switching diode is equivalent to a series circuit of resistance R = 7.8Ω and inductance L = 30pH in the simulation. Figure 5 It can be seen that the reconfigurable reflection phase difference bandwidth that satisfies 180°±37° is 6.6-13.9 GHz (71.2%), and the average difference in reflection amplitude within the bandwidth is less than 2 dB.

[0061] The commercial simulation software Ansoft HFSS is used to analyze and calculate the active standing wave ratio, antenna unit radiation gain, and antenna radiation far field phase of the above embodiment under different states under periodic boundary conditions. Figure 6 , Figure 7The radiation bandwidth of the antenna unit is 8-12GHz (40%), and when the unit switches between state 1 and state 2, the active standing wave ratio under the conditions of side-firing, E-plane 45° scanning, and H-plane 45° scanning is less than 3, maintaining good impedance matching, and the actual gain and far-field phase of the two states are basically consistent, indicating that the antenna can maintain stable radiation performance while adjusting the scattered beam.

[0062] The commercial simulation software Ansoft HFSS is used to calculate the curve of the single-station radar cross section changing with frequency for the above embodiment under the condition of vertical incidence of x-polarized electromagnetic waves. The calculation results are as follows: Figure 8 As shown in (a), the broadband reconfigurable scattering array uses an optimization algorithm to optimize the state distribution of the units in the array, and obtains the coded state distribution as shown in the figure to achieve broadband single-station radar cross-section reduction. Green indicates that the unit is in state 1, and yellow indicates that the unit is in state 2. The broadband scattering adjustable array of the embodiment achieves at least 6dB of radar cross-section reduction in a wide frequency band of 6.2-15GHz, wherein the radar cross-section reduction peaks of 33dB, 29dB, and 15dB are achieved at the three frequency points of 6.7GHz, 9.8GHz, and 12.7GHz, respectively.

[0063] The commercial simulation software Ansoft HFSS was used to simulate the radar cross section of the above embodiment at oblique incidence at 10 GHz. The results are shown in Figure 8 (b). Compared with the oblique-incidence single-station radar cross section when all array elements are in state 1, the coded array obtained by the optimization algorithm achieves a reduction in the scattering peak at 0° and 10°, with a reduction of 24.1dB and 22.4dB respectively. In addition, by calculating the scattering mean in the angular domain from 0° to 30°, the optimized array reduces the mean by 2dB.

[0064] The commercial simulation software Ansoft HFSS is used to simulate the radiation patterns of different surfaces of the above embodiment. The results are as follows: Fig. 9 As shown, where: Fig. 9 (a) is the radiation pattern of the E plane, i.e., the yoz plane, at the center frequency of 10 GHz when the array antenna of the embodiment is in the optimized coding state. Fig. 9 (b) is the radiation pattern of the H plane, i.e., the xoz plane, at the center frequency of 10 GHz when the array antenna of the embodiment is in the optimized coding state. It can be seen from the figure that the broadband scattering adjustable array antenna has a good radiation pattern when the E plane and H plane are scanned to 0°, 15°, 30°, and 45° respectively, and its E plane scanning simulation gain reaches 20.8dBi, 20.7dBi, 20.1dBi, and 18.9dBi respectively, and the H plane scanning simulation gain reaches 20.8dBi, 20.6dBi, 19.7dBi, and 18.4dBi.

[0065] The above simulation results show that, compared with the prior art, the broadband scattering beam reconfigurable antenna array of the present invention realizes the broadband scattering beam reconfiguration within 6.6-13.9GHz (71.2%) through the joint action of the asymmetric radiation array arm structure and the switching diode. At the same time, the polarization orthogonal design idea of ​​radiating y-polarized waves and regulating x-polarized incident waves is used to make the antenna unit maintain basically consistent radiation performance when switching the scattering state, thereby realizing independent radiation and scattering beam control design. When the x-polarized electromagnetic wave with vertical polarization is incident, the optimized coding array can achieve the reduction of the radar scattering cross section of a single station within the wide frequency band of 6.2-15GHz, and the reduction peak reaches 33dB. When the electromagnetic wave is obliquely incident at 10GHz, the optimized coding array also has the effect of reducing the radar scattering cross section, and the reduction peak reaches 22.4dB. At the same time, the antenna array of the invention can achieve a peak gain of 20.8dBi at 10GHz, and has good beam scanning capability. The entire antenna structure of the present invention uses only one layer of dielectric substrate, and each unit uses only two switching diodes, which reduces the complexity of the structure and improves the shortcomings of the prior art.

[0066] The above description and embodiments are only preferred examples of the present invention and do not constitute any limitation to the present invention. Obviously, for professionals in this field, after understanding the content and design principles of the present invention, they may make various modifications and changes in form and details based on the principles and structures of the present invention. However, these modifications and changes based on the ideas of the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A broadband scattering beam reconfigurable low RCS planar array antenna, characterized in that: The antenna array comprises, from top to bottom, a metal radiation array structure (1), a dielectric substrate (2), a bias line structure and a rectangular metal floor (3), a pin row (4), a slotted metal aluminum plate and a feed structure (5); the pin row (4) runs through the dielectric substrate (2); the antenna array is composed of N×N antenna units, wherein N≥2, and N is a positive integer; The metal radiation array structure (1) enables the antenna unit to control the phase of the reflected electromagnetic wave and control the beam direction of the scattered electromagnetic wave.

2. The broadband scattering beam reconfigurable low RCS planar array antenna according to claim 1, characterized in that: The metal radiation array structure (1) comprises a pair of asymmetric array arms, which are divided into a left arm and a right arm; The left arm includes two symmetrically designed metal patches one (1.1) and one metal patch two (1.2), wherein the metal patch two (1.2) is located between the two metal patches one (1.1) and is connected to the two metal patches one (1.1) respectively through a switching diode (1.3), wherein the switching diode (1.3) is placed in a mirror image along the y-axis.

3. The broadband scattering beam reconfigurable low RCS planar array antenna according to claim 2, characterized in that: A square gap ring is etched inside the metal patch (1.1), and a 4.7nH inductor (1.4) is used to connect the patch inside the square gap ring with the patch outside the square ring.

4. The broadband scattering beam reconfigurable low RCS planar array antenna according to claim 3, characterized in that: The right arm is a metal patch 2 (1.2), which is mirror-symmetric with the metal patch 2 (1.2) of the left arm along the x-axis; the middle of the two metal patches 1 (1.1) each has a metal disk, both located at the center of the square gap ring, the two metal patches 1 (1.1) are symmetrically placed along the y-axis, and the geometric center of the metal patch 2 (1.2) of the left arm is located at the center of the gap formed by the two metal patches 1 (1.1); The metal patch one (1.1) is a trapezoidal patch, and the metal patch two (1.2) is a polygonal patch. The bases of the two trapezoidal patches are arranged opposite to each other, the bases of the polygonal patch and the trapezoidal patch (1.1) are of equal length, and the hypotenuse of the metal patch two (1.2) is on the same oblique line as the waist of the metal patch one (1.1).

5. The broadband scattering beam reconfigurable low RCS planar array antenna according to claim 1, characterized in that: Metal pillars are installed between the metal radiation array structure (1) and the dielectric substrate (2), and the metal pillars include metal pillar one (2.1), metal pillar two (2.2) and metal pillar three (2.3); A pair of metal pillars (2.1) penetrate the dielectric substrate (2), one end of which is connected to the patch inside the square gap ring, that is, connected to the geometric center of the metal patch (1.1), and the other end is connected to the DC bias line at the bottom of the dielectric plate (2), that is, the bias line structure and the center position of the metal disc of the rectangular metal floor (3); A pair of metal pillars (2.2) are respectively located at the center of the opposite edges of the polygonal patch structure on the left and right arms of the metal radiation array (1), and vertically connect the bias line structure and the rectangular metal floor (3); The metal column three (2.3) is located at a position slightly below the geometric center of the right arm of the metal radiation array (1) and is connected to the rectangular metal floor (3).

6. The broadband scattering beam reconfigurable low RCS planar array antenna according to claim 4, characterized in that: The bias line structure and the rectangular metal floor (3) are both located at the bottom of the dielectric substrate (2), including the bias line structure arranged on the left side and the rectangular metal floor arranged on the right side; The bias line structure comprises an h-shaped bias line structure (3.1) and two 4.3nH inductors (3.2); The h-shaped bias line structure (3.1) has circular metal sheet structures printed on both ends, and the center position of the circle coincides with the center position of the metal column 1 (2.1); the two inductors (3.2) are symmetrically placed along the y-axis, and are located at the midpoint between the geometric center of the h-shaped bias line structure (3.1) and the center of the circular metal sheet; Wherein, the right bias line of the h-shaped bias line structure (3.1) is extended along the x-axis to the bottom of the antenna unit; A circular ring (3.4) is arranged on the surface of the rectangular metal floor (3.3); the center position of the circular ring (3.4) coincides with the center position of the second metal column (2.2) on the left arm.

7. The broadband scattering beam reconfigurable low RCS planar array antenna according to claim 6, characterized in that: The bottom position of the right extension line of the DC bias line (3.1) along the x-axis is connected to V1, and the bottom position of the rectangular metal floor (3.3) along the x-axis is connected to V2; V1 and V2 are DC voltages.

8. The broadband scattering beam reconfigurable low RCS planar array antenna according to claim 6, characterized in that: The slotted metal aluminum plate and feeding structure (5) include a slotted aluminum plate (5.1), the slotted aluminum plate (5.1) is located directly below the dielectric substrate (2), the slot of the slotted aluminum plate (5.1) is along the x-direction, the slot position coincides with the projection of the complete aluminum plate structure minus the rectangular metal floor (3.4) on the z-axis, and the feeding structure (5.2) is an SMP radio frequency connector, which is installed at the geometric center of the slotted aluminum plate (5.1).

9. The broadband scattering beam reconfigurable low RCS planar array antenna according to claim 1, characterized in that: The antenna unit period is p=13mm, the array size is 138mm×103mm×6mm, the pin header 4 is 2×8 in specification, and is a double-row pin header, each row has eight pins, and the number is N×N / 16; N×N antenna units are printed onto the surface of a dielectric substrate (2) by a printed circuit board manufacturing process; The pin rows (4) are evenly installed along the edges of both sides of the y-axis of the array antenna, and the number of the pin rows on each side is N×N / 32.

10. A control method for a broadband scattering beam reconfigurable low RCS array antenna according to any one of claims 1 to 9, characterized in that: The broadband scattering beam reconfigurable antenna array has two control states, named state 1 and state 2. The reflection phase difference between the two states is 180°, while the impedance matching, gain and radiation pattern of the two states are basically the same. The specific implementation method of the two states includes the following steps: When the bias voltage V1 is not connected to the DC voltage source and V2 is grounded, the antenna unit is in state 1; When the bias voltage V1 is connected to a 5.0V DC voltage source and V2 is grounded, the antenna unit is in state 2. By changing the state of the units in the array, the phase of the scattering field on the array surface is changed, thereby achieving active control of the scattering beam. At the same time, the antenna array ensures stable radiation capability.

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