Low-scattering array antenna based on dual-function unit and collaborative arrangement design

Abstract

The invention discloses a low-scattering array antenna based on a dual-function unit and a collaborative arraying design, which belongs to the technical field of array antenna stealth design, and is characterized in that reference array units and dual-function units cooperatively form an array to form a 4 * 4 two-dimensional array antenna, and the array antenna has four rows along a co-polarization direction; wherein each of the first row and the fourth row is provided with four dual-function units, and each of the second row and the third row is provided with four reference array units. The reference array unit comprises a radiation patch, a dielectric layer and a metal floor which are sequentially arranged from top to bottom; and an L-shaped feed structure is arranged in the dielectric layer. The difference between the dual-function unit and the reference array unit is that the radiation patch of the dual-function unit is provided with three parallel straight slits, and the straight slits penetrate through the radiation patch. The array antenna designed by the invention has the advantages of integration of radiation and scattering, wide band, dual polarization and low scattering, and can meet the stealth requirement.

Description

Technical Field

[0001] The present invention belongs to the technical field of array antenna stealth design, and proposes a low-scattering array antenna based on dual-function units and cooperative array design. Background Art

[0002] Currently, there are several existing technologies in the field of broadband low-scattering design of array antennas, but they all have certain defects in methods and performance: 1. Array antenna low-scattering design is achieved by using array element shaping technology. Based on the total current distribution of the array antenna elements, slot loading is performed at appropriate locations of the array antenna elements to cut off the scattered current, thereby achieving an RCS reduction design for the array antenna. However, for co-polarization, traditional shaping technology is difficult to achieve RCS reduction and often degrades the radiation performance of the array antenna, making it difficult to achieve a balanced radiation and scattering design for the array antenna.

[0003] 2. Utilizing loading technologies such as metamaterial absorbers, frequency selective surfaces, or electromagnetic metasurfaces, through rational arrangement and placement around the antenna, on the floor, or as a cladding, array antennas can ultimately achieve RCS reduction. However, these technologies increase the cross-section or aperture size of the array antenna, increasing the overall size of the antenna and making it difficult to achieve in-band RCS reduction.

[0004] 3. Array antenna scatter reduction design using scatter cancellation. This method achieves scatter reduction by designing two array antenna elements so that both elements exhibit scatter cancellation characteristics in the cross-polarization direction. However, this technology fails to apply scatter cancellation to co-polarization scatter reduction design, achieving RCS reduction for dual-polarization array antennas across a wide bandwidth. Summary of the Invention

[0005] The present invention aims to overcome the shortcomings of the aforementioned background technology and proposes a low-scattering array antenna based on dual-function units and a coordinated array design. In the co-polarization direction, the principle of scatter cancellation is utilized to form an array of reference array units and scatter cancellation units (dual-function units), achieving co-polarization RCS reduction. In the cross-polarization direction, low-RCS units (dual-function units) are partially replaced by reference array units to achieve cross-polarization RCS reduction. This design achieves a dual-polarization, broadband RCS reduction array antenna design suitable for the development of broadband, dual-polarization, low-scattering array antennas for stealth platforms.

[0006] In order to achieve the above effects, the technical solutions adopted by the present invention are as follows: A low-scattering array antenna based on a dual-function unit and a cooperative array design, wherein the reference array unit and the dual-function unit cooperate to form a 4×4 two-dimensional array antenna; There are four rows along the same polarization direction; the first row and the fourth row are each provided with four dual-function units, and the second row and the third row are each provided with four reference array units.

[0007] Furthermore, the reference array unit and the dual-function unit have the same transmission and radiation characteristics; the co-polarization scattering fields of the two have the characteristics of equal amplitude and opposite phase, and the cross-polarization scattering field of the dual-function unit has a low scattering characteristic.

[0008] Furthermore, the reference array unit and the dual-function unit each include a radiation patch, a dielectric layer, and a metal floor placed sequentially from top to bottom; an L-shaped feeding structure is provided in the dielectric layer; The radiation patch of the dual-function unit is provided with three parallel straight slots, which are the first straight slot, the second straight slot and the third straight slot from left to right, wherein the geometric center of the second straight slot coincides with the geometric center of the radiation patch where it is located.

[0009] Furthermore, the L-shaped feeding structure includes a metal coaxial cable and a feeding microstrip line; the feeding microstrip line is pre-buried in the dielectric layer and located directly below the radiating patch; the metal coaxial cable is perpendicular to the radiating patch above it and the top of its inner conductor is connected to the feeding microstrip line, and the outer conductor of the metal coaxial cable is connected to the metal floor; in the dual-function unit, the feeding microstrip line is parallel to the straight slot on the radiating patch.

[0010] Furthermore, a coupling slot is provided on the metal floor, and the coupling slot is perpendicular to the L-shaped feeding microstrip line; in the dual-function unit, the coupling slot is perpendicular to the straight slot on the radiation patch.

[0011] Furthermore, the design process of the dual-function unit is as follows: Step 1: Analyze the radiation patterns of the reference array elements; sort them by their amplitude, select important radiation patterns, and calculate their current distributions; based on the current distributions, select high current regions that need to be retained; Step 2: Perform scattering pattern analysis on the reference array element, select important scattering patterns of co-polarization and cross-polarization according to the scattering pattern amplitude, and calculate their phase and current distribution respectively; Step 3: Based on the current distribution of the important scattering modes under two polarizations of the reference array unit, the current distribution of the important radiation mode in step 1 is compared, and the strong current portion of the cross-polarization important scattering mode that can be removed or cut is selected. Straight slots are introduced along the co-polarization direction on the radiation patch of the reference array unit to obtain the designed array unit. Step 4: Calculate the amplitude and phase of the important scattering patterns of the designed array unit in a wide frequency band, and compare and analyze them with the amplitude and phase of the important scattering patterns of the reference array unit; Step 5: If, within the broadband, the effective scattering phase difference between the important scattering modes of the designed array element and the reference array element is not within the range of 143° to 217°, or the scattering amplitudes of the important scattering modes of the two elements differ significantly, then repeat steps 2, 3, and 4 for the designed array element, continue to analyze the scattering pattern at frequencies that do not meet the phase difference and amplitude requirements, and then perform a modified design on the designed array element. Repeat the iterations until the effective phase difference between the important scattering modes of the reference array element and the newly designed array element within the broadband is within the range of 143° to 217°, and the scattering amplitudes of the important scattering modes of the two elements are approximately equal, thus obtaining a co-polarization scattering cancellation element. Calculate the cross-polarization RCS of the co-polarization scattering cancellation element within the broadband and compare it with the cross-polarization RCS of the reference array element to confirm that the broadband cross-polarization RCS of the newly designed array element has been effectively reduced. Thus, a dual-function element with both co-polarization scattering cancellation characteristics and cross-polarization low scattering characteristics is designed.

[0012] Furthermore, the important scattering modes of the reference array unit and the co-polarization scattering cancellation unit respectively have the characteristics of equal scattering amplitudes and opposite scattering phases in the co-polarization direction.

[0013] Compared with the prior art, the present invention adopts the above technical solution to achieve the following beneficial effects:

[0014] 1. This invention implements three straight slots in the reference array element radiating patch, simultaneously achieving both co-polarization scatter cancellation and cross-polarization low scattering, resulting in a dual-function element. This is then coupled with a coordinated array design based on analysis of the reference array antenna's scattering pattern. This design utilizes co-polarization scatter cancellation elements and cross-polarization low scattering elements to achieve a broadband, dual-polarization, low-scattering array antenna. This design strategy for RCS reduction is clear, resulting in a streamlined and efficient design process.

[0015] 2. Compared with the low-scattering array design, the present invention does not compromise the radiation performance, does not increase the overall size of the antenna, and has a wider co-polarization RCS reduction bandwidth (100%, including the antenna operating frequency band) and cross-polarization RCS reduction bandwidth (88%, including the antenna operating frequency band). BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a structural diagram of the reference array unit.

[0017] Figure 2 It is a structural diagram of a dual-function unit.

[0018] Figure 3 It is a top view of the dual-function unit.

[0019] Figure 4It is a structural diagram of the metal floor.

[0020] Figure 5 It is a structural diagram of the L-type feeding structure.

[0021] Figure 6 is a schematic diagram of a reference array antenna.

[0022] Figure 7 This is a schematic diagram of a low-scattering array antenna.

[0023] Figure 8 is the calculation result of the reflection coefficient curve of the reference array antenna.

[0024] Figure 9 It is the calculated result of the radiation pattern of the reference array antenna at 4.5 GHz.

[0025] Figure 10 is the calculated radiation pattern amplitude of the reference array element.

[0026] Figure 11 is the calculated result of radiation mode 2 current of the reference array element.

[0027] Figure 12 is the calculated result of radiation mode 6 current of the reference array unit.

[0028] Figure 13 It is the calculation result of the amplitude of the polarization scattering pattern of the reference array unit at the typical frequency point x.

[0029] Figure 14 is the calculated result of the x-polarized scattering mode 1 current of the reference array element.

[0030] Figure 15 is the calculated current result of x-polarized scattering mode 6 of the reference array element.

[0031] Figure 16 It is the calculation result of the y-polarization scattering mode amplitude of the reference array unit at the typical frequency point.

[0032] Figure 17 is the current calculation result of the y-polarized scattering mode 1 of the reference array element.

[0033] Figure 18 is the current calculation result of the y-polarized scattering mode 2 of the reference array element.

[0034] Figure 19 is the calculated result of the y-polarized scattering mode 3 current of the reference array element.

[0035] Figure 20 These are the calculation results of the amplitudes of the important x-polarization scattering modes 1 and 6 of the reference array unit and the dual-function unit.

[0036] Figure 21 It is the calculation result of the phase difference between the x-polarization important scattering mode 1 and scattering mode 6 of the reference array unit and the dual-function unit.

[0037] Figure 22 are the y-polarization broadband RCS calculation results of the reference array unit and the dual-function unit.

[0038] Figure 23 is the calculation result of the y-polarization scattering pattern amplitude of the reference array antenna at 3 GHz.

[0039] Figure 24 is the calculation result of the y-polarization scattering pattern amplitude of the reference array antenna at 4 GHz.

[0040] Figure 25 is the calculation result of the y-polarization scattering pattern amplitude of the reference array antenna at 5 GHz.

[0041] Figure 26 is the calculation result of the y-polarization scattering mode amplitude of the reference array antenna at 6 GHz.

[0042] Figure 27 is the calculation result of the y-polarization scattering mode amplitude of the reference array antenna at 7 GHz.

[0043] Figure 28 is the current calculation result of the reference array antenna scattering mode 8.

[0044] Figure 29 is the current calculation result of the reference array antenna scattering pattern 24.

[0045] Figure 30 is the current calculation result of the reference array antenna scattering pattern 28.

[0046] Figure 31 It is the co-polarization RCS calculation result of the reference array antenna and the low-scattering array antenna.

[0047] Figure 32 It is the cross-polarization RCS calculation result of the reference array antenna and the low-scattering array antenna.

[0048] Figure 33 It is the calculation result of the reflection coefficient curve of the reference array antenna and the low-scattering array antenna.

[0049] Figure 34 Calculated results of the radiation patterns of the reference array antenna and the low-scattering array antenna at 4.5 GHz. DETAILED DESCRIPTION

[0050] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0051] The following is a specific example of a broadband dual-polarization low-scattering array antenna design: This embodiment, by reshaping the reference array element 5, proposes a dual-function element 6 with destructive scattering characteristics for the co-polarized scattering field and low scattering characteristics for the cross-polarized scattering field. Furthermore, based on a collaborative array approach and analysis of the scattering pattern of the reference array antenna, a layout strategy for the reference array element 5 and the dual-function element 6 is proposed. In the co-polarization direction (the same polarization direction as the reference array antenna), the dual-function element 6 forms an array with the reference array element 5, achieving a co-polarization, broadband, low-scattering design. Furthermore, the dual-function element 6 inherently exhibits cross-polarization, low-scattering characteristics. In the cross-polarization direction (orthogonal to the polarization direction of the reference array antenna), the dual-function element 6 partially replaces the reference array element 5 to form an array, achieving a cross-polarization, broadband, low-scattering design. Ultimately, an array antenna is achieved that combines radiation and scattering, and provides broadband, dual-polarization, low-scattering performance, meeting the requirements for array antenna stealth.

[0052] First, a schematic diagram of the structure of a reference array unit 5 is given, as shown in Figure 1. It includes a first radiating patch 1, a first dielectric layer 2, and a first metal floor 4. The radius of the first radiating patch 1 is D, D = 17-19 mm; the side length of the first dielectric layer 2 is L1, L1 = 29-31 mm, and the thickness is H1, H1 = 6 mm; Figure 2 shows the structure of dual-function unit 6, which includes a second radiating patch 11, a second dielectric layer 12, and a second metal floor 14. Compared to reference array unit 5, a first straight slot 11.1, a second straight slot 11.2, and a third straight slot 11.3 are placed in second radiating patch 11; the rest of the structure is identical to reference array unit 5.

[0053] Figure 3 shows a schematic diagram of the second radiation patch 11 of the dual-functional unit 6. Three parallel straight slots are provided on the second radiation patch 11 of the dual-functional unit 6, which are the first straight slot 11.1, the second straight slot 11.2 and the third straight slot 11.3 from left to right, wherein the geometric center of the second straight slot 11.2 coincides with the geometric center of the second radiation patch 11. The geometric centers of the first straight slot 11.1 and the third straight slot 11.3 are Y1 away from the geometric center of the second radiation patch 11, Y1=5~7mm, and the geometric center of the second straight slot 11.2 coincides with the geometric center of the second radiation patch 11; the widths of the first straight slot 11.1, the second straight slot 11.2 and the third straight slot 11.3 are W2, W2=1~2mm; the first straight slot 11.1, the second straight slot 11.2 and the third straight slot 11.3 all pass through the second radiation patch 11 on the y-axis.

[0054] Figure 4 shows a schematic diagram of the second metal floor 14 of the dual-function unit 6. A feed port 14.1 and a coupling slot 14.2 are located on the second metal floor 14. The side length of the second metal floor 14 is L1, which is 29-31 mm. A coupling slot 14.2 is etched into the second metal floor 14. The width of the coupling slot 14.2 is W2, which is 0.2-0.3 mm, and the length is L2, which is 19-21 mm. The geometric center of the coupling slot 14.2 coincides with the geometric center of the second metal floor 14. The structure of the first metal floor 4 of the reference array unit 5 is identical to that of the second metal floor 14, and the first metal floor 4 is also provided with a feed port and a coupling slot.

[0055] Figure 5 shows schematic diagrams of the L-shaped feed structure 13 of the dual-function unit 6 and the first L-shaped feed structure 3 of the reference array unit 5. Both structures consist of a metal coaxial line 13.1 and a feed microstrip line 13.2. The height of the metal coaxial line 13.1 is H2, which is 3 mm. The bottom surface of the metal coaxial line 13.1 is at the same height as the bottom surface of the second dielectric layer 12. The distance from the center of the bottom of the metal coaxial line 13.1 to the geometric center of the second metal floor 14 is X1, which is 6 to 8 mm. The diameter of the metal coaxial line 13.1 is D2, which is 1.2 to 1.4 mm. The wide side of the feed microstrip line 13.2 coincides with the top diameter of the inner conductor of the metal coaxial line 13.1, i.e., the two are equal. The long side of the metal coaxial line 13.2 is L3, which is 9 to 11 mm.

[0056] FIG6 shows a schematic diagram of the structure of the reference array antenna.

[0057] FIG7 shows a schematic structural diagram of a low-scattering array antenna.

[0058] The reference array antenna was calculated using the electromagnetic simulation software HFSS. The results show that the antenna has good transmission and radiation performance. In the frequency range of 3.0 GHz to 9.0 GHz, the calculated curve of the reference array antenna reflection coefficient is as follows: Figure 8 As shown in Figure 9, where the horizontal axis represents frequency in GHz and the vertical axis represents the reflection coefficient Γ in dB. The figure shows the calculated results for the reference array antenna Γ, demonstrating that the reference array antenna has a reflection coefficient better than -10 dB in the 4.12 GHz-5.78 GHz band, demonstrating good transmission performance. The calculated radiation pattern of the reference array antenna at 4.5 GHz is shown in Figure 9, where the horizontal axis represents angle in degrees and the vertical axis represents actual gain in dBi. The black solid line in the figure shows the radiation pattern of the reference array antenna calculated in the phi = 0° plane, and the red dashed line shows the radiation pattern of the reference array antenna calculated in the phi = 90° plane. The results show that the reference array antenna has good radiation performance at 4.5 GHz, with a normal gain of 15.9 dBi.

[0059] The radiation pattern of reference array element 5 was analyzed using the electromagnetic simulation software FEKO. The radiation pattern amplitude of reference array element 5 at 4.5 GHz is shown in Figure 10, where the horizontal axis represents the mode number and the vertical axis represents the mode amplitude in units of 10. -3 v / m. It can be seen that the reference array unit 5 has a total of 12 radiation modes, among which the mode amplitudes of radiation mode 2 and radiation mode 6 are much larger than those of other radiation modes, that is, the heavy radiation modes of the reference array unit 5 are mode 2 and mode 6. Then the current distribution of the main radiation modes 2 and 6 is calculated, and the results are shown in Figures 11 and 12. In the figures, the red arrows indicate the direction of current flow, and the colors indicate the current distribution intensity, in A / m. From the calculation results, it can be seen that the current distribution of the main radiation modes 2 and 6 on the radiation patch is shown above. The distribution is stronger on the left and right sides of the radiation patch, and along the x Since the electric field radiated by the reference array antenna is in the x-polarization direction, that is, the reference array antenna polarization is x-polarization. Therefore, when analyzing the scattering pattern of reference array element 5 and designing dual-function element 6, x-polarized plane waves are considered co-polarized, and y-polarized plane waves are considered cross-polarized.

[0060] Next, we analyze the scattering pattern of the reference array element 5 and then design the dual-function element 6: Based on the requirements of broadband dual-polarization stealth, the electromagnetic simulation software FEKO was used to analyze the scattering patterns of reference array element 5 with x-polarization and y-polarization at important broadband frequencies (3 GHz, 4 GHz, 5 GHz, 6 GHz, 7 GHz, 8 GHz, and 9 GHz). The analysis included the amplitude and phase of its mode weight coefficient, the amplitude and phase of the mode far field, and the mode current distribution. The mode amplitude of the scattering mode was calculated based on the mode weight coefficient and mode far field of the scattering mode. , and sort the scattering modes according to their amplitudes, and select the important scattering modes at important frequencies (3 GHz, 4 GHz, 5 GHz, 6 GHz, 7 GHz, 8 GHz, and 9 GHz). represents the incident wave pitch angle, represents the incident wave azimuth, represents the scattered wave pitch angle, Represents the azimuth of the scattered wave. As shown in Figure 13, the calculation results of the x-polarized scattering mode amplitude of reference array element 5 at important frequencies (3 GHz, 4 GHz, 5 GHz, 6 GHz, 7 GHz, 8 GHz, and 9 GHz) are shown, where the x-axis is the incident frequency in GHz. The y-axis is the mode number. The z-axis is the mode amplitude in 10 -3 v / m. According to the calculation results, scattering mode 1 is an important scattering mode in the low frequency range of 3 GHz-4 GHz, and scattering mode 6 is an important scattering mode in the high frequency range of 5 GHz-9 GHz. The current distribution calculation of x-polarization scattering mode 1 and scattering mode 6 is as shown in Figures 14 and Figure 15 The red arrow in the current diagram indicates the direction of current flow, and the color indicates the current distribution intensity in A / m.

[0061] As shown in Figure 16, the calculation results of the y-polarized scattering mode amplitude of reference array element 5 at important frequencies (3 GHz, 4 GHz, 5 GHz, 6 GHz, 7 GHz, 8 GHz, and 9 GHz) are shown, where the x-axis is the incident frequency in GHz, the y-axis is the mode number, and the z-axis is the mode amplitude in 10 -3 v / m. According to the calculation results, scattering mode 1 is an important scattering mode in the low-frequency range of 3GHz-4GHz, scattering mode 2 is an important scattering mode in the medium-frequency range of 4GHz-5GHz, and scattering mode 3 is an important scattering mode in the high-frequency range of 6GHz-9GHz. The current distribution calculations for y-polarized scattering mode 1, scattering mode 2, and scattering mode 3 are shown in Figures 17 and 17. Figure 18 and Figure 19As shown. The red arrow in the current diagram indicates the direction of current flow, and the color indicates the current distribution intensity in A / m. Based on the current distribution of x-polarized scattering mode 1 and scattering mode 6 and y-polarized scattering mode 1, scattering mode 2, and scattering mode 3 in each part of the antenna, compare the mode current distribution of important radiation mode 2 and mode 6 in step 1, select the current portion that can be removed or cut (cut off the y-polarized scattering mode current and retain the radiation mode current) and perform antenna shape modification design. Make the following shape modification design: Three straight slots are applied along the x-axis on the first radiating patch 1 to introduce an effective phase difference with the x-polarized scattering field of reference array element 5 (reducing the x-polarized RCS through scattering cancellation) and to intercept the y-polarized scattering mode current (reducing the y-polarized RCS). Figure 20 further shows the amplitudes of x-polarized scattering mode 1 and scattering mode 6 for reference array element 5 and dual-functional element 6. The black solid line shows the calculated amplitude of scattering mode 1 for reference array element 5, the red dashed line shows the amplitude of mode 1 for dual-functional element 6, the blue dashed line shows the amplitude of scattering mode 6 for reference array element 5, and the pink dashed line shows the amplitude of scattering mode 6 for dual-functional element 6. The results show that within the 3 GHz-4 GHz frequency band, the amplitudes of x-polarized scattering mode 1 for reference array element 5 and dual-functional element 6 are nearly equal and are the dominant scattering mode. Within the 4 GHz-9 GHz frequency band, the amplitudes of x-polarized scattering mode 6 for reference array element 5 and dual-functional element 6 are nearly equal and are the dominant scattering mode. Figure 21 shows the calculated results of the mode phase difference of the x-polarized scattering mode 1 and scattering mode 6 of the reference array element 5 and the dual-function element 6. The blue solid line is the calculated result of the phase difference of scattering mode 1, and the red dashed line is the calculated result of the phase difference of scattering mode 6. The results show that within 4 GHz-4.5 GHz, the x-polarized scattering mode 1 of the reference array element 5 and the dual-function element 6 achieves an effective phase difference, and within 4.5 GHz-9 GHz, the x-polarized scattering mode 6 of the reference array element 5 and the dual-function element 6 achieves an effective phase difference.

[0062] The cross-polarization RCS of reference array element 5 and dual-function element 6 are further calculated, and the results are shown in Figure 22. It can be seen that dual-function element 6 achieves cross-polarization RCS reduction in the 3 GHz-9 GHz range.

[0063] Figure 23 to Figure 27 The Y-polarization scattering pattern amplitudes of the reference array antenna at important frequencies (3 GHz, 4 GHz, 5 GHz, 6 GHz, 7 GHz, 8 GHz, and 9 GHz) are calculated in Figure 1, where the x-axis represents the mode number and the y-axis represents the mode amplitude. It can be seen that scattering modes 8, 24, and 28 are important scattering modes.

[0064] Figure 28 to Figure 30 Figure 4 calculates the currents for the reference array antenna's Y-polarization scattering modes 8, 24, and 28. As can be seen, the currents for these three important scattering modes are strongly distributed in the upper and lower rows of elements. Therefore, the upper and lower rows of reference array elements 5 are replaced with dual-function elements 6.

[0065] Finally, the reference array elements 5 and dual-function elements 6 are rationally arranged. In the x-polarization direction, the reference array elements 5 and the cancellation elements (leveraging the cancellation properties of the dual-function elements 6) form an array to achieve co-polarization RCS reduction for the array antenna. In the y-polarization direction, the low-scattering array is used to achieve cross-polarization RCS reduction for the array antenna. By forming an array using these x- and y-directional arrangements, a two-dimensional array antenna is formed, resulting in a broadband dual-polarization low-scattering array antenna. A schematic diagram of the array antenna structure is shown in Figure 7.

[0066] Through the dual-function unit 6 design and coordinated array design, a broadband dual-polarization low-scattering array antenna was finally realized. The broadband x-polarization RCS calculation results of the low-scattering array antenna and the reference array antenna are shown in Figure 31, and the broadband y-polarization RCS calculation results of the low-scattering array antenna and the reference array antenna are shown in Figure 32. The calculation results of the reflection coefficient curve of the low-scattering array antenna are shown in Figure 33. The radiation pattern calculation results of the low-scattering array antenna at 4.5 GHz are shown in Figure 34. Figure 34 shown.

[0067] The above calculation results show that by using pattern amplitude to select key scattering modes and comparing the current distribution of key radiation modes with broadband x- and y-polarization scattering modes, slot location and size can be determined. Slot loading can then be used to cancel x-polarization (co-polarization) scattering and suppress y-polarization (cross-polarization) scattering modes, effectively achieving broadband dual-polarization RCS reduction for the array antenna. Compared to the reference array antenna, the broadband dual-polarization low-scattering array antenna achieves an x-polarization RCS reduction bandwidth of 100%, including the antenna operating band, and an y-polarization RCS reduction bandwidth of 88%, including the antenna operating band. The average co-polarization RCS reduction is 8.0 dB, the average cross-polarization RCS reduction is 7.6 dB, and the average intra-band RCS reduction is 19 dB. Furthermore, the array antenna maintains excellent radiation performance. Compared to the reference array antenna, the broadband dual-polarization low-scattering array antenna maintains excellent transmission and radiation performance, with no significant changes.

[0068] In summary, the present invention separates the radiation mode from the scattering mode based on characteristic mode analysis. This ensures that the radiation mode is unaffected by performing scattering analysis on typical frequency points within the dual-polarization broadband range. The x-polarization broadband important scattering mode and the y-polarization broadband important scattering mode are selected based on the scattering mode amplitude. Furthermore, the important radiation mode current is compared with the x-polarization broadband important scattering mode and the y-polarization broadband important scattering mode current. Slot loading is used to simultaneously implement the design of an x-polarization scattering cancellation unit and a y-polarization low-scattering unit. Furthermore, the reference array unit 5 is designed to be combined with the scattering cancellation unit in the x-polarization (co-polarization) direction, and the low-scattering unit is designed to be combined in the y-polarization (cross-polarization) direction, thereby achieving a broadband dual-polarization low-scattering array antenna design.

[0069] It should be noted that the above description is only an example of a preferred application of the present invention and is not intended to limit the scope of protection of the present invention. Any technical solution that adopts equivalent replacement or equivalent transformation is within the scope of protection of the present invention.

Claims

1. A low-scattering array antenna based on dual-function units and cooperative array design, characterized in that: The reference array unit (5) and the dual-function unit (6) cooperate to form a 4×4 two-dimensional array antenna; There are four rows along the same polarization direction; wherein the first row and the fourth row are each provided with four dual-function units (6), and the second row and the third row are each provided with four reference array units (5).

2. The low-scattering array antenna based on dual-function units and cooperative array design according to claim 1, characterized in that: The reference array unit (5) and the dual-function unit (6) have the same transmission and radiation characteristics; their co-polarization scattering fields have characteristics of equal amplitude and opposite phase, and the cross-polarization scattering field of the dual-function unit (6) has a low scattering characteristic.

3. The low-scattering array antenna based on dual-function units and cooperative array design according to claim 1, characterized in that: The reference array unit (5) and the dual-function unit (6) both include a radiation patch, a dielectric layer, and a metal floor placed sequentially from top to bottom; an L-shaped feeding structure is provided in the dielectric layer; The radiation patch of the dual-function unit (6) is provided with three mutually parallel straight slots, which are, from left to right, a first straight slot (11.1), a second straight slot (11.2), and a third straight slot (11.3), wherein the geometric center of the second straight slot coincides with the geometric center of the radiation patch in which it is located.

4. The low-scattering array antenna based on dual-function units and cooperative array design according to claim 3, characterized in that: The L-shaped feeding structure comprises a metal coaxial cable (13.1) and a feeding microstrip line (13.2); the feeding microstrip line (13.2) is pre-buried in a dielectric layer and located directly below a radiation patch; the metal coaxial cable (13.1) is perpendicular to the radiation patch above it, and the top end of its inner conductor is connected to the feeding microstrip line (13.2), and the outer conductor of the metal coaxial cable (13.1) is connected to a metal floor; in a dual-function unit (6), the feeding microstrip line (13.2) is parallel to a straight slot on the radiation patch.

5. The low-scattering array antenna based on dual-function units and cooperative array design according to claim 3, characterized in that: A coupling slot is provided on the metal floor, and the coupling slot is perpendicular to the L-shaped feeding microstrip line; in the dual-function unit (6), the coupling slot is perpendicular to the straight slot on the radiation patch.

6. The low-scattering array antenna based on dual-function units and cooperative array design according to claim 1, characterized in that: The design process of the dual-function unit (6) is as follows: Step 1, analyzing the radiation pattern of the reference array unit (5); sorting the radiation patterns according to their amplitude, selecting important radiation patterns, and calculating their current distributions; and selecting high current regions to be retained based on the current distributions; Step 2, performing scattering pattern analysis on the reference array unit (5), selecting important scattering patterns of co-polarization and cross-polarization according to the scattering pattern amplitude, and calculating their phase and current distribution respectively; Step 3, based on the current distribution of the important scattering modes under two polarizations of the reference array unit (5), compared with the current distribution of the important radiation mode in step 1, a strong current portion of the cross-polarization important scattering mode can be removed or cut, and a straight gap is introduced along the same polarization direction on the radiation patch of the reference array unit (5) to obtain the designed array unit; Step 4, calculate the amplitude and phase of the important scattering mode of the designed array unit in the wide frequency band, and compare and analyze them with the amplitude and phase of the important scattering mode of the reference array unit (5); Step 5: If the effective scattering phase difference of the important scattering modes of the designed array unit and the reference array unit fails to fall within the range of 143° to 217° within the wide band, or the scattering amplitudes of the important scattering modes of the two differ greatly, then repeat steps 2, 3, and 4 for the designed array unit, continue to analyze the scattering mode at the frequency that does not meet the phase difference and amplitude requirements, and then perform a modified design on the designed array unit. Repeat the iterations until the effective phase difference of the important scattering modes of the reference array unit and the latest designed array unit in the wide band is within the range of 143° to 217°, and the scattering amplitudes of the important scattering modes of the two are approximately equal, thus obtaining a co-polarization scattering cancellation unit; calculate the cross-polarization RCS of the co-polarization scattering cancellation unit within the wide band, and compare it with the cross-polarization RCS of the reference array unit to confirm that the wide-band cross-polarization RCS of the latest designed array unit is effectively reduced. Thus, a dual-function unit (6) with co-polarization scattering cancellation characteristics and cross-polarization low scattering characteristics is designed.

7. The low-scattering array antenna based on dual-function units and cooperative array design according to claim 6, characterized in that: The important scattering modes of the reference array unit (5) and the co-polarization scattering cancellation unit respectively have the characteristics of equal scattering amplitudes and opposite scattering phases in the co-polarization direction.

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