A low-scattering array antenna based on a dual-function unit and a collaborative array design

Abstract

The application discloses a low-scattering array antenna based on a dual-function unit and a cooperative array design, belongs to the technical field of array antenna stealth design, and is formed by cooperatively arranging reference array units and dual-function units to form a 4*4 two-dimensional array antenna, which has four rows along the same polarization direction; wherein, 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. The reference array unit comprises, from top to bottom, a radiation patch, a dielectric layer and a metal ground plate; the dielectric layer is provided with an L-shaped feeding structure. 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 straight slits parallel to each other, and the straight slits penetrate through the radiation patch. The array antenna designed by the application has the advantages of radiation scattering integration and wide-band dual-polarization low scattering, and can meet the stealth requirement.

Description

Technical Field

[0001] This invention belongs to the field of array antenna stealth design technology, and proposes a low-scattering array antenna based on dual-functional units and cooperative array design. Background Technology

[0002] Currently, there are several existing technologies in the field of wideband low-scattering design of array antennas, but they all have certain shortcomings in terms of methodology and performance:

[0003] 1. Low-scattering design of array antennas is achieved by using array element shaping technology. Based on the total current distribution of the array antenna elements, the scattered current is cut off by slot loading at appropriate locations in the array antenna elements, thereby reducing the RCS of the array antenna. However, for co-polarized antennas, traditional shaping is difficult to achieve RCS reduction and usually degrades the radiation performance of the array antenna, making it difficult to achieve integrated radiation and scattering design of the array antenna.

[0004] 2. By utilizing metamaterial absorbers, frequency-selective surfaces, or electromagnetic metasurfaces, and through proper arrangement, these technologies can be applied around the antenna, on the ground plane, or in the cladding. This ultimately achieves RCS reduction in the array antenna design. However, all of these technologies increase the cross-sectional or aperture dimensions of the array antenna, thus increasing the overall size of the antenna, and making it difficult to achieve in-band RCS reduction.

[0005] 3. Using the scattering cancellation method for array antenna scattering reduction design. This method involves designing two array antenna elements such that both elements exhibit scattering cancellation characteristics in the cross-polarization direction, thereby achieving scattering reduction. However, this technique has failed to apply the scattering cancellation method to co-polarization scattering reduction design, thus failing to achieve RCS reduction for dual-polarization array antennas over a wide bandwidth. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the aforementioned background technology and propose a low-scattering array antenna based on dual-functional units and a cooperative array design. In the same polarization direction, the principle of scattering cancellation is utilized to array the reference array unit and the scattering cancellation unit (dual-functional unit) to achieve reduction of the same polarization RCS. In the cross-polarization direction, low-RCS units (dual-functional units) are used to partially replace the reference array unit to achieve reduction of the cross-polarization RCS, thereby realizing a dual-polarization wideband RCS reduction design for the array antenna, suitable for the development of wideband dual-polarization low-scattering array antennas for stealth platforms.

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

[0008] A low-scattering array antenna based on dual-functional units and cooperative array design, wherein the reference array unit and the dual-functional unit are cooperatively arrayed to form a 4×4 two-dimensional array antenna;

[0009] Along the same polarization direction, there are four rows; the first and fourth rows each have 4 dual-function units, and the second and third rows each have 4 reference array units.

[0010] Furthermore, the reference array unit and the dual-function unit have the same transmission and radiation characteristics; their co-polarized scattering fields have equal amplitude and opposite phase, and the cross-polarized scattering field of the dual-function unit has low scattering characteristics.

[0011] Furthermore, both the reference array unit and the dual-function unit include a radiating patch, a dielectric layer, and a metal ground plane arranged sequentially from top to bottom; an L-shaped feeding structure is provided in the dielectric layer;

[0012] The dual-function unit has three parallel straight slits on its radiating patch, which are the first straight slit, the second straight slit, and the third straight slit from left to right. The geometric center of the second straight slit coincides with the geometric center of the radiating patch on which it is located.

[0013] Furthermore, the L-shaped feeding structure includes a metal coaxial cable and a feeding microstrip line; the feeding microstrip line is embedded in the dielectric layer and located directly below the radiating patch; the metal coaxial cable is perpendicular to the radiating patch above it and its inner conductor tip is connected to the feeding microstrip line, and the outer conductor of the metal coaxial cable is connected to the metal ground plane; in the dual-function unit, the feeding microstrip line is parallel to the straight slot on the radiating patch.

[0014] Furthermore, the metal floor is provided with coupling slots, which are perpendicular to the L-shaped feed microstrip line; in the dual-function unit, the coupling slots are perpendicular to the straight slots on the radiating patch.

[0015] Furthermore, the design process of the dual-functional unit is as follows:

[0016] Step 1: Analyze the radiation modes of the reference array elements; sort them according to the amplitude of the radiation modes, select the important radiation modes, and calculate their current distribution; based on the current distribution, select the strong current regions that need to be retained.

[0017] Step 2: Perform scattering mode analysis on the reference array elements, select important scattering modes with co-polarization and cross-polarization according to the amplitude of the scattering modes, and calculate their phase and current distribution respectively;

[0018] Step 3: Based on the current distribution of important scattering modes under the two polarizations of the reference array unit, compare it with the current distribution of important radiation modes in Step 1, select the strong current part of the important scattering modes of cross polarization that can be removed or cut off, and introduce a straight gap along the same polarization direction on the radiation patch of the reference array unit to obtain the designed array unit.

[0019] Step 4: Calculate the amplitude and phase of the important scattering modes of the designed array element in the wide bandwidth, and compare and analyze them with the amplitude and phase of the important scattering modes of the reference array element.

[0020] Step 5: If the effective scattering phase difference of the important scattering modes of the designed array unit and the reference array unit is not within the range of 143° to 217° within the wide bandwidth, or if the scattering amplitudes of the important scattering modes of the two units differ significantly, then Steps 2, 3, and 4 are repeated for the designed array unit. Scattering mode analysis is continued at frequencies where the phase difference and amplitude requirements are not met. The designed array unit is then redesigned and iterated repeatedly until the effective phase difference of the important scattering modes of the reference array unit and the latest designed array unit is within the range of 143° to 217° within the wide bandwidth, and the scattering amplitudes of the important scattering modes of the two units are approximately equal. This yields a co-polarized scattering cancellation unit. The cross-polarization RCS of the co-polarized scattering cancellation unit within the wide bandwidth is calculated and compared with the cross-polarization RCS of the reference array unit. This confirms that the wideband cross-polarization RCS of the latest designed array unit has been effectively reduced. Thus, a dual-function unit with co-polarized scattering cancellation characteristics and cross-polarized low scattering characteristics has been designed.

[0021] Furthermore, the important scattering modes of the reference array unit and the co-polarization scattering cancellation unit each have the characteristics of equal scattering amplitude and opposite scattering phase in the co-polarization direction.

[0022] Compared with the prior art, the present invention, by adopting the above technical solution, has the following beneficial effects:

[0023] 1. This invention achieves both co-polarization scattering cancellation and cross-polarization low-scattering effects by loading three straight slots onto the radiating patch of the reference array unit, thus obtaining a dual-functional unit. Further analysis of the scattering modes of the reference array antenna allows for a collaborative array design. This involves assembling units with scattering cancellation in the co-polarization direction and low-scattering units in the cross-polarization direction, thereby realizing a wideband dual-polarization low-scattering array antenna design. The RCS reduction design approach is clear, and the design process is simple and efficient.

[0024] 2. Compared with low-scatter array design, the present invention does not compromise radiation performance, does not increase the overall size of the antenna, and has a wider co-polarized RCS reduction bandwidth (100%, including the antenna operating frequency band) and cross-polarized RCS reduction bandwidth (88%, including the antenna operating frequency band). Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the reference array cell.

[0026] Figure 2This is a schematic diagram of the structure of a dual-function unit.

[0027] Figure 3 This is a top view of the dual-function unit.

[0028] Figure 4 This is a structural diagram of a metal floor.

[0029] Figure 5 This is a schematic diagram of an L-shaped power supply structure.

[0030] Figure 6 This is a schematic diagram of a reference array antenna.

[0031] Figure 7 This is a schematic diagram of a low-scattering array antenna.

[0032] Figure 8 This is the calculated result of the reflection coefficient curve of the reference array antenna.

[0033] Figure 9 This is the calculated radiation pattern of the reference array antenna at 4.5 GHz.

[0034] Figure 10 This is the result of the radiation mode amplitude calculation for the reference array element.

[0035] Figure 11 This is the result of the radiation mode 2 current calculation for the reference array element.

[0036] Figure 12 This is the result of the radiation mode 6 current calculation for the reference array element.

[0037] Figure 13 The result is the amplitude calculation of the reference array element at a typical frequency x-polarization scattering mode.

[0038] Figure 14 This is the calculated current of the x-polarization scattering mode 1 of the reference array element.

[0039] Figure 15 This is the calculated current of the x-polarized scattering mode 6 of the reference array element.

[0040] Figure 16 The result is the amplitude calculation of the reference array element at a typical frequency for the y-polarized scattering mode.

[0041] Figure 17 This is the current calculation result for y-polarized scattering mode 1 of the reference array element.

[0042] Figure 18 The result is the current calculation for y-polarized scattering mode 2 of the reference array element.

[0043] Figure 19The result is the calculated current of the y-polarized scattering mode 3 of the reference array element.

[0044] Figure 20 These are the amplitude calculation results for the x-polarization important scattering modes 1 and scattering mode 6 of the reference array unit and the dual-function unit.

[0045] Figure 21 The results are the phase difference calculation results for the x-polarization important scattering modes 1 and scattering mode 6 of the reference array unit and the dual-function unit.

[0046] Figure 22 This is the calculated result of the y-polarized wideband RCS of the reference array unit and the dual-function unit.

[0047] Figure 23 The result is the amplitude calculation of the y-polarized scattering mode of the reference array antenna at 3 GHz.

[0048] Figure 24 The result is the amplitude calculation of the y-polarized scattering mode of the reference array antenna at 4 GHz.

[0049] Figure 25 The result is the amplitude calculation of the y-polarized scattering mode of the reference array antenna at 5 GHz.

[0050] Figure 26 The result is the amplitude calculation of the y-polarized scattering mode of the reference array antenna at 6 GHz.

[0051] Figure 27 The result is the amplitude calculation of the y-polarized scattering mode of the reference array antenna at 7 GHz.

[0052] Figure 28 This is the current calculation result for scattering mode 8 of the reference array antenna.

[0053] Figure 29 This is the current calculation result for reference array antenna scattering mode 24.

[0054] Figure 30 This is the current calculation result for scattering mode 28 of the reference array antenna.

[0055] Figure 31 The result is the calculated RCS of the reference array antenna and the low-scatter array antenna under the same polarization.

[0056] Figure 32 This is the calculated cross-polarization RCS result of the reference array antenna and the low-scatter array antenna.

[0057] Figure 33 These are the calculated reflection coefficient curves for the reference array antenna and the low-scattering array antenna.

[0058] Figure 34The results are the radiation patterns of the reference array antenna and the low-scatter array antenna at 4.5 GHz. Detailed Implementation

[0059] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0060] The following is a specific example of a wideband dual-polarization low-scatter array antenna design:

[0061] This embodiment proposes a dual-functional unit 6 with a modified design for the reference array element 5, exhibiting destructive scattering characteristics in the co-polarized scattered field and low scattering characteristics in the cross-polarized scattered field. Furthermore, based on a cooperative arraying method, and through analysis of the scattering modes of the reference array antenna, an arraying strategy for the reference array element 5 and the dual-functional unit 6 is proposed. In the co-polarization direction (the same direction as the polarization of the reference array antenna), the dual-functional unit 6 and the reference array element 5 form an array, achieving a co-polarized wideband low-scattering design. Simultaneously, the dual-functional unit 6 itself possesses cross-polarized low-scattering characteristics. In the cross-polarization direction (orthogonal to the polarization of the reference array antenna), the dual-functional unit 6 partially replaces the reference array element 5 to form an array, achieving a cross-polarized wideband low-scattering design. Ultimately, an array antenna with integrated radiation and scattering capabilities and wideband dual-polarization low-scattering performance is achieved, meeting the stealth requirements of the array antenna.

[0062] First, a schematic diagram of the reference array unit 5 is given, as shown in Figure 1, which includes a first radiating patch 1, a first dielectric layer 2, and a first metal ground plane 4. The radius of the first radiating patch 1 is D, where D = 17~19 mm; the side length of the first dielectric layer 2 is L1, where L1 = 29~31 mm, and the thickness is H1, where H1 = 6 mm.

[0063] Figure 2 shows a schematic diagram of the dual-function unit 6, which includes a second radiating patch 11, a second dielectric layer 12, and a second metal ground plane 14. Compared with the reference array unit 5, the second radiating patch 11 has a first straight slot 11.1, a second straight slot 11.2, and a third straight slot 11.3, while the rest is the same as the reference array unit 5.

[0064] Figure 3 shows a schematic diagram of the second radiating patch 11 of the dual-function unit 6. The second radiating patch 11 of the dual-function unit 6 has three parallel straight slits, which are the first straight slit 11.1, the second straight slit 11.2 and the third straight slit 11.3 from left to right. The geometric center of the second straight slit 11.2 coincides with the geometric center of the second radiating patch 11. The geometric center of the first straight slit 11.1 and the third straight slit 11.3 is Y1, where Y1 = 5~7mm, from the geometric center of the second radiating patch 11. The geometric center of the second straight slit 11.2 coincides with the geometric center of the second radiating patch 11. The width of the first straight slit 11.1, the second straight slit 11.2, and the third straight slit 11.3 is W2, where W2 = 1~2mm. The first straight slit 11.1, the second straight slit 11.2, and the third straight slit 11.3 all penetrate the second radiating patch 11 on the y-axis.

[0065] Figure 4 shows a schematic diagram of the second metal ground plane 14 of the dual-function unit 6. The second metal ground plane 14 has a feed port 14.1 and a coupling slot 14.2. The side length of the second metal ground plane 14 is L1, L1 = 29~31 mm. The coupling slot 14.2 is etched on it. The width of the coupling slot 14.2 is W2, W2 = 0.2~0.3 mm, and the length is L2, L2 = 19~21 mm. The geometric center of the coupling slot 14.2 coincides with the geometric center of the second metal ground plane 14. The structure of the first metal ground plane 4 of the reference array unit 5 is exactly the same as that of the second metal ground plane 14. The first metal ground plane 4 also has a feed port and a coupling slot.

[0066] 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 consisting of a metal coaxial cable 13.1 and a feed microstrip line 13.2. The metal coaxial cable 13.1 has a height of H2, H2 = 3 mm, and its bottom surface is at the same height as the bottom surface of the second dielectric layer 12. The distance between the center of the bottom surface of the metal coaxial cable 13.1 and the geometric center of the second metal ground plane 14 is X1, X1 = 6~8 mm, and the diameter of the metal coaxial cable 13.1 is D2, D2 = 1.2~1.4 mm. The wide side of the feed microstrip line 13.2 coincides with the top diameter of the inner conductor of the metal coaxial cable 13.1, i.e., they are equal, and its long side is L3, L3 = 9~11 mm.

[0067] Figure 6 shows a schematic diagram of the reference array antenna.

[0068] Figure 7 shows a schematic diagram of the low-scattering array antenna.

[0069] The reference array antenna was calculated using the electromagnetic simulation software HFSS, and the results show that the antenna has good transmission and radiation performance. The calculated curves of the reflection coefficient of the reference array antenna in the frequency range of 3.0 GHz–9.0 GHz are shown below. Figure 8 As shown in the figure, the horizontal axis represents frequency in GHz, and the vertical axis represents the reflection coefficient Γ in dB. The figure shows the calculated Γ result for the reference array antenna, which exhibits a reflection coefficient better than -10 dB in the 4.12 GHz-5.78 GHz band, demonstrating good transmission performance. Figure 9 shows the calculated radiation pattern of the reference array antenna at 4.5 GHz, where the horizontal axis represents angle in degrees, and the vertical axis represents the actual gain in dBi. The solid black line in the figure represents the calculated radiation pattern of the reference array antenna at phi=0°, and the dashed red line represents the calculated radiation pattern at phi=90°. The results show that the reference array antenna has good radiation performance at 4.5 GHz, with a normal gain of 15.9 dBi.

[0070] Radiation mode analysis of reference array element 5 was performed using the electromagnetic simulation software FEKO. The radiation mode amplitudes of reference array element 5 at 4.5 GHz are 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 reference array element 5 has 12 radiation modes, among which radiation modes 2 and 6 have much larger amplitudes than the other radiation modes, meaning that the re-radiation modes of reference array element 5 are modes 2 and 6. The current distribution of the main radiation modes 2 and 6 is then 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 color represents the current distribution intensity, with units of A / m. The calculation results show that the upper part represents the current distribution of the main radiation modes 2 and 6 on the radiation patch, with stronger distribution on the left and right sides of the radiation patch, and along... x Since the flow direction is directional, the radiated electric field of the reference array antenna is in the x-polarization direction, meaning the reference array antenna is x-polarized. Therefore, when performing the scattering mode analysis of reference array element 5 and the design of dual-function element 6, the incident x-polarized plane wave is a co-polarized plane wave, and the incident y-polarized plane wave is a cross-polarized plane wave.

[0071] Next, we will perform scattering mode analysis on reference array element 5, and then design the dual-function element 6:

[0072] Based on the broadband dual-polarization stealth requirements, the electromagnetic simulation software FEKO was used to perform x-polarization and y-polarization scattering mode analysis on reference array element 5 at key broadband frequencies (3 GHz, 4 GHz, 5 GHz, 6 GHz, 7 GHz, 8 GHz, and 9 GHz). This analysis included the amplitude and phase of its mode weighting coefficients, the amplitude and phase of the mode far field, and the mode current distribution. Based on the mode weighting coefficients and the mode far field, the mode amplitude of the scattering mode was calculated. The scattering modes were then sorted according to their amplitude, and important scattering modes were selected at key frequencies (3 GHz, 4 GHz, 5 GHz, 6 GHz, 7 GHz, 8 GHz, and 9 GHz). Represents the pitch angle of the incident wave. Represents the azimuth angle of the incident wave. Represents the pitch angle of the scattered wave. The azimuth angle of the scattered wave is represented. Figure 13 shows the calculated amplitude of the x-polarized scattering modes of reference array element 5 at key frequencies (3 GHz, 4 GHz, 5 GHz, 6 GHz, 7 GHz, 8 GHz, and 9 GHz). The x-axis represents the incident frequency in GHz, the y-axis represents the mode number, and the z-axis represents the mode amplitude in 10⁻⁶. -3 V / m. The calculation results show that scattering mode 1 is an important scattering mode in the low-frequency region (3 GHz-4 GHz), and scattering mode 6 is an important scattering mode in the high-frequency region (5 GHz-9 GHz). The current distribution calculations for x-polarized scattering mode 1 and scattering mode 6 are shown in Figure 14. Figure 15 As shown in the diagram, the red arrows in the current diagram indicate the direction of current flow, and the color represents the current intensity, with units of A / m.

[0073] Figure 16 shows the calculated amplitudes of the y-polarized scattering modes of reference array element 5 at key frequencies (3 GHz, 4 GHz, 5 GHz, 6 GHz, 7 GHz, 8 GHz, and 9 GHz). The x-axis represents the incident frequency in GHz, the y-axis represents the mode number, and the z-axis represents the mode amplitude in 10-1 GHz. -3 V / m. The calculation results show that scattering mode 1 is an important scattering mode in the low-frequency region (3 GHz-4 GHz), scattering mode 2 is an important scattering mode in the mid-frequency region (4 GHz-5 GHz), and scattering mode 3 is an important scattering mode in the high-frequency region (6 GHz-9 GHz). The current distribution calculations for y-polarized scattering mode 1, scattering mode 2, and scattering mode 3 are shown in Figure 17. Figure 18 and Figure 19As shown in the diagram, the red arrows in the current diagram indicate the direction of current flow, and the color represents the current distribution intensity, with units of A / m. Based on the current distribution of x-polarized scattering mode 1, scattering mode 6, and y-polarized scattering mode 1, scattering mode 2, and scattering mode 3 at various parts of the antenna, and comparing it with the mode current distribution of the important radiation modes 2 and 6 in step 1, select the current components that can be removed or cut off (truncate the y-polarized scattering mode current, retain the radiation mode current) to modify the antenna design. The following modification design is made:

[0074] Three straight slits are loaded along the x-axis on the first radiating patch 1 to introduce an effective phase difference with the x-polarized scattering field of the reference array unit 5 (reducing the x-polarized RCS through scattering cancellation) and to cut off 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 of the reference array unit 5 and the dual-function unit 6. The black solid line represents the calculated amplitude of scattering mode 1 of the reference array unit 5, the red dashed line represents the calculated amplitude of mode 1 of the dual-function unit 6, the blue dashed line represents the calculated amplitude of scattering mode 6 of the reference array unit 5, and the pink dashed line represents the calculated amplitude of scattering mode 6 of the dual-function unit 6. The results show that within the frequency band of 3 GHz-4 GHz, the amplitudes of x-polarized scattering mode 1 of the reference array unit 5 and the dual-function unit 6 are almost equal and are the dominant scattering mode. Within the frequency band of 4 GHz-9 GHz, the amplitudes of x-polarized scattering mode 6 of the reference array unit 5 and the dual-function unit 6 are almost equal and are the dominant scattering mode. Figure 21 shows the calculated phase difference between x-polarized scattering mode 1 and scattering mode 6 of reference array unit 5 and dual-function unit 6. The solid blue line represents the calculated phase difference of scattering mode 1, and the dashed red line represents the calculated phase difference of scattering mode 6. The results show that within 4 GHz-4.5 GHz, x-polarized scattering mode 1 of reference array unit 5 and dual-function unit 6 achieves an effective phase difference, and within 4.5 GHz-9 GHz, x-polarized scattering mode 6 of reference array unit 5 and dual-function unit 6 achieves an effective phase difference.

[0075] The cross-polarization RCS of reference array element 5 and dual-function element 6 were further calculated, and the results are shown in Figure 22. It can be seen that dual-function element 6 achieves cross-polarization RCS reduction within the range of 3 GHz to 9 GHz.

[0076] Figure 23 to Figure 27 The amplitudes of the y-polarized scattering modes of the reference array antenna at important frequencies (3 GHz, 4 GHz, 5 GHz, 6 GHz, 7 GHz, 8 GHz, and 9 GHz) were calculated, 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.

[0077] Figure 28 to Figure 30 The currents of y-polarized scattering modes 8, 24, and 28 of the reference array antenna were calculated. It can be seen that the currents of the 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.

[0078] Finally, the reference array element 5 and the dual-function element 6 are rationally arranged. In the x-polarization direction, the reference array element 5 and the cancellation element (utilizing the cancellation characteristic implemented by the dual-function element 6) are arranged into an array to achieve reduction of the same polarization RCS of the array antenna; in the y-polarization direction, a low-scattering array is used to achieve reduction of the cross-polarization RCS of the array antenna. By arranging the elements in the x and y directions as described above, a two-dimensional array antenna can be formed, thus obtaining a wideband dual-polarization low-scattering array antenna, the schematic diagram of which is shown in Figure 7.

[0079] Through the design of dual-functional unit 6 and collaborative array design, a wideband dual-polarization low-scattering array antenna was finally realized. The wideband x-polarization RCS calculation results for the low-scattering array antenna and the reference array antenna are shown in Figure 31, and the wideband y-polarization RCS calculation results 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 calculation results of the radiation pattern of the low-scattering array antenna at 4.5 GHz are shown in Figure 34. Figure 34 As shown.

[0080] Based on the above calculations, it can be seen that by selecting important scattering modes using mode amplitude, and by comparing the current distribution of important radiation modes with those of broadband x-polarized and y-polarized scattering modes, the location and size of the slot can be determined. By using slot loading to achieve x-polarized (co-polarized) scattering cancellation and y-polarized (cross-polarized) scattering mode suppression, broadband dual-polarized RCS reduction of the array antenna can be effectively achieved. Compared to the reference array antenna, the broadband dual-polarized low-scattering array antenna can achieve 100% reduction in x-polarized RCS bandwidth (including the antenna's operating frequency band) and 88% reduction in y-polarized RCS bandwidth (including the antenna's operating frequency band). The average reduction for co-polarized RCS is 8.0 dB, the average reduction for cross-polarized RCS is 7.6 dB, and the average in-band RCS reduction is 19 dB. Furthermore, the array antenna's radiation performance remains good. Compared to the reference array antenna, the broadband dual-polarized low-scattering array antenna maintains good transmission and radiation performance without significant changes.

[0081] In summary, this invention, based on characteristic mode analysis, separates radiation and scattering modes. While ensuring the radiation mode remains unaffected, it performs scattering analysis on typical frequencies within a dual-polarization broadband range. Important scattering modes in the x-polarization and y-polarization broadband are selected based on their amplitudes. Furthermore, the currents of the important radiation modes and the important scattering modes in the x-polarization and y-polarization broadband are compared. Through slot loading, both x-polarization scattering cancellation elements and y-polarization low-scattering elements are designed simultaneously. Finally, through the design of a reference array element 5 and scattering cancellation elements in the x-polarization (co-polarization) direction, and a low-scattering element array in the y-polarization (cross-polarization) direction, a broadband dual-polarization low-scattering array antenna design is achieved.

[0082] It should be noted that the above description is merely a preferred application example of the present invention and is not intended to limit the scope of protection of the present invention. All technical solutions employing equivalent substitutions or equivalent transformations are within the scope of protection of the present invention.

Claims

1. A low-scattering array antenna based on dual-functional units and cooperative array design, characterized in that, The reference array unit (5) and the dual-function unit (6) work together to form a 4×4 two-dimensional array antenna; Along the same polarization direction, there are four rows; among them, the first row and the fourth row each have 4 dual-function units (6), and the second row and the third row each have 4 reference array units (5). The reference array unit (5) and the dual-function unit (6) have the same transmission and radiation characteristics; their co-polarized scattering fields have the characteristics of equal amplitude and opposite phase, and the cross-polarized scattering field of the dual-function unit (6) has low scattering characteristics. The reference array unit (5) and the dual-function unit (6) each include a radiating patch, a dielectric layer and a metal ground plane placed from top to bottom; the dielectric layer is provided with an L-shaped feeding structure; the radius of the radiating patch is D, D=17~19mm; the side length of the dielectric layer is L1, L1=29~31mm and the thickness is H1, H1=6mm. The dual-function unit (6) has three parallel straight slits on its radiating patch, which are, from left to right, the first straight slit (11.1), the second straight slit (11.2), and the third straight slit (11.3). The geometric center of the second straight slit coincides with the geometric center of the radiating patch on which it is located. The distance from the geometric center of the first straight slit (11.1) and the third straight slit (11.3) to the geometric center of the radiating patch is Y1, where Y1 = 5~7mm. The width of the first straight slit (11.1), the second straight slit (11.2), and the third straight slit (11.3) is W2, where W2 = 1~2mm. The first straight slit (11.1), the second straight slit (11.2), and the third straight slit (11.3) all penetrate the radiating patch on which they are located in the same polarization direction. The L-shaped feed structure includes a metal coaxial cable (13.1) and a feed microstrip line (13.2); the feed microstrip line (13.2) is embedded in the dielectric layer and located directly below the radiating patch; the metal coaxial cable (13.1) is perpendicular to the radiating patch above it and its inner conductor tip is connected to the feed microstrip line (13.2), and the outer conductor of the metal coaxial cable (13.1) is connected to the metal ground plane; in the dual-function unit (6), the feed microstrip line (13.2) is parallel to the straight slot on the radiating patch; The metal floor is provided with a coupling slot, which is perpendicular to the feed microstrip line; in the dual-function unit (6), the coupling slot is perpendicular to the straight slot on the radiating patch.

2. The low-scattering array antenna based on dual-functional units and cooperative array design according to claim 1, characterized in that, The design process of the dual-functional unit (6) is as follows: Step 1: Analyze the radiation modes of the reference array unit (5); sort them according to the amplitude of the radiation modes, select the important radiation modes, and calculate their current distribution; based on the current distribution, select the strong current regions that need to be retained. Step 2: Perform scattering mode analysis on the reference array unit (5), select important scattering modes with the same polarization and cross polarization according to the amplitude of the scattering mode, and calculate their phase and current distribution respectively; Step 3: Based on the current distribution of important scattering modes under the two polarizations of the reference array unit (5), compare it with the current distribution of important radiation modes in Step 1, select the strong current part of the important scattering modes that can be removed or cut off by cross-polarization, and introduce a straight gap 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 modes of the designed array unit in the wide bandwidth, and compare and analyze them with the amplitude and phase of the important scattering modes 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 is not within the range of 143° to 217° within the wide bandwidth, or if the scattering amplitudes of the important scattering modes of the two units differ significantly, then Steps 2, 3, and 4 are repeated for the designed array unit. The scattering mode analysis is continued at frequencies where the phase difference and amplitude requirements are not met. The designed array unit is then redesigned and iterated repeatedly until the effective phase difference of the important scattering modes of the reference array unit and the latest designed array unit is within the range of 143° to 217° within the wide bandwidth, and the scattering amplitudes of the important scattering modes of the two units are equal. This yields a unit with co-polarization scattering cancellation. The cross-polarization RCS of the unit with co-polarization scattering cancellation within the wide bandwidth is calculated and compared with the cross-polarization RCS of the reference array unit. It is confirmed that the wide bandwidth cross-polarization RCS of the latest designed array unit has been effectively reduced. Thus, a dual-function unit (6) with co-polarization scattering cancellation characteristics and cross-polarization low scattering characteristics has been designed.

3. A low-scattering array antenna based on dual-functional units and cooperative array design according to claim 2, characterized in that, The important scattering modes of the reference array unit (5) and the same polarization scattering cancellation unit have the characteristics of equal scattering amplitude and opposite scattering phase in the same polarization direction.

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