Low-scattering conformal microstrip array antenna based on characteristic mode analysis
By loading parasitic patches onto a conformal microstrip array antenna, and utilizing characteristic mode analysis and the principle of scattering mode current cancellation, the problem of reducing the radar cross section of the conformal array antenna was solved, and the radar cross section was effectively reduced.
Patent Information
- Application Number
- CN202422929524.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-11-14
- Estimated Expiration
- 2034-11-29
AI Technical Summary
Existing technologies struggle to effectively reduce the radar cross section of conformal array antennas while ensuring antenna radiation performance. In particular, traditional methods such as loading radar absorbing materials and scattering cancellation techniques are ineffective in conformal array designs.
A low-scattering conformal microstrip array antenna design based on characteristic mode analysis is adopted. By loading parasitic patches onto a traditional microstrip patch antenna, the radar cross section is reduced by utilizing the cancellation principle of scattering mode currents.
Without affecting radiation performance, the radar cross section of the conformal array antenna was significantly reduced, achieving radar cross section reduction both in and out of the C-band.
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Figure CN223552691U_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of antenna technology and relates to a low-scattering conformal microstrip array antenna based on characteristic mode analysis, which can be used in stealth radar detection platforms. Background Technology
[0002] With the rapid development of radar cross section (RCS) reduction technology, achieving low radar cross section (RCS) characteristics in the information field is of paramount importance. If the effective scattering cross section reflected back when an enemy radar illuminates a friendly object is small enough, the enemy's detection system will be unable to determine the object's exact location, thus achieving stealth. Antennas, as indispensable equipment in radar and communication systems, significantly contribute to the overall RCS of the platform on which they are mounted. Furthermore, conformal antennas broaden their application range and offer many advantages over traditional antennas. First, conformal antennas can increase the effective aperture of the antenna array within a limited carrier area, greatly saving installation space and improving gain within that space. Second, conformal antennas not only reduce the impact on planar aerodynamics but also enhance stealth performance by reducing the antenna's radar cross section. Therefore, solving the design problem of low-scattering conformal array antennas is crucial to reducing the antenna's contribution to the overall RCS of the communication platform. Since an antenna is both a radiator and a scatterer, reducing its RCS while ensuring its radiation characteristics remain unaffected is a challenge. In the past, scholars have proposed many technologies and novel structures to reduce the antenna's RCS. For example, using new materials technology, by loading radar absorbing material RAM and frequency selective surface (FSS) with band-stop characteristics onto the antenna system, the RCS outside the antenna's operating frequency band can be significantly reduced. However, loading RAM will decrease the antenna's radiation efficiency, and loading FSS to reduce the in-band RCS is very difficult. Using novel structural technologies, such as fractal structures and biomimetic structures, can reduce the antenna RCS by optimizing the design of suitable structures. However, this method relies heavily on the antenna designer's experience and has low design efficiency. Using scattering cancellation technology, the normally incident electromagnetic wave is reflected to other angular domains by periodically arranging two structures with a 180° phase difference, thereby reducing the RCS in the normal incident direction. However, this method cannot obtain the unit reflection phase as it does in planar arrays when dealing with conformal arrays, making it difficult to apply in the design of low-scattering conformal arrays.
[0003] Characteristic mode theory, as a novel technical approach, offers significant advantages in the analysis and design of antenna radiation and scattering. By utilizing characteristic mode theory and studying antenna radiation and scattering modes, it is possible to control antenna scattering while maintaining radiation characteristics, thereby reducing the antenna's RCS (Radio Cross Section). Utility Model Content
[0004] The purpose of this invention is to address the shortcomings of existing technologies in current applications by proposing a low-scattering conformal microstrip array antenna based on characteristic mode analysis. After conformally designing a traditional microstrip patch antenna, simulations of its radiation and scattering modes are performed. Based on the simulation results, a parasitic patch is added to the traditional microstrip patch antenna. Without affecting radiation performance, the scattering current of the designed element cancels out the scattering current of the traditional microstrip patch element, thus reducing the radar cross-section of the conformal array. Simulation results show that, while maintaining antenna radiation performance, the radar cross-section of the conformal microstrip array antenna is reduced both in-band and out-of-band in the C-band.
[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows:
[0006] A low-scattering conformal microstrip array antenna based on characteristic mode analysis includes a first metal patch 1, a second metal patch 2, a first dielectric substrate 4, a microstrip feed line 5, a second dielectric substrate 6, a metal ground plane 7, and a coaxial-fed inner core 8.
[0007] The first dielectric substrate 4, the second dielectric substrate 6, and the metal ground plane 7 are stacked sequentially from top to bottom; the first metal patch 1 and the second metal patch 2 are located on the upper surface of the first dielectric substrate 4; the microstrip feed line 5 is located on the upper surface of the second dielectric substrate 6; the coaxial feed core 8 penetrates the metal ground plane 7 and the second dielectric substrate 6 and is connected to the microstrip feed line 5.
[0008] The second metal patch includes a main metal patch and two parasitic metal patches 3. The parasitic metal patches are U-shaped and are located on both sides of the main metal patch, with the openings of the two parasitic metal patches facing each other.
[0009] Both the first dielectric substrate and the second dielectric substrate are arc plates; N first metal patches are arranged along the axial direction of the first dielectric substrate to form N first metal patch groups; N second metal patches are arranged along the axial direction of the first dielectric substrate to form N second metal patch groups, where N≥2 and is a positive integer; the first metal patch groups and the second metal patch groups are arranged at intervals along the circumference of the first dielectric substrate to form a scattering cancellation array, and the second dielectric substrate 6, the microstrip feed line 5 and the metal ground plane 7 serve as the feed layer of the scattering cancellation array.
[0010] Furthermore, the geometric centers of the first dielectric substrate 4, the second dielectric substrate 6, and the metal ground plane 7 are projected to coincide on the conformal cylindrical surface.
[0011] Furthermore, the microstrip feed line 5 and the metal patch are in one-to-one correspondence, and the projection of the microstrip feed line on the upper surface of the first dielectric substrate coincides with the corresponding metal patch portion.
[0012] Furthermore, the projection of the microstrip feed line onto the upper surface of the first dielectric substrate is parallel to the axial direction of the first dielectric substrate.
[0013] Furthermore, the microstrip feed line 5 and the coaxial feed core 8 correspond one-to-one; the coaxial feed core 8 is connected to the end of the corresponding microstrip feed line that is offset from the metal patch.
[0014] Furthermore, the two parasitic metal patches surround their corresponding main metal patches; there is no contact between the two parasitic metal patches or between the parasitic metal patches and the main metal patches.
[0015] Furthermore, the opening formed by the gap between the two parasitic metal patches is directly opposite the first metal patch on its side.
[0016] Compared with the prior art, the present invention has the following advantages:
[0017] This invention controls the scattering mode current by loading parasitic metal patches onto metal patches, thereby achieving a reduction in the radar cross-section of the low-scattering conformal microstrip array antenna both inside and outside the C-band.
[0018] This invention employs a two-layer dielectric substrate structure, placing a metal patch on the upper surface of the first dielectric substrate, a microstrip feed line on the upper surface of the second dielectric substrate, and a metal ground plane on the lower surface of the second dielectric substrate. This simplifies the structure of each dielectric substrate layer, and the structures of the first and second metal patches are similar, making the overall process easier. Attached Figure Description
[0019] Figure 1 This is a schematic diagram of the overall structure of this utility model;
[0020] Figure 2 yes Figure 1 Side view;
[0021] Figure 3 This is a schematic diagram of the first metal patch unit structure in this utility model;
[0022] Figure 4 yes Figure 3 Top view;
[0023] Figure 5 This is a schematic diagram of the structure of the second metal patch unit in this utility model;
[0024] Figure 6 hour Figure 5 Top view;
[0025] Figure 7 This utility model relates to a low-scattering conformal microstrip array antenna element in the 4.5~6.5GHz frequency band. 11 Simulation result diagram;
[0026] Figure 8 The simulation results of the radiation pattern of the low-scattering conformal microstrip array antenna of this utility model at 5.5 GHz are shown.
[0027] Figure 9 This is a simulation result of the single-station RCS of the low-scattering conformal microstrip array antenna of this utility model under vertical illumination by x-polarized incident waves in the 4~8GHz frequency band;
[0028] Figure 10 This is a simulation result of the single-station RCS of the low-scattering conformal microstrip array antenna of this utility model under vertical illumination by y-polarized incident waves in the 4~8GHz frequency band. Detailed Implementation
[0029] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.
[0030] A low-scattering conformal microstrip array antenna based on characteristic mode analysis includes a first metal patch, a second metal patch, a parasitic metal patch, a first dielectric substrate, a microstrip feed line, a second dielectric substrate, a metal ground plane, and a coaxial feed core. The first and second metal patches are located on the upper surface of the first dielectric substrate; the microstrip feed line is located on the upper surface of the second dielectric substrate; the metal ground plane is located on the lower surface of the second dielectric substrate; and the coaxial feed core penetrates the second dielectric substrate and is connected to the microstrip feed line.
[0031] The upper surface of the first dielectric substrate is printed with M*N alternating first and second metal patches, wherein M and N are greater than or equal to 2, and parasitic metal patches are added to the surface of the second metal patch; the coaxial feed core is connected to the microstrip feed line through the second dielectric substrate;
[0032] The first and second metal patches, arranged alternately on the upper surface of the first dielectric substrate, constitute a scattering cancellation array. The second dielectric substrate, the microstrip feed line, and the metal ground plane serve as the feed layer for the scattering cancellation array.
[0033] The geometric centers of the first dielectric substrate, the second dielectric substrate, and the metal ground plane coincide on the surface of the conformal cylinder.
[0034] The spacing between the alternating arrangement of the first and second metal patches is d, where d is 27 mm.
[0035] The length and width of the first metal patch are both a1, and the value of a1 ranges from 11.8 to 12.2 mm.
[0036] The second metal patch has a length of a1 and a width of a2, with a value ranging from 11.6 to 11.8 mm.
[0037] The width of the parasitic metal patch is pw1, and the value of pw1 ranges from 0.9 to 1.1 mm; the length of the long branch is p1, and the value of p1 ranges from 15.8 to 16.2 mm; the length of the short branch is p2, and the value of p2 ranges from 3.2 to 3.4 mm.
[0038] The offset between the geometric center of the second metal patch and the geometric center of the parasitic metal patch in the normal projection of the conformal cylinder is d1, and the value of d1 ranges from 7.3 to 7.4 mm.
[0039] The microstrip feed line has a length of L1 and a width of W1, with L1 and W1 ranging from 8.1 to 8.2 mm and 1.2 to 1.3 mm, respectively.
[0040] The offset of the geometric center of the microstrip feed line relative to the geometric center of the alternating first or second metal patch in the normal projection of the conformal cylinder is d2, and the value of d2 ranges from 4.5 to 4.6 mm.
[0041] The offset of the geometric center of the coaxial power supply core relative to the geometric center of the alternating first or second metal patch in the normal projection of the conformal cylinder is d3, and the value of d3 ranges from 7.8 to 8.2 mm.
[0042] The thickness of the first dielectric substrate is h1, and the value of h1 ranges from 3 to 3.2 mm; the thickness of the second dielectric substrate is h2, and the value of h2 ranges from 1.8 to 2.2 mm.
[0043] The present invention will be further described below with reference to the embodiments, which are intended only to better understand the content of the present invention. Therefore, the specific embodiments given do not limit the protection scope of the present invention. In addition, only the parts related to the present invention are shown in the accompanying drawings, not the entire structure.
[0044] Reference Figure 1 and Figure 2 The present invention includes a first metal patch 1, a second metal patch 2, a parasitic metal patch 3, a first dielectric substrate 4, a microstrip feed line 5, a second dielectric substrate 6, a metal ground plane 7, and a coaxial feed core 8; the low-scattering conformal microstrip array antenna is conformal to a cylinder with a radius of R, where R is 100mm, and the central angle of the conformal region of the array antenna on the cylinder is 31°.
[0045] Reference Figure 1 The first dielectric substrate 4 has M*N periodically alternating first metal patches 1, second metal patches 2 and parasitic metal patches 3 printed on its upper surface, wherein M and N are greater than or equal to 2.
[0046] Reference Figure 3 and Figure 4The first metal patch 1 has a length and width of a1, with a value ranging from 11.8 to 12.2 mm; the first dielectric substrate 4 has a thickness of h1, with a value ranging from 3 to 3.2 mm; the second dielectric substrate 6 has a thickness of h2, with a value ranging from 1.8 to 2.2 mm; the first metal patch 1 is located on the upper surface of the first dielectric substrate; the microstrip feed line 5 is located on the upper surface of the second dielectric substrate 6; the radius of the coaxial feed core 8 is W1, with a value ranging from 1.2 to 1.4 mm, and its offset from the normal projection center of the first metal patch 1 is d3, with a value ranging from 7.8 to 8.2 mm. In this example, but not limited to, a1 = 12 mm, h1 = 3.08 mm, h2 = 2 mm, W1 = 1.3 mm, and d3 = 8 mm are used.
[0047] Reference Figure 4 The offset between the geometric center of the coaxially fed inner core 8 and the normal projection of the geometric center of the first metal patch 1 is d2, and the value of d2 ranges from 4.5 to 4.6 mm. In this example, d2 is taken as, but is not limited to, 4.575 mm.
[0048] Reference Figure 5 and Figure 6 The second metal patch 2 has a length of a1 and a width of a2, with a value ranging from 11.6 to 11.8 mm; the parasitic metal patch has a width of pw1, with a value ranging from 0.9 to 1.1 mm; the long branch has a length of p1, with a value ranging from 15.8 to 16.2 mm; and the short branch has a length of p2, with a value ranging from 3.2 to 3.4 mm. In this example, but not limited to a2 = 11.7 mm, pw1 = 1 mm, p1 = 16 mm, and p2 = 3.3 mm, the values are as follows:
[0049] Reference Figure 6 The offset between the geometric center of the second metal patch 2 and the geometric center of the parasitic metal patch 3 projected onto the conformal cylinder normal is d1, and the value of d1 ranges from 7.3 to 7.4 mm. In this example, d1 is taken as, but is not limited to, 7.35 mm.
[0050] The technical effects of this invention can be further illustrated by the following simulation experiments:
[0051] 1. Simulation software:
[0052] Commercial simulation software HFSS_19.0, commercial simulation software Feko2021
[0053] 2. Simulation content:
[0054] Simulation 1: Using simulation software, the S-band of the aforementioned low-scattering conformal microstrip array antenna in the 4.5–6.5 GHz frequency band was analyzed. 11 The simulation was performed, and the results are as follows: Figure 7 As shown.
[0055] from Figure 7 It can be seen that the S of the array antenna in the 5.08~5.85GHz frequency band... 11 Less than -10dB. This indicates that the low-scattering conformal microstrip array antenna of this embodiment has good return loss characteristics.
[0056] Simulation 2: The gain of the low-scattering conformal microstrip array antenna of the above embodiment at a frequency of 5.5 GHz was simulated using simulation software. The results are as follows: Figure 8 As shown.
[0057] from Figure 8 It can be seen that the gain of the conformal array antenna is greater than 16 dBi near the 5.5 GHz frequency, indicating that the present invention has good radiation characteristics near this resonant frequency.
[0058] Simulation 3: The monostatic RCS of the low-scattering conformal microstrip array antenna of the above embodiment under vertical illumination by x-polarized incident waves in the 4-8 GHz frequency band was simulated using simulation software. The results are as follows: Figure 9 As shown.
[0059] from Figure 9 It can be seen that, in the 4~8GHz frequency band, compared with the reference metal plate, the low-scattering conformal microstrip array antenna of this utility model embodiment has a lower radar cross section, and the radar cross section reduction peak is 21.8dB; in this frequency range, under x-polarized incident waves, the low-scattering conformal microstrip array antenna of this utility model embodiment has a good radar cross section reduction effect.
[0060] Simulation 4: The monostatic RCS of the low-scattering conformal microstrip array antenna of the above embodiment under vertical illumination by y-polarized incident waves in the 4-8 GHz frequency band was simulated using simulation software. The results are as follows: Figure 10 As shown.
[0061] from Figure 10 It can be seen that, in the 4~8GHz frequency band, compared with the reference metal plate, the radar cross section of the low-scattering conformal microstrip array antenna of this utility model embodiment is lower, and the radar cross section reduction peak is 11.5dB; under y-polarized incident waves in this frequency range, the low-scattering conformal microstrip array antenna of this utility model embodiment has a good radar cross section reduction effect.
[0062] In summary, this invention achieves a good reduction in radar cross section in the C-band.
[0063] The above description and embodiments are merely preferred examples of this utility model and do not constitute any limitation on this utility model. Obviously, those skilled in the art, after understanding the content and design principles of this utility model, may make various modifications and changes in form and detail based on the principles and structure of this utility model. However, these modifications and changes based on the concept of this utility model are still within the protection scope of the claims of this utility model.
[0064] This utility model is not limited to the above embodiments. Without departing from the concept of this utility model, it may include more other equivalent embodiments, and the scope of this utility model is determined by the scope of the appended claims.
Claims
1. A low-scattering conformal microstrip array antenna based on characteristic mode analysis, characterized in that, It includes a first metal patch (1), a second metal patch (2), a first dielectric substrate (4), a microstrip feed line (5), a second dielectric substrate (6), a metal ground plane (7), and a coaxial feed core (8). The first dielectric substrate (4), the second dielectric substrate (6), and the metal ground plane (7) are stacked sequentially from top to bottom; the first metal patch (1) and the second metal patch (2) are located on the upper surface of the first dielectric substrate (4); the microstrip feed line (5) is located on the upper surface of the second dielectric substrate (6); the coaxial feed core (8) penetrates the metal ground plane (7) and the second dielectric substrate (6) and is connected to the microstrip feed line (5); The second metal patch includes a main metal patch and two parasitic metal patches (3). The parasitic metal patches are U-shaped structures, located on both sides of the main metal patch and with their openings facing each other. Both the first dielectric substrate and the second dielectric substrate are arc plates; N first metal patches are arranged along the axial direction of the first dielectric substrate to form N first metal patch groups; N second metal patches are arranged along the axial direction of the first dielectric substrate to form N second metal patch groups, where N ≥ 2 and is a positive integer; the first metal patch groups and the second metal patch groups are arranged at intervals along the circumference of the first dielectric substrate to form a scattering cancellation array, and the second dielectric substrate (6), the microstrip feed line (5) and the metal ground plane (7) serve as the feed layer of the scattering cancellation array.
2. The low-scattering conformal microstrip array antenna based on characteristic mode analysis according to claim 1, characterized in that, The geometric centers of the first dielectric substrate (4), the second dielectric substrate (6), and the metal ground plane (7) coincide on the conformal cylindrical surface.
3. The low-scattering conformal microstrip array antenna based on characteristic mode analysis according to claim 1, characterized in that, The microstrip feed line (5) and the metal patch are in one-to-one correspondence, and the projection of the microstrip feed line on the upper surface of the first dielectric substrate coincides with the corresponding metal patch portion.
4. The low-scattering conformal microstrip array antenna based on characteristic mode analysis according to claim 3, characterized in that, The projection of the microstrip feed line onto the upper surface of the first dielectric substrate is parallel to the axial direction of the first dielectric substrate.
5. The low-scattering conformal microstrip array antenna based on characteristic mode analysis according to claim 1, characterized in that, The microstrip feed line (5) and the coaxial feed core (8) correspond one-to-one; the coaxial feed core (8) is connected to the end of the corresponding microstrip feed line that is offset from the metal patch.
6. The low-scattering conformal microstrip array antenna based on characteristic mode analysis according to claim 1, characterized in that, The two parasitic metal patches surround their corresponding main metal patches; there is no contact between the two parasitic metal patches or between the parasitic metal patches and the main metal patch.
7. A low-scattering conformal microstrip array antenna based on characteristic mode analysis according to claim 6, characterized in that, The opening formed by the gap between the two parasitic metal patches is directly opposite the first metal patch on its side.