Radiation and scattering integrated microstrip antenna based on artificial magnetic conductor

Abstract

The invention discloses a radiation and scattering integrated microstrip antenna based on an artificial magnetic conductor, and belongs to the technical field of microwave antennas. The antenna comprises a microstrip antenna, four first artificial magnetic conductor (AMC) arrays and four second AMC arrays, the microstrip antenna is located in the center, and the four first AMC arrays and the four second AMC arrays are distributed on the periphery in a chessboard structure mode. Compared with the original microstrip antenna, the radiation-scattering integrated microstrip antenna based on the artificial magnetic conductor has the advantages that the antenna bandwidth is basically unchanged, the gain of the antenna is improved, and the radiation performance of the original radiation antenna is not influenced; the RCS of the antenna is effectively reduced in a broadband, the overall profile is low, and the antenna can be used in the fields of modern wireless communication systems, electronic reconnaissance and confrontation and the like.

Description

Technical Field

[0001] This invention belongs to the field of microwave antenna technology, specifically relating to a radiation and scattering integrated microstrip antenna based on an artificial magnetic conductor. Background Technology

[0002] Radar systems achieve long-range detection by capturing the electromagnetic echoes reflected from targets, and the core of their stealth technology lies in effectively suppressing the intensity of the echo signal. Radar cross section (RCS) is a key physical parameter measuring the strength of a target's scattering capability. Microstrip antennas, due to their advantages such as low profile, low manufacturing cost, ease of fabrication, and conformal integration with the carrier surface, are widely used in modern military equipment such as aircraft and missiles. With the increasing maturity of low-observable shape design and the application of high-performance radar-absorbing materials, the RCS of the aircraft itself has been reduced to a low level, making the antenna system a major contributor to the overall electromagnetic scattering of the aircraft. Researching RCS reduction techniques targeting the antenna itself has become an important direction for improving the overall stealth performance of the platform. However, antennas have both radiation and scattering characteristics. Traditional RCS suppression methods, such as coating with absorbing materials or using shape shielding, often come at the cost of sacrificing the antenna's radiation efficiency, radiation pattern characteristics, or operating bandwidth. Therefore, the core challenge facing current stealth antenna design is: how to effectively reduce its in-band and out-of-band RCS while essentially maintaining or even optimizing the antenna's radiation performance. To resolve this contradiction, it is imperative to develop new methods and structures that can synergistically optimize radiation and scattering performance through continuous technological innovation, thereby promoting the development of high-performance, truly "stealthy" next-generation antenna systems.

[0003] Under the same radar illumination conditions, the reflection characteristics of artificial magnetic conductors (AMC) and ideal electrical conductors (PEC) are complementary: AMC produces reflected waves with a phase of 0°, while PEC produces reflected waves with a phase of 180°, and both have a reflection amplitude of 1. Based on this characteristic, by arranging the two materials alternately in a checkerboard pattern, the opposite phase of their reflected waves can be used to cancel out the far-field scattering energy, thereby reducing the target's RCS.

[0004] With the development of AMC design theory, researchers have been able to precisely control the reflection phase of individual elements. Current techniques are no longer limited to combinations of PEC / AMC; instead, AMC elements with a 180° phase difference can be arranged in a checkerboard pattern. This design creates a phase cancellation effect in the normal direction, functioning similarly to absorbing materials, but offering superior overall performance in reducing antenna RCS: maintaining antenna structural integrity while avoiding the negative impact of traditional absorbing materials on radiation performance. However, conventional AMC design processes require extensive simulations to calculate the phase difference, resulting in uncertainties and complexity.

[0005] The existing technology "A Low RCS microstrip antenna based on chessboard AMC structure in Ku-band" discloses a microstrip antenna with RCS reduction in the Ku-band based on artificial magnetic conductors. However, its reduced bandwidth is relatively narrow, and the specific optimization design process is not described. The existing technology "Research on Low Radar Cross Section Antenna Based on Metasurface" lacks specific explanation of its design optimization process, achieving a reduction of more than 5dB in the 8.6GHz-18.2GHz range, which is a relatively small reduction value. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a radiation and scattering integrated microstrip antenna based on artificial magnetic conductors. It involves a specific unit optimization design process, and the bandwidth and gain of the antenna are not degraded. It has a reduction value of more than 8dB in 8.7-19.6GHz, and the average RCS reduction value in 8GHz-18GHz reaches 14.3dB.

[0007] The technical problem addressed by this invention is solved as follows:

[0008] A radiation-scattering integrated microstrip antenna based on artificial magnetic conductors includes a microstrip antenna, four first artificial magnetic conductor (AMC) arrays, and four second AMC arrays. The microstrip antenna is located at the center, and the four first AMC arrays and four second AMC arrays are distributed around it in a checkerboard pattern.

[0009] The microstrip antenna includes a radiating microstrip patch, an antenna dielectric substrate, a ground plane, and a feeding structure. The radiating microstrip patch is located at the center of the upper surface of the antenna dielectric substrate, and the ground plane is located on the lower surface of the antenna dielectric substrate. The feeding structure adopts a coaxial feeding method, with the outer conductor of the coaxial line connected to the ground plane and the inner conductor of the coaxial line passing through the antenna dielectric substrate and connected to the radiating microstrip patch.

[0010] The first AMC array consists of 4×4 tightly bonded first AMC units. The first AMC unit includes a first dielectric substrate, a first metal pattern printed on the upper surface of the first dielectric substrate, and a first metal ground located on the lower surface of the first dielectric substrate. The first metal pattern has a 180° rotationally symmetrical structure and includes four circular patches. The four circular patches are divided into two groups with different radii and are located on the ±45° diagonal of the upper surface of the square first dielectric substrate.

[0011] The second AMC array consists of 4×4 tightly bonded second AMC units. The second AMC unit includes a second dielectric substrate, a second metal pattern printed on the upper surface of the second dielectric substrate, and a second metal ground located on the lower surface of the second dielectric substrate. The first metal pattern has a 90° rotationally symmetrical structure and is a cross-shaped ring patch structure.

[0012] The antenna dielectric substrate, the first dielectric substrate, and the second dielectric substrate constitute a complete dielectric substrate, and the ground plane, the first metal ground, and the second metal ground constitute a complete metal ground.

[0013] Furthermore, the structural dimensions of the two AMC units were jointly simulated using the full-wave electromagnetic simulation software CST, Visual Basic for Applications (VBA), and a genetic algorithm. The process is as follows:

[0014] Step 1: Using the built-in VBA scripting environment of CST, create a function library in Matlab to control CST operations, and then call the function in Matlab to realize the parametric modeling, automated simulation and phase result export of two AMC units;

[0015] Step 2: Using a genetic algorithm, optimize the structural dimensions of the two AMC units so that the phase difference between the two AMC units in the fitness function is greater than 143° and less than 217° in the range of 9GHz-17GHz, and can be satisfied under both TE and TM polarization;

[0016] Step 3: Save the optimized structural dimension parameters of the two AMC units and perform simulation verification.

[0017] Furthermore, both types of AMC elements are periodic structures, and the Floquet mode is used for solving in CST.

[0018] Furthermore, the period P of both AMC units is ≤ λ / (1+sin(θ)), where θ is the incident angle of the electromagnetic wave and λ is the wavelength.

[0019] More specifically, both AMC units have a period of 5mm, and the smaller period structure can prolong the generation of high-frequency grid lobes.

[0020] More specifically, the reflection amplitude of the two AMC units is above 0.82 when incident at different angles from 0 to 40°, indicating good reflection amplitude.

[0021] Furthermore, the antenna dielectric substrate, the first dielectric substrate, and the second dielectric substrate are all made of FR-4 (lossy), which has a relative permittivity of 4.3 and a loss tangent of 0.025.

[0022] The beneficial effects of this invention are:

[0023] The radiation-scattering integrated microstrip antenna based on artificial magnetic conductors described in this invention, within the frequency range of 9GHz-17GHz, exhibits a phase difference optimized by a genetic algorithm. Under different incident angles of 0-30°, the TE / TM polarization generally meets the requirements of being greater than 143° and less than 217°. Theoretically, this can achieve an RCS reduction of more than 10dB within this frequency range, demonstrating a wide bandwidth effect. Furthermore, by arranging two types of AMC units in a 4*4 array and then using a checkerboard pattern around the rectangular microstrip patch unit, simulation results show that, with unchanged bandwidth and improved gain, the designed antenna achieves an RCS reduction of more than 8dB compared to the original antenna in the 8.7GHz-19.6GHz range. Moreover, since the height of the AMC dielectric substrate is the same as that of the antenna dielectric substrate, the overall profile of the designed antenna is low, making it suitable for applications in modern wireless communication systems and other fields. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the antenna described in this invention from a top view.

[0025] Figure 2 This is a schematic diagram of the original microstrip antenna described in this invention from a top view.

[0026] Figure 3 This is a front view schematic diagram of the antenna described in this invention;

[0027] Figure 4 This is a structural diagram of the AMC1 described in this invention;

[0028] Figure 5 This is a structural diagram of the AMC2 described in this invention;

[0029] Figure 6 Reflection curves for two types of AMC units

[0030] Figure 7 Phase diagrams for the initial simulation of two types of AMC units;

[0031] Figure 8 The image shows the phase difference curves under different incident angles in TE polarization after optimization using a genetic algorithm.

[0032] Figure 9 The image shows the phase difference curves under different incident angles in TM polarization after optimization using a genetic algorithm.

[0033] Figure 10 The S of the antenna described in this embodiment and the original microstrip antenna 11 Comparison chart;

[0034] Figure 11 This is a gain comparison diagram of the antenna described in this embodiment and the original microstrip antenna in the H-plane;

[0035] Figure 12 This is a gain comparison diagram of the antenna described in this embodiment and the original microstrip antenna in the E-plane;

[0036] Figure 13 This is a comparison diagram of the monostatic RCS of the antenna described in this embodiment and the original microstrip antenna;

[0037] Figure 14 This is a graph showing the reduction in RCS of the antenna described in this embodiment and the original microstrip antenna at a single station. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] This embodiment provides a radiation-scattering integrated microstrip antenna based on an artificial magnetic conductor, such as... Figure 1 As shown, it includes a microstrip antenna, four first artificial magnetic conductor (AMC) arrays, and four second AMC arrays; the microstrip antenna is located in the center, and the four first AMC arrays and four second AMC arrays are distributed around it in a checkerboard pattern.

[0041] The microstrip antenna includes a radiating microstrip patch, an antenna dielectric substrate, a ground plane, and a feeding structure. The radiating microstrip patch is located at the center of the upper surface of the antenna dielectric substrate, and the ground plane is located on the lower surface of the antenna dielectric substrate. The feeding structure adopts a coaxial feeding method, with the outer conductor of the coaxial line connected to the ground plane and the inner conductor of the coaxial line passing through the antenna dielectric substrate and connected to the radiating microstrip patch.

[0042] The first AMC array consists of 4×4 tightly bonded first AMC units. The first AMC unit includes a first dielectric substrate, a first metal pattern printed on the upper surface of the first dielectric substrate, and a first metal ground located on the lower surface of the first dielectric substrate. The first metal pattern has a 180° rotationally symmetrical structure and includes four circular patches. The four circular patches are divided into two groups with different radii and are located on the ±45° diagonal of the upper surface of the square first dielectric substrate.

[0043] The second AMC array consists of 4×4 tightly bonded second AMC units. The second AMC unit includes a second dielectric substrate, a second metal pattern printed on the upper surface of the second dielectric substrate, and a second metal ground located on the lower surface of the second dielectric substrate. The first metal pattern has a 90° rotationally symmetrical structure and is a cross-shaped ring patch structure.

[0044] The period P of both AMC units is ≤ λ / (1+sin(θ)), where θ is the incident angle of the electromagnetic wave and λ is the wavelength. In this embodiment, the period of both AMC units is 5mm. The smaller period structure can prolong the generation of high-frequency grating lobes.

[0045] The antenna dielectric substrate, the first dielectric substrate, and the second dielectric substrate constitute a complete dielectric substrate, and the ground plane, the first metal ground, and the second metal ground constitute a complete metal ground plane. The antenna dielectric substrate, the first dielectric substrate, and the second dielectric substrate are all made of FR-4 (lossy), with a relative permittivity of 4.3 and a loss tangent of 0.025.

[0046] In this embodiment, the structural dimensions of the two AMC units are jointly simulated using the full-wave electromagnetic simulation software CST, Visual Basic for Applications (VBA), and a genetic algorithm. The process is as follows:

[0047] Step 1: Using the built-in VBA scripting environment of CST, establish a function library in Matlab to control CST operations, and then call the function in Matlab to realize the parametric modeling, automated simulation and phase result export of the two AMC elements; both AMC elements are periodic structures, and the Floquet mode is used for solving in CST.

[0048] Step 2: Using a genetic algorithm, optimize the structural dimensions of the two AMC units so that the phase difference between the two AMC units in the fitness function is greater than 143° and less than 217° in the range of 9GHz-17GHz, and can be satisfied under both TE and TM polarization;

[0049] Step 3: Save the optimized structural dimension parameters of the two AMC units and perform simulation verification.

[0050] The original microstrip antenna structure diagram is as follows: Figure 2 As shown in the diagram, the coaxial power supply structure is as follows: Figure 3 As shown, the dielectric between the inner and outer conductors is PTFE (lossy).

[0051] The structural diagrams of the first AMC unit and the second AMC unit are shown below. Figure 4 and Figure 5As shown, this was obtained through joint modeling using Matlab and CST. In this embodiment, the reflection radiance of the two AMC units is above 0.82 when incident at different angles from 0 to 30°, with the reflection value of AMC1 remaining above 0.91. Figure 6 As shown, the reflection amplitude under normal incidence is given, which has a good effect.

[0052] like Figure 7 As shown, the initial reflection phase of the two AMC units under normal incidence was simulated using Matlab and CST. It can be seen that the reflection phase of AMC1 is basically linear, with a zero-degree reflection phase at 12.69 GHz, while the zero-degree reflection phase of AMC2 is at 12.70 GHz. The combination of the two is intended to provide a wider reflection phase bandwidth.

[0053] The absolute value of the phase difference between two units is used as the fitness function for genetic algorithm optimization. Inequality optimization is performed, where the phase difference is greater than 143° and less than 217°. The optimization results of TE polarization under different incident angles are as follows: Figure 8 As shown, the optimization results of TM polarization under different incident angles are as follows: Figure 9 As shown, it basically satisfies the condition of being greater than 143° and less than 217° in the 9GHz-17GHz range.

[0054] In this embodiment, the structural parameters of the first AMC unit are r1=1.033mm and r2=0.340mm, and the structural parameters of the second AMC unit are b=4.837mm, a=0.163mm and w=0.410mm.

[0055] In this embodiment, the optimized AMC elements are first arranged into a 4*4 array, and then placed around the antenna. The radiation performance of the antenna is then simulated using the time-domain solver in CST, and compared with the S-axis of the original microstrip antenna. 11 like Figure 10 As shown, the gains of the antenna in the H-plane and E-plane are respectively as follows: Figure 11 and Figure 12 As shown, the resonant point decreases from 9.34 GHz to 9.27 GHz with minimal impact on bandwidth, resulting in an improved antenna gain. Comparing the antenna's RCS, from... Figure 13 and Figure 14 As shown, the antenna described in this embodiment achieves maximum reduction at 13.7GHz, with an RCS reduction of 43.39dB. It achieves a reduction of more than 8dB in the range of 8.7GHz-19.6GHz, and the average RCS reduction value reaches 14.3dB in the range of 8GHz-18GHz.

[0056] In this embodiment, joint simulation using Matlab and CST, followed by iterative optimization of the phase difference between two elements via a genetic algorithm, enables rapid determination of the element's structural parameters. This offers the advantage of automated design, eliminating the need for the traditional process of obtaining simulation results first and then calculating the phase, thus improving efficiency. Furthermore, the final antenna design achieves RCS reduction over a wide bandwidth without compromising antenna radiation performance.

[0057] The embodiments described above are merely preferred embodiments of this application and are not intended to limit the scope of this application. Any modifications and improvements made to the technical solutions of this application by those skilled in the art without departing from the spirit of this application shall fall within the protection scope defined by the claims of this application.

Claims

1. A radiation-scattering integrated microstrip antenna based on an artificial magnetic conductor, characterized in that, It includes a microstrip antenna, four first artificial magnetic conductor (AMC) arrays, and four second AMC arrays; the microstrip antenna is located in the center, and the four first AMC arrays and four second AMC arrays are distributed around it in a checkerboard pattern. A microstrip antenna includes a radiating microstrip patch, an antenna dielectric substrate, a ground plane, and a feed structure; the radiating microstrip patch is located at the center of the upper surface of the antenna dielectric substrate, and the ground plane is located on the lower surface of the antenna dielectric substrate. The feeding structure adopts a coaxial feeding method. The outer conductor of the coaxial line is connected to the ground plane, and the inner conductor of the coaxial line passes through the antenna dielectric substrate and is connected to the radiating microstrip patch. The first AMC array consists of 4×4 tightly bonded first AMC units. The first AMC unit includes a first dielectric substrate, a first metal pattern printed on the upper surface of the first dielectric substrate, and a first metal ground located on the lower surface of the first dielectric substrate. The first metal pattern has a 180° rotationally symmetrical structure and includes four circular patches. The four circular patches are divided into two groups with different radii and are located on the ±45° diagonal of the upper surface of the square first dielectric substrate. The second AMC array consists of 4×4 tightly fitted second AMC units. The second AMC unit includes a second dielectric substrate, a second metal pattern printed on the upper surface of the second dielectric substrate, and a second metal ground located on the lower surface of the second dielectric substrate. The first metal pattern has a 90° rotational symmetry structure and is a cross-shaped ring patch structure; The antenna dielectric substrate, the first dielectric substrate, and the second dielectric substrate constitute a complete dielectric substrate, and the ground plane, the first metal ground, and the second metal ground constitute a complete metal ground.

2. The integrated radiation and scattering microstrip antenna based on an artificial magnetic conductor according to claim 1, characterized in that, The structural dimensions of two types of AMC units were jointly simulated using the full-wave electromagnetic simulation software CST, VBA, and a genetic algorithm. The process is as follows: Step 1: Using the built-in VBA scripting environment of CST, create a function library in Matlab to control CST operations, and then call the function in Matlab to realize the parametric modeling, automated simulation and phase result export of two AMC units; Step 2: Using a genetic algorithm, optimize the structural dimensions of the two AMC units so that the phase difference between the two AMC units in the fitness function is greater than 143° and less than 217° in the range of 9GHz-17GHz, and can be satisfied under both TE and TM polarization; Step 3: Save the optimized structural dimension parameters of the two AMC units and perform simulation verification.

3. The integrated radiation and scattering microstrip antenna based on an artificial magnetic conductor according to claim 2, characterized in that, Both types of AMC elements are periodic structures, and the Floquet mode is used for solving in CST.

4. The integrated radiation and scattering microstrip antenna based on an artificial magnetic conductor according to claim 1, characterized in that, The period of both AMC units is P≤λ / (1+sin(θ)), where θ is the incident angle of the electromagnetic wave and λ is the wavelength.

5. The integrated radiation and scattering microstrip antenna based on an artificial magnetic conductor according to claim 2, characterized in that, When incident at different angles from 0 to 30°, the reflection radiance of the two AMC units is above 0.

82.

6. The integrated radiation and scattering microstrip antenna based on artificial magnetic conductor according to claim 1, characterized in that... The antenna dielectric substrate, the first dielectric substrate, and the second dielectric substrate are all made of FR-4 (lossy), which has a relative permittivity of 4.3 and a loss tangent of 0.025.

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