A design method for an ultrawideband absorber based on the antenna reciprocity principle and multi-scale current reconstruction, and an ultrawideband antipodal Vivaldi absorber.

Abstract

This invention provides a design method for an ultra-wideband absorber and an ultra-wideband anti-pontine Vivaldi absorber based on the antenna reciprocity principle and multi-scale current reconstruction. This method abandons the traditional stacking of micro-units and constructs a design paradigm that conforms to the traveling wave transmission law: First, the contour of a gradient traveling wave antenna is extracted as the macroscopic topology to establish a reflection-free impedance transition channel; second, lumped dissipation nodes are configured at the energy convergence port to form an impedance matching path from broadband coupling to thermal energy conversion; finally, a gradient non-uniform slot array is etched along the outer edge to reconstruct the high-frequency current path using the local slow-wave effect, and combined with the underlying suppression pattern layer to block parasitic effects, achieving fine multi-scale high-frequency impedance compensation. This invention achieves a stable absorption rate above 0.9 within the target frequency band, demonstrating high engineering practicality and wide applicability, and is suitable for radar stealth and electromagnetic compatibility fields.

Description

Technical Field

[0001] This invention belongs to the fields of microwave and antenna engineering and artificial electromagnetic materials technology, and particularly relates to an ultra-wideband absorber design method based on the antenna reciprocity principle and multi-scale current reconstruction, and an ultra-wideband antipodal Vivaldi absorber. Background Technology

[0002] With the rapid development of modern radar reconnaissance technology, reducing the radar cross section (RCS) of high-value military targets has become crucial for victory. Ultra-wideband microwave absorbers, as a core means of achieving radar stealth, have significant strategic value in areas such as military electromagnetic stealth, electromagnetic compatibility (EMC), and the construction of high-performance anechoic chamber environments. An ideal absorber must achieve efficient acquisition and energy dissipation of electromagnetic waves under extremely wide frequency bands and wide incident angles.

[0003] However, from the perspective of the intrinsic mechanism of electromagnetic fields, the resonant system has an inherent physical limitation that cannot be overcome in achieving ultra-wideband absorption: the resonant mechanism is constrained by the intrinsic contradiction between energy storage and dissipation. The essence of resonance is the efficient storage of electromagnetic field energy in a local space. Limited by the Bode-Fano limit theorem for impedance matching in passive linear systems, the impedance of a high-Q single-mode resonant system is purely resistive only within an extremely narrow frequency band. Once the frequency deviates from the resonant center, the imaginary part of the input impedance will undergo a drastic inductive or capacitive abrupt change, causing electromagnetic waves at non-resonant frequencies to be totally reflected. This fundamentally locks the upper limit of its relative bandwidth.

[0004] To overcome the physical limitations of resonant systems, the gradually varying impedance design based on the traveling wave mechanism has demonstrated significant technical advantages. The traveling wave mechanism completely abandons the method of localized standing wave energy storage. Through a continuous, gradually varying process at the macroscopic geometric boundaries, it guides free waves in space to be smoothly transmitted to the terminal in the form of traveling waves and then dissipated in a concentrated manner. This mechanism fundamentally avoids the high quality factor limitations imposed by resonance and naturally possesses extremely wide bandwidth potential in constructing spatially continuous impedance transition channels.

[0005] In summary, existing technologies face insurmountable physical bottlenecks in achieving ultra-wideband absorbing: traditional resonant systems are limited by the Bode-Fano limit, with an insurmountable bandwidth upper limit; while introducing conventional traveling wave mechanisms inevitably leads to strong reverse interference from the total internal reflection metal backplate at the bottom of the absorber, resulting in severe input impedance degradation and broadband matching failure. Therefore, how to overcome the narrowband limitations of resonant systems and effectively mitigate the impedance distortion caused by backplate interference from the underlying mechanism, thereby achieving an efficient and stable absorber design method across an extremely wide frequency band, is a key challenge that urgently needs to be addressed in this field. Summary of the Invention

[0006] Purpose of the invention: To address the limitations of existing resonant absorbers due to their bandwidth physical limits, and the technical shortcomings of traditional longitudinal traveling wave absorbers which are prone to edge dispersion and energy escape in the mid-to-high frequency bands, this invention provides an ultra-wideband absorber design method and an ultra-wideband antipodal Vivaldi absorber based on the antenna reciprocity principle and multi-scale current reconstruction. It establishes a progressive forward design paradigm that conforms to the traveling wave transmission law in principle, resolving the inherent physical contradiction between low-reflection smooth coupling of spatial impedance and edge scattering of high-frequency parasitic modes within an extremely wide bandwidth.

[0007] The method includes the following steps:

[0008] Step 1, Broadband macroscopic geometric topology construction based on antenna reciprocity principle: According to the target absorption frequency band and incident space angle requirements, the profile of the gradient traveling wave antenna that meets the corresponding radiation index in the transmission state is extracted as the macroscopic geometric topology. The continuous physical boundary of the macroscopic geometric topology is used to construct the low reflection coupling entrance and smooth impedance transition channel of the incident electromagnetic wave in space.

[0009] Step 2, based on the backbone impedance matching of space-to-terminal cascaded transmission: using the physical convergence structure of macroscopic geometric topology, the coupled electromagnetic energy undergoes a continuous and smooth transition from spatial wave impedance to internal equivalent impedance. Impedance dissipation nodes are configured at the energy convergence end of the physical convergence structure to construct a conjugate matching and centralized dissipation mechanism for the full-band backbone energy transmission path, which is used to convert the coupled broadband electromagnetic energy into heat dissipation.

[0010] Step 3, Local Multi-Scale Impedance Compensation Based on Non-Uniform Slot Loading: Addressing the parasitic high-order mode scattering caused by edge dispersion in the mid-to-high frequency bands of the macroscopic geometric topology, a non-uniform slot array with a gradient depth is etched along the electromagnetic wave propagation direction at the outer edge of the topology. This slot array is used to truncate and reconstruct the mid-to-high frequency surface current path, introducing a localized slow-wave effect to compensate for the local equivalent high-frequency reactance. Simultaneously, a polarization-symmetric suppression pattern layer is configured in the projection region of the bottom layer of the dielectric substrate to limit the lateral and backward diffusion of internal parasitic modes. By synergistically tuning the slot gradient and the bottom layer suppression parameters, the relative bandwidth and electromagnetic absorption rate of the absorber meet certain conditions, such as achieving a relative bandwidth of 93% and an electromagnetic absorption rate meeting the target threshold of 0.9, while ensuring angular stability of the absorption performance under oblique incidence conditions from 0° to 30°.

[0011] In step 1, the profile of the gradient traveling wave antenna must meet the size boundary constraints and radiation pattern index requirements.

[0012] In step 1, the size boundary constraints include: the lateral periodic size of the antenna element in the periodic array. The spatial grating-lobe-free electromagnetic boundary condition must be satisfied, and the constraint relationship is as follows:

[0013] ,

[0014] in, This represents the wavelength in free space corresponding to the highest frequency of the target operating frequency band. This represents the maximum oblique incidence angle set, used to suppress electromagnetic scattering caused by high-frequency parasitic grating lobes at the macroscopic geometric topology level;

[0015] The radiation pattern specification includes: based on the antenna reciprocity principle, the radiation pattern of the antenna element in free space transmission state within the target operating frequency band. Half-power beamwidth (HPBW) must meet the following requirements: Furthermore, within the target operating frequency band, the main lobe axial radiation gain curve is smooth and there are no large-angle sidelobes (for example, within the target operating frequency band, the main lobe axial radiation gain of the tapered traveling wave antenna profile changes continuously with frequency in the transmission state, and the change in main lobe axial gain between any adjacent sampling frequency points is no greater than 3dB; no sidelobes with peak gain higher than -10dB of the main lobe peak gain appear outside the maximum oblique incidence angle range, which is used to establish equivalent broadband impedance matching and low reflection coupling of plane waves in the spatial incidence angle region in the receiving mode), which is used to establish equivalent broadband impedance matching and low reflection coupling of plane waves in the spatial incidence angle region in the receiving mode.

[0016] In step 2, the conjugate matching and concentrated dissipation mechanism for constructing the full-band backbone energy transmission path includes impedance smoothness screening and load value calibration.

[0017] The impedance smoothness screening includes: the terminal equivalent input impedance of the selected macroscopic geometry topology. Frequency domain characteristics are limited, requiring that the real part of the input impedance be within the target operating frequency band. The frequency-dependent fluctuation is smooth (when the maximum deviation of the real part of the input impedance from the center impedance value does not exceed 65%, it is determined to meet the frequency domain fluctuation constraint), and the imaginary part of the input impedance... Approaching zero or without drastic abrupt changes in inductive and capacitive resonance (when the imaginary part of the input impedance fluctuates within ±100 ohms, it is determined to meet the frequency domain fluctuation constraint) to ensure that the prerequisite for fixed load loading is met; where j is the imaginary unit;

[0018] The load calibration includes: based on the broadband conjugate matching principle, loading a lumped element with purely resistive characteristics as an impedance dissipation node at the energy convergence end of the macroscopic geometric topology; the resistance value of the lumped element is... Based on macroscopic geometric topology, the real part of the equivalent input impedance at the terminal in the target operating frequency band. The frequency domain statistical mean or optimal convergence value is determined to achieve high-efficiency pure active power conversion and dissipation across the entire frequency band.

[0019] In step 3, a non-uniform slit array is etched along the direction of electromagnetic wave propagation, and the cutting depth of each slit is monotonically increasing along the direction of the incident wave vector.

[0020] In step 3, the polarization-symmetric wave suppression pattern layer is a Jerusalem cross metamaterial unit structure.

[0021] The present invention also provides an ultrawideband antipodal Vivaldi absorber constructed using the method described above, comprising a dielectric substrate layer, a first metal patch, a second metal patch, a patch-type lumped resistor, a non-uniform gradient slot array, and a polarization-symmetric bottom-layer suppression structure.

[0022] The first and second metal patches are symmetrically printed on the front and back sides of the dielectric substrate;

[0023] The outer contours of the first metal patch and the second metal patch together form an antipodal Vivaldi index gradient boundary. The purpose of the antipodal Vivaldi index gradient boundary is to establish a low-reflection coupling entrance for incident electromagnetic waves in space.

[0024] The patch lumped resistor is connected across the narrowest region at the feed terminals of the first and second metal patches, and its function is to serve as a concentrated dissipation node for active power.

[0025] The non-uniform gradient slit array is etched on the outer edges of the first metal patch and the second metal patch. The cutting depth of each slit increases monotonically along the direction of the exponential gradient boundary extending into the structure. The function of this array is to introduce local slow wave effect and reconstruct high-frequency surface current path.

[0026] The polarized symmetric bottom-layer suppression structure is printed on the bottom surface of the dielectric substrate to block the back transmission of parasitic modes.

[0027] The first metal patch and the second metal patch are centrally symmetrically distributed in space, and the first metal patch, the second metal patch, and the non-uniform gradient gap array are formed by planar printed circuit board technology.

[0028] The projected region of the polarization symmetric bottom-layer suppression structure completely covers the patch-type lumped resistor and the narrowed region of the feed end, which is used to achieve cooperative mode lock-up in a wide frequency band.

[0029] The ultra-wideband antipodal Vivaldi absorber exhibits angular stability at oblique incidence angles from 0° to 30°, and its equivalent absorption rate remains stable at over 90% over a relative bandwidth exceeding 93% (covering the 5.7GHz to 16.1GHz frequency band).

[0030] The present invention also provides a multi-band stealth and communication integrated device, wherein the electromagnetic absorption core of the device includes the ultra-wideband antipodal Vivaldi absorber, which is applied in a radar radome or conformal skin structure.

[0031] Beneficial effects:

[0032] 1. This invention proposes a forward design method for ultra-wideband absorbers based on the principle of antenna reciprocity. By using the broadband radiation profile of a gradient traveling wave antenna in the transmission state in reverse for the macroscopic topology construction of the absorber, the absorber design is transformed from the traditional empirical stacking of resonant units to a traveling wave coupling design process with clear physical basis, thereby improving the systematicness and predictability of ultra-wideband absorber design.

[0033] 2. This invention introduces a cascaded impedance matching mechanism from the incident wave in space to the terminal dissipation node in the design method, so that the incident electromagnetic energy can form a continuous transmission path along the macroscopically gradually changing topology and be concentrated and dissipated at the energy convergence end. This helps to reduce interface reflection in a wide frequency band and overcomes the problem of limited bandwidth of traditional resonant absorbers.

[0034] 3. In the design process, this invention further introduces a local multi-scale impedance compensation step of non-uniform slot array. By using gradient slots to cut off, extend and reconstruct the surface current path in the mid-to-high frequency range, the design method can locally correct problems such as edge dispersion and parasitic high-order mode scattering in the mid-to-high frequency range, thereby improving the continuity of broadband absorption performance.

[0035] 4. The method described in this invention has strong versatility. It can coordinate the design of macroscopic topology, lumped load, slot gradient and bottom layer suppression parameters according to different target frequency bands, incident angle ranges, period size and absorption rate requirements. It is applicable to the design and development of ultra-wideband absorbers, stealth skins, radar radomes and electromagnetic compatibility structures. Attached Figure Description

[0036] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0037] Figure 1 This is a schematic diagram of the overall structure of an ultrawideband antipodal Vivaldi absorber fabricated using an ultrawideband absorber design method based on the antenna reciprocity principle and multi-scale current reconstruction provided in an embodiment of the present invention.

[0038] Figure 2 for Figure 1 A front view of the main absorbing structure of the mid-opistho Vivaldi. Figure 3 for Figure 1 A magnified view of a non-uniformly gradient slit array and a schematic diagram showing the increasing depth gradient. Figure 4 for Figure 1A schematic diagram of the middle and bottom layer wave suppression structure.

[0039] Figure 5 for Figure 1 A graph showing the absorption rate of the structure as a function of frequency under normal incidence conditions.

[0040] Figure 6 for Figure 1 Contour plot of the absorbance of the structure under TE polarization conditions as a function of frequency and incident angle.

[0041] Figure 7 for Figure 1 A comparison curve of the absorption rate as a function of frequency when the structure is equipped with a non-uniform gradient slot array and when it is not equipped with a non-uniform gradient slot array.

[0042] Figure 8 for Figure 1 The curve showing the real part of the input impedance of the structure as a function of frequency.

[0043] Figure 9 for Figure 1 The curve showing the change of the imaginary part of the input impedance of the structure with frequency.

[0044] Explanation of reference numerals in the attached figures: Figures 1 to 4 In the middle: 1. Dielectric substrate; 2. First metal patch; 3. Second metal patch; 4. Non-uniform gradient slot array; 5. Bottom layer suppression structure; 6. Feed port lumped resistor. Detailed Implementation

[0045] This embodiment provides an ultra-wideband antipodal Vivaldi absorber based on non-uniformly graded slit loading, such as... Figure 1 As shown, the structure includes a dielectric substrate 1, a first metal patch 2 and a second metal patch 3 distributed on both sides of the dielectric substrate 1, a feed port lumped resistor 6 disposed at the feed ports of the first metal patch 2 and the second metal patch 3, and a bottom layer suppression structure 5 disposed at the bottom of the Vivaldi main absorbing structure. The first metal patch 2 and the second metal patch 3 are disposed opposite to each other and form an antipodal Vivaldi main absorbing structure.

[0046] like Figure 2 As shown, the antipodal Vivaldi main absorbing structure is disposed on both sides of the dielectric substrate 1, forming a gradually changing impedance channel that transitions from free space to the interior of the structure. A lumped resistor 6 is connected across the feed ports of the first metal patch 2 and the second metal patch 3. The resistance of the lumped resistor 6 is R1, preferably 80Ω. The lumped resistor 6 is used to receive and dissipate the electromagnetic energy coupled, transmitted, and converged to the feed port region through the antipodal Vivaldi gradual structure; it is the main dissipation device for achieving the absorbing function in this embodiment.

[0047] The present invention is designed based on the antenna reciprocity principle, and reversely applies the gradual impedance transformation process when the antipodal Vivaldi ultra-wideband radiation antenna radiates from the feeding port to free space to the electromagnetic absorption structure. The incident electromagnetic wave is first coupled into the absorber through the antipodal Vivaldi gradual structure and converges towards the feeding port area along the gradual transmission path, and then the coupling energy is converted into heat dissipation by the lumped resistor 6 at the feeding port, thereby reducing the interface reflection and improving the broadband absorption performance.

[0048] As Figure 3 shown, a non-uniformly tapered slot array 4 is formed at the outer edges of the first metal patch 2 and the second metal patch 3. The slot depths of the non-uniformly tapered slot array 4 increase sequentially along the direction of electromagnetic wave incidence, satisfying d1 < d2 < d3 < d4 < d5 < d6 < d7. Among them, the material of the dielectric substrate 1 is FR-4, its relative permittivity is εr = 4.35, the loss tangent is tanδ = 0.025, and the thickness is h = 0.422 mm. The materials of the first metal patch 2 and the second metal patch 3 are copper, and the thickness is t = 0.035 mm. The length of the dielectric substrate 1 is L1 = 14.744 mm, and the width is W1 = 11.243 mm. The opening width of the antipodal Vivaldi structure is W2 = 5.160 mm. The depths of the respective slots in the non-uniformly tapered slot array 4 are d1 = 0.80 mm, d2 = 1.00 mm, d3 = 1.20 mm, d4 = 1.56 mm, d5 = 2.11 mm, d6 = 2.61 mm, and d7 = 3.13 mm respectively, the adjacent slot pitch is p = 0.27 mm, and the slot width is g = 0.22 mm.

[0049] Furthermore, lumped dissipation elements can be loaded between adjacent slots of the non-uniformly tapered slot array 4, and the resistance value of the lumped dissipation element between the slots is R2 = 200 Ω, which is used for dissipating the local edge current and assisting in improving the impedance matching characteristics in the medium and high frequency bands. By setting the non-uniformly tapered slot array 4, the impedance transition process from the surface to the inside of the absorber is optimized, improving the coupling and transmission of electromagnetic waves from free space to the inside of the structure. Preferably, the slot edges can adopt an arc chamfer structure with a chamfer radius of r = 0.01 mm to improve the surface current distribution and reduce high-frequency scattering.

[0050] As Figure 4As shown, the bottom wave suppression structure 5 is disposed below the Vivaldi main absorbing structure to suppress parasitic modes, surface wave propagation, and edge diffraction effects within the structure, thereby improving the stability of the overall absorption performance of the absorber. Preferably, the bottom wave suppression structure 5 is a Jerusalem cross wave suppression layer. The substrate material of the bottom wave suppression structure 5 is FR-4 with a thickness of 0.5 mm; the cross arm length is a = 2.4 mm, the arm width is b = 0.2 mm, the end dimension is c = 4.01 mm, and the arc radius is r1 = 3.15 mm.

[0051] Furthermore, a bottom-level lumped dissipative element can be loaded at the adjacent cross ends of the bottom-level suppression structure 5. The resistance of the bottom-level lumped dissipative element is R3 = 200Ω. The bottom-level lumped dissipative element is used to assist in suppressing parasitic resonances and local surface currents in the bottom-level structure, and together with the bottom-level suppression structure 5, improves the broadband stability of the absorber. It should be noted that the lumped resistor 6 at the feed port is the main dissipation load in this embodiment, while the lumped dissipative element in the gap and the bottom-level lumped dissipative element are auxiliary dissipation and matching optimization structures.

[0052] The above-mentioned absorber element was simulated, and the change of absorbance with frequency under normal incidence was recorded. The results are as follows: Figure 5 As shown, the absorption rate of the absorber remains above 90% in the range of 5.7 GHz to 16.1 GHz; near 13.3 GHz, the maximum absorption rate reaches 99.8%. This result indicates that the absorber of the present invention exhibits excellent broadband absorption performance due to the dissipation effect of the lumped resistance 6 at the feed port, the coupling effect of the Vivaldi gradient structure, and the synergistic effect of the non-uniform gradient slot array 4 and the bottom suppression structure 5.

[0053] Furthermore, the absorption characteristics of the absorber under TE polarization conditions were simulated, and the changes in absorptivity with frequency and incident angle were recorded. The results are as follows: Figure 6 As shown, within the incident angle range of θ1=0° to θ2=30° and the frequency range of 9GHz to 15.3GHz, the absorber can maintain an absorption rate of over 90%; within the incident angle range of θ1=0° to θ2=45° and the frequency range of 5.7GHz to 16.1GHz, the absorber can still maintain an absorption rate of over 80%, indicating that it has good wide-angle absorption capability.

[0054] Furthermore, comparative simulations or tests were conducted on structures with and without the non-uniformly gradient slot array 4, and the results are as follows: Figure 7As shown, after setting the non-uniform gradient slot array 4, the absorption performance of the absorber in the frequency band of 14GHz to 16GHz is significantly improved; compared with the structure without the slot array, its absorption rate increases from about 50% to about 90%, and the effective absorption bandwidth is broadened by about 2GHz. This indicates that the non-uniform gradient slot array 4 can further optimize the impedance matching in the mid-to-high frequency band and improve the absorption performance based on the lumped resistance 6 of the feed port as the main dissipation terminal.

[0055] The real part of the equivalent input impedance of the absorber as a function of frequency was simulated, and the results are as follows: Figure 8 As shown. By Figure 8 It can be seen that within the target operating frequency band, the real part of the equivalent input impedance of the absorber is generally within a range that is conducive to broadband energy coupling and power dissipation, indicating that an effective broadband impedance cooperative matching can be formed between the plantar Vivaldi gradient structure, the lumped resistance of the feed port 6, the non-uniform gradient slot array 4, and the bottom suppression structure 5.

[0056] The simulation results show that the imaginary part of the equivalent input impedance of the absorber varies with frequency. Figure 9 As shown. By Figure 9 It can be seen that within the target operating frequency band, the imaginary part of the equivalent input impedance of the absorber does not exhibit a persistent strong inductive or strong capacitive mismatch state. This indicates that this embodiment can reduce the adverse effects of local resonance mutations on broadband absorption performance through gradual traveling wave coupling, terminal concentrated dissipation, and multi-scale current reconstruction, thereby maintaining good broadband absorption stability.

[0057] This invention provides a design method for an ultra-wideband absorber based on the antenna reciprocity principle and multi-scale current reconstruction, as well as an ultra-wideband antipodal Vivaldi absorber. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A design method for an ultrawideband absorber based on the antenna reciprocity principle and multi-scale current reconstruction, characterized in that, Includes the following steps: Step 1, Broadband macroscopic geometric topology construction based on antenna reciprocity principle: According to the target absorption frequency band and incident space angle requirements, the profile of the gradient traveling wave antenna that meets the corresponding radiation index in the transmission state is extracted as the macroscopic geometric topology. The continuous physical boundary of the macroscopic geometric topology is used to construct the low reflection coupling entrance and smooth impedance transition channel of the incident electromagnetic wave in space. Step 2, based on the backbone impedance matching of space-to-terminal cascaded transmission: using the physical convergence structure of macroscopic geometric topology, the coupled electromagnetic energy undergoes a continuous and smooth transition from spatial wave impedance to internal equivalent impedance. Impedance dissipation nodes are configured at the energy convergence end of the physical convergence structure to construct a conjugate matching and centralized dissipation mechanism for the full-band backbone energy transmission path, which is used to convert the coupled broadband electromagnetic energy into heat dissipation. Step 3, Local Multi-Scale Impedance Compensation Based on Non-Uniform Slot Loading: To address the parasitic high-order mode scattering caused by edge dispersion in the mid-to-high frequency band of the macroscopic geometric topology, a non-uniform slot array with a gradient depth is etched along the electromagnetic wave propagation direction on the outer edge of the topology. The slot array is used to truncate and reconstruct the mid-to-high frequency surface current path, introducing a local slow wave effect to compensate for the local equivalent high-frequency reactance. Simultaneously, a polarization-symmetric wave suppression pattern layer is configured in the projection area of ​​the bottom layer of the dielectric substrate. By synergistically tuning the slot gradient and the bottom layer wave suppression parameters, the relative bandwidth and electromagnetic absorption rate of the absorber meet the conditions.

2. The method according to claim 1, characterized in that, In step 1, the profile of the gradient traveling wave antenna must meet the size boundary constraints and radiation pattern index requirements.

3. The method according to claim 2, characterized in that, In step 1, the size boundary constraints include: the lateral periodic dimension p of the antenna element in the periodic array satisfies the spatial lobe-free electromagnetic boundary condition, and the constraint relationship is: ， in, This represents the wavelength in free space corresponding to the highest frequency of the target operating frequency band. This indicates the maximum angle of incidence set. The radiation pattern specification includes: based on the antenna reciprocity principle, the radiation pattern of the antenna element in free space transmission state within the target operating frequency band. Half-power beamwidth (HPBW) must meet the following requirements: Furthermore, within the target operating frequency band, the main lobe axial radiation gain curve is smooth and there are no large-angle sidelobes.

4. The method according to claim 3, characterized in that, In step 2, the conjugate matching and concentrated dissipation mechanism for constructing the full-band backbone energy transmission path includes impedance smoothness screening and load value calibration. The impedance smoothness screening includes: the terminal equivalent input impedance of the selected macroscopic geometry topology. Frequency domain characteristics are limited, requiring that the real part of the input impedance be within the target operating frequency band. Frequency-dependent fluctuations are mild, and the imaginary part of the input impedance is... Approaching zero or without drastic abrupt changes in inductive and capacitive resonances; where j is the imaginary unit; The load calibration includes: based on the broadband conjugate matching principle, loading a lumped element with purely resistive characteristics as an impedance dissipation node at the energy convergence end of the macroscopic geometric topology; the resistance value of the lumped element is... Based on macroscopic geometric topology, the real part of the equivalent input impedance at the terminal in the target operating frequency band. The frequency domain statistical mean or optimal convergence value is determined to achieve high-efficiency pure active power conversion and dissipation across the entire frequency band.

5. The method according to claim 4, characterized in that, In step 3, a non-uniform slit array is etched along the direction of electromagnetic wave propagation, and the cutting depth of each slit is monotonically increasing along the direction of the incident wave vector.

6. The method according to claim 5, characterized in that, In step 3, the polarization-symmetric wave suppression pattern layer is a Jerusalem cross metamaterial unit structure.

7. An ultrawideband antipodal Vivaldi absorber constructed using the method described in any one of claims 1 to 6, characterized in that, It includes a dielectric substrate layer, a first metal patch, a second metal patch, a patch-type lumped resistor, a non-uniform gradient slot array, and a polarized symmetrical bottom-layer suppression structure. The first and second metal patches are symmetrically printed on the front and back sides of the dielectric substrate; The outer contours of the first metal patch and the second metal patch together form an antipodal Vivaldi index gradient boundary. The purpose of the antipodal Vivaldi index gradient boundary is to establish a low-reflection coupling entrance for incident electromagnetic waves in space. The patch lumped resistor is connected across the narrowest region at the feed terminals of the first and second metal patches, and its function is to serve as a concentrated dissipation node for active power. The non-uniform gradient slit array is etched on the outer edges of the first metal patch and the second metal patch, and the cutting depth of each slit increases monotonically along the direction of the exponential gradient boundary extending into the structure. The polarized symmetric bottom wave suppression structure is printed on the bottom surface of the dielectric substrate.

8. The ultra-wideband anti-plantar Vivaldi absorber according to claim 7, characterized in that, The first metal patch and the second metal patch are centrally symmetrically distributed in space, and the first metal patch, the second metal patch, and the non-uniform gradient gap array are formed by planar printed circuit board technology.

9. The ultra-wideband anti-plantar Vivaldi absorber according to claim 8, characterized in that, The orthogonal projection area of ​​the polarization symmetric bottom-layer suppression structure completely covers the patch-type lumped resistor and the narrowed area of ​​the feed terminal, which is used to achieve cooperative mode lock-up in a wide frequency band.

10. A multi-band stealth and communication integrated device, characterized in that, The electromagnetic absorption core of the device comprises the ultrawideband antipodal Vivaldi absorber as described in claim 7, and is applied in a radar radome or conformal skin structure.

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