Folded wave absorber design method for narrowband and wideband switching and folded wave absorber

Abstract

The application relates to the technical field of wave absorbers, and discloses a design method of a folded wave absorber for narrowband and broadband switching and the folded wave absorber, which comprises the following steps: constructing a wave absorption unit, including a first functional surface containing a first structure for exciting narrowband resonance and a second functional surface containing a second structure for exciting broadband resonance; integrating a flexible connecting film between adjacent wave absorption units to realize connection and folding; connecting multiple wave absorption units and adjusting the spatial orientation of the wave absorption units by changing the folding angle, so that the first functional surface or the second functional surface faces the electromagnetic wave incidence side, and a folded wave absorber capable of realizing reversible switching between narrowband absorption mode and broadband absorption mode is obtained. The application solves the technical problem that the conventional wave absorption unit cannot separately arrange narrowband and broadband resonance structures on different sides, can only rely on deformation to realize continuous fine adjustment of frequency bands, and cannot reversibly switch between narrowband absorption and broadband absorption by folding and reversing to make different functional surfaces face the incident electromagnetic wave.

Description

Technical Field

[0001] This application relates to the field of microwave absorber technology, specifically a design method for a folded microwave absorber for narrowband and broadband switching, and a folded microwave absorber. Background Technology

[0002] In existing foldable adjustable absorbers, the patch structure of each working surface of the absorbing unit is uniform, and it is impossible to distinguish between narrowband resonant structure and broadband resonant structure in a single unit. Relying on bending and stretching can only adjust the unit spacing and tilt angle, and can only achieve continuous fine adjustment of the absorption frequency band. It is impossible to change the orientation of the unit and selectivity to make different functional surfaces face the incident electromagnetic wave by folding. It is also impossible to achieve discrete reversible switching between narrowband absorption mode and broadband absorption mode, which makes it difficult to meet the usage requirements of quickly switching between narrowband and broadband absorption in different scenarios. Summary of the Invention

[0003] The purpose of this application is to provide a design method and a folded absorber for switching between narrowband and broadband, so as to solve the technical problem in the prior art that it is impossible to quickly switch between narrowband and broadband absorption modes through folding.

[0004] To achieve the above objectives, this application discloses a design method for a folded absorber for narrowband and broadband switching, comprising: A three-dimensional absorbing unit with two functional surfaces is constructed. The two functional surfaces are a first functional surface and a second functional surface that are adjacent to each other. A first structure for exciting narrowband resonance is arranged on the first functional surface, and a second structure for exciting broadband resonance is arranged on the second functional surface. A flexible connecting film is integrated between adjacent absorbing units to achieve connection and folding between the absorbing units; By connecting multiple absorbing units and adjusting the spatial orientation of the absorbing units by changing the folding angle, one of the first or second functional surfaces can be oriented toward the electromagnetic wave incident side to switch the corresponding working state, thus obtaining a folded absorbing body. This folded absorbing body can achieve reversible switching between narrowband absorption mode and broadband absorption mode.

[0005] Preferably, the matrix of the absorbing unit is made of FR-4 material.

[0006] Preferably, the first structure is a cross-shaped metal patch, which is used to excite a narrowband resonance at a single frequency point so that the folded absorber can operate in a narrowband absorption mode.

[0007] Preferably, the second structure is a rectangular metal patch placed diagonally, which is used to excite broadband resonance of multimode coupling so that the folded absorber can operate in broadband absorption mode.

[0008] Preferably, the bottom of the wave-absorbing unit is provided with a metal reflector, which is used to prevent electromagnetic waves from being transmitted.

[0009] Preferably, the flexible connecting film is a PET film, which is used to assist in achieving reversible folding.

[0010] Preferably, the absorbing unit is cubic in shape, and the absorbing units in the same row are connected sequentially along the side by means of a flexible connecting film to form a unit strip. Multiple sets of unit strips are arranged in parallel to each other and are spliced ​​together to form a whole folded absorbing body.

[0011] Preferably, when the folding angle is 0°, the unit strip is laid flat as a whole, and the first functional surface of each absorbing unit faces the electromagnetic wave incident side, and the folded absorbing body works in narrowband absorption mode.

[0012] Preferably, when the folding angle is 180°, the unit strip is flipped and repositioned as a whole, and the second functional surface of each absorbing unit faces the electromagnetic wave incident side, and the folded absorbing body works in broadband absorption mode.

[0013] To achieve the above objectives, this application also discloses a folded absorber for narrowband and broadband switching, which is fabricated using the folded absorber design method for narrowband and broadband switching described above, and includes: The absorbing unit has a first functional surface and a second functional surface that are adjacent to each other. The first functional surface is provided with a first structure for exciting narrowband resonance, and the second functional surface is provided with a second structure for exciting broadband resonance. A flexible connecting film is disposed between adjacent absorbing units to realize the connection and folding of the absorbing units; The folded absorber can adjust the spatial orientation of the absorbing unit by changing the folding angle, and choose to make either the first functional surface or the second functional surface face the electromagnetic wave incident side, thus completing the reversible switching between narrowband absorption mode and broadband absorption mode.

[0014] Beneficial Effects: This application presents a design method and folded absorber for narrowband and broadband switching: It proposes an integrated structural and functional design, which differs from traditional adjustable absorbers that rely on active devices to adjust a single structural parameter. It cleverly utilizes different faces of a cube to carry different functional patches, switching between functional faces through folding, thus achieving two distinctly different high-performance absorption modes—narrowband and broadband—on the same physical entity. A simple and reliable control mechanism is proposed, utilizing the flexible connection of a PET film to achieve folding from 0° to 180° without complex external bias circuits and control algorithms, solving the problems of difficult integration and high power consumption of active devices in high-frequency bands. A clear bistable operating mode is proposed, with definite geometric configurations and stable electromagnetic responses at the two extreme positions of 0° and 180°. The intermediate angle serves only as a transition range for performance evolution. This discrete dual-mode switching characteristic makes the system control logic simpler and more reliable, providing a low-cost, high-reliability solution for electromagnetic compatibility design and intelligent spectrum management. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a flowchart of the folded absorber design method for narrowband and broadband switching provided in this embodiment; Figure 2 The image shows the finished product of the folded absorber provided in this embodiment; in the image: (a) is the intermediate state of folding; (b) is the first state obtained by folding; (c) is the second state obtained by folding. Figure 3 The diagram shows the design concept of the folded absorber provided in this embodiment; in the diagram: (a) and (d) are the unit structure and periodic structure diagram of the folded absorber in the first state, respectively; (b) and (e) are the unit structure and periodic structure diagram of the folded absorber in the folding conversion process, respectively; (c) and (f) are the unit structure and periodic structure diagram of the folded absorber in the second state, respectively. Figure 4 This is a schematic diagram of the structure and materials of each layer of the absorbing unit provided in this embodiment; Figure 5 The reflection loss curves at different folding angles α provided in this embodiment; Figure 6 The equivalent impedance curve provided in this embodiment; in the figure: (a) corresponds to the first state; (b) corresponds to the second state.

[0017] The implementation, functional features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0018] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0019] In this document, the term "comprising" is intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0020] With the increasing frequency and integration of wireless communication, radar detection, and electronic information systems, the electromagnetic spectrum is becoming increasingly congested, and electromagnetic interference and electromagnetic compatibility (EMC) issues are becoming more prominent. Microwave absorbing materials and structures, as key technologies for controlling electromagnetic waves and ensuring EMC and EMC protection functions, are in increasingly urgent demand. Traditional absorbers, such as structures based on ferrite, carbon-based composite materials, or resonant metasurfaces, typically have fixed absorption bands, bandwidths, and operating modes after fabrication, making them difficult to adapt to dynamically changing electromagnetic environments.

[0021] To improve adaptability, tunable absorbing technology has become a research focus. Existing technologies mainly achieve electrical tuning by integrating active devices, such as varactor diodes and PIN switches, into the structure, continuously adjusting the absorption peak frequency or intensity by changing the bias voltage. However, these methods suffer from system complexity, the need for additional power supply, high power consumption, and limitations in the high-frequency performance of active devices, posing reliability challenges. Furthermore, existing tunable technologies mostly focus on frequency shifting or intensity adjustment of a single absorption peak, making it difficult to achieve rapid and reversible switching between two distinctly different and high-performance electromagnetic response modes—narrowband high selectivity and broadband strong absorption—on the same basic structure using simple, low-power physical mechanisms. Therefore, developing a novel reconfigurable absorber with a simple structure, convenient control, and the ability to switch between two high-performance modes without complex circuitry is of great significance for meeting the urgent needs of advanced electronic equipment, communication systems, and electromagnetic functional platforms for dynamic spectrum management.

[0022] Based on the above analysis, in summary, the main drawbacks of existing technologies for reconfigurable absorbers are: current mainstream tunable absorbing technologies primarily achieve electrical control through the integration of active electronic devices, such as varactor diodes and PIN switches, which suffers from system complexity, the need for additional power supply, high power consumption, limited high-frequency performance, and reliability challenges. Furthermore, existing technologies mostly focus on the continuous adjustment of the frequency or intensity of a single absorption peak, making it difficult to achieve rapid and reversible switching between two distinctly different and high-performance electromagnetic response modes—narrowband high selectivity and broadband strong absorption—on the same basic structure using simple, low-power physical mechanisms.

[0023] To address the aforementioned technical shortcomings, this embodiment discloses a design method and a folded absorber for narrowband and broadband switching. In summary, the technical problem this embodiment aims to solve is that fixed-function absorbers cannot adapt to the dynamic and diverse spectrum of interference sources and detection signals in complex electromagnetic environments. For example, when precise suppression of strong interference at specific frequencies is required, broadband absorbers may be ineffective due to insufficient selectivity; while narrowband absorbers have too narrow a coverage range when facing broadband detection threats. Existing circuit-tuned solutions suffer from the aforementioned complexity and reliability issues, making them difficult to implement practically. Therefore, a novel absorber with a simple structure, convenient control, and reliable switching between high-performance narrowband and broadband absorption modes without complex circuitry is needed to solve the adaptive challenges in dynamic spectrum management and optimize electromagnetic compatibility and electromagnetic protection effects.

[0024] It should be noted that the folded absorber design method and folded absorber for narrowband and broadband switching in this embodiment have specific application scenarios including: reconfigurable electromagnetic absorption structures for complex electromagnetic environment platforms such as aerospace and marine equipment, which can switch between narrowband precise absorption and broadband broad-spectrum absorption modes according to the spectral characteristics of electromagnetic waves in different frequency bands; adaptive electromagnetic compatibility management units for high-density electronic devices, which can selectively suppress interference at specific frequency points or broadband noise; and as reconfigurable microwave functional devices, applied to next-generation intelligent communication, imaging and sensing systems.

[0025] The technical terms used in the subsequent description of this embodiment will now be explained in detail.

[0026] A folded absorber is an artificial electromagnetic structure that changes its spatial configuration through physical folding, thereby switching between narrowband and broadband absorption modes.

[0027] Narrowband absorption: refers to the response mode in which an absorber efficiently absorbs electromagnetic waves only at a specific frequency, such as 8.01 GHz, exhibiting extremely high frequency selectivity.

[0028] Broadband absorption: refers to the mode in which the absorber maintains efficient absorption over a wide frequency range, such as 9.1 to 10.6 GHz, with reflection loss typically below -10 dB.

[0029] Reflection loss: A key parameter for evaluating the performance of an absorber, measured in decibels (dB). A lower value indicates less reflection and higher absorption efficiency.

[0030] Impedance matching: When the input impedance of the absorber is approximately equal to the impedance of the free space wave, that is, when the real part is close to 1 and the imaginary part is close to 0, the incident wave reflection is minimized and the energy is dissipated into the interior to the maximum extent.

[0031] FR-4: A commonly used glass fiber epoxy resin copper clad laminate material, used as the dielectric substrate for microwave absorbers.

[0032] PET film: Polyethylene terephthalate film, which has flexible and foldable properties, is used to connect the microwave absorber unit and assist in folding.

[0033] PIN switch: An active device based on a PIN diode, commonly used in existing tunable absorption technology to adjust the absorption frequency by changing circuit parameters through an external bias voltage. Compared to traditional solutions using PIN switches, this embodiment avoids complex bias circuits and additional power consumption, and achieves more reliable mode switching through mechanical folding.

[0034] This embodiment provides a general description of a foldable absorber design method for narrowband and broadband switching, as well as the technical solution and effects of the foldable absorber. In summary, this embodiment discloses a foldable artificial electromagnetic structure that changes its spatial configuration through physical folding, thereby dynamically switching its electromagnetic absorption mode without complex circuitry or external power supply. In one configuration, this artificial electromagnetic structure exhibits high-efficiency narrowband absorption (up to 99.9%) at a specific frequency (e.g., 8.01 GHz), while in another configuration, it exhibits strong broadband absorption (reflection loss less than -10 dB) at a wider frequency band (e.g., 9.1-10.6 GHz). The technical effect of this embodiment is that it provides a novel reconfigurable absorber with a simple structure, reliable control, and the ability to quickly switch between high-performance narrowband selectivity and strong broadband absorption. This effectively solves the technical problems of traditional fixed absorbers being unable to adapt to dynamic spectrum environments and the complexity and high power consumption of existing electrical tuning schemes. This solution provides an innovative hardware foundation for spectrum adaptation, intelligent electromagnetic compatibility management, and multifunctional microwave devices in complex electromagnetic environments.

[0035] The present embodiment will now provide a detailed description of a folded absorber design method for narrowband and broadband switching and the folded absorber itself.

[0036] Reference Figure 1 ,Figure 1 This is a flowchart illustrating the design method for a folded absorber for narrowband and broadband switching provided in this embodiment.

[0037] like Figure 1 As shown, in a first aspect, this embodiment discloses a design method for a folded absorber for narrowband and broadband switching, comprising: S10: Construct a three-dimensional absorbing unit with two functional surfaces. The two functional surfaces are a first functional surface and a second functional surface that are adjacent to each other. A first structure for exciting narrowband resonance is arranged on the first functional surface, and a second structure for exciting broadband resonance is arranged on the second functional surface.

[0038] In the specific application of this embodiment, S10 constructs the basic structure of the folded absorber, namely the absorber unit.

[0039] Specifically, the matrix of the absorbing unit is made of FR-4 material.

[0040] Specifically, the first structure is a cross-shaped metal patch, which is used to excite a narrowband resonance at a single frequency point so that the folded absorber can operate in a narrowband absorption mode.

[0041] Specifically, the second structure is a rectangular metal patch placed diagonally, which is used to excite broadband resonance of multimode coupling so as to realize that the folded absorber operates in broadband absorption mode.

[0042] Specifically, a metal reflector is provided at the bottom of the wave-absorbing unit to prevent electromagnetic waves from being transmitted.

[0043] S20: A flexible connecting film is integrated between adjacent absorbing units to achieve connection and folding between absorbing units.

[0044] Specifically, the flexible connecting film is a PET film, which is used to assist in achieving reversible folding.

[0045] In this specific application, a thin PET film is applied to the bottom between adjacent unit structures. This PET film possesses excellent foldability and mechanical toughness. The PET film not only serves as a connecting medium to assemble multiple units into an array, but also as a folding aid mechanism, guiding the structure to stably and reversibly switch between two spatial states: the first functional surface facing the electromagnetic wave incident side and the second functional surface facing the electromagnetic wave incident side. This design avoids complex hinge structures and simplifies the system configuration.

[0046] S30: Connect multiple absorbing units, adjust the spatial orientation of the absorbing units by changing the folding angle, select one of the first or second functional surfaces to face the electromagnetic wave incident side to switch the corresponding working state, and obtain a folded absorbing body, so that the folded absorbing body can realize reversible switching between narrowband absorption mode and broadband absorption mode.

[0047] The following description, in conjunction with a specific implementation example, illustrates a novel reconfigurable absorber obtained by using the folded absorber design method for narrowband and broadband switching in this embodiment.

[0048] Specifically, the absorbing unit is cubic in shape. The absorbing units in the same row are connected sequentially along the side by a flexible connecting film to form a unit strip. Multiple sets of unit strips are arranged in parallel to each other and are spliced ​​together to form a whole folded absorbing body.

[0049] Reference Figure 2 , Figure 2 The image shows the finished product of the folded absorber provided in this embodiment; in the image: (a) is the intermediate state of folding; (b) is the first state obtained by folding; (c) is the second state obtained by folding.

[0050] like Figure 2 As shown, the folded microwave absorber of this embodiment first forms unit strips by arranging cubic microwave absorbing units in the same row, and then multiple sets of unit strips are arranged in parallel. All of the above arrangements are spliced ​​together using PET film. In the specific application of this embodiment, the first functional surface facing the electromagnetic wave incident side is the first state, and the second functional surface facing the electromagnetic wave incident side is the second state.

[0051] Specifically, when the folding angle is 0°, the unit strip is laid flat as a whole, and the first functional surface of each absorbing unit faces the electromagnetic wave incident side, and the folded absorbing body works in narrowband absorption mode.

[0052] Specifically, when the folding angle is 180°, the unit strip is flipped and repositioned as a whole, and the second functional surface of each absorbing unit faces the electromagnetic wave incident side, and the folded absorbing body works in broadband absorption mode.

[0053] like Figure 2 As shown, in a second aspect, this embodiment discloses a folded absorber for narrowband and broadband switching, which is fabricated using the folded absorber design method for narrowband and broadband switching described above, and includes: The absorbing unit has a first functional surface and a second functional surface that are adjacent to each other. The first functional surface is provided with a first structure for exciting narrowband resonance, and the second functional surface is provided with a second structure for exciting broadband resonance. A flexible connecting film is disposed between adjacent absorbing units to realize the connection and folding of the absorbing units; The folded absorber can adjust the spatial orientation of the absorbing unit by changing the folding angle, and choose to make either the first functional surface or the second functional surface face the electromagnetic wave incident side, thus completing the reversible switching between narrowband absorption mode and broadband absorption mode.

[0054] Reference Figure 3 , Figure 3 The diagram shows the design concept of the folded absorber provided in this embodiment. In the diagram: (a) and (d) are the unit structure and periodic structure diagram of the folded absorber in the first state, respectively; (b) and (e) are the unit structure and periodic structure diagram of the folded absorber in the folding conversion process, respectively; (c) and (f) are the unit structure and periodic structure diagram of the folded absorber in the second state, respectively.

[0055] like Figure 3 As shown, in a specific application of this embodiment, the specific dimensions of adjacent absorbing units are P=10mm, H=10mm, =7.5mm =2mm =9.5mm =2.5mm. Figure 3 In the diagram, (a) and (d) are the unit cell structure and periodic structure diagram of the structure in the first state, respectively; (b) and (e) are the unit cell structure and periodic structure diagram of the structure during the transformation process, respectively; and (c) and (f) are the unit cell structure and periodic structure diagram of the structure in the second state, respectively. Specifically, in applications, two stable states can be obtained by adjusting the folding angle α: the first state corresponds to a folding angle of 0°, and the second state corresponds to a folding angle of 180°.

[0056] Reference Figure 4 , Figure 4 This is a schematic diagram of the structure and materials of each layer of the absorbing unit provided in this embodiment.

[0057] Figure 4 The diagram shows the layer structure and materials of two adjacent absorbing units in this embodiment. Specifically, the PET film is used to assist in folding, and the metal backing plate is used to prevent transmission.

[0058] In this specific application: a cross-shaped copper patch is designed on the front of the absorbing unit, which is mainly used to excite narrowband resonant modes; rectangular copper patches are designed on the side of the absorbing unit, placed diagonally, which is mainly used to excite broadband resonant modes. The complete absorbing unit is placed on a metal plate, which acts as a reflective floor to prevent electromagnetic wave transmission and ensure that the incident wave energy is fully dissipated inside the structure.

[0059] The technical principles of this embodiment will now be explained with reference to specific data.

[0060] This embodiment achieves dual-mode switching based on the electromagnetic response modulation of the folding angle. Specifically, this embodiment achieves precise control over absorption performance by changing the single physical degree of freedom of the folding angle. The specific process is as follows: In the narrowband absorption mode, or the first state, when the folding angle is 0°, the folded absorber is in its unfolded state with the front facing upwards, meaning the first functional surface faces the electromagnetic wave incident side. In this mode, the copper patch with the cross-shaped structure acts as the main response unit, generating a specific resonant frequency under electromagnetic wave excitation. Subsequent data shows that the folded absorber in this first state exhibits extremely high frequency selectivity at a specific frequency point, achieving narrowband absorption.

[0061] In the broadband absorption mode, or the second state, when the folding angle is 180°, the folded absorber transforms into a side-up state through the folding action, meaning the second functional surface faces the incident electromagnetic wave. In this state, the diagonally placed rectangular copper patches become the main response units, and their geometry supports the coupling and superposition of multimode resonances. Subsequent data show that the absorber's operating bandwidth is significantly broadened in this state, achieving broadband absorption.

[0062] To further illustrate the technical principles of this embodiment, a transition state characteristic analysis was also conducted. Specifically, to investigate the influence mechanism of folding angle changes on absorption performance, this embodiment analyzed the reflection loss performance at folding angles of 60° and 120°. Subsequent data showed that the electromagnetic response of the folded absorber exhibited a regular evolution with changes in the folding angle, revealing the physical process of transitioning from a narrowband mode to a broadband mode, and further verifying the modulating effect of the folding action on the electromagnetic response.

[0063] Reference Figure 5 , Figure 5 The reflection loss curves at different folding angles α are provided for this embodiment.

[0064] like Figure 5 The diagram shows the reflection loss curves of the folded absorber in this embodiment at different folding angles. When the folding angle is 0°, i.e., the first state, the curve exhibits a sharp resonance peak at 8.01 GHz, demonstrating narrowband absorption characteristics. When the folding angle is 180°, i.e., the second state, the curve shows that the reflection loss is less than -10 dB in the 9.1-10.6 GHz range and less than -15 dB in the 9.2-10.4 GHz range, achieving broadband absorption. Figure 5 The study also demonstrated intermediate transition states with folding angles of 60° and 120°. During the transition from 180° to 0°, the absorption peak that was originally near 10.145 GHz gradually weakened, while the peak at 9.325 GHz shifted to lower frequencies, eventually transforming into a single-peak absorption mode.

[0065] Reference Figure 6 , Figure 6 The equivalent impedance curve provided in this embodiment; in the figure: (a) corresponds to the first state; (b) corresponds to the second state.

[0066] Figure 6 The diagram illustrates the real and imaginary parts of the equivalent impedance of the folded absorber in this embodiment under two different folding states. In the first state, the curve shows that at a frequency of 8.01 GHz, the real part of the equivalent impedance is close to 1, and the imaginary part is close to 0. In the second state, within the frequency range of 9.1-10.6 GHz, the real part of the equivalent impedance is close to 1, and the imaginary part is close to 0. According to impedance matching theory, a real part close to 1 and an imaginary part close to 0 means that the input impedance of the absorber is approximately equal to the free-space wave impedance. This indicates that the reflection of incident electromagnetic waves at the absorber surface is minimal, and most of the energy can enter the absorber and be dissipated, thus achieving efficient electromagnetic wave absorption.

[0067] Referring to Table 1, which shows the absorption performance data under different conditions provided in this embodiment.

[0068] Table 1. Absorption performance data under different conditions As shown in Table 1, this embodiment exhibits distinctly different electromagnetic response characteristics in two folding states. With a folding angle of 0° (front facing up, i.e., the first functional surface facing the electromagnetic wave incident side), a significant resonance peak is generated at 8.01 GHz, with an absorption rate of 99.9%, demonstrating excellent narrowband absorption performance. With a folding angle of 180° (side facing up, i.e., the second functional surface facing the electromagnetic wave incident side), its operating bandwidth is significantly broadened, with reflection loss below -10 dB in the 9.1-10.6 GHz range and below -15 dB in the 9.2-10.4 GHz range, achieving efficient broadband absorption. Furthermore, combining the reflection loss performance at the aforementioned intermediate folding angles of 60° and 120° confirms the evolution of structural performance with changing folding angle, further confirming the modulating effect of the folding mechanism on the electromagnetic response.

[0069] Based on the above, this embodiment discloses a structural design for a folded absorber used for narrowband and broadband switching, which achieves dual-mode switching based on mechanical folding. This differs from the traditional approach in existing technologies that relies on active devices such as varactor diodes or PIN diodes for electrical tuning. This embodiment utilizes a differentiated structural design with a front cross and side rectangles on a cubic unit to physically switch between narrowband and broadband absorption modes through physical folding. This avoids the introduction of complex bias circuits, significantly reducing system power consumption and structural complexity, and improving the reliability of the device at high frequencies. Furthermore, this embodiment uses a PET film to connect adjacent units and assist in folding, achieving physical programming of the electromagnetic response characteristics. Most existing technologies can only achieve continuous shifts in the absorption peak frequency, making it difficult to achieve a leapfrog switching between narrowband high selectivity and broadband strong absorption. Therefore, this embodiment can achieve a complete functional conversion through a simple folding action, providing a low-cost and easy-to-implement solution for dynamic electromagnetic protection and spectrum management in complex electromagnetic environments.

[0070] In summary, this embodiment discloses a folded absorber design method and folded absorber for narrowband and broadband switching. It presents a dual-mode reconfigurable absorber structure based on a folding mechanism. By utilizing the geometric pattern differences of different faces of the unit structure, such as a cross on the front and rectangular patches on the side, the orientation of the structure is changed by folding, thereby achieving stable switching between narrowband and broadband absorption modes. Furthermore, the flexible connection characteristics of the bottom PET film are used to assist in folding. Physical control of the absorber's working mode can be achieved without external electrical energy. It has the advantages of simple structure, intuitive control, and stable dual-mode performance.

[0071] In summary, the significant advancements of the folded absorber design method and folded absorber for narrowband and broadband switching in this embodiment compared to existing technologies are as follows: An integrated structural and functional design is proposed. Unlike traditional adjustable absorbers that rely on active devices (such as varactor diodes) to adjust a single structural parameter, this embodiment cleverly utilizes different faces of a cube to carry different functional patches (such as a cross on the front and a rectangle on the side). By switching the functional faces through a folding action, two distinctly different high-performance absorption modes, narrowband and broadband, are achieved on the same physical entity.

[0072] A simple and reliable control mechanism was proposed. By utilizing the flexible connection of PET film, folding from 0° to 180° can be achieved without complex external bias circuits and control algorithms, thus solving the problems of difficult integration and high power consumption of active devices in the high-frequency band.

[0073] A clearly defined bistable operating mode is proposed. This embodiment has a defined geometric configuration and stable electromagnetic response at the two extreme positions of 0° and 180°, with the intermediate angle serving only as a transitional range for performance evolution. This discrete dual-mode switching characteristic makes the system control logic simpler and more reliable, providing a low-cost, high-reliability solution for dynamic electromagnetic protection and intelligent spectrum management.

[0074] In the embodiments provided in this application, it should be understood that the embodiments described herein can be implemented in hardware, software, firmware, middleware, code, or any suitable combination thereof. For hardware implementation, the processor may be implemented in one or more of the following: application-specific integrated circuits (ASICs), digital signal processors (DSPs), digital signal processing devices (DSPDs), programmable logic devices (PLDs), field-programmable gate arrays (FPGAs), processors, controllers, microcontrollers, microprocessors, other electronic units designed to implement the functions described herein, or combinations thereof. For software implementation, some or all of the processes of the embodiments may be performed by a computer program instructing the associated hardware. During implementation, the program may be stored in a computer-readable storage medium or transmitted as one or more instructions or code on a computer-readable storage medium. Computer-readable storage media include computer storage media and communication media, wherein communication media include any medium that facilitates the transmission of a computer program from one place to another. Storage media may be any available medium accessible to a computer. Computer-readable storage media may include, but are not limited to, RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage media or other magnetic storage devices, or any other medium capable of carrying or storing desired program code having the form of instructions or data structures and accessible to a computer.

[0075] Finally, it should be noted that the above description is only a preferred embodiment of this application and is not intended to limit this application. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A design method for a folded absorber for narrowband and broadband switching, characterized in that, include: A three-dimensional absorbing unit with two functional surfaces is constructed. The two functional surfaces are a first functional surface and a second functional surface that are adjacent to each other. A first structure for exciting narrowband resonance is arranged on the first functional surface, and a second structure for exciting broadband resonance is arranged on the second functional surface. A flexible connecting film is integrated between adjacent absorbing units to achieve connection and folding between the absorbing units; By connecting multiple absorbing units and adjusting the spatial orientation of the absorbing units by changing the folding angle, one of the first or second functional surfaces can be oriented toward the electromagnetic wave incident side to switch the corresponding working state, thus obtaining a folded absorbing body. This folded absorbing body can achieve reversible switching between narrowband absorption mode and broadband absorption mode.

2. The design method for a folded absorber for narrowband and broadband switching according to claim 1, characterized in that, The substrate of the absorbing unit is made of FR-4 material.

3. The design method for a folded absorber for narrowband and broadband switching according to claim 1, characterized in that, The first structure is a cross-shaped metal patch, which is used to excite a narrowband resonance at a single frequency point so that the folded absorber can operate in a narrowband absorption mode.

4. The design method for a folded absorber for narrowband and broadband switching according to claim 1, characterized in that, The second structure is a rectangular metal patch placed diagonally, which is used to excite broadband resonance of multimode coupling so that the folded absorber can operate in broadband absorption mode.

5. The design method for a folded absorber for narrowband and broadband switching according to any one of claims 1 to 4, characterized in that, The bottom of the wave-absorbing unit is provided with a metal reflector, which is used to prevent electromagnetic waves from being transmitted.

6. The design method for a folded absorber for narrowband and broadband switching according to any one of claims 1 to 4, characterized in that, The flexible connecting film is a PET film, which is used to assist in achieving reversible folding.

7. The design method for a folded absorber for narrowband and broadband switching according to claim 1, characterized in that, The absorbing unit is cubic in shape. The absorbing units in the same row are connected sequentially along the side by a flexible connecting film to form a unit strip. Multiple units are arranged in parallel and side by side, and are spliced ​​together to form a whole folded absorbing body.

8. The design method for a folded absorber for narrowband and broadband switching according to claim 7, characterized in that, When the folding angle is 0°, the unit strip is laid flat as a whole, and the first functional surface of each absorbing unit faces the electromagnetic wave incident side. The folded absorbing body works in narrowband absorption mode.

9. The design method for a folded absorber for narrowband and broadband switching according to claim 7, characterized in that, When the folding angle is 180°, the unit strip is flipped and repositioned as a whole, and the second functional surface of each absorbing unit faces the electromagnetic wave incident side, and the folded absorbing body works in broadband absorption mode.

10. A folded absorber for narrowband and broadband switching, characterized in that, The folded absorber for narrowband and broadband switching is prepared using the design method described in any one of claims 1 to 9, comprising: The absorbing unit has a first functional surface and a second functional surface that are adjacent to each other. The first functional surface is provided with a first structure for exciting narrowband resonance, and the second functional surface is provided with a second structure for exciting broadband resonance. A flexible connecting film is disposed between adjacent absorbing units to realize the connection and folding of the absorbing units; The folded absorber can adjust the spatial orientation of the absorbing unit by changing the folding angle, and choose to make either the first functional surface or the second functional surface face the electromagnetic wave incident side, thus completing the reversible switching between narrowband absorption mode and broadband absorption mode.

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