A design method for dual-polarized ultrawideband energy-selective materials

Abstract

This invention discloses a design method for dual-polarized ultrawideband energy-selective materials. The method includes: integrating diodes with surface plasmon polaritons (SSPPs) and etching them onto the surface of a dielectric waveguide to form a centrosymmetric structure; wherein the SSPPs are periodic metal strips etched onto the dielectric waveguide surface, each SSPP metal strip integrating two diodes, symmetrically integrated on both sides of the metal strip, with etched gaps at the diodes connecting the metal strips; when the diodes are off, the metal strip transmission between the two diodes is below the asymptotic frequency. f 1. Electromagnetic waves; when the diode is turned on, the metal strip connecting the two diodes increases in equivalent length, and the asymptotic frequency decreases to 1. f 2, make f 2~ f Electromagnetic waves in the 1-band exhibit energy selectivity. This invention integrates a diode and a surface plasmon polariton (SSPP) structure and etches them onto the surface of a dielectric waveguide to achieve dual polarization, ultra-wideband coverage, and low cost.

Description

Technical Field

[0001] This invention relates to the field of electromagnetic protection technology, specifically to a design method for dual-polarized ultrawideband energy selective materials. Background Technology

[0002] Electromagnetic energy-selective materials (EMS) are low-pass structures that allow low-energy electromagnetic waves to pass through with low loss while blocking high-energy electromagnetic waves with high reflectivity. The design of EMS is typically based on electromagnetic equivalent modeling (EMM) techniques. This involves designing a high-performance circuit filter structure, mapping that structure to a microstrip structure, and optimizing the metal pattern to achieve the desired result. EMS achieved using this technique usually have a narrow frequency band; for example, traditional cross-shaped structures typically operate in the L-band. As the frequency increases, insertion loss and shielding performance deteriorate significantly. To extend the bandwidth, higher-order filter structures need to be designed, along with diodes with smaller junction capacitances. This results in more complex microstrip structures and higher costs (the smaller the junction capacitance of the diode, the higher the purchase cost), drastically increasing the feasibility of design and fabrication. For example, in the paper "Design of a Broadband Energy Selective Surface with Ultra-High Shielding Efficiency" published by Nanjing University of Science and Technology, a three-layer cascaded spatial filter structure was designed, which achieved an insertion loss of less than 1dB and a protection efficiency of more than 50dB in the 3.5GHz~5.3GHz frequency band. It is already an excellent case of ultra-wideband energy selective material. However, its metal pattern complexity is high and the relative bandwidth is only 40.9%, which needs to be improved. At the same time, the unit side length is small, and each unit needs to use 8 MADP-0009 diodes. The junction capacitance of the diode is very small, so the cost is high, which leads to a sharp increase in the cost of the structure in practical applications [1]. In the paper "A Wideband Energy Selective SurfaceWith Quasi-Elliptic Bandpass Response and High-Power Microwave Shielding" published by the National University of Defense Technology, a broadband energy selective material was realized. The working frequency band is 6GHz~10GHz, the relative bandwidth is 50%, which needs to be improved, and it is a single-polarization structure [2].

[0003] Surface plasmon polaritons (SSPPs) are artificially constructed structures that generate surface waves with similar characteristics to surface plasmon polaritons (SPPs). They are confined to the metal surface, do not radiate outwards, and propagate forward. They have low-pass characteristics and are widely used in the antenna field. In the paper "A 3D Bandpass FrequencySelective Structure Utilizing Spoof Surface Plasmon Polaritons for Millimeter-Wave Applications" published by the National University of Defense Technology in 2020, a frequency selective surface was designed using waveguide and SSPP structure. The frequency selection function was realized by utilizing the high-pass characteristics of the waveguide and the low-pass characteristics of SSPPs [3]. This invention draws on this idea and proposes to integrate a diode with a surface plasmon polariton (SSPP) structure and etch it on the surface of the dielectric waveguide to form a centrally symmetrical structure. This effectively expands the bandwidth while achieving dual polarization and low cost.

[0004] References: [1]Li, Chunyu&Zhang, Tiancheng&Bao, Huaguang&Ding, Dazhi. (2024). Design of a Broadband Energy Selective Surface with Ultra-High ShieldingEfficiency. IEEE Antennas and Wireless Propagation Letters. PP. 1-5. 10.1109 / LAWP.2024.3443118. [2]Tian, ​​Tao & Huang, Xianjun & Xu, Yanlin & Liu, Peiguo & Chenxi, Liu & Hu, Ning & Zhang, Jihong & Wu, Zhaofeng. (2023). A Wideband Energy Selective SurfaceWith Quasi-Elliptic Bandpass Response and High-Power Microwave Shielding. IEEE Transactions on Electromagnetic Compatibility. PP. 1-10. 10.1109 / TEMC.2023.3325438. [3] Li, Liu & Guan, Dongfang & Yang, Zhangbiao & Xu, Shenda & Xu, Han-Tao & Lin, Ming-Tuan & Yong, Shao-Wei. (2020). A 3D Bandpass Frequency Selective Structure Utilizing Spoof Surface Plasmon Polaritons for Millimeter-Wave Applications. 1-3. 10.1109 / ICMMT49418.2020.9386980. Summary of the Invention This invention provides a design method for dual-polarized ultrawideband energy selective materials, which mainly solves the problems of narrow frequency band of traditional energy selective surfaces, high cost, high insertion loss, low protection effectiveness and single polarization when extending to higher frequencies. This method achieves dual polarization, ultrawideband and low cost by integrating diodes and SSPPs structures and etching them on the surface of the dielectric waveguide.

[0005] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows: In a first aspect, the present invention provides a method for designing dual-polarization ultrawideband energy-selective materials, the method comprising: A diode and a surface plasmon polariton (SSPP) structure are integrated and etched onto the surface of a dielectric waveguide to form a centrosymmetric structure. The SSPPs are periodic metal strips etched onto the surface of the dielectric waveguide. Each SSPP metal strip integrates two diodes, which are symmetrically integrated on both sides of the metal strip. The diodes are etched with slots, and the metal strips are connected through the diodes. When the diodes are off, the metal strip transmission between the two diodes is below the asymptotic frequency. f 1. Electromagnetic waves; when the diode is turned on, the metal strip connecting the two diodes increases in equivalent length, and the asymptotic frequency decreases to 1. f 2, make f 2~ f Electromagnetic waves in frequency band 1 exhibit energy selectivity.

[0006] Following the above technical solution, the dielectric waveguide is a square dielectric waveguide.

[0007] Following the above technical solution, the dielectric material selected for the dielectric waveguide is FR-4 printed circuit board material.

[0008] Following the above technical solution, the metal strip and diode are integrated and etched on the inside of the square dielectric waveguide.

[0009] Following the above technical solution, each metal strip is divided into three segments by two diodes, and the length of the metal strip between the diodes and the entire metal strip are all linearly modulated.

[0010] According to the above technical solution, the length of the entire metal strip determines the lower cutoff frequency of the passband, and the length of the metal strip between the two diodes determines the upper cutoff frequency of the passband.

[0011] Following the above technical solution, the periodic unit size of the energy selection material is 1 / 2 of the wavelength corresponding to the center frequency of the operating frequency band.

[0012] Following the above technical solution, the diode is an NSR201 Schottky chip diode.

[0013] Based on the above technical solution, the equivalent circuit parameters of the diode are: C=0.15pF, L=0.45nH, R=1.5Ω.

[0014] In a second aspect, the present invention provides a dual-polarized ultrawideband energy selective material, comprising: Dielectric waveguide; The surface plasmon polariton (SSPP) structure consists of periodic metal strips etched on the surface of a dielectric waveguide, forming a centrosymmetric structure together with a diode. Diodes: Two diodes are integrated into each SSPPs metal strip. The two diodes are symmetrically integrated on both sides of the metal strip, and the diodes are etched with slots to connect the metal strips. When the diodes are off, the metal strip transmission between the two diodes is below the asymptotic frequency. f 1. Electromagnetic waves; when the diode is turned on, the metal strip connecting the two diodes increases in equivalent length, and the asymptotic frequency decreases to 1. f 2, make f 2~ f Electromagnetic waves in frequency band 1 exhibit energy selectivity.

[0015] In summary, compared with the prior art, the above-described technical solutions conceived by this invention can achieve the following beneficial effects: (1) The present invention innovatively adopts diode and SSPPs structure integrated and etched on the surface of dielectric waveguide, with the whole structure being centrally symmetrical, thus realizing the function of dual polarization.

[0016] (2) This invention utilizes the low-pass characteristics of SSPPs, controls the conduction and cutoff of the diodes to make the two low-pass curves form a channel window, and achieves the ultra-wideband function by controlling the position of the diodes and the length of SSPPs.

[0017] (3) The present invention utilizes the field confinement effect of SSPPs to convert spatial waves into surface waves and then back into spatial waves, thereby reducing insertion loss; and utilizes the steep cutoff characteristics of SSPPs to improve protection effectiveness.

[0018] (4) The energy selection unit proposed in this invention has a size of λ / 2, while the size of traditional energy selection units is usually less than λ / 10, and the diode junction capacitance used is larger than that used in ordinary energy selection units, thus achieving the effect of low cost. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of a dual-polarized ultrawideband energy selective material according to an embodiment of the present invention; Figure 2 This is a simulation result diagram of the x-polarization insertion loss and protection effectiveness of an energy-selective material according to an embodiment of the present invention; Figure 3 The figure shows the simulation results of the y-polarization insertion loss and protection effectiveness of an energy-selective material according to an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention. All other embodiments obtained by those skilled in the art based on the embodiments provided by this invention without inventive effort are within the scope of protection of this invention.

[0021] Obviously, the accompanying drawings described below are merely some examples or embodiments of the present invention. Those skilled in the art can apply the present invention to other similar scenarios based on these drawings without any inventive effort. Furthermore, it is understood that although the efforts made in this development process may be complex and lengthy, for those skilled in the art related to the content disclosed in this invention, modifications to design, manufacturing, or production based on the technical content disclosed in this invention are merely conventional technical means and should not be construed as insufficient disclosure of the present invention.

[0022] In this invention, the reference to "embodiment" means that a specific feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of the invention. The appearance of this phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it a mutually exclusive, independent, or alternative embodiment. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described in this invention may be combined with other embodiments without conflict.

[0023] Unless otherwise defined, the technical or scientific terms used in this invention shall have the ordinary meaning understood by one of ordinary skill in the art to which this invention pertains. The terms "a," "an," "an," "the," and similar words used in this invention do not indicate quantity limitation and may indicate singular or plural. The terms "comprising," "including," "having," and any variations thereof used in this invention are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units not listed, or may include other steps or units inherent to these processes, methods, products, or devices. The terms "connected," "linked," "coupled," and similar words used in this invention are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "A plurality" used in this invention refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships may exist; for example, "A and / or B" can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following objects have an "or" relationship. The terms "first," "second," and "third" used in this invention are merely to distinguish similar objects and do not represent a specific ordering of the objects.

[0024] This invention provides a method for designing dual-polarization ultrawideband energy-selective materials, such as... Figure 1 As shown, the diodes are integrated with the SSPPs structure and etched on the surface of the dielectric waveguide. Each SSPPs strip contains two diodes. The SSPPs are linearly modulated both inside and outside to reduce the loss during the conversion between space waves and surface waves.

[0025] The dielectric waveguide is a square waveguide, and the dielectric material used is FR-4 printed circuit board material.

[0026] SSPPs are periodic metal strips etched onto the surface of a dielectric waveguide, used to transmit SSPP surface waves. The length, width, and spacing of the slots determine the upper cutoff frequency for transmitted electromagnetic waves.

[0027] Linear modulation is the modulation of the strip length, used to reduce the conversion loss between space waves and surface waves.

[0028] Diodes are symmetrically integrated in pairs on both sides of a metal strip, with etched gaps at the diodes, and the metal strip is connected through the diodes.

[0029] The diode selected is an NSR201 Schottky chip diode, with equivalent circuit parameters of: C=0.15pF, L=0.45nH, R=1.5Ω.

[0030] The metal strip and diode are integrated and etched on the inside of the square dielectric waveguide.

[0031] When the diodes are off, the length of the metal strip between the paired diodes plays a major role in transmission, allowing transmission below the asymptotic frequency. f 1. Electromagnetic waves; when the diode is turned on, the two ends of the strip are connected, the equivalent length of the metal strip increases, and the asymptotic frequency decreases to 1. f 2. Therefore, for f 2~ f Electromagnetic waves in frequency band 1 exhibit energy selectivity.

[0032] Furthermore, the present invention also provides a dual-polarized ultrawideband energy selective material prepared using the above method, such as... Figure 1 As shown, it consists of a square dielectric waveguide, diodes, and a linearly modulated SSPPs structure (periodic metal strips). The square dielectric waveguide is made of FR4 printed circuit board. Each metal strip is divided into three segments by pairs of diodes. The length of the metal strips between the diodes and the length of the entire metal strip are all linearly modulated.

[0033] The square waveguide has a period of λ / 2. The length of the entire metal strip determines the lower cutoff frequency of the passband, while the length of the metal strip between the diodes determines the upper cutoff frequency of the passband.

[0034] Simulations show the insertion loss and protective performance of selectable materials, with results as follows: Figure 2 and Figure 3 As shown in the figure. The simulation results show that the energy-selective material proposed in this invention has basically the same insertion loss and protection performance under x-polarized and y-polarized incident conditions, exhibiting dual-polarization performance; under both polarizations, the 1dB insertion loss frequency band is 4.65GHz~9.23GHz, and the relative bandwidth is (9.23-4.65) / (9.23+4.65)×2=66%, achieving ultra-wideband performance.

[0035] The energy selective material unit size proposed in this invention is λ / 2, with each unit containing 152 NSR201 Schottky chip diodes. The market price is 1.5 yuan per diode, and the cost per unit is 228 yuan. Comparing this to the three-layer cascaded spatial filter structure designed in the paper "Design of a Broadband Energy Selective Surface with Ultra-High Shielding Efficiency" published by Nanjing University of Science and Technology, the unit size of this invention can encompass 16 of the units proposed in that paper, totaling 128 MADP-0009 diodes (market price 15 yuan per diode), with a diode cost of 1920 yuan. Therefore, this invention achieves a low-cost effect.

[0036] In summary, this invention innovatively integrates diodes and SSPPs structures and etches them onto the surface of a dielectric waveguide, resulting in a centrally symmetrical structure that achieves dual polarization functionality.

[0037] This invention utilizes the low-pass characteristics of SSPPs, and by controlling the conduction and cutoff of the diode, two low-pass curves form a channel window. Furthermore, by controlling the position of the diode and the length of the SSPPs, ultra-wideband functionality is achieved.

[0038] This invention utilizes the field confinement effect of SSPPs to convert space waves into surface waves and then back into space waves, thereby reducing insertion loss; and utilizes the steep cutoff characteristics of SSPPs to improve protection effectiveness.

[0039] The energy selection unit proposed in this invention has a size of λ / 2, while the size of traditional energy selection units is usually less than λ / 10. Furthermore, the diode junction capacitance used is larger than that of ordinary energy selection units, thus achieving a low-cost effect.

[0040] It should be noted that, depending on the implementation needs, the various steps / components described in this invention can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0041] Those skilled in the art will readily understand that the above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for designing dual-polarization ultrawideband energy-selective materials, characterized in that, The method includes: A diode and a surface plasmon polariton (SSPP) structure are integrated and etched onto the surface of a dielectric waveguide to form a centrosymmetric structure. The SSPPs are periodic metal strips etched onto the surface of the dielectric waveguide. Each SSPP metal strip integrates two diodes, which are symmetrically integrated on both sides of the metal strip. The diodes are etched with slots, and the metal strips are connected through the diodes. When the diodes are off, the metal strip transmission between the two diodes is below the asymptotic frequency. f 1. Electromagnetic waves; when the diode is turned on, the metal strip connecting the two diodes increases in equivalent length, and the asymptotic frequency decreases to 1. f 2, make f 2~ f Electromagnetic waves in frequency band 1 exhibit energy selectivity.

2. The dual-polarization ultrawideband energy selective material design method according to claim 1, characterized in that, The dielectric waveguide is a square dielectric waveguide.

3. The dual-polarization ultrawideband energy-selective material design method according to claim 1 or 2, characterized in that, The dielectric waveguide uses FR-4 printed circuit board material as the dielectric.

4. The dual-polarization ultrawideband energy selective material design method according to claim 1 or 2, characterized in that, The metal strip and diode are integrated and etched on the inside of the square dielectric waveguide.

5. The dual-polarization ultrawideband energy selective material design method according to claim 1, characterized in that, Each metal strip is divided into three segments by two diodes, and the length of the metal strip between the diodes and the entire metal strip are all linearly modulated.

6. The dual-polarization ultrawideband energy-selective material design method according to claim 1 or 5, characterized in that, The length of the entire metal strip determines the lower cutoff frequency of the passband, while the length of the metal strip between the two diodes determines the upper cutoff frequency of the passband.

7. The dual-polarization ultrawideband energy selective material design method according to claim 1, characterized in that, The periodic unit size of the energy-selective material is half the wavelength corresponding to the center frequency of the operating band.

8. The dual-polarization ultrawideband energy selective material design method according to claim 1, characterized in that, The diode is an NSR201 Schottky chip diode.

9. The dual-polarization ultrawideband energy-selective material design method according to claim 1 or 8, characterized in that, The equivalent circuit parameters of the diode are: C=0.15pF, L=0.45nH, R=1.5Ω.

10. A dual-polarization ultrawideband energy selective material, characterized in that, include: Dielectric waveguide; The surface plasmon polariton (SSPP) structure consists of periodic metal strips etched on the surface of a dielectric waveguide, forming a centrosymmetric structure together with a diode. Diodes: Two diodes are integrated into each SSPPs metal strip. The two diodes are symmetrically integrated on both sides of the metal strip, and the diodes are etched with slots to connect the metal strips. When the diodes are off, the metal strip transmission between the two diodes is below the asymptotic frequency. f 1. Electromagnetic waves; when the diode is turned on, the metal strip connecting the two diodes increases in equivalent length, and the asymptotic frequency decreases to 1. f 2, make f 2~ f Electromagnetic waves in frequency band 1 exhibit energy selectivity.

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