Tunable electromagnetic metamaterial and wireless communication network system

Abstract

The invention provides a tunable electromagnetic metamaterial and a wireless communication network system, and the tunable electromagnetic metamaterial comprises a dielectric plate, and a first conductive structure and a second conductive structure which are respectively arranged on the first surface and the second surface of the dielectric plate. Each of the first conductive structure and the second conductive structure comprises a plurality of strip units and a resistor connected with the strip units, the two conductive structures are conducted through metal via holes, each strip unit comprises a first strip, a second strip and a connecting strip, and a variable capacitor is arranged on each connecting strip. When high-frequency electromagnetic waves are incident, sawtooth-shaped currents are formed on the first surface and the second surface of the dielectric plate, every two adjacent connecting strips are staggered in the thickness direction of the dielectric plate, the opposite area of the two connecting strips can be reduced, the capacitance value of the formed capacitor plate is reduced, and therefore when the capacitance value of the variable capacitor is adjusted, the capacitance value of the variable capacitor plate is adjusted. And the influence ratio on the resonant frequency is larger, and when the adjusting range of the variable capacitor is not changed, the variable capacitor has a wider frequency adjusting range.

Description

Technical Field

[0001] The present invention belongs to the field of electromagnetic wave technology, and more specifically, relates to a tunable electromagnetic metamaterial and a wireless communication network system. Background Art

[0002] With the development of the wireless communication industry, 4G has been widely used in various fields, and its data rate, reliability, latency and spectrum efficiency have been significantly improved. However, with the rise of new applications such as the metaverse, holographic video and ultra-high-definition video, higher requirements are placed on the data rate and spectrum efficiency of communication systems. The goal of communication is to achieve ultra-low latency and ultra-high throughput in a higher frequency range, but existing technologies still face some challenges. For example, massive multiple-input multiple-output (MIMO) technology requires a large number of antennas and RF links, resulting in high hardware costs and high energy consumption; traditional frequency selective surface (FSS) structures have limitations in frequency tuning range, flexibility and bandwidth expansion.

[0003] Active frequency selective surface (AFSS) is a structure that adds tunable wave-transmitting elements (such as varactor diodes) to the FSS structure. In a high-interference environment, AFSS can shield interference signals and improve communication quality by adjusting the frequency selection properties. Compared with passive frequency selective surfaces, AFSS can achieve in-band signal confidentiality, increase channel capacity and improve performance stability by controlling the voltage and current of the varactor diode. Embedding AFSS into the radar antenna cover design can improve the stealth performance and communication quality of combat weapons and equipment, and can reduce the working bandwidth limitation of the antenna and increase functional diversity in complex electromagnetic environments.

[0004] Although the frequency selective surface (AFSS) structure of the varactor diode has better flexibility than the traditional FSS structure, its complex structure will cause problems such as parasitic capacitance. The varactor diode cannot efficiently adjust the resonant frequency and the adjustment range is narrow. In addition, in order to avoid mutual coupling between structures, a larger spacing space needs to be designed, resulting in large size and large space occupied. Summary of the invention

[0005] The purpose of the embodiments of the present invention is to provide a tunable electromagnetic metamaterial and a wireless communication network system to solve the technical problems of narrow resonant frequency adjustment range and large size existing in the prior art.

[0006] To achieve the above object, the technical solution adopted by the present invention is: to provide a tunable electromagnetic metamaterial, comprising: The dielectric plate has a first surface and a second surface disposed opposite to each other in a thickness direction thereof; A first conductive structure, disposed on the first surface, the first conductive structure comprising a plurality of strip units sequentially disposed along a first direction and a resistor connecting two adjacent strip units; and A second conductive structure, disposed on the second surface, the second conductive structure comprising a plurality of strip units sequentially disposed along the first direction and a resistor connecting two adjacent strip units; The strip unit comprises a first strip, a second strip and a connecting strip, the first strip and the second strip are arranged at intervals in the second direction, in two adjacent strip units, two adjacent first strips and two adjacent second strips are connected by the resistor, and a variable capacitor is arranged on the connecting strip; the first direction, the second direction and the thickness direction of the dielectric plate are perpendicular to each other; In an orthographic projection in the thickness direction of the dielectric plate, the connecting strips of the first conductive structure and the connecting strips of the second conductive structure are spaced apart from each other in the first direction; In the area of ​​one of the strip units, the dielectric board is provided with a first metal via and a second metal via that connect the first conductive structure and the second conductive structure, the first metal via connects the first strip of the first conductive structure and the first strip of the second conductive structure, and the second metal via connects the second strip of the first conductive structure and the second strip of the second conductive structure.

[0007] Optionally, in the first conductive structure, the first metal via is located at a connection between the first strip and the connecting strip, and the second metal via is located at an end of the second strip close to the resistor.

[0008] Optionally, the first conductive structure and the second conductive structure have the same structure, and in an orthographic projection in a thickness direction of the dielectric plate, the first conductive structure and the second conductive structure are arranged at a first distance in the first direction.

[0009] Optionally, in the first conductive structure, a distance between the connecting strips of two adjacent strip units is a second distance, and the second distance is twice the first distance.

[0010] Optionally, the tunable electromagnetic metamaterial comprises a plurality of unit cells connected in sequence along a first direction, each of the unit cells comprises a variable capacitor located on the first surface and a variable capacitor located on the second surface, and in the same unit cell, two connecting strips form a parallel plate capacitor, and the capacitance value of each parallel plate capacitor after superposition is C p .

[0011] Optionally, the resonant frequency of the tunable electromagnetic metamaterial ,in, C T is the capacitance value after superposition of each variable capacitor, L is the equivalent inductance of the first strip, the second strip and the connecting strip, Δ L is the mutual coupling inductance of each adjacent strip unit, C T >> C p .

[0012] Optionally, the capacitance value of each parallel plate capacitor after superposition is ,in, ε 0 is the dielectric constant of vacuum, ε r is the dielectric constant of the dielectric plate, A is the effective overlapping area of ​​the two connecting strips, d is the distance between the two connecting strips, k is the superposition coefficient, C T >> C p .

[0013] Optionally, the resistance value of the resistor is 10 kΩ±2 kΩ.

[0014] Optionally, the tunable electromagnetic metamaterial further includes a feeding structure, a high level of the feeding structure is located at a first stripe of the first conductive structure, and a low level of the feeding structure is located at a second stripe of the first conductive structure.

[0015] The present invention also provides a wireless communication network system, comprising the above-mentioned tunable electromagnetic metamaterial.

[0016] The beneficial effect of the tunable electromagnetic metamaterial provided by the present invention is that: compared with the prior art, the tunable electromagnetic metamaterial of the present invention includes a dielectric plate, a first conductive structure and a second conductive structure, the first conductive structure and the second conductive structure both include a plurality of strip units and resistors connecting the strips, the strip units include a first strip, a second strip and a connecting strip connecting the first strip and the second strip, and a variable capacitor is arranged on the connecting strip. The first conductive structure and the second conductive structure are staggered in the first direction, so that the connecting strips of the first surface and the second surface are arranged at intervals from each other in the first direction, and the first conductive structure and the second conductive structure are connected through the first metal via and the second metal via. In this way, when a high-frequency electromagnetic wave is incident, the current on the surface of the tunable electromagnetic metamaterial is blocked by the resistor and preferentially passes through the metal strip and the variable capacitor, thereby forming a sawtooth current on the first surface and the second surface of the dielectric plate, and forming a magnetic field in the thickness direction of the dielectric plate. Conductive structures are provided on both the first surface and the second surface. In the strips corresponding to the sawtooth current, two adjacent connecting strips are staggered in the thickness direction of the dielectric plate. Even when the distance between the two strips in the first direction is relatively close, the coupling between the two strips can be greatly reduced. Therefore, under the premise that the resonant frequency adjustment range remains unchanged, the size of the metamaterial can be reduced. At the same time, the two adjacent connecting strips are staggered in the thickness direction of the dielectric plate, which can reduce the facing area of ​​the two connecting strips and reduce the capacitance value of the formed capacitor plate. In this way, when adjusting the capacitance value of the variable capacitor, the influence on the resonant frequency accounts for a larger proportion. When the adjustment range of the variable capacitor remains unchanged, the present application has a wider frequency adjustment range. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of a portion of the structure of a tunable electromagnetic metamaterial provided by an embodiment of the present invention; Figure 2 A schematic diagram of the current flow of a tunable electromagnetic metamaterial provided by an embodiment of the present invention; Figure 3 A schematic diagram of current simulation of a tunable electromagnetic metamaterial provided by an embodiment of the present invention; Figure 4 A schematic diagram of the structure of a unit cell provided by an embodiment of the present invention; Figure 5 A schematic diagram of an equivalent circuit of a tunable electromagnetic metamaterial provided by an embodiment of the present invention; Figure 6 A tunable S-parameter curve diagram of a tunable electromagnetic metamaterial provided by an embodiment of the present invention; Figure 7 A schematic diagram of a zigzag active tuning selection surface in the related art; Figure 8 for Figure 1 and Figure 7 Comparison of tunable S-parameter curves of tunable electromagnetic metamaterials.

[0019] Among them, the reference numerals in the figure are: 10-first conductive structure; 11-strip unit; 111-first strip; 112-second strip; 113-connecting strip; 12-resistance; 13-variable capacitor; 20-second conductive structure; 30-dielectric plate; 31-first surface; 32-second surface; 33-first metal via; 34-second metal via. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0022] It should be understood that the orientation or position relationship indicated by terms such as "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0023] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0024] AFSS is a structure that adds tunable wave-transmitting elements (such as varactor diodes) to the FSS structure. In a high-interference environment, AFSS can shield interference signals and improve communication quality by adjusting the frequency selection properties. Compared with passive frequency selective surfaces, AFSS can achieve in-band signal confidentiality, increase channel capacity and improve performance stability by controlling the voltage and current of the varactor diode. Embedding AFSS into the radar antenna cover design can improve the stealth performance and communication quality of combat weapons and equipment, and can reduce the working bandwidth limitation of the antenna and increase functional diversity in a complex electromagnetic environment.

[0025] Although the AFSS structure of the varactor diode has better flexibility than the traditional FSS structure, due to its complex structure, firstly, it will bring about the problem of parasitic capacitance. The varactor diode cannot efficiently adjust the resonant frequency and the adjustment range is narrow. Secondly, in order to avoid mutual coupling between structures, a larger spacing space needs to be designed, resulting in large size and large space occupied.

[0026] In order to alleviate or solve the above technical problems, the present invention proposes a tunable electromagnetic metamaterial, including a dielectric plate 30, and a first conductive structure 10 and a second conductive structure 20 respectively arranged on a first surface 31 and a second surface 32 of the dielectric plate 30, the first conductive structure 10 and the second conductive structure 20 each including a plurality of strip units 11 and a resistor 12 connecting the strip units 11, and a first metal via 33 and a second metal via 34 are also provided on the dielectric plate 30, the first metal via 33 connects the first strip 111 of the first conductive structure 10 and the second strip 112 of the second conductive structure 20, and the second metal via 34 connects the second strip 112 of the first conductive structure 10 and the first strip 111 of the second conductive structure 20. When a high-frequency electromagnetic wave is incident on the tunable electromagnetic metamaterial, the resistor 12 is equivalent to a short circuit, and the current flows from the first strip 111 of the first conductive structure 10 through the connecting strip 113 (having a variable capacitor 13), the second strip 112 of the first conductive structure 10, and the second metal via 34 to the second conductive structure 20, thereby forming a sawtooth current. In this way, the strips through which the current passes are distributed on the first surface 31 and the second surface 32, and the adjacent connecting strips 113 are staggered in the thickness direction of the dielectric plate 30, which can not only reduce the size of the metamaterial, but also increase the frequency adjustment range of the metamaterial.

[0027] The tunable electromagnetic metamaterial provided by the embodiment of the present invention is now described. When a vertically polarized plane wave is incident, the current inside the tunable electromagnetic metamaterial changes, forming resonance, and only incident electromagnetic waves with non-resonant frequencies (tunable electromagnetic metamaterial) can pass through the tunable electromagnetic metamaterial.

[0028] Please also read Figures 1 to 3 , tunable electromagnetic metamaterials include: The dielectric plate 30 has a first surface 31 and a second surface 32 disposed opposite to each other in the thickness direction thereof; A first conductive structure 10 is disposed on the first surface 31 , and includes a plurality of strip units 11 sequentially disposed along a first direction and a resistor 12 connecting two adjacent strip units 11 ; and A second conductive structure 20 is disposed on the second surface 32 , and includes a plurality of strip units 11 sequentially disposed along the first direction and a resistor 12 connecting two adjacent strip units 11 ; The strip unit 11 includes a first strip 111, a second strip 112 and a connecting strip 113. The first strip 111 and the second strip 112 are arranged at intervals in the second direction. In two adjacent strip units 11, two adjacent first strips 111 and two adjacent second strips 112 are connected by a resistor 12. A variable capacitor 13 is arranged on the connecting strip 113. The first direction, the second direction and the thickness direction of the dielectric plate 30 are perpendicular to each other. In the orthographic projection in the thickness direction of the dielectric plate 30 , the connecting strips 113 of the first conductive structure 10 and the connecting strips 113 of the second conductive structure 20 are spaced apart from each other in the first direction; In the area of ​​a strip unit 11, a first metal via 33 and a second metal via 34 that connect the first conductive structure 10 and the second conductive structure 20 are provided on the dielectric plate 30. The first metal via 33 connects the first strip 111 of the first conductive structure 10 and the first strip 111 of the second conductive structure 20, and the second metal via 34 connects the second strip 112 of the first conductive structure 10 and the second strip 112 of the second conductive structure 20.

[0029] The dielectric plate 30 is an important component used to support and isolate circuit components in electronic devices, and is usually made of insulating materials. The main function of the dielectric plate 30 is to provide electrical insulation, prevent interference between circuits, and support and fix electronic components. The dielectric plate 30 has a first surface 31 and a second surface 32, which are respectively arranged on opposite sides of the dielectric plate 30 in the thickness direction. The first surface 31 and the second surface 32 can also be understood as the front and back of the dielectric plate 30, respectively.

[0030] The first conductive structure 10 is located on the first surface 31. The first conductive structure 10 includes a strip unit 11 and a resistor 12. The number of the strip units 11 is multiple and they are sequentially distributed along the first direction. The strip unit 11 is a metal structure with conductive properties. The resistor 12 is used to connect two adjacent strip units 11. In a high-frequency electromagnetic wave environment, the resistor 12 is equivalent to a short circuit and is a non-conductive structure. The second conductive structure 20 is located on the second surface 32. The second conductive structure 20 includes a strip unit 11 and a resistor 12. The number of the strip units 11 is multiple and they are sequentially distributed along the first direction. The strip unit 11 is a metal structure with conductive properties. The resistor 12 is used to connect two adjacent strip units 11. In a high-frequency electromagnetic wave environment, the resistor 12 is equivalent to a short circuit and is a non-conductive structure.

[0031] The strip units 11 of the first conductive structure 10 and the second conductive structure 20 each include a first strip 111, a second strip 112 and a connecting strip 113, the two ends of the connecting strip 113 are respectively connected to the first strip 111 and the second strip 112, and a variable capacitor 13 is provided on the connecting strip 113. It can be understood that the connecting strip 113 includes two conductive strips, and the variable capacitor 13 connects the two conductive strips, one end of one conductive strip is connected to the first strip 111, and one end of the other conductive strip is connected to the second strip 112. In two adjacent strip units 11, two adjacent first strips 111 are connected through a resistor 12, and two adjacent second strips 112 are connected through another resistor 12. Among them, the variable capacitor 13 is a capacitor whose capacitance value can be adjusted, and the variable capacitor 13 can be a device such as a varactor diode. When the capacitance value of the variable capacitor 13 changes, the resonant frequency of the tunable electromagnetic metamaterial changes accordingly.

[0032] Among them, in the orthographic projection in the thickness direction of the dielectric plate 30, the connecting strips 113 of the first conductive structure 10 and the connecting strips 113 of the second conductive structure 20 are spaced apart from each other in the first direction. It can be understood that the orthographic projections of the connecting strips 113 of the first conductive structure 10 and the connecting strips 113 of the second conductive structure 20 in the thickness direction of the dielectric plate 30 are both in the shape of strips, and the two strip shapes are spaced apart from each other in the first direction. It can also be understood that in the thickness direction of the dielectric plate 30, the first conductive structure 10 and the second conductive structure 20 are staggered from each other, and the connecting strips 113 of the first surface 31 and the connecting strips 113 of the second surface 32 are not directly opposite to each other.

[0033] In the region of one of the strip units 11, a first metal via 33 and a second metal via 34 are provided on the dielectric plate 30. The first metal via 33 and the second metal via 34 are both through holes that penetrate the dielectric plate 30, and the interior of the through hole has a metal surface layer, and the metal surface layer can conduct the first conductive structure 10 and the second conductive structure 20. The first metal via 33 conducts the first strip 111 of the first conductive structure 10 and the first strip 111 of the second conductive structure 20, and the second metal via 34 conducts the second strip 112 of the first conductive structure 10 and the second strip 112 of the second conductive structure 20.

[0034] See also Figure 2 and Figure 3 When a vertically polarized plane wave (high-frequency electromagnetic wave) is incident, the resistor 12 in the tunable electromagnetic metamaterial is equivalent to an open circuit, so the current flows according to Figure 2 Specifically, the current first flows from the first strip 111 of the first conductive structure 10 toward the connecting strip 113, passes through the variable capacitor 13, the second strip 112 of the first conductive structure 10, and the second metal via 34, flows to the second strip 112 of the second conductive structure 20, and then passes through the connecting strip 113 of the second conductive structure 20, the variable capacitor 13, the first strip 111, and the first metal via 33, and flows again to the first strip 111 of the first conductive structure 10. Figure 3 The current simulation results in Figure 2 As a result, the current in the tunable electromagnetic metamaterial is a sawtooth current, and is staggeredly distributed on the first surface 31 and the second surface 32.

[0035] In the tunable electromagnetic metamaterial of the embodiment of the present invention, the resonant frequency is proportional to the capacitance value of the variable capacitor 13. C T and the capacitance value of the capacitor plate formed by two adjacent connecting strips 113 (the connecting strip 113 of the first conductive structure 10 and the connecting strip 113 of the second conductive structure 20) C p The capacitance value of two adjacent connecting strips 113 is C p The larger the capacitance of the variable capacitor 13 is, C T The smaller the change in the resonant frequency caused by the change in C p The smaller the capacitance value of the variable capacitor 13 is, C TIn this embodiment, two adjacent connecting strips 113 are located on the first surface 31 and the second surface 32 respectively, so the effective overlapping area of ​​the two connecting strips 113 is small. Accordingly, the capacitance value C p is also small, so the capacitance value of the variable capacitor 13 is C T The change in resonant frequency caused by the change increases. Compared with the related art, the variable capacitor 13 with the same adjustable range is used. The resonant frequency range that can be adjusted by the embodiment of the present invention is larger and the bandwidth is wider. In this embodiment, two adjacent connecting strips 113 are respectively located on the first surface 31 and the second surface 32. In the related art, two adjacent connecting strips 113 are located on the same surface, which is more likely to produce mutual coupling, affecting the resonance effect of the metamaterial. Therefore, the spacing between the two adjacent connecting strips 113 needs to be set larger. By setting the two connecting strips 113 on different surfaces, the coupling between the two connecting strips 113 can be reduced. In the embodiment of the present invention, the distance between the two connecting strips 113 (the size in the first direction) can be set closer. Accordingly, the size of the tunable electromagnetic metamaterial is smaller and the space occupied is smaller. Under the same size, more strip units 11 can be set to enhance magnetic coupling.

[0036] The tunable electromagnetic metamaterial in the above embodiment includes a dielectric plate 30, a first conductive structure 10 and a second conductive structure 20, wherein the first conductive structure 10 and the second conductive structure 20 both include a plurality of strip units 11 and a resistor 12 connecting the strips 113, the strip unit 11 includes a first strip 111, a second strip 112 and a connecting strip 113 connecting the first strip 111 and the second strip 112, and a variable capacitor 13 is provided on the connecting strip 113. The first conductive structure 10 and the second conductive structure 20 are staggered in the first direction, so that the connecting strips 113 on the first surface 31 and the second surface 32 are spaced apart from each other in the first direction, and the first conductive structure 10 and the second conductive structure 20 are connected through the first metal via 33 and the second metal via 34. Thus, when a high-frequency electromagnetic wave is incident, the current on the surface of the tunable electromagnetic metamaterial passes preferentially through the metal strip and the variable capacitor 13 under the obstruction of the resistor 12, thereby forming a sawtooth current on the first surface 31 and the second surface 32 of the dielectric plate 30, and forming a magnetic field in the thickness direction of the dielectric plate 30 (combined with the magnetic field of the first surface 31 and the second surface 32 of the dielectric plate 30). Figure 2"·" means perpendicular to the paper and outward, "×" means perpendicular to the paper and outward). Conductive structures are provided on both the first surface 31 and the second surface 32. In the strips corresponding to the sawtooth current, two adjacent connecting strips 113 are staggered in the thickness direction of the dielectric plate 30. Even when the distance between the two is close in the first direction, the coupling between the two can be greatly reduced. Therefore, under the premise that the resonant frequency adjustment range remains unchanged, the size of the metamaterial can be reduced. At the same time, two adjacent connecting strips 113 are staggered in the thickness direction of the dielectric plate 30, which can reduce the facing area of ​​the two connecting strips 113 and reduce the capacitance value of the formed capacitor plate. In this way, when adjusting the capacitance value of the variable capacitor 13, the influence on the resonant frequency accounts for a larger proportion. When the adjustment range of the variable capacitor 13 remains unchanged, the present application has a wider frequency adjustment range.

[0037] In some embodiments of the present invention, see Figure 1 and Figure 4 In the first conductive structure 10, the first metal via 33 is located at the connection between the first strip 111 and the connecting strip 113, and the second metal via 34 is located at the end of the second strip 112 close to the resistor 12. Correspondingly, in the second conductive structure 20, the first metal via 33 is located at the end of the first strip 111 close to the resistor 12, and the second metal via 34 is located at the connection between the second strip 112 and the connecting strip 113. In this way, the metal via design of the tunable electromagnetic metamaterial can be made simpler, the current distribution on the first surface 31 and the second surface 32 can be more balanced, and the resonance effect of the metamaterial can be better.

[0038] It should be noted that in one strip unit 11, there is a first metal via 33 and a second metal via 34, and the first surface 31 of the dielectric plate 30 has N strip units 11. Accordingly, the number of the first metal via 33 and the number of the second metal via 34 are both N.

[0039] In some embodiments of the present invention, the strip unit 11 is H-shaped, and the length direction of the connecting strip 113 is parallel to the second direction. This can reduce the difficulty of design and processing as much as possible, and can also make the strip unit 11 a symmetrical structure, and the connecting strips 113 on the first surface 31 and the second surface 32 are parallel to each other.

[0040] In some embodiments of the present invention, see Figure 1 and Figure 2, the first conductive structure 10 and the second conductive structure 20 have the same structure. In the orthographic projection in the thickness direction of the dielectric plate 30, the first conductive structure 10 and the second conductive structure 20 are arranged at a first distance in the first direction. The first conductive structure 10 and the second conductive structure 20 have the same structure, but are staggered in the first direction, and the staggered spacing is the first distance. It should be noted that the spacing between the first conductive structure 10 and the second conductive structure 20 in the first direction is understood as the spacing between the center of the first conductive structure 10 and the center of the second conductive structure 20 in the first direction. The two sides of the dielectric plate 30 in the second direction can be understood as the left and right sides of the dielectric plate 30, the first strip 111 of the first surface 31 and the first strip 111 of the second surface 32 are both arranged on the left side of the dielectric plate 30, and the second strip 112 of the first surface 31 and the second strip 112 of the second surface 32 are both arranged on the right side of the dielectric plate 30.

[0041] In some embodiments, in the first conductive structure 10, the distance between the connecting strips 113 of two adjacent strip units 11 is a second distance, and the second distance is twice the first distance. Among them, two adjacent strip units 11 refer to two strip units 11 close to each other on the first surface 31, and the distance between the connecting strips 113 refers to the distance between the centers of the two connecting strips 113. When the second distance is twice the first distance, all the connecting strips 113 are projected along the thickness direction of the dielectric plate 30, and the distance between every two adjacent connecting strips 113 is equal. It can also be understood that the distance between one of the connecting strips 113 on the second surface 32 and the two connecting strips 113 on the first surface 31 adjacent to it is equal. In this way, the resonance effect of the tunable electromagnetic metamaterial can be better.

[0042] In some embodiments of the present invention, see Figure 4 The tunable electromagnetic metamaterial includes a plurality of unit cells connected in sequence along a first direction, each unit cell includes a variable capacitor 13 located on a first surface 31 and a variable capacitor 13 located on a second surface 32. In the same unit cell, two connecting strips 113 form a parallel plate capacitor, and the capacitance value of each parallel plate capacitor after superposition is C p. It can be understood that the tunable electromagnetic metamaterial is divided along the first direction to form a plurality of unit cells. Therefore, the structures on the front and back sides of the unit cell are not the same, but both sides have connecting strips 113 and variable capacitors 13. Although the connecting strips 113 on the front and back sides are not arranged directly opposite each other (the thickness of the dielectric plate 30 causes the two connecting strips 113 to be staggered), since the edges of the two connecting strips 113 still have current, a parallel plate capacitor with a smaller capacitance value will still be formed. Each unit cell corresponds to a parallel plate capacitor, and the capacitance value formed by the superposition of the parallel plate capacitors is C p .

[0043] In some embodiments of the present invention, see Figure 5 , the resonant frequency of tunable electromagnetic metamaterials (Formula 1), where C T is the capacitance value of each variable capacitor 13 after superposition, L is the equivalent inductance of the first strip 111, the second strip 112 and the connecting strip 113, Δ L is the mutual coupling inductance of each adjacent strip unit 11, C T >> C p . R is the resistance value of resistor 12. When high-frequency electromagnetic waves are incident, the electromagnetic waves with the same frequency as the resonant frequency of the metamaterial are absorbed by the metamaterial, and electromagnetic waves of other frequencies pass through the tunable electromagnetic metamaterial. There are multiple variable capacitors 13, and the capacitance value after the multiple variable capacitors 13 are superimposed is recorded as C T In order to enable the variable capacitor 13 to achieve a larger adjustment bandwidth (frequency range) within the same adjustment range, C p , L , Δ L The smaller the better. C T >> C p , means C T Compare C p is at least three orders of magnitude larger, so that C p Very small, C T When it changes, the impact on the resonant frequency is smaller and the frequency adjustment range is larger.

[0044] LThe size of is related to the length of the metal strip. The longer the metal strip, L Compared with the prior art, this embodiment can reduce the size, and accordingly, the length of the metal strip becomes smaller. L Since the connecting strips 113 on the front and back sides are not arranged opposite to each other (the thickness of the dielectric plate 30 causes the two connecting strips 113 to be staggered with each other), only a parallel plate capacitor with a smaller capacitance value can be formed between the two connecting strips 113. In other words, C p Smaller, so a wider adjustment bandwidth can be achieved.

[0045] In some embodiments of the present invention, see Figure 5 The capacitance of each parallel plate capacitor after superposition is ,in, ε 0 is the dielectric constant of vacuum, ε r is the dielectric constant of the dielectric plate 30, A is the effective overlapping area of ​​the two connecting strips 113, d is the distance between the two connecting strips 113, k is the superposition coefficient, C T >> C p When multiple parallel plate capacitors are superimposed on each other, the total capacitance value has a superposition coefficient with a single parallel plate capacitor. k , k It is related to the number of parallel plate capacitors and the connection method of each parallel plate capacitor. In a unit cell, since the connecting strips 113 on the front and back sides are not arranged opposite to each other (the thickness of the dielectric plate 30 causes the two connecting strips 113 to be staggered with each other), the effective overlapping area A between the two connecting strips 113 is very small. Accordingly, C p Very small.

[0046] The tuning capability of tunable metamaterials can be achieved through adjustable ratio r To express, ,in, C T1 and C T2 are the capacitance values ​​of the variable capacitor 13 in the first state and the second state respectively, f 1 is the resonant frequency of the variable capacitor 13 in the first state, f 2 is the resonant frequency of the variable capacitor 13 in the second state. C p The smaller it is, the larger r is, and the stronger the tuning ability of the tunable metamaterial is.

[0047] Thus, by providing conductive structures on both the first surface 31 and the second surface 32 of the dielectric plate 30, two adjacent connecting strips 113 can be staggered in the thickness direction of the dielectric plate 30, thereby reducing the capacitance value formed between the two. C p , compared with the related art, variable capacitor 13 C T When the adjustable range remains unchanged, the tuning ability of the tunable metamaterial is enhanced, and it can be adjusted within a larger resonant frequency range.

[0048] In some embodiments of the present invention, the resistance 12 of the resistor 12 is 10 kΩ±2 kΩ. The resistance 12 is relatively large, and forms a short circuit under the high-frequency electromagnetic wave state. The resistance 12 of each resistor 12 can be the same or different.

[0049] For example, the resistance value of the resistor 12 is 10 kΩ, 11 kΩ, 11.5 kΩ, 12 kΩ, and the like.

[0050] In some embodiments of the present invention, see Figure 1 and Figure 2 , the tunable electromagnetic metamaterial also includes a feeding structure, the high level of the feeding structure ( Figure 2 The “+” sign in the figure) is located in the first strip 111 of the first conductive structure 10, and the low level of the feeding structure ( Figure 2 The “-” sign in the figure) is located in the second strip 112 of the first conductive structure 10. The feeding structure provides a bias voltage for the tunable electromagnetic metamaterial, so that the variable capacitor 13 can adjust the capacitance value.

[0051] In other embodiments, the tunable electromagnetic metamaterial may not include a feeding structure, and a bias voltage may be provided to the tunable electromagnetic metamaterial by an external power supply.

[0052] In order to verify that the tunable electromagnetic metamaterial of the embodiment of the present invention can achieve a larger tuning bandwidth in a smaller size, the applicant Figure 1The tunable electromagnetic metamaterial shown is simulated. The dielectric plate 30 is made of a FR4 substrate with a dielectric constant of 4.4, the thickness of the first conductive structure 10 and the second conductive structure 20 is 0.035 mm, and a 10 kΩ resistor 12 is selected to block high-frequency signals. The dimensions of the unit cell used are as follows: the width of the unit cell (the dimension in the second direction) is 5 mm, the length of the unit cell (the dimension in the first direction) is 4 mm, the width of each strip is 0.4 mm, the length of the connecting strip 113 (excluding the length of the variable capacitor 13) is 3.3 mm, the length of the variable capacitor 13 is 0.4 mm, the radius of the first metal via 33 and the second metal via 34 is 0.2 mm, and in the first conductive structure 10, the distance between the connecting strip 113 and the end of the second strip 112 having the second metal via 34 is 1.9 mm. In this embodiment, the bias voltage is applied to make the variable capacitor 13 adjustable from 0.54pF to 6.6pF. According to formula (1), the resonant frequencies of the variable capacitor 13 of the metamaterial at 0.54pF and 6.6pF can be calculated. The capacitance can be changed between 0.54pF and 6.6pF, and the capacitance ratio of the variable capacitor 13 is 12.2. This embodiment has been verified by simulation, and by changing the bias voltage of the variable capacitor 13, the capacitance is changed, so as to achieve the following Figure 6 The ultra-wide tunable frequency band shown in the figure shows that the stopband (resonant frequency) of the metamaterial can be adjusted from 1.03 GHz to 3.53 GHz, and the relative bandwidth (RBW) can be calculated to be 109.6%. Its size can be minimized, which significantly broadens the tuning range compared to traditional metamaterials.

[0053] For a comparative illustration of the tuning range and size advantages of embodiments of the present invention, see Figure 7 , Figure 7 The surface is selected for the zigzag active tuning. The varactor diodes are all BB857. The tuning range of the varactor diodes is from 0.54pF to 6.6pF. Figure 7 The specific dimensions are: a=18mm, b=11mm, s=0.3mm. Figure 7 The structure in the simulation is compared with Figure 6 The simulation results are compared with those of Figure 8 As shown, Figure 7 The tuning range of the meander structure in the embodiment is from 2.2 to 3.53 GHz, the relative bandwidth is 43.4%, and the size is much larger than that in the present application.

[0054] The present invention also provides a wireless communication network system, which includes the tunable electromagnetic metamaterial in any of the above embodiments. When the tunable electromagnetic metamaterial is used in the wireless communication network system, it can filter the incident electromagnetic waves and reduce the electromagnetic waves of a specific frequency (the resonant frequency of the metamaterial).

[0055] The wireless communication network system provided by the present invention adopts the above-mentioned tunable electromagnetic metamaterial. When a high-frequency electromagnetic wave is incident, the current on the surface of the tunable electromagnetic metamaterial passes preferentially through the metal strip and the variable capacitor 13 under the obstruction of the resistor 12, thereby forming a sawtooth current on the first surface 31 and the second surface 32 of the dielectric plate 30, and forming a magnetic field in the thickness direction of the dielectric plate 30. Conductive structures are provided on both the first surface 31 and the second surface 32. In the strips corresponding to the sawtooth current, two adjacent connecting strips 113 are staggered in the thickness direction of the dielectric plate 30. Even if the distance between the two is close in the first direction, the coupling between the two can be greatly reduced. Therefore, the size of the metamaterial can be reduced under the premise that the resonant frequency adjustment range remains unchanged. At the same time, two adjacent connecting strips 113 are staggered in the thickness direction of the dielectric plate 30, which can reduce the facing area of ​​the two connecting strips 113 and reduce the capacitance value of the formed capacitor plate. In this way, when adjusting the capacitance value of the variable capacitor 13, the influence on the resonant frequency accounts for a larger proportion. When the adjustment range of the variable capacitor 13 remains unchanged, the present application has a wider frequency adjustment range, and the application scenarios of the wireless network communication system are richer.

[0056] The above description is only a preferred embodiment of the present invention and is 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 in the protection scope of the present invention.

Claims

1. A tunable electromagnetic metamaterial, characterized in that: include: The dielectric plate has a first surface and a second surface disposed opposite to each other in a thickness direction thereof; A first conductive structure, disposed on the first surface, the first conductive structure comprising a plurality of strip units sequentially disposed along a first direction and a resistor connecting two adjacent strip units; as well as A second conductive structure, disposed on the second surface, the second conductive structure comprising a plurality of strip units sequentially disposed along the first direction and a resistor connecting two adjacent strip units; The strip unit comprises a first strip, a second strip and a connecting strip, the first strip and the second strip are arranged at intervals in the second direction, in two adjacent strip units, two adjacent first strips and two adjacent second strips are connected by the resistor, and a variable capacitor is arranged on the connecting strip; the first direction, the second direction and the thickness direction of the dielectric plate are perpendicular to each other; In an orthographic projection in the thickness direction of the dielectric plate, the connecting strips of the first conductive structure and the connecting strips of the second conductive structure are spaced apart from each other in the first direction; In the area of ​​one of the strip units, the dielectric board is provided with a first metal via and a second metal via that connect the first conductive structure and the second conductive structure, the first metal via connects the first strip of the first conductive structure and the first strip of the second conductive structure, and the second metal via connects the second strip of the first conductive structure and the second strip of the second conductive structure.

2. The tunable electromagnetic metamaterial according to claim 1, characterized in that: In the first conductive structure, the first metal via is located at the connection between the first strip and the connecting strip, and the second metal via is located at one end of the second strip close to the resistor.

3. The tunable electromagnetic metamaterial according to claim 1, characterized in that: The first conductive structure and the second conductive structure have the same structure. In an orthographic projection in the thickness direction of the dielectric plate, the first conductive structure and the second conductive structure are arranged at a first distance apart in the first direction.

4. The tunable electromagnetic metamaterial according to claim 3, characterized in that: In the first conductive structure, a distance between the connecting strips of two adjacent strip units is a second distance, and the second distance is twice the first distance.

5. The tunable electromagnetic metamaterial according to claim 1, characterized in that: The tunable electromagnetic metamaterial comprises a plurality of unit cells connected in sequence along a first direction, each of the unit cells comprises a variable capacitor located on the first surface and a variable capacitor located on the second surface, and in the same unit cell, two connecting strips form a parallel plate capacitor, and the capacitance value of each parallel plate capacitor after superposition is C p .

6. The tunable electromagnetic metamaterial according to claim 5, characterized in that: The resonant frequency of the tunable electromagnetic metamaterial ,in, C T is the capacitance value after superposition of each variable capacitor, L is the equivalent inductance of the first strip, the second strip and the connecting strip, Δ L is the mutual coupling inductance of each adjacent strip unit, C T >> C p .

7. The tunable electromagnetic metamaterial according to claim 5, characterized in that: The capacitance value of each parallel plate capacitor after superposition is ,in, ε 0 is the dielectric constant of vacuum, ε r is the dielectric constant of the dielectric plate, A is the effective overlapping area of ​​the two connecting strips, d is the distance between the two connecting strips, k is the superposition coefficient, C T >> C p .

8. The tunable electromagnetic metamaterial according to any one of claims 1 to 7, characterized in that: The resistance value of the resistor is 10 kΩ±2 kΩ.

9. The tunable electromagnetic metamaterial according to any one of claims 1 to 7, characterized in that: The tunable electromagnetic metamaterial further includes a feeding structure, wherein a high level of the feeding structure is located at a first stripe of the first conductive structure, and a low level of the feeding structure is located at a second stripe of the first conductive structure.

10. A wireless communication network system, characterized in that: The invention comprises the tunable electromagnetic metamaterial as described in any one of claims 1 to 9.

Images