Active electromagnetic wave absorption metasurface with reconfigurable frequency

Abstract

The utility model provides an active electromagnetic wave absorption metasurface with reconfigurable frequency, which belongs to the field of reconfigurable artificial surfaces and comprises a plurality of unit structures which are periodically and tightly arranged, and each unit structure comprises a metal pattern layer, a first dielectric layer, a metal grounding layer, a second dielectric layer and a direct current wiring layer which are sequentially arranged from top to bottom. The metal pattern layer comprises two metal patches, the two metal patches are connected to the direct current wiring layer through metal through holes respectively, a variable capacitance diode is connected between the two metal patches, isolation holes are formed in the periphery of the metal through hole connected with an anode of the variable capacitance diode, and each unit structure adopts three metal layers and two dielectric layers. The unit structure is simple and easy to integrate to achieve large-scale expansion, the metal grounding layer serves as a grounding layer of the unit structure and also serves as a shielding layer of the direct-current wiring layer, the influence of a direct-current control line on the performance of the unit structure can be overcome, the unit structure consistency is good, and the absorption performance of the electromagnetic wave absorption metasurface is good.

Description

TECHNICAL FIELD

[0001] The utility model belongs to reconfigurable artificial surface technical field especially, it relates to a kind of frequency reconfigurable active electromagnetic wave absorption super surface. BACKGROUND

[0002] Electromagnetic wave absorbing material can realize the absorption of electromagnetic wave by converting the energy of incident electromagnetic wave into heat or other forms of energy, and has wide application prospects in the fields of electromagnetic shielding, radar detection, interference elimination, human safety, etc.

[0003] Metamaterials are composed of periodic arrangements of subwavelength artificial resonant units, and have equivalent permittivity and permeability that can be designed artificially. By adjusting the equivalent constitutive parameters of metamaterials, the required electromagnetic wave propagation behavior can be achieved. In order to realize the absorption of electromagnetic wave, the wave-absorbing body needs to have good impedance matching and electromagnetic loss characteristics. However, the current widely studied metamaterial wave-absorbing bodies mainly rely on electromagnetic resonance, and the strong electromagnetic dispersion leads to narrow-band operation of these wave-absorbing bodies. In order to broaden the electromagnetic wave absorption band, multi-layer metamaterials, multi-size metal pattern nested metamaterials and three-dimensional structure metamaterials have been widely studied. However, multi-layer metamaterial wave-absorbing bodies are relatively thick; multi-size metal pattern nested metamaterials have serious coupling between absorption peaks, and can only achieve limited expansion of the working frequency band in limited size; three-dimensional structure metamaterials face difficulties in manufacturing, limited working frequency band and conformal difficulties. Therefore, it is extremely important to study low-cost, easy-to-process, high-performance and wide-band metamaterial wave-absorbing bodies.

[0004] In recent years, frequency-tunable metamaterial wave-absorbing bodies have received extensive attention. By adjusting the electromagnetic parameters of the absorbing units, the continuous tunability of the working frequency of the absorbing material is achieved. Compared with wide-band wave-absorbing bodies, it improves the bandwidth utilization rate on the basis of adjustability and applicability. PIN diodes, varactor diodes and other electronic components are widely used in frequency-tunable metamaterial wave-absorbing bodies due to their low cost, sensitive response and integration advantages. SUMMARY

[0005] The technical problem to be solved by the utility model is how to design an electromagnetic wave absorption super surface with simple structure, easy integration and good absorption performance.

[0006] The utility model discloses a frequency reconfigurable active electromagnetic wave absorption super surface which is composed of a plurality of unit structures arranged periodically and closely, each unit structure comprises, from top to bottom, a metal pattern layer, a first dielectric layer, a metal ground layer, a second dielectric layer and a direct current wiring layer, the metal pattern layer comprises two metal patches, the two metal patches are connected to the direct current wiring layer through metal through holes respectively, a variable capacitance diode is connected between the two metal patches, there is an isolation hole around the metal through hole connected to the anode of the variable capacitance diode, and the metal through hole connected to the cathode of the variable capacitance diode is in conduction with the metal ground layer.

[0007] The electromagnetic wave absorption super surface is composed of a plurality of unit structures arranged periodically and closely, each unit structure comprises three metal layers and two dielectric layers, the unit structure is simple and easy to integrate and realize large-scale expansion, the metal ground layer serves as the ground layer of the unit structure and also serves as the shielding layer of the direct current wiring layer, the influence of the direct current control line on the performance of the unit structure can be overcome, the number of wiring lines of the direct current wiring layer does not have a significant impact on the working performance of the unit structure, the unit structure has good consistency, and the electromagnetic wave absorption super surface integrated by the unit structure has good absorption performance.

[0008] Preferably, the super surface further comprises a voltage control panel and a plurality of busbars, and the voltage control panel is connected to the direct current wiring layer through the busbars.

[0009] Preferably, the N*N unit structures are arranged periodically in the X-axis and Y-axis directions, the plurality of busbars are located on the left side and the right side of the super surface respectively, in the X-axis direction, the direct current wiring layers of the unit structures in each row are connected to the busbars on the left side, and the direct current wiring layers of the unit structures in the other half of each row are connected to the busbars on the right side.

[0010] Preferably, the metal patch comprises a first metal straight line, a second metal straight line, a third metal straight line and a fourth metal straight line, one end of the second metal straight line is connected to the middle part of the first metal straight line, the other end of the second metal straight line is connected to the middle part of the third metal straight line, the fourth metal straight line is in the shape of L, one end of the fourth metal straight line is connected to the end part of the third metal straight line, and the metal through hole is located in the middle part of the third metal straight line.

[0011] Preferably, the two first metal straight lines are connected to the anode and the cathode of the variable capacitance diode through metal pads respectively.

[0012] Preferably, the center of the metal through hole coincides with the center of the isolation hole.

[0013] Preferably, the dielectric constant of the first dielectric layer is 2.55, and the loss tangent is 0.003, and the dielectric constant of the second dielectric layer is 4.67, and the loss tangent is 0.016.

[0014] Preferably, the variable capacitance diode is model MA45H120.

[0015] Preferably, the operating frequency of the metasurface is adjustable in the range of 4GHz-5.6GHz, and the electromagnetic wave absorption efficiency is greater than 80%.

[0016] Preferably, the size of the unit structure is 5*7mm 2 , and the total thickness is 0.9mm.

[0017] The advantages of the utility model provided are:

[0018] (1) the electromagnetic wave absorption metasurface of the utility model is composed of a plurality of unit structures arranged periodically and closely, each unit structure adopts three metal layers and two dielectric layers, the unit structure is simple and easy to integrate and realize scale expansion, the metal grounding layer is used as the grounding layer of the unit structure and is also the shielding layer of the direct current wiring layer, the influence of the direct current control line on the performance of the unit structure can be overcome, the number of wiring lines of the direct current wiring layer will not obviously affect the working performance of the unit structure, and the unit structure has good consistency, and the electromagnetic wave absorption metasurface integrated by the unit structure has good absorption performance.

[0019] (2) the unit structures in the electromagnetic wave absorption metasurface of the utility model are arranged closely with the same spacing, scale expansion is easy to realize, the unit structure, the busbar and the voltage control panel are integrated on the same plane, and the utility model has the advantages of high integration, small space occupation and high reliability.

[0020] (3) the electromagnetic wave absorption metasurface of the utility model is not sensitive to the incident angle of electromagnetic waves, can realize good shielding effect on oblique incidence direction electromagnetic waves, and is suitable for electromagnetic shielding, radar detection and other fields. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 The schematic view of the frequency reconfigurable active electromagnetic wave absorption metasurface provided by the embodiment of the utility model is shown;

[0022] Figure 2 The schematic view of the unit structure in the frequency reconfigurable active electromagnetic wave absorption metasurface provided by the embodiment of the utility model is shown;

[0023] Figure 3 The schematic view of the unit structure in the frequency reconfigurable active electromagnetic wave absorption metasurface provided by the embodiment of the utility model is shown;

[0024] Figure 4 The simulation diagram of the electromagnetic wave absorption performance of the unit structure in the frequency reconfigurable active electromagnetic wave absorption metasurface provided by the embodiment of the utility model is shown;

[0025] Figure 5A simulation diagram of the absorption performance of a unit structure in a frequency-reconfigurable active electromagnetic wave absorbing metasurface provided by an embodiment of the present invention under different electromagnetic wave incident angles;

[0026] Figure 6 A simulation diagram of the absorption performance of a unit structure in a frequency-reconfigurable active electromagnetic wave absorption metasurface provided by an embodiment of the present invention when the number of DC traces in the DC trace layer is increased;

[0027] Figure 7 The electric field distribution diagram of the frequency-reconfigurable active electromagnetic wave absorbing metasurface provided by the embodiment of the present utility model at different capacitance values;

[0028] Figure 8 The electric field distribution diagram of the frequency-reconfigurable active electromagnetic wave absorbing metasurface provided by the embodiment of the present invention at different electromagnetic wave incident angles;

[0029] In the figure: 10 unit structure, 11 metal graphic layer, 111 first metal straight line, 112 second metal straight line, 113 third metal straight line, 114 fourth metal straight line, 115 metal pad, 12 first dielectric layer, 13 metal ground layer, 14 second dielectric layer, 15 DC routing layer, 16 metal through hole, 17 varactor diode, 18 isolation hole, 20 voltage control board, 30 busbar, 40 DC control line. DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions, and advantages of the present invention more clearly understood, the following describes the technical solutions of the present invention in a clear and complete manner, in conjunction with specific embodiments and with reference to the accompanying drawings. It is apparent that the embodiments described are only a portion of the embodiments of the present invention, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are intended to fall within the scope of protection of the present invention.

[0031] like Figure 1 As shown, this embodiment provides a frequency reconfigurable active electromagnetic wave absorbing metasurface, including a plurality of periodically and closely arranged unit structures 10, a voltage control board 20 and a plurality of busbars 30, as shown in FIG. Figure 2As shown, each unit structure 10 includes, from top to bottom, a metal pattern layer 11, a first dielectric layer 12, a metal ground layer 13, a second dielectric layer 14 and a DC trace layer 15, the metal pattern layer 11 includes two metal patches, the two metal patches are connected to the DC trace layer 15 through metal vias 16 respectively, a varactor diode 17 is connected between the two metal patches, there are isolation holes 18 around the metal via 16 connected to the anode of the varactor diode, a voltage control board 20 is connected to the DC trace layer 15 through a busbar 30, for providing a reverse bias voltage for the varactor diode, changing the reverse bias voltage of the varactor diode can adjust the absorption frequency of the unit structure.

[0032] The metal ground layer 13 serves as a ground layer of the unit structure, the metal via 16 connected to the cathode of the varactor diode is in conduction with the metal ground layer 13, meanwhile, the metal ground layer 13 is located between the metal pattern layer 11 and the DC trace layer 15, and is also a shielding layer of the DC trace layer 15, which can overcome the influence of the DC control line on the performance of the unit structure 10, due to the presence of the metal ground layer 13, the number of trace lines of the DC trace layer 15 will not have a significant impact on the working performance of the unit structure 10, and the unit structure has good consistency, which is conducive to the realization of large-scale expansion.

[0033] Continuing to refer to Figure 1 , the N×N unit structures are arranged periodically in the X-axis and Y-axis directions, and a plurality of busbars are located on the left and right sides of the super surface, Figure 1 It is shown that 12×18 unit structures are arranged periodically in the X-axis and Y-axis directions, 12 busbars of 2×10 are located on the left and right sides of the super surface, in the X-axis direction, the DC trace layers of half of the unit structures in each row are connected to the busbar on the left side, and the DC trace layers of the other half of the unit structures are connected to the busbar on the right side, the voltage control board 20 is connected to the busbar 30 through a metal wire, and the busbar 30 is connected to the unit structure 10 through a DC control line 40, for providing a required reverse bias voltage for the varactor diode 17, so as to control the working frequency of the unit structure, and the DC control line 40 is located on the DC trace layer 15.

[0034] Due to the large number of unit structures, by connecting half of the DC traces in each row of unit structures to the busbar on the left side and the other half of the DC traces to the busbar on the right side, the arrangement of the large number of DC control lines is more orderly, and the arrangement of the DC control lines is avoided to be too dense. The spacing between each unit structure of the utility model is the same, and the unit structures are arranged closely, so that large-scale expansion is easy to realize, and by integrating the busbar, the voltage control board and the absorption unit on the same plane, the utility model has the advantages of high integration, small space occupation and high reliability.

[0035] As Figure 3As shown, the metal patch includes a first metal straight line 111, a second metal straight line 112, a third metal straight line 113, and a fourth metal straight line 114. The first metal straight line 111, the second metal straight line 112, and the third metal straight line 113 form an I-shape, one end of the second metal straight line 112 is connected to the middle of the first metal straight line 111, and the other end of the second metal straight line 112 is connected to the middle of the third metal straight line 113. The fourth metal straight line 114 is L-shaped, one end of the fourth metal straight line 114 is connected to the end of the third metal straight line 113, and the metal through hole 16 is located in the middle of the third metal straight line 113.

[0036] The two first metal lines 111 are connected to the anode and cathode of the varactor diode 17 through metal pads 115 , respectively.

[0037] The center of the metal through hole 16 coincides with the center of the isolation hole 18 . The inner diameter of the metal through hole 16 is 0.1 mm, and the inner diameter of the isolation hole 18 is 0.18 mm.

[0038] The first dielectric layer is made of F4B low-loss board with a dielectric constant of 2.55 and a loss tangent of 0.003. The second dielectric layer is made of FR4 with a dielectric constant of 4.67 and a loss tangent of 0.016.

[0039] The unit structure has three metal layers and two dielectric layers, and the size of the unit structure is 5×7mm. 2 The total thickness is 0.9mm. The absorption metasurface is obtained by multi-layer printed circuit board pressing process. The overall size of the layout is 126×90×0.9mm. 3 .

[0040] The model of the varactor diode is MA45H120. When the reverse bias voltage changes from 0V to 12V, the capacitance changes from 1.1pF to 0.1pF. The simulation results of the absorption performance of the single frequency reconfigurable active electromagnetic wave absorption unit under different capacitance values ​​of the varactor diode are shown in Figure 4 . It was observed that the frequency-reconfigurable active electromagnetic wave absorption metasurface has an adjustable operating frequency range of 4GHz-5.6GHz, and the absorption efficiency is above 80%.

[0041] In order to verify the sensitivity of the frequency-reconfigurable active electromagnetic wave absorbing metasurface to the incident angle, Figure 5 The simulation results show the unit's absorption performance at different incident angles. As can be seen from the figure, the frequency-reconfigurable active electromagnetic wave absorbing metasurface is insensitive to the incident angle of the electromagnetic wave. As the incident angle increases from 0° to 50°, its electromagnetic wave absorption efficiency increases from 99% to 94%. Figure 6The relationship between the number of traces on the third DC trace layer and the absorption performance of the unit is given. It is observed that the number of traces has almost no effect on the operating frequency and absorption performance of the unit.

[0042] The electric field distribution of the frequency-reconfigurable active electromagnetic wave absorbing metasurface under different capacitance values ​​is shown in Figure 2. Figure 7 As shown, Figure 7 (a)~ Figure 7 (e) shows the electric field plots for capacitances ranging from 0.2pF to 1pF. It can be seen that the operating frequency of the surface varies with different capacitance values. Furthermore, the electric field distribution incident on the absorbing surface is relatively flat, and the standing wave effect is not significant. Therefore, the operating frequency of the constructed surface is adjustable and it can achieve excellent shielding against electromagnetic waves from the normal incidence direction.

[0043] Figure 8 The electric field distribution of the frequency-reconfigurable active electromagnetic wave absorbing metasurface with a capacitance of 0.2pF at different electromagnetic wave incident angles is given. Figure 8 (a)~ Figure 8 (f) shows the electric field at electromagnetic wave incident angles of 0° to 50°. Similarly, the electric field distribution incident on the absorbing surface is relatively flat, with no significant standing wave effect. Therefore, the constructed frequency-reconfigurable active electromagnetic wave absorbing metasurface can achieve excellent shielding against obliquely incident electromagnetic waves. Frequency-reconfigurable active electromagnetic wave absorbing metasurfaces have applications in electromagnetic shielding, radar detection, and other fields.

[0044] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments can still be modified, or some of the technical features thereof can be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A frequency reconfigurable active electromagnetic wave-absorbing metasurface, characterized in that: The super surface comprises a plurality of periodically closely arranged unit structures (10), each unit structure (10) comprises, from top to bottom, a metal pattern layer (11), a first dielectric layer (12), a metal ground layer (13), a second dielectric layer (14) and a DC trace layer (15), the metal pattern layer (11) comprises two metal patches, the two metal patches are connected to the DC trace layer (15) through metal vias (16) respectively, a varactor diode is connected between the two metal patches, there is an isolation hole (18) around the metal via (16) connected to the anode of the varactor diode, and the metal via (16) connected to the cathode of the varactor diode is in communication with the metal ground layer (13).

2. The frequency reconfigurable active electromagnetic wave-absorbing metasurface of claim 1, wherein: The super surface further comprises a voltage control board (20) and a plurality of busbars (30), the voltage control board (20) is connected to the DC trace layer (15) through the busbars (30).

3. The frequency reconfigurable active electromagnetic wave-absorbing metasurface of claim 2, wherein: The N×N unit structures (10) are periodically arranged in the X and Y directions, the plurality of busbars (30) are respectively located on the left and right sides of the super surface, in the X direction, the DC trace layers of every half unit structures in each row are connected to the busbar on the left side, and the DC trace layers of the other half unit structures are connected to the busbar on the right side.

4. The frequency reconfigurable active electromagnetic wave-absorbing metasurface of claim 1, wherein: The metal patch comprises a first metal straight line (111), a second metal straight line (112), a third metal straight line (113) and a fourth metal straight line (114), one end of the second metal straight line (112) is connected to the middle part of the first metal straight line (111), the other end of the second metal straight line (112) is connected to the middle part of the third metal straight line (113), the fourth metal straight line (114) is in L shape, one end of the fourth metal straight line (114) is connected to the end part of the third metal straight line (113), and the metal via (16) is located in the middle part of the third metal straight line (113).

5. The frequency reconfigurable active electromagnetic wave-absorbing metasurface of claim 4, wherein: The two first metal straight lines (111) are respectively connected to the anode and cathode of the varactor diode through metal pads (115).

6. The frequency reconfigurable active electromagnetic wave-absorbing metasurface of claim 4, wherein: The center of the metal via (16) coincides with the center of the isolation hole (18).

7. The frequency reconfigurable active electromagnetic wave-absorbing metasurface of claim 1, wherein: The dielectric constant of the first dielectric layer (12) is 2.55, and the loss tangent is 0.003, the dielectric constant of the second dielectric layer (14) is 4.67, and the loss tangent is 0.

016.

8. The frequency reconfigurable active electromagnetic wave-absorbing metasurface of claim 1, wherein: The model of the varactor diode is MA45H120.

9. The frequency reconfigurable active electromagnetic wave-absorbing metasurface of claim 1, wherein: The adjustable range of the working frequency of the super surface is 4GHz-5.6GHz, and the electromagnetic wave absorption efficiency is greater than 80%.

10. The frequency reconfigurable active electromagnetic wave-absorbing metasurface of claim 1, wherein: The size of the unit structure (10) is 5 x 7 mm 2 The total thickness is 0.9 mm.

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