2-bit reconfigurable metasurface cell design method based on 1-bit assumption

Abstract

The application relates to a 2-bit electromagnetic metasurface unit design method based on a 1-bit design idea, which comprises the following steps: step 1, a 1-bit metasurface unit 10 is designed by using an electromagnetic resonance method, the on-off of an electric control device is controlled, and the 1-bit metasurface unit 10 has a 270-degree reflection phase difference at a required frequency point; step 2, a phase-shifting layer 20 is added below the 1-bit unit 10 obtained in step 1, and a transmission metal via is introduced into the unit 10, so that electromagnetic energy on the unit 10 is transmitted to the phase-shifting layer 20; and step 3, a phase-shifting microstrip line on the phase-shifting layer 20 in step 2 is designed by using a guided wave method, the on-off of an electric control device is controlled, electromagnetic waves transmitted back to the 1-bit unit 10 through the phase-shifting layer 20 are phase-shifted by 90 degrees and 180 degrees, and finally a 2-bit electromagnetic metasurface unit with 0-degree, 90-degree, 180-degree and 270-degree phase control capabilities is formed. The method provided by the application combines the electromagnetic resonance method and the guided wave method, improves the defects of the electromagnetic resonance method, such as complex design process and the guided wave method, such as too many electric control devices, the design idea is clear, the method is simple, and a 2-bit unit with good performance can be quickly and efficiently designed.

Description

Technical Field

[0001] This invention relates to the design technology of artificial electromagnetic metasurfaces, specifically to a design method for 2-bit reconfigurable metasurface units based on the 1-bit design concept. Background Technology

[0002] Electromagnetic metasurfaces, capable of flexibly controlling the amplitude, phase, and polarization of electromagnetic waves, have become a research hotspot in recent years. The concept of intelligent metasurfaces further expands their application areas. Intelligent metasurfaces can autonomously sense changes in the system and external environment, and can adaptively switch between different electromagnetic functions. As the hardware foundation of intelligent metasurfaces, the electromagnetic control capability of reconfigurable metasurfaces determines their performance. By loading electrically controlled switching devices into the metasurface unit structure, dynamic control of the reflected phase between specific digital quantization values ​​can be achieved. Most existing research uses 1-bit phase modulation structures, which have a simple and clear design concept, but can only achieve two phase states, resulting in low phase accuracy and insufficient precision in electromagnetic wave control. Theoretical research shows that 2-bit reconfigurable metasurface units can significantly reduce phase compensation errors, and electromagnetic metasurfaces based on 2-bit units can achieve good electromagnetic performance. However, the design of 2-bit units requires simultaneous consideration of four phase states, making the design process very complex and inefficient. Furthermore, 2-bit units suffer from structural complexity, numerous loaded devices, and high losses, directly affecting the practical application of reconfigurable metasurfaces. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention proposes a 2-bit reconfigurable metasurface unit based on a 1-bit design concept. The 2-bit reconfigurable metasurface unit 10, based on the 1-bit design concept, comprises, from top to bottom, a metal patch 11, a first electronic control device 101, a dielectric substrate 12, and a metal ground plane 13; and wherein...

[0004] A spatial rectangular coordinate system is established with the center of the upper surface of unit 10 as the origin. The positive x-axis is horizontal to the right, the positive y-axis is vertically upward, and the positive z-axis is perpendicular to the paper and outward. The dielectric substrate 12 is a square sheet. A rectangular metal patch 11 is printed on the dielectric substrate 12, and a rectangular slot 14 is etched on the metal patch 11. Both the metal patch 11 and the slot 14 are symmetrical about the x-axis. The electronic control device 101 is soldered on the x-axis at the midpoint on the left side of the slot 14. The two poles of the electronic control device 101 are connected across the metal patches on both sides of the slot. The metal ground plate 13 is located below the dielectric substrate 12. The metal ground plate 13 has the same size as the dielectric substrate 12, and their projections on the horizontal plane completely overlap.

[0005] Its features are,

[0006] A phase-shifting layer 20 is added below the 1-bit unit 10, and a transmission metal via 15 is introduced into the 1-bit unit 10 to transmit the electromagnetic energy on the 1-bit unit 10 to the phase-shifting layer 20. The dielectric substrate 21 of the phase-shifting layer 20 is located below the metal ground plane 13, and the projections of the dielectric substrate 21 and the dielectric substrate 12 on the horizontal plane are completely coincident. The transmission metal via 15 is located on the metal patch 11 inside the gap 14, and the center of the via is located on the x-axis, close to the edge of the first electronic control device 101 but maintaining a certain distance. The transmission metal via 15 penetrates the dielectric substrate 12 and the dielectric substrate 21 vertically downward from the metal patch 11, connecting the metal patch 11 on the upper surface of the dielectric substrate 12 to the microstrip branch 22 on the lower surface of the dielectric substrate 21. The metal ground plane 13 has a circular opening located at the position corresponding to the passage of the transmission metal via 15. This circular opening isolates the metal via 15 from the metal ground plane 13 to prevent short circuits.

[0007] A phase-shifting microstrip line is printed on the lower surface of the dielectric substrate 21, including a first phase-shifting microstrip line 23, a third electronic control device 202, and a second phase-shifting microstrip line 24. The first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 are along the x-axis. The two poles of the third electronic control device 202 are connected between the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24. A short-circuit metal via 25 is located at the end of the second phase-shifting microstrip line 24 away from the first phase-shifting microstrip line 23. While ensuring the required microstrip line length, the first phase-shifting microstrip line... The microstrip line 23 and the second phase-shifting microstrip line 24 can be straight or zigzag. In addition, the main body of the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 extends along the x-direction. If the length of the microstrip line is too long, it is bent along the y-direction. The phase-shifting microstrip line 23 is connected to the microstrip stub 22 through the second electronic control device 201. Under the condition of ensuring the length requirement of the microstrip line, the microstrip stub 22 can be straight or zigzag. The microstrip stub 22 transmits the phase-shifted guided electromagnetic wave back to the 1-bit unit 10.

[0008] In one embodiment of the present invention,

[0009] Both the metal patch 11 and the slot 14 are rectangular. The side length of the metal patch 11 along the x-axis is in the range of 5.0 to 12.0 mm, and the side length along the y-axis is in the range of 5.0 to 12.0 mm. The side length of the slot 14 along the x-axis is in the range of 4.0 to 11.0 mm, and the side length along the y-axis is in the range of 4.0 to 11.0 mm. The width of the slot is in the range of 0.01 to 1.0 mm. The side length of the dielectric substrate 12 is in the range of 8.0 to 15.0 mm, and the thickness is in the range of 1.0 to 5.0 mm.

[0010] The distance between the center of the metal via 15 and the edge of the electronic control device 101 is in the range of 0.2 to 5.0 mm; the thickness of the dielectric substrate 21 is in the range of 0.1 to 5.0 mm.

[0011] The length of the microstrip stub 22 is in the range of 1.0 to 3.0 mm, the total length of the phase-shifting microstrip line 23 is in the range of 1.0 to 10.0 mm, the total length of the phase-shifting microstrip line 24 is in the range of 1.0 to 10.0 mm, and the width of the microstrip line is in the range of 0.2 to 3.0 mm.

[0012] In one specific embodiment of the present invention,

[0013] The metal patch 11 has a side length of 6.5 mm along the x-axis and a side length of 7.0 mm along the y-axis. The gap 14 has a side length of 5.5 mm along the x-axis and a side length of 5.3 mm along the y-axis, and the gap width is 0.1 mm. The dielectric substrate 12 has a side length of 10.0 mm, a thickness of 2.0 mm, and a dielectric constant in the range of 2.0 to 4.0.

[0014] The distance between the center of the metal via 15 and the edge of the electronic control device 101 is 0.5 mm; the thickness of the dielectric substrate 21 is 0.28 mm, and its dielectric constant is in the range of 2.0 to 4.0.

[0015] The length of microstrip stub 22 is 1.5 mm, the total length of phase-shifting microstrip line 23 is 3.0 mm, the total length of phase-shifting microstrip line 24 is 7.5 mm, and the width of the microstrip line is 0.5 mm.

[0016] In another embodiment of the present invention, the first electronic control device 101, the second electronic control device 201, and the third electronic control device 202 are microelectromechanical system switches, PIN diode switches, or field-effect transistor switches.

[0017] In another specific embodiment of the present invention, the first electronic control device 101, the second electronic control device 201, and the third electronic control device 202 are PIN diode switches SMP1352-040LF.

[0018] A method for designing a 2-bit reconfigurable metasurface unit based on a 1-bit design concept is also provided. The unit is the aforementioned 2-bit reconfigurable metasurface unit based on a 1-bit design concept. The method specifically includes the following steps:

[0019] Step 1: Design a 1-bit metasurface unit 10 using the electromagnetic resonance method. By controlling the on and off of the electronic control device, make it have a 270° reflection phase difference at the required frequency.

[0020] The 2-bit reconfigurable metasurface unit 10, based on a 1-bit design concept, comprises, from top to bottom, a metal patch 11, a first electronic control device 101, a dielectric substrate 12, and a metal ground plane 13; and wherein...

[0021] A spatial rectangular coordinate system is established with the center of the upper surface of unit 10 as the origin. The positive x-axis is horizontal to the right, the positive y-axis is vertically upward, and the positive z-axis is perpendicular to the paper and outward. The dielectric substrate 12 is a square sheet. A rectangular metal patch 11 is printed on the dielectric substrate 12, and a rectangular slot 14 is etched on the metal patch 11. Both the metal patch 11 and the slot 14 are symmetrical about the x-axis. The electronic control device 101 is soldered on the x-axis at the midpoint on the left side of the slot 14. The two poles of the electronic control device 101 are connected across the metal patches on both sides of the slot. The metal ground plate 13 is located below the dielectric substrate 12. The metal ground plate 13 has the same size as the dielectric substrate 12, and their projections on the horizontal plane completely overlap.

[0022] Step 2: Add a phase-shifting layer 20 below the 1-bit cell 10 obtained in step 1, and introduce a transmission metal via 15 into the cell 10 to transmit the electromagnetic energy on the cell 10 to the phase-shifting layer 20.

[0023] A phase-shifting layer 20 is added below the 1-bit unit 10, and a transmission metal via 15 is introduced into the 1-bit unit 10 to transmit the electromagnetic energy on the 1-bit unit 10 to the phase-shifting layer 20. The dielectric substrate 21 of the phase-shifting layer 20 is located below the metal ground plane 13, and the projections of the dielectric substrate 21 and the dielectric substrate 12 on the horizontal plane are completely coincident. The transmission metal via 15 is located on the metal patch 11 inside the gap 14, and the center of the via is located on the x-axis, close to the edge of the first electronic control device 101 but maintaining a certain distance. The transmission metal via 15 penetrates the dielectric substrate 12 and the dielectric substrate 21 vertically downward from the metal patch 11, connecting the metal patch 11 on the upper surface of the dielectric substrate 12 to the microstrip branch 22 on the lower surface of the dielectric substrate 21. The metal ground plane 13 has a circular opening located at the position corresponding to the passage of the transmission metal via 15. This circular opening isolates the metal via 15 from the metal ground plane 13 to prevent short circuits.

[0024] Step 3: Using the guided wave method, design the phase-shifting microstrip line on the phase-shifting layer 20 in Step 2. By controlling the on and off of the electronic control device, the electromagnetic wave transmitted back to the 1-bit unit 10 through the phase-shifting layer 20 is phase-shifted by 90° and 180°, and finally a 2-bit electromagnetic metasurface unit with phase modulation capabilities of 0°, 90°, 180° and 270° is formed.

[0025] A phase-shifting microstrip line is printed on the lower surface of the dielectric substrate 21, including a first phase-shifting microstrip line 23, a third electronic control device 202, and a second phase-shifting microstrip line 24. The first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 are along the x-axis. The two poles of the third electronic control device 202 are connected between the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24. A short-circuit metal via 25 is located at the end of the second phase-shifting microstrip line 24 away from the first phase-shifting microstrip line 23. While ensuring the required microstrip line length, the first phase-shifting microstrip line... The microstrip line 23 and the second phase-shifting microstrip line 24 can be straight or zigzag. In addition, the main body of the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 extends along the x-direction. If the length of the microstrip line is too long, it is bent along the y-direction. The phase-shifting microstrip line 23 is connected to the microstrip stub 22 through the second electronic control device 201. Under the condition of ensuring the length requirement of the microstrip line, the microstrip stub 22 can be straight or zigzag. The microstrip stub 22 transmits the phase-shifted guided electromagnetic wave back to the 1-bit unit 10.

[0026] A 2-bit reconfigurable metasurface unit based on a 1-bit design concept is also provided, wherein...

[0027] The 2-bit reconfigurable metasurface unit 10, based on the 1-bit design concept, is a resonant 1-bit metasurface unit.

[0028] A phase-shifting layer 20 is added below the 1-bit cell 10, and a transmission metal via 15 is introduced into the 1-bit cell 10 to transmit the electromagnetic energy on the 1-bit cell 10 to the phase-shifting layer 20. The dielectric substrate 21 of the phase-shifting layer 20 is located below the metal ground plane 13, and the projections of the dielectric substrate 21 and the dielectric substrate 12 on the horizontal plane are completely coincident. The transmission metal via 15 penetrates vertically downward from the metal patch of the 1-bit metasurface cell 10 through the dielectric substrate 12 and the dielectric substrate 21, connecting the metal patch of the 1-bit metasurface cell 10 on the upper surface of the dielectric substrate 12 to the microstrip stub 22 on the lower surface of the dielectric substrate 21. The metal ground plane 13 has a circular opening located at the position through which the transmission metal via 15 passes. This circular opening isolates the metal via 15 from the metal ground plane 13 to prevent short circuits. The position of the transmission metal via 15 is adjusted according to the actual situation, as long as the energy on the upper surface can be transmitted to the microstrip stub 22 through the transmission metal via 15.

[0029] A phase-shifting microstrip line is printed on the lower surface of the dielectric substrate 21, including a first phase-shifting microstrip line 23, a third electronic control device 202, and a second phase-shifting microstrip line 24. The first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 are along the x-axis. The two poles of the third electronic control device 202 are connected between the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24. A short-circuit metal via 25 is located at the end of the second phase-shifting microstrip line 24 away from the first phase-shifting microstrip line 23. While ensuring the required microstrip line length, the first phase-shifting microstrip line... The microstrip line 23 and the second phase-shifting microstrip line 24 can be straight or zigzag. In addition, the main body of the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 extends along the x-direction. If the length of the microstrip line is too long, it is bent along the y-direction. The phase-shifting microstrip line 23 is connected to the microstrip stub 22 through the second electronic control device 201. Under the condition of ensuring the length requirement of the microstrip line, the microstrip stub 22 can be straight or zigzag. The microstrip stub 22 transmits the phase-shifted guided electromagnetic wave back to the 1-bit unit 10.

[0030] A method for designing a 2-bit reconfigurable metasurface unit based on a 1-bit design concept is also provided. The unit is the aforementioned 2-bit reconfigurable metasurface unit based on a 1-bit design concept. The method specifically includes the following steps:

[0031] Step 1: Design a 1-bit metasurface unit 10 using the electromagnetic resonance method. By controlling the on and off of the electronic control device, make it have a 270° reflection phase difference at the required frequency.

[0032] The 2-bit reconfigurable metasurface unit 10, based on the 1-bit design concept, is a resonant 1-bit metasurface unit.

[0033] Step 2: Add a phase-shifting layer 20 below the 1-bit cell 10 obtained in step 1, and introduce a transmission metal via 15 into the cell 10 to transmit the electromagnetic energy on the cell 10 to the phase-shifting layer 20.

[0034] A phase-shifting layer 20 is added below the 1-bit cell 10, and a transmission metal via 15 is introduced into the 1-bit cell 10 to transmit the electromagnetic energy on the 1-bit cell 10 to the phase-shifting layer 20. The dielectric substrate 21 of the phase-shifting layer 20 is located below the metal ground plane 13, and the projections of the dielectric substrate 21 and the dielectric substrate 12 on the horizontal plane are completely coincident. The transmission metal via 15 penetrates vertically downward from the metal patch of the 1-bit metasurface cell 10 through the dielectric substrate 12 and the dielectric substrate 21, connecting the metal patch of the 1-bit metasurface cell 10 on the upper surface of the dielectric substrate 12 to the microstrip stub 22 on the lower surface of the dielectric substrate 21. The metal ground plane 13 has a circular opening located at the position through which the transmission metal via 15 passes. This circular opening isolates the metal via 15 from the metal ground plane 13 to prevent short circuits. The position of the transmission metal via 15 is adjusted according to the actual situation, as long as the energy on the upper surface can be transmitted to the microstrip stub 22 through the transmission metal via 15.

[0035] Step 3: Using the guided wave method, design the phase-shifting microstrip line on the phase-shifting layer 20 in Step 2. By controlling the conduction and disconnection of the electronic control device, the electromagnetic wave transmitted back to the 1-bit unit 10 through the phase-shifting layer 20 will generate phase shifts of 90° and 180°, and finally form a 2-bit electromagnetic metasurface unit with phase modulation capabilities of 0°, 90°, 180° and 270°.

[0036] A phase-shifting microstrip line is printed on the lower surface of the dielectric substrate 21, including a first phase-shifting microstrip line 23, a third electronic control device 202, and a second phase-shifting microstrip line 24. The first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 are along the x-axis. The two poles of the third electronic control device 202 are connected between the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24. A short-circuit metal via 25 is located at the end of the second phase-shifting microstrip line 24 away from the first phase-shifting microstrip line 23. While ensuring the required microstrip line length, the first phase-shifting microstrip line... The microstrip line 23 and the second phase-shifting microstrip line 24 can be straight or zigzag. In addition, the main body of the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 extends along the x-direction. If the length of the microstrip line is too long, it is bent along the y-direction. The phase-shifting microstrip line 23 is connected to the microstrip stub 22 through the second electronic control device 201. Under the condition of ensuring the length requirement of the microstrip line, the microstrip stub 22 can be straight or zigzag. The microstrip stub 22 transmits the phase-shifted guided electromagnetic wave back to the 1-bit unit 10.

[0037] The advantages of this invention are:

[0038] 1. A novel design method for 2-bit reconfigurable metasurface units is provided, which is based on the 1-bit design concept to design 2-bit reconfigurable metasurface units. The method combines electromagnetic resonance method and guided wave method. Based on the relatively mature resonant 1-bit unit, guided wave phase-shifting microstrip line is combined to quickly and efficiently design 2-bit reconfigurable metasurface units with four different phase states.

[0039] 2. Compared with the prior art, the present invention proposes a general design flow for 2-bit reconfigurable metasurface units. According to this design flow, the design difficulty of 2-bit units can be greatly reduced, the complex full-wave simulation optimization work can be reduced, and the rapid and efficient design of 2-bit reconfigurable metasurface units can be achieved.

[0040] 3. The 2-bit reconfigurable metasurface unit proposed in this invention requires fewer electronic control devices, has the characteristics of low loss and easy implementation, and has broad application prospects. Attached Figure Description

[0041] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood in conjunction with the following description of the embodiments, in which:

[0042] Figure 1 This is a flowchart of the design method of the present invention;

[0043] Figure 2 This is a schematic diagram of the structure of the 1-bit metasurface unit 10 in this invention. Figure 2 (a) is a top view. Figure 2 (b) is the front view;

[0044] Figure 3 for Figure 2 The equivalent circuit of the SMP1352-040LF diode loaded on bit cell 10 under different states is shown below. Figure 3 (a) is the equivalent circuit when the diode is off. Figure 3 (b) is the equivalent circuit when the diode is conducting;

[0045] Figure 4 for Figure 2 The reflection phase curves of 1-bit unit 10 under different operating states are shown below;

[0046] Figure 5 for Figure 2 The diagram shown is a schematic of the structure of a 1-bit unit 10 after adding a transmission metal via 15 and a phase-shifting layer 20. Figure 5 (a) is a top view. Figure 5 (b) is the front view. Figure 5 (c) is a top view of metal floor 13;

[0047] Figure 6This is a schematic diagram of the structure of the 2-bit reconfigurable metasurface unit in this invention. Figure 6 (a) is a 3D diagram. Figure 6 (b) is the front view. Figure 6 (c) is a top view of the phase-shifted microstrip line;

[0048] Figure 7 for Figure 6 The reflection phase curves of the 2-bit unit are shown in different operating states;

[0049] Figure 8 for Figure 6 The reflection amplitude curves of the 2-bit unit under different operating conditions are shown.

[0050] Figure label:

[0051] 11 Metal patch; 101 First electronic control device; 12 Upper dielectric substrate; 13 Metal ground plane; 14 Gap; 15 Transmission metal via; 21 Lower dielectric substrate; 22 Microstrip stub; 23 First phase-shifting microstrip line; 24 Second phase-shifting microstrip line; 25 Short-circuit metal via; 201 Second electronic control device; 202 Third electronic control device. Detailed Implementation

[0052] This invention provides a detailed description of an embodiment to illustrate a 2-bit reconfigurable metasurface unit design method based on a 1-bit design concept. The invention is described below with reference to the accompanying drawings.

[0053] like Figure 1 As shown, a design method for 2-bit reconfigurable metasurface units based on the 1-bit design concept includes the following steps:

[0054] Step 1: Design a 1-bit metasurface unit 10 using the electromagnetic resonance method. By controlling the on and off of the electronic control device, make it have a 270° reflection phase difference at the required frequency.

[0055] The metasurface unit 10 defined in the embodiment is as follows: Figure 2 As shown, Figure 2 (a) is a top view. Figure 2 (b) is a front view. Unit 10, from top to bottom, includes a metal patch 11, a first electronic control device 101, a dielectric substrate 12, and a metal ground plane 13. With the center of the upper surface of unit 10 as the origin of the coordinate system, ... Figure 2(a) A spatial rectangular coordinate system is established in the top view. The positive x-axis points horizontally to the right, the positive y-axis points vertically upward, and the positive z-axis points outward perpendicular to the paper. A rectangular metal patch 11 is printed on a square dielectric substrate 12. A rectangular slot 14 is etched on the metal patch 11. Both the metal patch 11 and the slot 14 are symmetrical about the x-axis, and their centers may not coincide, nor may they coincide with the origin of the coordinate system. An electronic control device 101 is soldered onto the x-axis at the midpoint on the left side of the slot 14. The two poles of the electronic control device 101 are connected across the metal patches on both sides of the slot. The electronic control device 101 can be any of the following: microelectromechanical system switch, PIN diode switch, or field-effect transistor switch. By changing the on and off states of the switch, it can change the unit structure and thus control the phase. Below the dielectric substrate 12 is a metal ground plane 13. The metal ground plane 13 is the same size as the dielectric substrate 12, and their projections on the horizontal plane completely coincide.

[0056] In this embodiment, both the metal patch 11 and the gap 14 are rectangular. The side length of the metal patch 11 along the x-axis is in the range of 5.0–12.0 mm, preferably 6.5 mm, and the side length along the y-axis is in the range of 5.0–12.0 mm, preferably 7.0 mm. The side length of the gap 14 along the x-axis is in the range of 4.0–11.0 mm, preferably 5.5 mm, and the side length along the y-axis is in the range of 4.0–11.0 mm, preferably 5.3 mm. The gap width is in the range of 0.01–1.0 mm, preferably 0.1 mm. The side length of the dielectric substrate 12 is in the range of 8.0–15.0 mm, preferably 10.0 mm, the thickness is in the range of 1.0–5.0 mm, preferably 2.0 mm, and its dielectric constant is in the range of 2.0–4.0, preferably 3.66.

[0057] In this embodiment, the electronic control device 101 used is a PIN diode switch SMP1352-040LF. Figure 3 This is the equivalent circuit diagram of the SMP1352-040LF diode under different conditions. (Reference) Figure 3 (a) When the diode is off, it is equivalent to a series connection of a 10Ω resistor, an 86pF capacitor, and a 450pH inductor. (Ref) Figure 3 (b) When the diode is turned on, it is equivalent to a series connection of a 1Ω resistor and a 450pH inductor.

[0058] Figure 4To obtain the optimal reflection phase curves of the 1-bit unit 10 under different operating states, an infinite period boundary was set in the simulation to simulate an infinitely large array. Since the electromagnetic resonance size of unit 10 differs when the electronic control device 101 is in different operating states, different reflection phases will occur. For simplicity, the operating states of the electronic control device 101 are represented by coded numbers, where "1" indicates conduction and "0" indicates deactivation. Figure 4 As can be seen, the reflected waves under the two working states have a phase difference of 270° at 10.45 GHz, that is, a 1-bit metasurface unit 10 was designed using the electromagnetic resonance method.

[0059] It should be noted that the 1-bit metasurface unit 10 mentioned in step 1 of the design method proposed in this invention is not limited to... Figure 2 The unit cell structure shown can be used to achieve fast 2-bit unit cell design using the proposed design method, as long as it is a resonant 1-bit metasurface unit. The position of the transmission metal via 15 on the resonant 1-bit metasurface unit can be adjusted according to the actual situation, as long as the energy on the upper surface can be completely transferred to the microstrip stub 22 through the transmission metal via 15.

[0060] Step 2: Add a phase-shifting layer 20 below the 1-bit cell 10 obtained in step 1, and introduce a transmission metal via 15 into the cell 10 to transmit the electromagnetic energy on the cell 10 to the phase-shifting layer 20.

[0061] Figure 5 for Figure 2 The diagram shown is a schematic of the structure of a 1-bit unit 10 after adding a transmission metal via 15 and a phase-shifting layer 20. Figure 5 (a) is a top view. Figure 5 (b) is the front view. Figure 5 (c) is a top view of the metal floor 13. A transmission metal via 15 is located on the metal patch 11 inside the slot 14, with its center on the x-axis, close to the edge of the electronic control device 101 but maintaining a certain distance. Below the metal floor 13 is the dielectric substrate 21 of the phase-shifting layer 20, whose projection on the horizontal plane completely overlaps with that of the dielectric substrate 12. The transmission metal via 15 penetrates vertically downwards from the metal patch 11 through the dielectric substrate 12 and the dielectric substrate 21, connecting the metal patch 11 on the upper surface of the dielectric substrate 12 to the microstrip branch 22 on the lower surface of the dielectric substrate 21. When the electronic control device 101 is disconnected, the transmission metal via 15 functions to transmit electromagnetic energy. The metal floor 13 has a circular opening located at the position through which the transmission metal via 15 passes. This circular opening isolates the metal via 15 from the metal floor 13, preventing energy short circuits. A detailed description of the microstrip branch 22 is provided below.

[0062] In this embodiment, the distance between the center of the metal via 15 and the edge of the electronic control device 101 is in the range of 0.2 to 5.0 mm, preferably 0.5 mm. The thickness of the dielectric substrate 21 is in the range of 0.1 to 5.0 mm, preferably 0.28 mm, and its dielectric constant is in the range of 2.0 to 4.0, preferably 3.66.

[0063] Step 3: Using the guided wave method, design the phase-shifting microstrip line on the phase-shifting layer 20 in Step 2. By controlling the on and off of the electronic control device, the electromagnetic wave transmitted back to the 1-bit unit 10 through the phase-shifting layer 20 is phase-shifted by 90° and 180°, and finally a 2-bit electromagnetic metasurface unit with phase modulation capabilities of 0°, 90°, 180° and 270° is formed.

[0064] Figure 6 This is a schematic diagram of the structure of the 2-bit reconfigurable metasurface unit proposed in an embodiment of the present invention. Figure 6 (a) is a 3D diagram. Figure 6 (b) is the front view. Figure 6 (c) is a top view of the phase-shifted microstrip line. The phase-shifted microstrip line is printed on the lower surface of the dielectric substrate 21 and includes a first phase-shifted microstrip line 23, a third electronic control device 202, and a second phase-shifted microstrip line 24. The first phase-shifted microstrip line 23 and the second phase-shifted microstrip line 24 are along the x-axis. The two poles of the third electronic control device 202 are connected between the first phase-shifted microstrip line 23 and the second phase-shifted microstrip line 24. A short-circuit metal via 25 is located at the end of the second phase-shifted microstrip line 24 away from the first phase-shifted microstrip line 23. The linewidths of the phase-shifted microstrip lines 23 and 24 may not be equal, provided that the length of the microstrip line remains constant (the length range of the microstrip line is described in the following paragraph). Figure 6 (c) is not the only possible form. The figure shows the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 as being in a "U" shape, but they are not limited to this. As long as the length of the microstrip line meets the requirements, it is acceptable. The shapes of the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 can be straight lines or bends. Generally speaking, the simpler the structure, the better. Furthermore, the main body of the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 extends along the x-direction (which can be understood as meaning that a portion of these three microstrip lines is always in a direction parallel to the x-axis). The length of the microstrip line is adjusted according to the required phase. If the microstrip line is too long, it can be bent along the y-direction. Therefore, the shapes of the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24 can be straight lines or bends. The phase-shifted microstrip line 23 is connected to the microstrip stub 22 through the second electronic control device 201. The microstrip stub 22 can be a straight line or a zigzag line, as long as the length of the microstrip stub meets the requirements. The microstrip stub 22 transmits the phase-shifted guided electromagnetic wave back to the 1-bit unit 10.

[0065] In this embodiment, the length of the microstrip stub 22 is in the range of 1.0 to 3.0 mm, preferably 1.5 mm; the total length of the phase-shifting microstrip line 23 is in the range of 1.0 to 10.0 mm, preferably 3.0 mm; the total length of the phase-shifting microstrip line 24 is in the range of 1.0 to 10.0 mm, preferably 7.5 mm; and the width of the microstrip line is in the range of 0.2 to 3.0 mm, preferably 0.5 mm.

[0066] The electronic control devices 201 and 202 are any one of, for example, microelectromechanical system switches, PIN diode switches, and field-effect transistor switches. In this embodiment, the electronic control devices 201 and 202 are the same as 101, both being PIN diode switches SMP1352-040LF. Figure 7 The reflection phase curves of the 2-bit unit under different operating states are shown for optimal value selection. For simplicity, the operating states are represented by a combination of ordered coded numbers: "1" indicates that the control device is on, and "0" indicates that the control device is off. Taking the code "0+10" as an example, the first "0" indicates that the first control device 101 is off, the second "1" indicates that the second control device 201 is on, and the third "0" indicates that the third control device 202 is off. Since electromagnetic energy can only be transmitted to the phase-shifting layer when control device 101 is off, the phase-shifting microstrip line will only perform phase shifting when control device 101 is in the "0" state. At this time, the 2-bit unit has three operating states: State 1: "0+00", that is, both control devices 201 and 202 are off. In this case, the electromagnetic wave does not pass through the phase-shifting microstrip line and no additional phase shift is generated. State 2: "0+10" state, i.e., controller 201 is on and 202 is off. At this time, microstrip stub 22 is connected to the first phase-shifting microstrip line 23, and the reflected wave lags behind the phase of state 1 by 90° at 10.45 GHz. State 3: "0+11" state, i.e., controllers 201 and 202 are on simultaneously. Microstrip stub 22 is connected to the first phase-shifting microstrip line 23 and the second phase-shifting microstrip line 24. Since the electromagnetic wave path is longer at this time, the phase shift is greater, and the phase of state 10.45 GHz lags behind state 1 by 180°. These three operating states, plus the "1+00" state when controller 101 is on, ultimately form a 2-bit electromagnetic metasurface unit with phase modulation capabilities of 0°, 90°, 180°, and 270°.

[0067] Figure 8 The reflection amplitude curves of the 2-bit unit with the optimal value under different operating states show that the reflection amplitude loss of each operating state at 10.45 GHz is within 2.5 dB.

Claims

1. A 2-bit reconfigurable metasurface unit based on a 1-bit design concept, wherein... A 2-bit reconfigurable metasurface unit (10) based on a 1-bit design concept includes, from top to bottom, a metal patch (11), a first electronic control device (101), a dielectric substrate (12), and a metal ground plane (13); and wherein A spatial rectangular coordinate system is established with the center of the upper surface of unit (10) as the origin. The positive direction of the x-axis is horizontal to the right, the positive direction of the y-axis is vertical upward, and the positive direction of the z-axis is perpendicular to the paper and outward. The dielectric substrate (12) is a square sheet. A rectangular metal patch (11) is printed on the dielectric substrate (12). A rectangular slot (14) is etched on the metal patch (11). Both the metal patch (11) and the slot (14) are symmetrical about the x-axis. The electronic control device (101) is soldered on the x-axis at the midpoint on the left side of the slot (14). The two poles of the electronic control device (101) are connected across the metal patches on both sides of the slot. The metal ground plate (13) is located below the dielectric substrate (12). The metal ground plate (13) and the dielectric substrate (12) have the same size. Their projections on the horizontal plane completely overlap. Its features are, A phase-shifting layer (20) is added below the unit (10), and a transmission metal via (15) is introduced into the unit (10) to transmit the electromagnetic energy on the unit (10) to the phase-shifting layer (20); the dielectric substrate (21) of the phase-shifting layer (20) is located below the metal floor (13), and the projections of the dielectric substrate (21) and the dielectric substrate (12) on the horizontal plane are completely coincident; the transmission metal via (15) is located on the metal patch (11) inside the gap (14), and the center of the via is located on the x-axis, close to the first electronic control device ( The metal via (15) is perpendicular to the metal patch (11) and penetrates the dielectric substrate (12) and dielectric substrate (21) vertically downwards, connecting the metal patch (11) on the upper surface of the dielectric substrate (12) with the microstrip branch (22) on the lower surface of the dielectric substrate (21); the metal ground plane (13) has a circular opening located at the position corresponding to the passage of the metal via (15), which isolates the metal via (15) from the metal ground plane (13) to prevent short circuits; A phase-shifting microstrip line is printed on the lower surface of a dielectric substrate (21), including a first phase-shifting microstrip line (23), a third electronic control device (202), and a second phase-shifting microstrip line (24). The first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) are along the x-axis direction. The two poles of the third electronic control device (202) are connected between the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24). A short-circuit metal via (25) is located at the end of the second phase-shifting microstrip line (24) away from the first phase-shifting microstrip line (23). Under the condition of ensuring the length requirement of the microstrip line, the shape of the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) can be a straight line or a zigzag line. In addition, the main bodies of the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) extend along the x direction. If the length of the microstrip line is too long, it is bent along the y direction. The phase-shifting microstrip line (23) is connected to the microstrip stub (22) through the second electronic control device (201). Under the condition of ensuring the length requirement of the microstrip line, the microstrip stub (22) can be a straight line or a bend. The microstrip stub (22) transmits the phase-shifted guided electromagnetic wave back to the unit (10).

2. The 2-bit reconfigurable metasurface unit based on the 1-bit design concept as described in claim 1, characterized in that, Both the metal patch (11) and the slot (14) are rectangular. The side length of the metal patch (11) along the x-axis is in the range of 5.0 to 12.0 mm, and the side length along the y-axis is in the range of 5.0 to 12.0 mm. The side length of the slot (14) along the x-axis is in the range of 4.0 to 11.0 mm, and the side length along the y-axis is in the range of 4.0 to 11.0 mm. The width of the slot is in the range of 0.01 to 1.0 mm. The side length of the dielectric substrate (12) is in the range of 8.0 to 15.0 mm, and the thickness is in the range of 1.0 to 5.0 mm. The distance between the center of the transmission metal via (15) and the edge of the electronic control device (101) is in the range of 0.2 to 5.0 mm; the thickness of the dielectric substrate (21) is in the range of 0.1 to 5.0 mm. The length of the microstrip branch (22) is in the range of 1.0 to 3.0 mm, the total length of the phase-shifting microstrip line (23) is in the range of 1.0 to 10.0 mm, the total length of the phase-shifting microstrip line (24) is in the range of 1.0 to 10.0 mm, and the width of the microstrip line is in the range of 0.2 to 3.0 mm.

3. The 2-bit reconfigurable metasurface unit based on the 1-bit design concept as described in claim 2, characterized in that, The metal patch (11) has a side length of 6.5 mm along the x-axis and a side length of 7.0 mm along the y-axis. The gap (14) has a side length of 5.5 mm along the x-axis and a side length of 5.3 mm along the y-axis. The gap width is 0.1 mm. The dielectric substrate (12) has a side length of 10.0 mm and a thickness of 2.0 mm. Its dielectric constant is in the range of 2.0 to 4.

0. The distance between the center of the transmission metal via (15) and the edge of the electronic control device (101) is 0.5 mm; the thickness of the dielectric substrate (21) is 0.28 mm, and its dielectric constant is in the range of 2.0 to 4.

0. The length of the microstrip branch (22) is 1.5 mm, the total length of the phase-shifting microstrip line (23) is 3.0 mm, the total length of the phase-shifting microstrip line (24) is 7.5 mm, and the width of the microstrip line is 0.5 mm.

4. The 2-bit reconfigurable metasurface unit based on the 1-bit design concept as described in claim 1, characterized in that, The first electronic control device (101), the second electronic control device (201), and the third electronic control device (202) adopt microelectromechanical system switches, PIN diode switches, or field-effect transistor switches.

5. The 2-bit reconfigurable metasurface unit based on the 1-bit design concept as described in claim 4, characterized in that, The first electronic control device (101), the second electronic control device (201), and the third electronic control device (202) are PIN diode switches SMP1352-040LF.

6. A design method for a 2-bit reconfigurable metasurface unit based on a 1-bit design concept, wherein the unit is a 2-bit reconfigurable metasurface unit based on a 1-bit design concept as described in any one of claims 1 to 5, characterized in that, Specifically, the following steps are included: Step 1: Design unit (10) using electromagnetic resonance method, and control the conduction and disconnection of electronic control device to make it have a reflection phase difference of 270° at the required frequency point; Unit (10) includes, from top to bottom, a metal patch (11), a first electronic control device (101), a dielectric substrate (12), and a metal ground plane (13); and wherein A spatial rectangular coordinate system is established with the center of the upper surface of unit (10) as the origin. The positive direction of the x-axis is horizontal to the right, the positive direction of the y-axis is vertical upward, and the positive direction of the z-axis is perpendicular to the paper and outward. The dielectric substrate (12) is a square sheet. A rectangular metal patch (11) is printed on the dielectric substrate (12). A rectangular slot (14) is etched on the metal patch (11). Both the metal patch (11) and the slot (14) are symmetrical about the x-axis. The electronic control device (101) is soldered on the x-axis at the midpoint on the left side of the slot (14). The two poles of the electronic control device (101) are connected across the metal patches on both sides of the slot. The metal ground plate (13) is located below the dielectric substrate (12). The metal ground plate (13) and the dielectric substrate (12) have the same size. Their projections on the horizontal plane completely overlap. Step 2: Add a phase-shifting layer (20) below the unit (10) obtained in step 1, and introduce a transmission metal via (15) in the unit (10) to transmit the electromagnetic energy on the unit (10) to the phase-shifting layer (20); A phase-shifting layer (20) is added below the unit (10), and a transmission metal via (15) is introduced into the unit (10) to transmit the electromagnetic energy on the unit (10) to the phase-shifting layer (20); the dielectric substrate (21) of the phase-shifting layer (20) is located below the metal floor (13), and the projections of the dielectric substrate (21) and the dielectric substrate (12) on the horizontal plane are completely coincident; the transmission metal via (15) is located on the metal patch (11) inside the gap (14), and the center of the via is located on the x-axis, close to the first electronic control device ( The metal via (15) is perpendicular to the metal patch (11) and penetrates the dielectric substrate (12) and dielectric substrate (21) vertically downwards, connecting the metal patch (11) on the upper surface of the dielectric substrate (12) with the microstrip branch (22) on the lower surface of the dielectric substrate (21); the metal ground plane (13) has a circular opening located at the position corresponding to the passage of the metal via (15), which isolates the metal via (15) from the metal ground plane (13) to prevent short circuits; Step 3: Using the guided wave method, design the phase-shifting microstrip line on the phase-shifting layer (20) in Step 2. By controlling the conduction and disconnection of the electronic control device, the electromagnetic wave transmitted back to the unit (10) through the phase-shifting layer (20) generates a phase shift of 90° and 180°, and finally forms a 2-bit electromagnetic metasurface unit with phase modulation capabilities of 0°, 90°, 180° and 270°. A phase-shifting microstrip line is printed on the lower surface of a dielectric substrate (21), including a first phase-shifting microstrip line (23), a third electronic control device (202), and a second phase-shifting microstrip line (24). The first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) are along the x-axis direction. The two poles of the third electronic control device (202) are connected between the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24). A short-circuit metal via (25) is located at the end of the second phase-shifting microstrip line (24) away from the first phase-shifting microstrip line (23). Under the condition of ensuring the length requirement of the microstrip line, the shape of the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) can be a straight line or a zigzag line. In addition, the main bodies of the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) extend along the x direction. If the length of the microstrip line is too long, it is bent along the y direction. The phase-shifting microstrip line (23) is connected to the microstrip stub (22) through the second electronic control device (201). Under the condition of ensuring the length requirement of the microstrip line, the microstrip stub (22) can be a straight line or a bend. The microstrip stub (22) transmits the phase-shifted guided electromagnetic wave back to the unit (10).

7. A 2-bit reconfigurable metasurface unit based on a 1-bit design concept, wherein... Unit (10) is a resonant 1-bit metasurface unit; Its features are, A phase-shifting layer (20) is added below the unit (10), and a transmission metal via (15) is introduced into the unit (10) to transmit the electromagnetic energy on the unit (10) to the phase-shifting layer (20); the dielectric substrate (21) of the phase-shifting layer (20) is located below the metal ground plane (13), and the projections of the dielectric substrate (21) and the dielectric substrate (12) on the horizontal plane are completely superimposed; the transmission metal via (15) penetrates vertically downward from the metal patch of the unit (10) through the dielectric substrate (12) and the dielectric substrate (21), connecting the metal patch of the unit (10) on the upper surface of the dielectric substrate (12) with the microstrip branch (22) on the lower surface of the dielectric substrate (21); there is a circular opening on the metal ground plane (13), which is located at the position corresponding to the passage of the transmission metal via (15), and the circular opening isolates the transmission metal via (15) from the metal ground plane (13) to prevent short circuit; The position of the transmission metal via (15) can be adjusted according to the actual situation, as long as the energy on the upper surface can be transmitted to the microstrip stub (22) through the transmission metal via (15); A phase-shifting microstrip line is printed on the lower surface of a dielectric substrate (21), including a first phase-shifting microstrip line (23), a third electronic control device (202), and a second phase-shifting microstrip line (24). The first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) are along the x-axis direction. The two poles of the third electronic control device (202) are connected between the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24). A short-circuit metal via (25) is located at the end of the second phase-shifting microstrip line (24) away from the first phase-shifting microstrip line (23). Under the condition of ensuring the length requirement of the microstrip line, the shape of the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) can be a straight line or a zigzag line. In addition, the main bodies of the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) extend along the x direction. If the length of the microstrip line is too long, it is bent along the y direction. The phase-shifting microstrip line (23) is connected to the microstrip stub (22) through the second electronic control device (201). Under the condition of ensuring the length requirement of the microstrip line, the microstrip stub (22) can be a straight line or a bend. The microstrip stub (22) transmits the phase-shifted guided electromagnetic wave back to the unit (10).

8. A design method for a 2-bit reconfigurable metasurface unit based on a 1-bit design concept, wherein the unit is a 2-bit reconfigurable metasurface unit based on a 1-bit design concept as described in claim 7, characterized in that... Specifically, the following steps are included: Step 1: Design unit (10) using electromagnetic resonance method, and control the conduction and disconnection of electronic control device to make it have a reflection phase difference of 270° at the required frequency point; Unit (10) is a resonant 1-bit metasurface unit; Step 2: Add a phase-shifting layer (20) below the unit (10) obtained in step 1, and introduce a transmission metal via (15) in the unit (10) to transmit the electromagnetic energy on the unit (10) to the phase-shifting layer (20); A phase-shifting layer (20) is added below the unit (10), and a transmission metal via (15) is introduced into the unit (10) to transmit the electromagnetic energy on the unit (10) to the phase-shifting layer (20); the dielectric substrate (21) of the phase-shifting layer (20) is located below the metal ground plane (13), and the projections of the dielectric substrate (21) and the dielectric substrate (12) on the horizontal plane are completely superimposed; the transmission metal via (15) penetrates vertically downward from the metal patch of the unit (10) through the dielectric substrate (12) and the dielectric substrate (21), connecting the metal patch of the unit (10) on the upper surface of the dielectric substrate (12) with the microstrip branch (22) on the lower surface of the dielectric substrate (21); there is a circular opening on the metal ground plane (13), which is located at the position corresponding to the passage of the transmission metal via (15), and the circular opening isolates the transmission metal via (15) from the metal ground plane (13) to prevent short circuit; The position of the transmission metal via (15) can be adjusted according to the actual situation, as long as the energy on the upper surface can be transmitted to the microstrip stub (22) through the transmission metal via (15); Step 3: Using the guided wave method, design the phase-shifting microstrip line on the phase-shifting layer (20) in Step 2. By controlling the conduction and disconnection of the electronic control device, the electromagnetic wave transmitted back to the unit (10) through the phase-shifting layer (20) generates a phase shift of 90° and 180°, and finally forms a 2-bit electromagnetic metasurface unit with phase modulation capabilities of 0°, 90°, 180° and 270°. A phase-shifting microstrip line is printed on the lower surface of a dielectric substrate (21), including a first phase-shifting microstrip line (23), a third electronic control device (202), and a second phase-shifting microstrip line (24). The first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) are along the x-axis direction. The two poles of the third electronic control device (202) are connected between the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24). A short-circuit metal via (25) is located at the end of the second phase-shifting microstrip line (24) away from the first phase-shifting microstrip line (23). Under the condition of ensuring the length requirement of the microstrip line, the shape of the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) can be a straight line or a zigzag line. In addition, the main bodies of the first phase-shifting microstrip line (23) and the second phase-shifting microstrip line (24) extend along the x direction. If the length of the microstrip line is too long, it is bent along the y direction. The phase-shifting microstrip line (23) is connected to the microstrip stub (22) through the second electronic control device (201). Under the condition of ensuring the length requirement of the microstrip line, the microstrip stub (22) can be a straight line or a bend. The microstrip stub (22) transmits the phase-shifted guided electromagnetic wave back to the unit (10).

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