Reconfigurable electromagnetic metasurface units and metasurfaces integrating transmission, reflection, and absorption

Abstract

This invention discloses a reconfigurable electromagnetic metasurface unit integrating transmission, reflection, and absorption functions. The metasurface unit includes two identical polarized resonant patches connected by a central metal via. Four positive intrinsic negative PIN diodes are integrated into the tunable patch layer, and the state of the four PIN diodes is dynamically controlled by a DC bias voltage. This invention can flexibly switch the operating mode of the metasurface by a DC bias voltage, and control the electromagnetic wavefront in real time in absorption mode (low RCS), transmission mode, and reflection mode. Through array coding, it can realize functions such as high-gain beamforming, beam scanning, beam focusing, RCS reduction, beamforming, and vortex beam generation. It has the advantages of simple design, low cost, and excellent performance, and has great potential in fields such as smart skin, electronic countermeasures, and wireless communication systems.

Description

Technical Field

[0001] This invention belongs to the field of wireless communication technology and relates to a reconfigurable electromagnetic metasurface unit that integrates transmission, reflection and absorption functions.

[0002] This invention also relates to a reconfigurable electromagnetic metasurface that integrates transmission, reflection, and absorption functions. Background Technology

[0003] Electromagnetic metasurfaces, as two-dimensional equivalents of electromagnetic metamaterials, have emerged as a promising alternative to beam-controlled antennas due to their high integration, ease of fabrication, low cost, surface uniformity, and low insertion loss. By utilizing the generalized Snell's law, metasurfaces can flexibly control electromagnetic wavefronts through carefully designed subwavelength structures at the interface, enabling the creation of various functional devices and applications in the microwave band. To achieve real-time control of electromagnetic waves, digitally encoded and reconfigurable metasurfaces have been proposed. These involve integrating active devices (such as PIN diodes, varactor diodes, and transistors) into the metasurface; digitally encoding the physical properties of electromagnetic waves (such as amplitude, phase, and polarization) using binary code, allowing for arbitrary control of electromagnetic characteristics; and using field-programmable gate arrays (FPGAs) to encode and regulate the states of active devices, thereby establishing a connection between the digital information domain and the physical field. Based on this concept, various theoretical and functional designs have been explored. With the rapid development of metasurfaces, full-space control has become a steadily growing interest due to the enormous potential of possessing multiple EM functions. Specifically, most research focuses on achieving precise control of electromagnetic waves in half-space, particularly in regulating the absorption, reflection, or transmission of these waves. Therefore, the development of multifunctional metasurfaces capable of modulating electromagnetic waves across the entire space has great potential for numerous applications in various fields. Summary of the Invention

[0004] The purpose of this invention is to provide a reconfigurable electromagnetic metasurface unit that integrates transmission, reflection, and absorption functions. The operating mode of the metasurface can be flexibly switched by a DC bias voltage, and the electromagnetic wavefront in the absorption mode, transmission mode, and reflection mode can be controlled in real time. Through array coding, functions such as high-gain beamforming, beam scanning, beam focusing, RCS reduction, beamforming, and vortex beam generation can be realized.

[0005] The technical solution adopted in this invention is a reconfigurable electromagnetic metasurface unit that integrates transmission, reflection, and absorption functions. The metasurface unit includes two identical polarization resonant patches, which are connected by a central metal via. Four positive intrinsic negative PIN diodes are integrated into the tunable patch layer, and the state of the four PIN diodes is dynamically controlled by a DC bias voltage.

[0006] The invention is further characterized by:

[0007] The metasurface unit has a four-layer metal structure; the top layer of the unit has a receiving patch, a first PIN diode, a second PIN diode, a first capacitor, a matching resistor, and a circuit breaker inductor arranged horizontally; the middle layer has a metal ground plane arranged horizontally; the middle two layers have a first bias circuit, a second bias circuit, a third bias circuit, and a DC stub; the bottom layer of the unit has a radiating patch, a third PIN diode, a fourth PIN diode, a second capacitor, and a third capacitor arranged horizontally.

[0008] The first bias circuit is connected to the receiving patch through the third metal via and the circuit breaker inductor; the second bias circuit and the third bias circuit are connected to the radiating patch through the fourth metal via and the fifth metal via, respectively; the first metal via is connected to the DC stub located in the middle two layers; the second metal via is connected to the receiving patch and the metal ground plane.

[0009] The four-layer metal structure is a four-layer stacked structure formed by horizontally placing and stacking the first dielectric plate, the second dielectric plate, and the third dielectric plate. It includes the top layer of the first dielectric plate, the middle layer connecting the first dielectric plate and the second dielectric plate, the middle two layers connecting the second dielectric plate and the third dielectric plate, and the bottom layer of the third dielectric plate.

[0010] The first and third dielectric substrates are F4B substrates with a dielectric constant of 2.2; the second dielectric substrate is a Rogers 4450 adhesive layer with a dielectric constant of 3.67.

[0011] The top layer of the unit specifically consists of: a horizontally laid receiving patch, which is a patch antenna with a U-shaped slot and a matching stub. A first PIN diode is soldered at the edge of the receiving patch and the connection of the matching stub. An open-circuit inductor is soldered at the other edge of the receiving patch. A second PIN diode and a first capacitor are soldered to the U-shaped slot of the receiving patch respectively. The second PIN diode is close to the first PIN diode. A matching resistor is soldered on the matching stub of the receiving patch.

[0012] The bottom layer of the unit includes a horizontally arranged radiating patch, which is a patch antenna with O-shaped slots. A third PIN diode and a fourth PIN diode are soldered into the slots of the radiating patch, and the radiating patch is connected by a second capacitor and a third capacitor respectively.

[0013] The metal floor has two circular slits for non-contact passage through the first and third metal vias;

[0014] Four of them are PIN diodes, model number SKYWORKS SMP1345-79LF;

[0015] The first and second capacitors are model GJM1555C1H3R0BA16.

[0016] The second technical solution of the present invention is a reconfigurable electromagnetic metasurface integrating transmission, reflection, and absorption. It adopts a reconfigurable electromagnetic metasurface unit integrating transmission, reflection, and absorption functions, including 16×16 metasurface units placed horizontally to form a square array. 96 shift registers and 768 current-limiting resistors are placed on both sides of the array. A 360-ohm current-limiting resistor is welded to each control line. Every 8×1 metasurfaces are grouped together, including 3×8×1 DC bias control lines, and controlled by 3 shift registers in series to form a reconfigurable electromagnetic metasurface.

[0017] The beneficial effects of this invention are:

[0018] The electromagnetic metasurface integrated with the reconfigurable electromagnetic metasurface unit of this invention, which integrates transmission, reflection, and absorption, can achieve a 1-dB transmission bandwidth and 1-bit transmission phase modulation in transmission mode (4.4-5.8 GHz); a 1-bit reflection phase modulation bandwidth in reflection mode (4.4-5.6 GHz); and a -10dB (90% absorption rate) absorption bandwidth in absorption mode (4.7-5.3 GHz). The operating mode of the metasurface can be flexibly switched by a DC bias voltage, allowing real-time control of the electromagnetic wavefront in low RCS absorption mode, transmission mode, and reflection mode. Array coding enables functions such as high-gain beamforming, beam scanning, beam focusing, RCS reduction, beamforming, and vortex beam generation. Furthermore, this invention features simple design, low cost, and excellent performance, showing great potential in fields such as smart skin, electronic warfare, and wireless communication systems. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural schematic diagram of the metasurface unit disclosed in the embodiments of the present invention;

[0020] Figure 2 This is a top view of the top layer of the metasurface unit disclosed in the embodiments of the present invention;

[0021] Figure 3 This is a top view of the middle layer of the metasurface unit disclosed in the embodiments of the present invention;

[0022] Figure 4 This is a top view of the middle two layers of the metasurface unit disclosed in the embodiments of the present invention;

[0023] Figure 5 This is a top view of the bottommost layer of the metasurface unit disclosed in the embodiments of the present invention;

[0024] Figure 6 This is a graph showing the reflection and transmission amplitude data of the metasurface unit in absorption mode as disclosed in the embodiments of the present invention;

[0025] Figure 7This is a graph showing the reflection and transmission coefficients of the metasurface unit in transmission mode as disclosed in the embodiments of the present invention;

[0026] Figure 8 This is a graph showing the reflection coefficient and transmission coefficient data of the metasurface unit in reflection mode as disclosed in the embodiments of the present invention;

[0027] Figure 9 This is a top view of the reconfigurable electromagnetic metasurface structure disclosed in Embodiment 1 of the present invention.

[0028] In the diagram, 1. First dielectric substrate; 2. Second dielectric substrate; 3. Third dielectric substrate; 4. Receiving patch; 5. Metal ground plane; 6. Radiation patch; 7. First metal via; 8. Second metal via; 9. Third metal via; 10. Fourth metal via; 11. Fifth metal via; 12. First bias circuit; 13. Second bias circuit; 14. Third bias circuit; 15. DC stub; 16. First PIN diode; 17. Second PIN diode; 18. Third PIN diode; 19. Fourth PIN diode; 20. First capacitor; 21. Second capacitor; 22. Third capacitor; 23. Matching resistor; 24. Opening inductor. Detailed Implementation

[0029] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0030] This invention provides a reconfigurable electromagnetic metasurface unit that integrates transmission, reflection, and absorption, as shown in the following embodiments:

[0031] Example 1

[0032] A reconfigurable electromagnetic metasurface unit integrating transmission, reflection, and absorption functions includes a first dielectric substrate 1, a second dielectric substrate 2, a third dielectric substrate 3, a receiving patch 4, a metal ground plane 5, a radiating patch 6, a first metal via 7, a second metal via 8, a third metal via 9, a fourth metal via 10, a fifth metal via 11, a first bias circuit 12, a second bias circuit 13, a third bias circuit 14, a DC stub 15, a first PIN diode 16, a second PIN diode 17, a third PIN diode 18, a fourth PIN diode 19, a first capacitor 20, a second capacitor 21, a third capacitor 22, a matching resistor 23, and a circuit-breaking inductor 24.

[0033] like Figure 1 As shown, the first dielectric plate 1, the second dielectric plate 2, and the third dielectric plate 3 are stacked horizontally together to form a multi-layer unit with a four-layer metal structure.

[0034] like Figure 2As shown, the receiver patch 4 is a patch antenna with a U-shaped slot and a matching stub, which is placed on the top layer of the unit structure. A first PIN diode 16 is soldered to its edge and the connection of the matching stub to control whether the matching stub is working. An open circuit inductor 24 is soldered to the edge of the receiver patch 4 to isolate the radio frequency signal. A second PIN diode 17 and a first capacitor 20 are soldered to the U-shaped slot of the receiver patch 4. The second PIN diode 17 is used to control whether the U-shaped slot mode is working. A matching resistor 23 is soldered to the matching stub of the receiver patch 4 to absorb the current of the receiver patch 4 in the absorption mode.

[0035] like Figure 5 As shown, the radiating patch 6 is a patch antenna with an O-shaped slot, which is placed at the bottom of the unit structure. The third PIN diode 18 and the fourth PIN diode 19 are soldered in the slot. The radiating patch 6 is separated by the second capacitor 21 and the third capacitor 22 to isolate DC signals so that the third PIN diode 18 and the fourth PIN diode 19 can be controlled independently.

[0036] like Figure 3 As shown, the metal ground plane 5 is placed in the middle layer between the first dielectric substrate 1 and the second dielectric substrate 2 to isolate the radio frequency signals between the receiving patch 4 and the radiating patch 6; the metal ground plane 5 is engraved with two circular gaps to ensure that the first metal via 7 and the third metal via 9 can pass through the metal ground plane 5 without contact; the first bias circuit 12 is placed in the middle second layer and is connected to the receiving patch 4 through the third metal via 9 and the circuit breaker inductor, and controls the on / off state of the first PIN diode 16 and the second PIN diode 17 by changing the DC signal voltage;

[0037] like Figure 4 As shown, the second bias circuit 13 and the third bias circuit 14 are placed in the middle two layers connecting the second dielectric substrate 2 and the third dielectric substrate 3, and are connected to the radiating patch through the fourth metal via 10 and the fifth metal via 11, respectively, to control the third PIN diode 18 and the fourth PIN diode 19, respectively; the DC stub 15 is connected to the first metal via 7 to provide the same DC reference voltage for the first PIN diode 16, the third PIN diode 18 and the fourth PIN diode 19; the second metal via 8 connects the metal ground plate 5 and the receiving patch 4, so that the second PIN diode 17 also obtains the same DC reference voltage as the other diodes.

[0038] Example 2

[0039] The first dielectric substrate, the second dielectric substrate, and the third dielectric substrate are placed horizontally and stacked to form a four-layer stacked structure, including the top layer of the first dielectric substrate 1, the middle layer connecting the first dielectric substrate 1 and the second dielectric substrate 2, the middle two layers connecting the second dielectric substrate 2 and the third dielectric substrate 3, and the bottom layer of the third dielectric substrate 3.

[0040] The receiving patch 4, the first PIN diode 16, the second PIN diode 17, the first capacitor 20, the matching resistor 23, and the circuit-breaking inductor 24 are horizontally placed on the top layer of the first dielectric substrate; a metal ground plane 5 is placed in the middle layer to isolate the coupling between the receiving patch 4 and the radiating patch 6 and to reflect electromagnetic waves; the first bias circuit 12, the second bias circuit 13, the third bias circuit 14, and the DC stub 15 are placed in the middle two layers between the second and third dielectric substrates; the radiating patch 6, the third PIN diode 18, the fourth PIN diode 19, the second capacitor 21, and the third capacitor 22 are horizontally placed on the bottom layer of the third dielectric substrate;

[0041] In this embodiment, the first dielectric substrate 1 and the third dielectric substrate 3 are F4B boards with a dielectric constant of 2.2, a thickness of 3mm, and a size of 25mm×25mm; the second dielectric substrate 2 is a Rogers 4450 adhesive layer with a dielectric constant of 3.67, a thickness of 0.2mm, and a size of 25mm×25mm.

[0042] The receiver patch 4 is a rectangular patch antenna with a U-shaped slot and matching stub, measuring 17.5mm × 16mm, used to receive, reflect, and absorb electromagnetic waves. The size of the U-shaped slot and the size of the receiver patch can change the resonant frequency. A first PIN diode 16 is soldered at the matching stub connection of the receiver patch 4 to control its operation. A second PIN diode 17 is soldered on the U-shaped slot, which controls whether the U-shaped slot mode is working. A second metal via 8 extends from the matching stub of the receiver patch 4 to the metal ground plane 5 to transmit the DC signal from the metal ground plane. A circuit breaker inductor 24 is soldered to the edge of the receiver patch 4 and connected to a third metal via 9 to transmit the DC signal from the first bias circuit 12.

[0043] The radiating patch 6 is a square patch antenna with an O-shaped slot, measuring 15mm × 15mm; the radiating patch 6 is divided by the second capacitor 21 and the third capacitor 22 to isolate DC signals;

[0044] The length and width of the receiving patch 4, the length and width of the U-shaped slit, the length and width of the radiating patch 6, and the length and width of the O-shaped slit are used to match the transmission loss and bandwidth of the metasurface unit, and also to adjust the reflection phase; adjusting the width and length of the matching stub of the receiving patch 4 and the resistance value of the matching resistor 23 are used to adjust the absorption bandwidth and absorptivity of the metasurface unit.

[0045] The metal floor 5, measuring 25mm x 25mm, covers the entire unit and is used to isolate the radio frequency signals from the receiving patch 4 and the radiating patch 6.

[0046] DC stub 15 provides the same DC reference voltage to the first PIN diode 16, the third PIN diode 18, and the fourth PIN diode 19 through the first metal via 7; the DC signal of the first bias circuit 12 controls the state of the first PIN diode 16 and the second PIN diode 17; the DC signal of the second bias circuit 13 controls the state of the third PIN diode 18; and the DC signal of the third bias circuit 14 controls the state of the fourth PIN diode 19.

[0047] The first capacitor 20 and the second capacitor 21 are short-circuit capacitors in 0402 packages.

[0048] The first PIN diode 16, the second PIN diode 17, the third PIN diode 18, and the fourth PIN diode 19 are model SMP1345-79LF;

[0049] The first metal via 7 is located at the center of the cell, connecting the receiving patch 4 and the radiating patch 6 to transmit energy, and is not connected to the metal ground plane 5. The first metal via 7 is connected to the metal ground plane 5 through the matching branch of the receiving patch 4, and is used to transmit the DC signal of the metal ground plane 5.

[0050] The DC signal from the first bias circuit 12 is transmitted to the receiving patch 4 through the third metal via 9 to control the on / off state of the first PIN diode 16 and the second PIN diode 17; the third PIN diode 18 and the fourth PIN diode 19 are soldered onto the O-groove of the radiating patch; the DC signal from the second bias circuit 13 is transmitted to the cathode of the third PIN diode 18 through the fourth metal via 10 and controls its on / off state; the DC signal from the third bias circuit 14 is transmitted to the fourth PIN diode 19 through the fifth metal via 11 and controls its on / off state.

[0051] When the first bias circuit 12, the second bias circuit 13, and the third bias circuit 14 transmit a DC signal of 0V, the PIN diodes they control are turned on; conversely, when the DC signal is 3.3V, the PIN diodes they control are turned off.

[0052] When the first PIN diode 16 and the second PIN diode 17 are turned on, the slot mode of the receiving patch 4 is destroyed, and at the same time the matching stub of the receiving patch 4 starts to work. The radio frequency signal of the receiving patch 4 is transmitted to the matching stub and perfectly absorbed by the matching resistor. At this time, the metasurface unit works in absorption mode.

[0053] When the first PIN diode 16 and the second PIN diode 17 are cut off, the slot mode of the receiving patch 4 is operated, and the matching branch of the receiving patch is turned off. The radio frequency signal of the receiving patch is transmitted to the radiating patch 6 through the first metal via 7. At this time, when the third PIN diode 18 and the fourth PIN diode 19 are switched on and off, a low-loss transmission mode is formed, and 1-bit transmission phase modulation can be obtained by switching the state of the third PIN diode 18 and the fourth PIN diode 19.

[0054] When the first PIN diode 16 and the second PIN diode 17 are cut off, the receiving patch 4 operates in slot mode, and the matching branch of the receiving patch 4 is turned off. The radio frequency signal of the receiving patch 4 is transmitted to the radiating patch 6 through the first metal via 7. When the third PIN diode 18 and the fourth PIN diode 19 are simultaneously turned on or simultaneously cut off, the center input impedance of the radiating patch is approximately 0, which disrupts the matching path of the transmission path, thereby reflecting electromagnetic waves. In reflection mode, the simultaneous turning on and off of the third PIN diode 18 and the fourth PIN diode 19 will change the boundary conditions of the receiving patch, thereby changing the reflection phase and obtaining 1-bit reflection phase modulation.

[0055] The working mode of the metasurface unit can be specifically analyzed as follows:

[0056] When both the first PIN diode 16 and the second PIN diode 17 are in the ON state, the metasurface unit operates in absorption mode, such as Figure 6 As shown, the metasurface unit in absorption mode can achieve -10 dB power absorption (90% absorption rate) within a bandwidth of 4.7-5.3 GHz.

[0057] The first PIN diode 16 and the second PIN diode 17 are both in the cutoff state, while the third PIN diode 18 and the fourth PIN diode 19 maintain a state where one is on and the other is off, or one is off and the other is on. The metasurface unit operates in transmission mode, and the S-parameters and phase response in transmission mode are as follows: Figure 7 As shown; in transmission mode, a 1-dB transmission bandwidth and 1-bit transmission phase modulation of 4.4-5.8 GHz can be obtained;

[0058] The first PIN diode 16 and the second PIN diode 17 are both in the cutoff state, and the third PIN diode 18 and the fourth PIN diode 19 are both in the cutoff or conduction state. The metasurface unit operates in reflection mode. The S-parameters and phase response in reflection mode are as follows: Figure 8 As shown, a 1-bit reflection phase modulation bandwidth of 4.4-5.6 GHz can be obtained in reflection mode.

[0059] Example 3

[0060] Design reconfigurable electromagnetic metasurfaces that integrate transmission, reflection, and absorption functions, such as Figure 9 As shown, it includes 16×16 metasurface units; these 16×16 metasurface units are horizontally arranged to form a square array for real-time control of the electromagnetic wavefront in all space. This metasurface can switch between transmission, reflection, and absorption modes within the same aperture. A total of 96 shift registers and 768 current-limiting resistors are placed on both sides of the array. Each control line is soldered with a 360-ohm current-limiting resistor. We group every 8×1 metasurfaces into a group, which includes 3×8×1 DC bias control lines. Using 3 shift registers in series for control can reduce the number of control lines by two-thirds. Finally, a reconfigurable transmissive and reflective integrated metasurface array is designed.

Claims

1. A reconfigurable electromagnetic metasurface unit integrating transmission, reflection, and absorption functions, characterized in that, The top layer of the unit is horizontally equipped with a receiving patch (4), a first PIN diode (16), a second PIN diode (17), a first capacitor (20), a matching resistor (23), and a circuit breaker inductor (24); the middle layer is horizontally equipped with a metal ground plane (5); the middle second layer is equipped with a first bias circuit (12), a second bias circuit (13), a third bias circuit (14), and a DC stub (15); the bottom layer of the unit is horizontally equipped with a radiating patch (6), a third PIN diode (18), a fourth PIN diode (19), a second capacitor (21), and a third capacitor (22). The first bias circuit (12) is connected to the receiving patch (4) through the third metal via (9) and the circuit breaker inductor (24); the second bias circuit (13) and the third bias circuit (14) are connected to the radiating patch (6) through the fourth metal via (10) and the fifth metal via (11), respectively; the first metal via (7) is connected to the DC stub (15) located in the middle second layer; The second metal via (8) is connected to the receiving patch (4) and the metal floor (5); The four-layer metal structure is a four-layer stacked structure formed by horizontally stacking the first dielectric plate (1), the second dielectric plate (2), and the third dielectric plate (3), including the top layer of the first dielectric plate (1), the middle layer connecting the first dielectric plate (1) and the second dielectric plate (2), the middle two layers connecting the second dielectric plate (2) and the third dielectric plate (3), and the bottom layer of the third dielectric plate (3). The top layer of the unit is specifically: a horizontally laid receiving patch (4), the receiving patch (4) is a patch antenna with a U-shaped slot and a matching stub, a first PIN diode (16) is welded at the edge of the receiving patch (4) and the connection of the matching stub, an open circuit inductor (24) is welded at the other edge of the receiving patch (4), a second PIN diode (17) and a first capacitor (20) are welded to the U-shaped slot of the receiving patch (4) respectively, the second PIN diode (17) is close to the first PIN diode (16), and a matching resistor (23) is welded on the matching stub of the receiving patch (4). The unit bottom layer includes a horizontally arranged radiating patch (6), which is a patch antenna with an O-shaped slot. A third PIN diode (18) and a fourth PIN diode (19) are soldered into the slot of the radiating patch (6), and the radiating patch (6) is connected by a second capacitor (21) and a third capacitor (22). The state of the four PIN diodes is dynamically controlled by a DC bias voltage.

2. The reconfigurable electromagnetic metasurface unit integrating transmission, reflection, and absorption functions according to claim 1, characterized in that, The first dielectric substrate (1) and the third dielectric substrate (3) are F4B substrates with a dielectric constant of 2.2; the second dielectric substrate (2) is a Rogers 4450 adhesive layer with a dielectric constant of 3.

67.

3. The reconfigurable electromagnetic metasurface unit integrating transmission, reflection, and absorption functions according to claim 1, characterized in that, The metal floor (5) has two circular slits for non-contact passage through the first metal via (7) and the third metal via (9).

4. The reconfigurable electromagnetic metasurface unit integrating transmission, reflection, and absorption functions according to claim 1, characterized in that, The four PIN diodes are model SKYWORKS SMP1345-79LF.

5. The reconfigurable electromagnetic metasurface unit integrating transmission, reflection, and absorption functions according to claim 1, characterized in that, The first capacitor (20) and the second capacitor (21) are model GJM1555C1H3R0BA16.

6. A reconfigurable electromagnetic metasurface integrating transmission, reflection, and absorption functions, employing the reconfigurable electromagnetic metasurface unit integrating transmission, reflection, and absorption functions as described in any one of claims 1 to 5, characterized in that... It consists of a square array of several horizontally placed metasurface units.

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