Polarization conversion transmission type reconfigurable metamaterial structure with amplitude-phase independent regulation and control

Abstract

A polarization conversion transmission type reconfigurable metamaterial structure with amplitude-phase independent regulation and control is formed by copying and translating n * n basic units, and each basic unit comprises three dielectric layers, five metal layers and two air layers; the dielectric layers comprise a first dielectric layer, a second dielectric layer and a third dielectric layer from top to bottom; a first air layer is arranged between the first dielectric layer and the second dielectric layer, and a second air layer is arranged between the second dielectric layer and the third dielectric layer; the amplitude regulation and control layer is located on the upper surface of the first dielectric layer, and the amplitude regulation and control bias circuit layer is located on the lower surface of the first dielectric layer; the polarization conversion phase regulation and control layer is located on the upper surface of the second dielectric layer, and the polarization conversion phase regulation and control bias circuit layer is located on the lower surface of the second dielectric layer; the polarization gate layer is located on the upper surface of the third dielectric layer. According to the invention, efficient electromagnetic regulation and control in a transmission mode are realized, independent regulation and control in two dimensions of amplitude and phase are realized, and unification of high transmissivity and accurate regulation and control in a microwave frequency band is realized.

Description

Technical Field

[0001] This invention belongs to the field of metamaterial structure technology, specifically relating to a polarization conversion transmission type reconfigurable metamaterial structure with amplitude-phase independent control. Background Technology

[0002] Current electromagnetic metamaterials technology still faces significant technical challenges in achieving independent amplitude and phase control. Existing research mainly focuses on reflective active / passive metamaterials. While these structures can utilize metal backplates to increase reflection amplitude, simplify bias circuit design, and effectively isolate DC signal interference, their inherent reflective operating mode severely limits their applicability in transmissive applications. In contrast, transmissive reconfigurable metamaterials, although overcoming this limitation, generally suffer from the drawback of a single control dimension, enabling only single-parameter control of phase or amplitude. This is primarily because transmissive structures require complex multilayer designs to obtain sufficient electromagnetic response, and the inherent characteristics of resonant units cause amplitude and phase parameters to be coupled, making independent control difficult. Furthermore, the design of control circuits in transmissive structures faces severe challenges, requiring both the normal transmission of high-frequency electromagnetic fields and the avoidance of DC signal interference with the electromagnetic response. This technical dilemma is particularly pronounced in applications such as wireless communication and holographic imaging, where existing solutions often force optimization of phase control by maximizing transmission amplitude, severely restricting the system's control freedom. Especially in the microwave band, achieving independent control at high transmittance is more challenging due to the similarity between device size and operating wavelength. Existing technologies suffer from limitations in reflection modes, single control dimensions, severe amplitude-phase coupling, and difficulties in circuit integration, necessitating innovative technical solutions.

[0003] For example, Yongxin Guo et al. published a paper titled "A Metasurface With Independent Amplitude-Phase Co-Control for Recognition Deception Based on the Mimicry of Micro-Doppler Signatures and Flicker Mechanisms" in IEEE TRANSACTIONS ON MICROWAVE THEORY AND TECHNIQUES, proposing a metamaterial that achieves independent dynamic control of amplitude and phase by loading PIN diodes. Its application is in radar signal jamming and deception; therefore, it only needs to be designed as a reflective structure with all active circuit bias lines integrated behind a metal backplate. However, for certain specific scenarios involving secure communication and integrated communication stealth, reflective structures are clearly unsuitable. Another example is Fan Yang et al.'s paper titled "A Novel Wideband and High-Efficiency Electrically Scanning Transmitarray Using Transmission Metasurface Polarizer" in IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, which proposes a highly efficient transmissive digital coding metamaterial. The polarization conversion layer, which employs two polarization gates and a PIN diode loaded in the middle, achieves a higher transmission amplitude, but can only control a single phase mode. Therefore, it only implements a simple beam control function, and its functional expansion is limited.

[0004] In summary, existing amplitude-phase modulated metamaterial technologies suffer from several key drawbacks: First, while reflective structures are relatively simple to manipulate, their operating modes are limited to reflected wave manipulation, failing to meet the requirements of transmissive applications. This severely restricts their application in fields such as transmissive imaging, encrypted communication, and transmissive stealth. Second, although transmissive structures overcome the limitations of operating modes, they generally suffer from a single control dimension, only able to achieve single-parameter control of phase or amplitude, failing to meet the dynamic control requirements in complex electromagnetic environments. Third, there is a severe coupling effect between amplitude and phase parameters in existing technologies, and this mutual constraint significantly reduces the system's control freedom. Furthermore, the multi-layer design requirements of transmissive structures pose a severe challenge to the integration of active devices, requiring both the normal transmission of high-frequency electromagnetic fields and the avoidance of DC signal interference with the electromagnetic response, greatly increasing the complexity of system design. Finally, in microwave applications, existing technologies often require compromises between transmittance and control performance, making it difficult to simultaneously achieve both high transmittance and precise control—two key performance indicators. Summary of the Invention

[0005] To overcome the shortcomings of the existing technology, the present invention aims to provide a polarization conversion transmissive reconfigurable metamaterial structure with independent amplitude-phase control, which realizes efficient electromagnetic control in the transmission mode and achieves independent control in both amplitude and phase dimensions. Through the optimized design of the multilayer structure, the control circuit design is simplified while ensuring high transmittance, thus achieving the unity of high transmittance and precise control in the microwave band.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A polarization-conversion transmission-type reconfigurable metamaterial structure with amplitude-phase independent control is formed by copying and translating n×n basic units. Each basic unit includes 3 dielectric layers, 5 metal layers and 2 air layers.

[0008] The dielectric layers are distributed from top to bottom as a first dielectric layer, a second dielectric layer, and a third dielectric layer;

[0009] There is a first air layer between the first dielectric layer and the second dielectric layer, and a second air layer between the second dielectric layer and the third dielectric layer;

[0010] The metal layers, distributed from top to bottom, are: amplitude modulation layer, amplitude modulation bias circuit layer, polarization conversion phase modulation layer, polarization conversion phase modulation bias circuit layer, and polarization gate layer.

[0011] The amplitude modulation layer is located on the upper surface of the first dielectric layer, and the amplitude modulation bias circuit layer is located on the lower surface of the first dielectric layer; the polarization conversion phase modulation layer is located on the upper surface of the second dielectric layer, and the polarization conversion phase modulation bias circuit layer is located on the lower surface of the second dielectric layer; the polarization gate layer is located on the upper surface of the third dielectric layer.

[0012] The thickness H1 of the first dielectric layer is 2 mm, the thickness H2 of the second dielectric layer is 2 mm, and the thickness H3 of the third dielectric layer is 2 mm. All dielectric layers are made of a material with a relative permittivity of ε. r =3 Rogers 3003 material, the first dielectric layer and the second dielectric layer are separated by a first air layer, the thickness of the first air layer is H air1 The thickness is 2 mm; the second dielectric layer and the third dielectric layer are separated by a second air layer, the thickness of which is H. air2 It is 1mm.

[0013] The amplitude control layer consists of two elongated metal patches, two U-shaped metal patches, a PIN diode, a bias line, and a ground line.

[0014] Two long strip metal patches are placed parallel to each other on the upper surface of the first dielectric layer. Two U-shaped metal patches are placed symmetrically between the two long strip metal patches. The openings of the two U-shaped metal patches face away from each other and are respectively aligned with one of the long strip metal patches.

[0015] The bottoms of the two U-shaped metal patches are connected in the middle through the PIN diode, with the positive terminal of the PIN diode located on the right side. The period of the basic unit is P, and its value ranges from 13 to 17 mm.

[0016] The bias line 1 and the ground line 1 are respectively set on the left and right U-shaped metal patches, wherein the distance between the bias line 1 and the bottom of the U-shaped metal patch to which it is connected is D. 6_4 The distance between the grounding wire and the bottom of the U-shaped metal patch it is connected to is D. 6_5 D 6_4 The value range is 0.5-0.7mm, D 6_5 The value range is 0.4-0.6 mm.

[0017] The bias line 1 and the ground line 1 are located on the asymmetrical arms of the two U-shaped metal patches, respectively, and extend outward from the U-shaped metal patches.

[0018] Among them, the two elongated metal patches have the same geometric dimensions, with a width W. 6_1 The range is 0.8-1mm, and the length is L. 6_1 The range is 10-12 mm, and two elongated metal patches are placed symmetrically with a distance of D from the periodic boundary of the first dielectric layer. 6_1Its value ranges from 1.35 to 1.75 mm; the two U-shaped metal patches have the same geometric dimensions, and their length is L. 6_2 The range is 3.5-4.5mm, and the width is W. 6_2 The range is 1-2mm, and the distance between the two arms is W. 6_U The range is 0.25-0.75mm, and the distance D between the two U-shaped metal patches is... 6_2 The thickness is 0.5mm; two U-shaped metal patches are connected to bias line one and ground line one, wherein the length of bias line one is L. 6_3 The range is 2.25-4.25mm, and the length L of the grounding wire is... 6_4 The width W of the bias line and the ground line is in the range of 1.25-3.25mm. 6_3 Same, W 6_3 It is 0.2mm.

[0019] The PIN diode is model SMP1340-040LF. Its equivalent circuit in the "conducting" state consists of a lumped resistor and a lumped inductor connected in series, with an equivalent resistance value R. PIN and equivalent inductance value L PIN1 The equivalent circuit of the PIN diode in the "off" state is a series connection of a lumped resistor, a lumped inductor, and a lumped capacitor, with an equivalent resistance value R. The values ​​are 1 ohm and 0.45 nH respectively. PIN2 Equivalent inductance value L PIN2 and equivalent capacitance value C PIN2 The values ​​are 10 ohms, 0.45 nH, and 0.16 pF, respectively. The amplitude-controlled bias circuit layer includes a second ground line, a second bias line, a fan-shaped filter capacitor metal sheet, a lumped inductor, and a metallized via.

[0020] Grounding wire two is connected to grounding wire one in the amplitude control layer through a metallized via; the metallized via penetrates the first dielectric layer and has a radius R. 7_0 It is 0.2mm;

[0021] The second bias line is L-shaped and is composed of the first bias line and the second bias line. The first bias line is parallel to the ground line. The fan-shaped filter capacitor metal sheet is connected to the second bias line. The lumped inductor is connected to the end of the second bias line away from the first bias line.

[0022] The apex of the fan-shaped filter capacitor metal sheet is connected to the second bias line, and the whole is located inside the L-shaped structure of the second bias line.

[0023] Grounding wire one and grounding wire two are in the same vertical position; the distance between the first bias line two and grounding wire two is D7_1, with a value ranging from 6 to 6.9 mm; the fan-shaped filter capacitor metal sheet is connected in parallel to the second bias line two, and the distance between it and the periodic boundary of the first dielectric layer is D.7_2 Its value ranges from 4 to 5.2 mm; the lumped inductor is connected in series on the second bias line, and the distance between it and the periodic boundary of the first dielectric layer is D. 7_3 Its value ranges from 5.5 to 6.5 mm, and the width W of the grounding wire two and the bias wire two is... 7_1 Same, W 7_1 The radius R of the metal sheet of the sector-shaped filter capacitor is 0.2mm. 7_1 The range is 2-4mm, and the angle A of the metal sheet of the fan-shaped filter capacitor is... 7_1 The range is 30-90°; the lumped inductor uses a 0201 package, and the inductance value is L. 8_RLC It is 2.8nH.

[0024] The second bias line is L-shaped and consists of a first bias line and a second bias line connected together, wherein the first bias line is parallel to the second ground line. A sector-shaped filter capacitor metal sheet is connected to the second bias line, and a lumped inductor is connected to the end of the second bias line away from the first bias line.

[0025] Furthermore, the apex of the fan-shaped filter capacitor metal sheet is connected to the second bias line, and the whole is located inside the L-shaped structure of the second bias line.

[0026] The polarization conversion phase control layer comprises a metal square ring, a metal circular ring, a circular metal patch, and two PIN diodes connecting the metal circular ring and the circular metal patch.

[0027] PIN diode one and PIN diode two are located in different polarization directions.

[0028] A square metal ring is placed on the outermost side, and concentric metal rings are placed inside the square metal ring; concentric circular metal patches are placed inside the concentric metal rings.

[0029] An annular gap is left between the circular metal patch and the metal ring, and a PIN diode and a second PIN diode are connected between the annular gap;

[0030] The length of the metal square ring is equal to the period P of the basic unit, and the width W of the metal square ring is... 8_1 The range is 0.1-0.2 mm; the outer diameter R of the metal ring. 8_1 The range is 5.1-7.1 mm, and the inner diameter R of the metal ring is... 8_2 The range is 4.1-6.1mm; the radius R of the circular metal patch. 8_3 The range is 3.6-5.6mm; the metal square ring and the metal round ring are connected by a thin metal wire, the width of which is W. 8_2The diameter is 0.2mm; PIN diode one and PIN diode two are located at 135° and 225° respectively in the annular gap. The positive terminal of PIN diode one is connected to the circular metal patch, and the positive terminal of PIN diode two is connected to the metal ring. The model numbers of PIN diode one and PIN diode two are the same as those of PIN diode.

[0031] The polarization conversion phase control bias circuit layer includes a third bias line, a sector-shaped filter capacitor metal sheet, and a lumped inductor; wherein, the sector-shaped filter capacitor metal sheet is connected in parallel on the third bias line, and the distance between it and the center of the second dielectric layer is D. 9_1 Its value ranges from 5.1 to 7.1 mm; the lumped inductor is connected in series on the bias line three, and the distance between it and the center of the second dielectric layer is D. 9_2 Its value ranges from 1.5 to 1.8 mm.

[0032] The circular metal patch in the polarization conversion phase control layer is connected to the bias line three in the polarization conversion phase control bias circuit layer through a metallized via. The metallized via is located at the geometric center of the circular metal patch, penetrates the second dielectric layer, and has a radius of R. 7_0 .

[0033] The polarization gate layer consists of four long metal strips, each with a length equal to the basic unit period P and a width W. 10_1 The range is 2-2.6mm, with four long metal strips evenly distributed;

[0034] The period P of the metamaterial ranges from 13 to 17 mm.

[0035] The beneficial effects of this invention are:

[0036] 1. Overcoming operational mode limitations. Existing reflective solutions can only achieve reflected wave manipulation, limiting the application of reflective metasurfaces in fields such as holographic imaging. This invention, through an innovative transmissive structural design, uses a reflective layer to reflect the incident wave, achieving amplitude manipulation, and a polarization conversion layer to convert the incident y-polarized electromagnetic wave into + / -x-polarized electromagnetic waves, achieving phase modulation. Furthermore, the FP resonant cavity operation mode is utilized to improve polarization conversion transmittance. The reflective layer and polarization conversion layer work together to achieve independent amplitude and phase manipulation with two degrees of freedom in transmissive mode. This overcomes the current limitation of only achieving dual-degree-of-freedom amplitude and phase manipulation in reflective mode, expanding its application scope to emerging fields such as dynamic holographic imaging, encrypted communication, and transmissive stealth.

[0037] 2. Amplitude and Phase Decoupling Control. Compared with existing coupling control schemes for transmissive metamaterials, this invention adopts a layered decoupling design, integrating electrically controlled PIN diodes into the reflective layer and polarization conversion layer and independently controlling different structures. Optimized interlayer coupling design is performed on different layers, and different resonances are controlled to eliminate parameter coupling, ensuring that the amplitude control layer and phase control layer do not interfere with each other. This achieves electromagnetic parameter decoupling, enabling independent control of each layer's function and dynamically adjustable electromagnetic response characteristics.

[0038] 3. Improve system integration. Existing solutions that use multiple PIN diodes to independently control different electromagnetic parameters are primarily reflective, with their active circuitry positioned behind a metal reflector to shield against interference. Transmissive solutions, however, are constrained by the bias circuitry's impact on high-frequency performance, necessitating a strict limitation on the number of PIN diodes, which also restricts their control dimensions.

[0039] This invention utilizes the polarization conversion function. Before polarization conversion, the PIN diode bias circuit for amplitude control is designed to be orthogonal to the y-polarization direction of the incident wave along the x-polarization direction, thereby reducing interference from the bias circuit to high-frequency signals. Similarly, after the polarization conversion layer converts the y-polarized incident wave to the x-polarization direction, the bias line of the polarization conversion layer is designed to be orthogonal to the x-polarization after polarization conversion along the y-polarization direction, also reducing interference from the bias circuit to high-frequency signals. Ultimately, effective shielding of the bias circuit is achieved without affecting transmission performance. Attached Figure Description

[0040] Figure 1 This is a three-dimensional schematic diagram of the basic unit structure of the metamaterial of this invention.

[0041] Figure 2 This is a top view of the first dielectric layer and the amplitude modulation layer in the basic unit of the metamaterial of the present invention.

[0042] Figure 3 This is a top view of the first dielectric layer and the amplitude-controlled bias circuit layer in the basic unit of the metamaterial of this invention.

[0043] Figure 4 This is a top view of the second dielectric layer and the polarization conversion phase modulation layer in the basic unit of the metamaterial of this invention.

[0044] Figure 5 This is a top view of the second dielectric layer and the polarization conversion phase modulation bias circuit layer 28 in the basic unit of the metamaterial of the present invention.

[0045] Figure 6 This is a top view of the third dielectric layer and the polarization gate layer in the basic unit of the metamaterial of this invention.

[0046] Figure 7This is a three-dimensional schematic diagram of the metamaterial array structure in this invention, which is composed of 20×20 basic units translated and replicated.

[0047] Figure 8 The simulation results show the amplitude modulation of the cross-polarized transmitted wave when the basic unit of the metamaterial of this invention is in the state of PIN diode one being "on" and PIN diode two being "off", respectively, with the PIN diodes being "on" and "off".

[0048] Figure 9 The simulation results show the phase modulation of the cross-polarized transmitted wave when the basic unit structure of the metamaterial of this invention is in the "conducting" state of the PIN diode, and when PIN diode one and PIN diode two are "conducting" and "disconnected", or "disconnected" and "conducting", respectively.

[0049] Figure 10 The simulation results show the phase modulation of the cross-polarized transmitted wave when the basic unit structure of the metamaterial of this invention is in the "disconnected" state of the PIN diode, and when PIN diode one and PIN diode two are "conducting" and "disconnected" or "disconnected" and "conducting" respectively.

[0050] Figure 11 This is an amplitude encoding diagram of near-field amplitude imaging in Example 1 of the metamaterial of the present invention.

[0051] Figure 12 This is a near-field amplitude imaging effect diagram in Example 1 of the metamaterial of the present invention.

[0052] Figure 13 This is a phase encoding diagram of near-field phase imaging in Example 2 of the metamaterial of the present invention.

[0053] Figure 14 This is a near-field phase imaging effect diagram of Example 2 of the metamaterial of the present invention. Detailed Implementation

[0054] The present invention will now be described in further detail with reference to the accompanying drawings. Specific implementation method one:

[0056] Reference Figures 1 to 7 This embodiment is described in detail. The transmissive reconfigurable metamaterial structure with amplitude-phase independent control described in this embodiment is formed by copying and translating 20×20 basic units. Each basic unit includes 3 dielectric layers, 5 metal layers and 2 air layers.

[0057] The dielectric layers are distributed from top to bottom as a first dielectric layer 20, a second dielectric layer 22, and a third dielectric layer 24;

[0058] There is a first air layer 21 between the first dielectric layer 20 and the second dielectric layer 22, and a second air layer 23 between the second dielectric layer 22 and the third dielectric layer 24;

[0059] The metal layers are distributed from top to bottom as follows: amplitude control layer 25, amplitude control bias circuit layer 26, polarization conversion phase control layer 27, polarization conversion phase control bias circuit layer 28, and polarization gate layer 29.

[0060] The amplitude modulation layer 25 is located on the upper surface of the first dielectric layer 20, and the amplitude modulation bias circuit layer 26 is located on the lower surface of the first dielectric layer 20; the polarization conversion phase modulation layer 27 is located on the upper surface of the second dielectric layer 22, and the polarization conversion phase modulation bias circuit layer 28 is located on the lower surface of the second dielectric layer 22; the polarization gate layer 29 is located on the upper surface of the third dielectric layer 24.

[0061] The thickness H1 of the first dielectric layer 20 is 2 mm, the thickness H2 of the second dielectric layer 22 is 2 mm, and the thickness H3 of the third dielectric layer 24 is 2 mm. All dielectric layers are made of materials with a relative permittivity of ε. r The Rogers 3003 material has a thickness of 3, with the first dielectric layer 20 and the second dielectric layer 22 separated by a first air layer 21, the thickness of which is H. air1 The thickness is 2mm; the second dielectric layer 22 and the third dielectric layer 24 are separated by a second air layer 23, the thickness of which is H. air2 It is 1mm.

[0062] The amplitude control layer 25 consists of two elongated metal patches 1, two U-shaped metal patches 2, a PIN diode 3, a bias line 4-1, and a ground line 4-2.

[0063] Two elongated metal patches 1 are placed parallel to each other on the upper surface of the first dielectric layer 20. Two U-shaped metal patches 2 are symmetrically placed between the two elongated metal patches 1. The openings of the two U-shaped metal patches 2 are opposite to each other and are respectively aligned with one of the elongated metal patches 1.

[0064] The bottoms of the two U-shaped metal patches 2 are connected in the middle through the PIN diode 3. The positive terminal of the PIN diode 3 is located on the right side. The period of the basic unit is P, and its value is 15mm.

[0065] The bias line 4-1 and the ground line 4-2 are respectively set on the left and right U-shaped metal patches 2, wherein the distance between the bias line 4-1 and the bottom of the U-shaped metal patch it is connected to is D. 6_4 The distance between the grounding wire 4-2 and the bottom of the U-shaped metal patch it is connected to is D. 6_5 D 6_4 The values ​​are 0.6mm and D. 6_5The value is 0.5mm.

[0066] Among them, the two elongated metal patches 1 have the same geometric dimensions, with a width W 6_1 It is 0.9mm, and the length is L. 6_1 The two elongated metal patches 1 are 11 mm in diameter and are symmetrically placed, with a distance D between them and the periodic boundary of the first dielectric layer 20. 6_1 Its value is 1.55mm; the two U-shaped metal patches 2 have the same geometric dimensions, and their length is L. 6_2 It is 4mm thick and has a width of W. 6_2 It is 1.5mm, and the distance between the two arms is W. 6_U The diameter is 0.5mm, and the two U-shaped metal patches 2 are placed symmetrically with a distance D between them. 6_2 The thickness is 0.5mm; the two U-shaped metal patches 2 are connected to the bias line 4-1 and the ground line 4-2, and the length L of the bias line 4-1 is... 6_3 The length L of the grounding wire is 3.25mm. 6_4 The width W of the bias line 4-1 and the ground line 4-2 is 2.25mm. 6_3 Same, W 6_3 It is 0.2mm.

[0067] The PIN diode 3 is model SMP1340-040LF. Its equivalent circuit in the "conducting" state consists of a lumped resistor and a lumped inductor connected in series, with an equivalent resistance value R. PIN and equivalent inductance value L PIN1 The equivalent circuit of PIN diode 3 in the "off" state is a series connection of a lumped resistor, a lumped inductor, and a lumped capacitor, with an equivalent resistance value R of 1 ohm and 0.45 nH respectively. PIN2 Equivalent inductance value L PIN2 and equivalent capacitance value C PIN2 The values ​​are 10 ohms, 0.45 nH, and 0.16 pF, respectively.

[0068] In this invention, a U-shaped metal patch is selected as the top reflective layer, but it is not the only option. Any reflective structure whose dimensions approximate half the wavelength of the reflection frequency is acceptable.

[0069] The amplitude-controlled bias circuit layer 26 includes a ground line 2 5, a bias line 2 6, a fan-shaped filter capacitor metal sheet 7, a lumped inductor 8, and a metallized via 9;

[0070] Grounding wire 25 is connected to bias line 4-2 in amplitude control layer 25 through metallized via 9; metallized via 9 penetrates the first dielectric layer 20, and its radius R 7_0The distance is 0.2mm; grounding wire 4-2 and grounding wire 5 are in the same vertical position; the distance between bias line 6 and grounding wire 5 is D7_1, which is 6.45mm; the fan-shaped filter capacitor metal sheet 7 is connected in parallel on bias line 6, and the distance between it and the periodic boundary of the first dielectric layer 20 is D. 7_2 Its value is 4.6mm; the lumped inductor 8 is connected in series on the bias line 6, and the distance between it and the periodic boundary of the first dielectric layer 20 is D. 7_3 Its value is 6mm, and the width W of the grounding wire 5 and the bias wire 6 is... 7_1 Same, W 7_1 The radius R of the fan-shaped filter capacitor metal sheet 7 is 0.2mm. 7_1 The angle A of the 3mm fan-shaped filter capacitor metal sheet 7 is... 7_1 The inductance is 60°; the lumped inductor 8 uses a 0201 package, and the inductance value L 8_RLC It is 2.8nH.

[0071] The polarization conversion phase control layer 27 comprises a metal square ring 10, a metal circular ring 11, a circular metal patch 12, and PIN diode 13 and PIN diode 14 connecting the metal circular ring and the circular metal patch.

[0072] A metal square ring 10 is placed on the outermost side, and a metal circular ring 11 is placed concentrically inside the metal square ring 10; a circular metal patch 12 is placed concentrically inside the metal ring 11.

[0073] An annular gap is left between the circular metal patch 12 and the metal ring 11, and PIN diode 13 and PIN diode 14 are connected between the annular gap.

[0074] The length of the metal square ring 10 is equal to the period P of the basic unit, and the width W of the metal square ring 10 is... 8_1 The outer diameter R of the metal ring 11 is 0.15mm. 8_1 The inner diameter R of the metal ring 11 is 6.1 mm. 8_2 The radius R of the circular metal patch 12 is 5.1mm. 8_3 The diameter is 4.6 mm; the metal square ring 10 and the metal circular ring 11 are connected by a thin metal wire, the width of which is W. 8_2 The diameter is 0.2mm; PIN diode 13 and PIN diode 14 are located at 135° and 225° respectively in the annular gap. The positive terminal of PIN diode 13 is connected to the circular metal patch, and the positive terminal of PIN diode 14 is connected to the metal ring. The model numbers of PIN diode 13 and PIN diode 14 are the same as those of PIN diode 3.

[0075] In this invention, an annular gap structure composed of a metal ring and a circular metal patch is selected, and a PIN diode is loaded at an angle of 45° to form a polarization conversion structure. However, the structure is not unique, and any structure that can produce a polarization conversion effect within the operating frequency band can also be used as an alternative.

[0076] While an electrically controlled PIN diode is used in this invention, it is not essential. Other RF switching devices that can be integrated into the unit structure can also be used as alternatives. For example, MEMS switches, RF switching ICs, or phase change materials can be used to achieve non-volatile control.

[0077] The polarization conversion phase control bias circuit layer 28 includes a bias line 15, a fan-shaped filter capacitor metal sheet 16, and a lumped inductor 17; wherein, the fan-shaped filter capacitor metal sheet 16 is connected in parallel on the bias line 15, and the distance between it and the center of the second dielectric layer 22 is D. 9_1 Its value is 6.1mm; the lumped inductor 17 is connected in series on the bias line 15, and the distance between it and the center of the second dielectric layer 22 is D. 9_2 Its value is 1.65mm.

[0078] The circular metal patch 12 in the polarization conversion phase control layer 27 is connected to the bias line 15 in the polarization conversion phase control bias circuit layer 28 through a metallized via 18. The metallized via 18 is located at the geometric center of the circular metal patch 13 and penetrates the second dielectric layer 22, with a radius of R. 7_0 .

[0079] The polarization gate layer 29 is composed of four elongated metal patches 19, the length of which is equal to the basic unit period P, and the width of which is equal to W. 10_1 It is 2.3mm thick, with four long metal strips 19 evenly distributed;

[0080] The metamaterial is composed of 20×20 basic units replicated and translated, with a replication and translation period P of 15 mm.

[0081] The following is based on simulation experiments, with reference to Figures 8 to 10 The technical effects of the basic unit proposed in this invention will be further explained as follows:

[0082] 1. Simulation software: Commercial simulation software HFSS2021.

[0083] 2. Simulation Content and Results: The aforementioned transmissive reconfigurable metamaterial unit with independent amplitude-phase control, for a vertically incident y-polarized electromagnetic wave, is... Figure 8It can be seen that, under the conditions of PIN diode 13 being "conducting" and PIN diode 14 being "disconnected" on the second dielectric layer 22: when the top-layer PIN diode 3 is "conducting," the y-polarized electromagnetic wave is reflected by the U-shaped metal patch 2, and the cross-polarized transmitted wave amplitude at 9.3 GHz is 0.05; when the top-layer PIN diode 3 is "disconnected," the y-polarized electromagnetic wave undergoes polarization conversion after passing through the polarization conversion phase modulation layer 27, and the cross-polarized transmitted wave amplitude is greater than 0.8 in the 8-9.5 GHz range, thus achieving transmission amplitude modulation. Figure 9 It can be seen that when the top-layer PIN diode 3 is "conducting," PIN diode 13 and PIN diode 14 are "conducting" and "disconnected" respectively (state ①), and PIN diode 13 and PIN diode 14 are "disconnected" and "conducting" respectively (state ②). States ① and ② maintain a phase difference of 180°±10° within the 7.7-10GHz frequency band. Figure 10 It can be seen that when the top-level PIN diode (3) is "disconnected", PIN diode 13 and PIN diode 2 are "conducting" and "disconnected" respectively in state ③, and PIN diode 13 and PIN diode 2 are "disconnected" and "conducting" respectively in state ④. State ③ and state ④ can maintain a phase difference of 180°±10° in the frequency band of 7.7-10GHz.

[0084] In summary, by using PIN diode 3 to connect two U-shaped metal patches 2, the effective length of the connected U-shaped metal patches in the y-polarization direction is approximately half a wavelength of 9.3 GHz, thereby reducing the amplitude of the transmitted wave. When PIN diode 3 is "off", the y-polarized electromagnetic wave passes through the first dielectric layer 20. At this time, if PIN diode 13 and PIN diode 14 are "on" and "off" respectively, the y-polarized electromagnetic wave is converted into an x-polarized electromagnetic wave in the polarization conversion phase modulation layer 27 and passes through. The top strip metal patch 1 and the bottom polarization gate layer 29 are used to reflect secondary and multiple reflected waves. The polarization conversion rate is further improved through the FP resonance (Fabry-Perot Resonance) principle. Finally, the amplitude modulation of the cross-polarized transmitted wave is achieved by controlling the on / off state of the top PIN diode 3. A special design was implemented for the bias circuit of PIN diode 3. Before the electromagnetic wave polarization conversion, for the y-polarized incident wave, the PIN diode bias circuit for amplitude control was designed to be orthogonal to the y-polarization direction of the incident wave along the x-polarization direction, thereby suppressing interference of the bias circuit to high-frequency signals. Similarly, after the polarization conversion layer converts the y-polarized incident wave to the x-polarization direction, the bias lines of PIN diodes 13 and 14 in the polarization conversion layer were designed to be orthogonal to the x-polarization direction after the polarization conversion, also suppressing interference of the bias circuit to high-frequency signals. Ultimately, effective shielding of the bias circuit was achieved without affecting the transmission performance.

[0085] Furthermore, regardless of whether PIN diode 3 is "on" or "off", when PIN diode 13 and PIN diode 14 are "on" and "off", or "off" and "on", the cross-polarized transmission phase difference in both states is 180°±10°. Thus, phase modulation can be completed in the state of switching between high and low cross-polarized wave transmittance, achieving decoupling of amplitude and phase.

[0086] Meanwhile, this embodiment utilizes the amplitude-phase decoupling characteristics of the proposed metamaterial unit to design near-field amplitude imaging. For example... Figure 11 The image shows a digitally encoded array for near-field amplitude imaging. Figure 11 The number "1" represents PIN diode 3 being "on", and the number "0" represents PIN diode 3 being "off", while PIN diode 13 and PIN diode 14 are in the "on" and "off" states, respectively. For example... Figure 12 The image shown is the simulation result of near-field amplitude imaging, which realizes the image reconstruction of the letter "P" in the amplitude dimension.

[0087] Specific Implementation Method Two: The transmissive reconfigurable metamaterial with amplitude-phase independent control described in Specific Implementation Method One above includes: multiple transmissive reconfigurable metamaterial units with amplitude-phase independent control, and the multiple metamaterial units are arranged in a periodic array with one unit as the period.

[0088] In this embodiment, near-field phase imaging is designed by utilizing the amplitude-phase decoupling characteristics of the proposed metamaterial unit. For example... Figure 13 The image shows a digitally encoded array for near-field phase imaging. Figure 13 In the diagram, the number "1" represents PIN diode 13 being in the "on" and PIN diode 14 being in the "off" state, while the number "0" represents PIN diode 13 being in the "off" and PIN diode 14 being in the "on" state. Since the phase difference between the two states is approximately 180°, a near-field phase imaging system was designed using this phase difference. The simulation results are as follows: Figure 14 As shown, the image reconstruction of the letter "E" was achieved in the phase dimension.

[0089] This invention designs a multi-layer composite structure: it includes a specially designed double-layer resonant unit structure and an FP resonant cavity design. The double-layer resonant unit structure includes a reflection layer and a polarization conversion layer. The reflection layer is responsible for controlling the reflection of the incident wave to achieve amplitude modulation, and the polarization conversion layer is responsible for converting the y-polarized incident electromagnetic wave into a + / -x polarized electromagnetic wave to achieve phase modulation. The FP resonant cavity improves the transmittance.

[0090] This invention is based on an amplitude and phase independent control mechanism: PIN diodes are integrated into the reflective layer and polarization conversion layer to independently control different structures. The interlayer coupling mechanism of different layers is optimized to complete the decoupling of electromagnetic parameters and realize independent control of the functions of each layer and dynamically adjustable electromagnetic response characteristics.

[0091] This invention adopts a polarization conversion transmission design path: a polarization conversion layer is used to realize the polarization conversion of a specific polarization incident wave, and the orientation of the slit opening is changed by switching the on and off of two PIN diodes on the polarization conversion layer, so as to achieve phase modulation while ensuring the polarization conversion purpose; and the electromagnetic wave encryption dimension is further broadened by polarization conversion.

[0092] This invention employs an active device integration scheme: using SMP1340-040LF PIN diodes, one diode is integrated in the reflective layer, and the amplitude is independently modulated by controlling the transmitted wave through a switch; two diodes are integrated in the polarization conversion layer, and the phase is independently controlled by controlling the polarization conversion direction through a switch; the two layers of PIN diodes are independently modulated by each other through optimized layout of the PIN diodes in the multilayer structure; a bias network design of parallel fan-shaped metal capacitors and series lumped inductors is adopted to minimize the impact on high-frequency performance; the bias voltage of the PIN diodes used is about 0.85V, the operating current is about 10mA, the power consumption is low, and dynamic control of the metamaterial array can be achieved.

[0093] This invention specifically designs an active device bias circuit: fully utilizing the orthogonal polarization suppression characteristics of electromagnetic waves and the polarization conversion function of this invention, before the electromagnetic wave polarization conversion, for a y-polarized incident wave, the PIN diode bias circuit for amplitude control is designed to be orthogonal to the y-polarization direction of the incident wave along the x-polarization direction, thereby suppressing the bias circuit's interference with high-frequency signals. Similarly, after the polarization conversion layer converts the y-polarized incident wave to the x-polarization direction, the bias line of the polarization conversion layer is designed to be orthogonal to the x-polarization direction after the polarization conversion, also reducing the bias circuit's interference with high-frequency signals. Ultimately, effective shielding of the bias circuit is achieved without affecting transmission performance.

Claims

1. A polarization-conversion transmissive reconfigurable metamaterial structure with amplitude-phase independent control, characterized in that, It is formed by copying and translating n×n basic units. Each basic unit includes 3 dielectric layers, 5 metal layers and 2 air layers. The dielectric layers are distributed from top to bottom as a first dielectric layer (20), a second dielectric layer (22), and a third dielectric layer (24); There is a first air layer (21) between the first dielectric layer (20) and the second dielectric layer (22), and there is a second air layer (23) between the second dielectric layer (22) and the third dielectric layer (24); The metal layers are distributed from top to bottom as follows: amplitude control layer (25), amplitude control bias circuit layer (26), polarization conversion phase control layer (27), polarization conversion phase control bias circuit layer (28), and polarization gate layer (29). The amplitude modulation layer (25) is located on the upper surface of the first dielectric layer (20), the amplitude modulation bias circuit layer (26) is located on the lower surface of the first dielectric layer (20), the polarization conversion phase modulation layer (27) is located on the upper surface of the second dielectric layer (22), the polarization conversion phase modulation bias circuit layer (28) is located on the lower surface of the second dielectric layer (22), and the polarization gate layer (29) is located on the upper surface of the third dielectric layer (24).

2. The polarization-conversion transmission-type reconfigurable metamaterial structure with amplitude-phase independent control according to claim 1, characterized in that, The thickness H1 of the first dielectric layer (20) is 2 mm, the thickness H2 of the second dielectric layer (22) is 2 mm, and the thickness H3 of the third dielectric layer (24) is 2 mm. The dielectric layers are all made of materials with a relative permittivity of ε. r =3 Rogers 3003 material, the first dielectric layer (20) and the second dielectric layer (22) are separated by a first air layer (21), the thickness of the first air layer (21) is H air1 The thickness is 2 mm; the second dielectric layer (22) and the third dielectric layer (24) are separated by a second air layer (23), the thickness of which is H. air2 It is 1mm.

3. The polarization-conversion transmission-type reconfigurable metamaterial structure with amplitude-phase independent control according to claim 1, characterized in that, The amplitude control layer (25) consists of two elongated metal patches (1), two U-shaped metal patches (2), a PIN diode (3), a bias line (4-1), and a ground line (4-2); Two long strip metal patches (1) are placed parallel to each other on the upper surface of the first dielectric layer (20). Two U-shaped metal patches (2) are placed symmetrically between the two long strip metal patches (1). The openings of the two U-shaped metal patches (2) are opposite to each other and are respectively aligned with one of the long strip metal patches (1). The bottoms of the two U-shaped metal patches (2) are connected in the middle through the PIN diode (3), with the positive terminal of the PIN diode (3) located on the right side. The period of the basic unit is P, and its value range is 13-17 mm. The bias line 1 (4-1) and the ground line 1 (4-2) are respectively set on the left and right U-shaped metal patches (2), wherein the distance between the bias line 1 (4-1) and the bottom of the U-shaped metal patch it is connected to is D. 6_4 The distance between the grounding wire 1 (4-2) and the bottom of the U-shaped metal patch it is connected to is D. 6_5 D 6_4 The value range is 0.5-0.7mm, D 6_5 The value range is 0.4-0.6 mm; The bias line 1 (4-1) and the ground line 1 (4-2) are located on the asymmetrical arms of the two U-shaped metal patches (2) and extend outward from the U-shaped metal patches (2).

4. The polarization-conversion transmission-type reconfigurable metamaterial structure with amplitude-phase independent control according to claim 3, characterized in that, Two elongated metal patches (1) have the same geometric dimensions, with a width W. 6_1 The range is 0.8-1mm, and the length is L. 6_1 The range is 10-12 mm, and the distance between the two elongated metal patches (1) and the periodic boundary of the first dielectric layer (20) is D. 6_1 The value ranges from 1.35 to 1.75 mm; the two U-shaped metal patches (2) have the same geometric dimensions, and their length is L. 6_2 The range is 3.5-4.5mm, and the width is W. 6_2 The range is 1-2mm, and the distance between the two arms is W. 6_U The range is 0.25-0.75mm, and the distance D between the two U-shaped metal patches (2) is... 6_2 The thickness is 0.5mm; two U-shaped metal patches (2) are connected to bias line one (4-1) and ground line one (4-2), and the length of bias line one (4-1) is L. 6_3 The range is 2.25-4.25mm, and the length L of grounding wire one (4-2) is... 6_4 The width W of the bias line 1 (4-1) and the ground line 1 (4-2) is in the range of 1.25-3.25mm. 6_3 Same, W 6_3 It is 0.2mm.

5. The polarization-conversion transmission-type reconfigurable metamaterial structure with amplitude-phase independent control according to claim 4, characterized in that, The amplitude-controlled bias circuit layer (26) includes ground line two (5), bias line two (6), fan-shaped filter capacitor metal sheet (7), lumped inductor (8) and metallized via (9); Grounding wire 2 (5) is connected to grounding wire 1 (4-2) in the amplitude control layer (25) through a metallized via (9); the metallized via (9) penetrates the first dielectric layer (20) and has a radius R. 7_0 It is 0.2mm; The second bias line (6) is L-shaped and is composed of the first bias line and the second bias line. The first bias line is parallel to the ground line (5). The fan-shaped filter capacitor metal sheet (7) is connected to the second bias line. The lumped inductor (8) is connected to the end of the second bias line away from the first bias line. The vertex of the fan-shaped filter capacitor metal sheet (7) is connected to the second bias line 2, and the whole is located inside the L-shaped structure of the bias line 2. Grounding wire one (4-2) and grounding wire two (5) are in the same vertical position; the distance between the first bias line two and the grounding wire (5) is D7_1, and its value ranges from 6 to 6.9 mm; the fan-shaped filter capacitor metal sheet (7) is connected in parallel to the second bias line two, and the distance between it and the periodic boundary of the first dielectric layer (20) is D 7_2 Its value ranges from 4 to 5.2 mm; the lumped inductance (8) is connected in series on the second bias line 2, and the distance between it and the periodic boundary of the first dielectric layer 20 is D. 7_3 Its value ranges from 5.5 to 6.5 mm, and the width W of the grounding wire (5) and the bias wire (6) is... 7_1 Same, W 7_1 The radius R of the fan-shaped filter capacitor metal sheet (7) is 0.2mm. 7_1 The range is 2-4mm, and the angle A of the fan-shaped filter capacitor metal sheet (7) is... 7_1 The range is 30-90°; the lumped inductor (8) uses a 0201 package, and the inductance value L 8_RLC It is 2.8nH.

6. The polarization-conversion transmission-type reconfigurable metamaterial structure with amplitude-phase independent control according to claim 1, characterized in that, The polarization conversion phase control layer (27) comprises a metal square ring (10), a metal circular ring (11), a circular metal patch (12), and a PIN diode one (13) and a PIN diode two (14) connecting the metal circular ring and the circular metal patch; PIN diode one (13) and PIN diode two (14) are located in different polarization directions; A metal square ring (10) is placed on the outermost side, and a metal circular ring (11) is placed concentrically inside the metal square ring (10); a circular metal patch (12) is placed concentrically inside the metal circular ring (11); An annular gap is left between the circular metal patch (12) and the metal ring (11), and PIN diode one (13) and PIN diode two (14) are connected between the annular gap; The length of the metal square ring (10) is equal to the period P of the basic unit, and the width W of the metal square ring (10) is... 8_1 The range is 0.1-0.2 mm; the outer diameter R of the metal ring (11) 8_1 The inner diameter R of the metal ring (11) ranges from 5.1 to 7.1 mm. 8_2 The range is 4.1-6.1 mm; the radius R of the circular metal patch (12) 8_3 The range is 3.6-5.6 mm; the metal square ring (10) and the metal circular ring (11) are connected by a thin metal wire, the width of which is W. 8_2 The diameter is 0.2mm; PIN diode one (13) and PIN diode two (14) are located at 135° and 225° of the annular gap, respectively. The positive terminal of PIN diode one (13) is connected to the circular metal patch, and the positive terminal of PIN diode two (14) is connected to the metal ring. The model of PIN diode one (13) and PIN diode two (14) are the same as that of PIN diode (3).

7. The polarization-conversion transmission-type reconfigurable metamaterial structure with amplitude-phase independent control according to claim 6, characterized in that, The polarization conversion phase control bias circuit layer (28) includes a bias line three (15), a fan-shaped filter capacitor metal sheet (16), and a lumped inductor (17); wherein, the fan-shaped filter capacitor metal sheet (16) is connected in parallel on the bias line three (15), and the distance between it and the center of the second dielectric layer (22) is D. 9_1 Its value ranges from 5.1 to 7.1 mm; the lumped inductance (17) is connected in series on the bias line three (15), and the distance between it and the center of the second dielectric layer (22) is D. 9_2 Its value ranges from 1.5 to 1.8 mm.

8. A polarization-conversion transmission-type reconfigurable metamaterial structure with amplitude-phase independent control, as described in claim 7, characterized in that, The circular metal patch (12) in the polarization conversion phase control layer (27) is connected to the bias line 3 (15) in the polarization conversion phase control bias circuit layer (28) through a metallized via (18). The metallized via is located at the geometric center of the circular metal patch (13), and the metallized via (18) penetrates the second dielectric layer (22), with a radius of R. 7_0 .

9. A polarization-conversion transmission-type reconfigurable metamaterial structure with amplitude-phase independent control according to claim 1, characterized in that, The polarization gate layer (29) consists of four long metal strips (19), the length of which is the basic unit period P, and the width of which is W. 10_1 The range is 2-2.6mm, and four long metal strips (19) are evenly distributed.

10. A polarization-conversion transmissive reconfigurable metamaterial structure with amplitude-phase independent control according to claim 4, characterized in that, The period P of the metamaterial ranges from 13 to 17 mm.

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