Wearable metasurface device for magnetic resonance imaging

Abstract

The invention provides a wearable metasurface device for magnetic resonance imaging. The wearable metasurface device comprises a plurality of first polar plates; the plurality of first polar plates and the plurality of second polar plates are arranged in a one-to-one correspondence manner; the first pole plate and the second pole plate are attached and can slide relatively to form a variable structure capacitor; the plurality of first polar plates and the plurality of second polar plates are arranged on the annular connecting part in a circumferential array manner. According to the wearable super-structure surface device for magnetic resonance imaging, the problem of frequency deviation caused by strain of the wearable super-structure surface is perfectly solved, and the signal-to-noise ratio of magnetic resonance imaging can be improved.

Description

Technical Field

[0001] This application relates to the field of nuclear magnetic resonance imaging technology, and particularly relates to a wearable metasurface device for magnetic resonance imaging. Background Art

[0002] Magnetic resonance imaging (MRI) is one of the high-end medical imaging diagnostic technologies. The image quality mainly depends on the signal-to-noise ratio (SNR) of the image. A high-quality SNR can make the magnetic resonance image clearer, provide higher-quality detection for clinical diagnosis, and can also be used to shorten the scanning time to improve the detection efficiency. In the prior art, the SNR is mainly improved by increasing the static magnetic field strength B0 or by using a multi-channel phased array receiving coil. However, increasing B0 means a substantial increase in cost. And the multi-channel phased array coil has also encountered bottlenecks. The increase in the number of channels will bring problems such as increased cost, overweight and oversize in volume, and complex decoupling.

[0003] Although the theoretical SNR of the wearable metasurface is higher, due to the flexible wearable design, the configuration of the metasurface is not fixed. When worn on different human bodies, the wearable metasurface may be in different stretching states, which will cause the resonant frequency of the metasurface to shift. When the resonant frequency of the metasurface shifts from the operating frequency of the MRI system, the performance of SNR improvement will drop rapidly. Summary of the Invention

[0004] The present invention provides a wearable metasurface device for magnetic resonance imaging to solve the problem that when the wearable metasurface undergoes tensile deformation, the resonant frequency shifts, thereby resulting in a decrease in the performance of magnetic resonance SNR enhancement.

[0005] To solve at least one of the above problems existing in the prior art, an embodiment of the present application provides a wearable metasurface device for magnetic resonance imaging.

[0006] According to an embodiment of the present application, the present application provides a wearable metasurface device for magnetic resonance imaging, which includes:

[0007] A plurality of first electrodes;

[0008] A plurality of second electrodes, the plurality of first electrodes and the plurality of second electrodes are arranged in one-to-one correspondence; the first electrode and the second electrode are attached and can slide relative to each other to form a variable structure capacitor;

[0009] At least one annular connecting portion, the plurality of first electrodes and the plurality of second electrodes are arranged on the annular connecting portion in a circular array.

[0010] In some embodiments of the present application, any one of the second plates is electrically connected to a first plate corresponding to one of the two adjacent second plates;

[0011] The first plate corresponding to any one of the second plates is electrically connected to the other second plate among the two adjacent second plates of any one of the second plates.

[0012] In some embodiments of the present application, the first plate includes: a first substrate and a first conductive layer;

[0013] The second plate includes: a second substrate and a second conductive layer; wherein, the first conductive layer is attached to the second substrate; or

[0014] The second conductive layer is attached to the first substrate.

[0015] In some embodiments of the present application, the first plate and the second plate are flexible circuit boards.

[0016] In some embodiments of the present application, the annular connecting portion is composed of a plurality of elastic connecting members, and the first plate and the corresponding second plate are arranged on one elastic connecting member.

[0017] In some embodiments of the present application, the number of the annular connecting portions is two, and the plurality of first plates and the plurality of second plates are arranged in a circumferential array between the two annular connecting portions;

[0018] The annular connecting portion includes: a plurality of chute fixing seats having the same number as the first plates;

[0019] At least one of the first plate and the second plate slides inside the chute fixing seat.

[0020] In some embodiments of the present application, the chute fixing seat includes an elastic reset member for resetting at least one of the first plate and the second plate after sliding.

[0021] In some embodiments of the present application, the second plate and the first plate have different lengths, and the second plate is arranged inside the chute fixing seat.

[0022] In some embodiments of the present application, there are gaps between multiple first plates, and there are gaps between the first plate and the adjacent second plate.

[0023] In some embodiments of the present application, the number of the first plates is an even number.

[0024] As can be seen from the above description, an embodiment of the present invention provides a wearable metasurface device for magnetic resonance imaging, including: a plurality of first electrodes; a plurality of second electrodes, wherein the plurality of first electrodes are arranged in one-to-one correspondence with the plurality of second electrodes; the first electrodes and the second electrodes are attached and can slide relative to each other to form a variable structure capacitor; at least one annular connecting portion, and the plurality of first electrodes and the plurality of second electrodes are arranged on the annular connecting portion in a circumferential array.

[0025] The wearable metasurface device for magnetic resonance imaging proposed in the embodiment of the present invention perfectly solves the problem of frequency shift caused by strain in wearable metasurfaces, and helps to improve the signal-to-noise ratio of magnetic resonance imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings. In the drawings:

[0027] Figure 1 It is a schematic diagram of the overall structure of the wearable metasurface device for magnetic resonance imaging according to an embodiment of the present application.

[0028] Figure 2 It is a schematic diagram of the principle of the metasurface resonance frequency compensation method of the wearable metasurface device for magnetic resonance imaging according to an embodiment of the present application.

[0029] Figure 3 It is a schematic diagram of the series formation method of the variable structure capacitor according to an embodiment of the present application.

[0030] Figure 4 It is a schematic diagram of the structures of the first electrode 1 and the second electrode 2 according to an embodiment of the present application;

[0031] Figure 5 It is a schematic diagram of the initial state and the stretched state of the wearable metasurface device for magnetic resonance imaging according to an embodiment of the present application.

[0032] Figure 6 It is a schematic diagram of the application scenario of the wearable metasurface device for magnetic resonance imaging in a specific application example of the present application.

[0033] Figure 7 It is a schematic diagram of the overall structure of the wearable metasurface device for magnetic resonance imaging in a specific application example of the present application.

[0034] Reference numerals:

[0035] 1: First electrode plate;

[0036] 2: Second electrode plate;

[0037] 3: Ring-shaped connecting part;

[0038] 4: Slide groove fixing seat;

[0039] 5: Wearable metasurface device for magnetic resonance imaging;

[0040] 6: Mobile hospital bed;

[0041] 7: Radio frequency transmitting coil (body coil);

[0042] 8: Gradient coil;

[0043] 9: Main magnet coil;

[0044] 10: Elastic fabric;

[0045] 24: Elastic reset component;

[0046] 111: First substrate;

[0047] 221: Second substrate; Detailed implementation manners

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0049] It should be noted that the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above-mentioned accompanying drawings are intended to cover non-exclusive inclusion. For example, a process, method, system, product, or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but may include other steps or units not clearly listed or inherent to these processes, methods, products, or devices. Without conflict, the embodiments in this application and the features in the embodiments may be combined with each other. The present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0050] Metasurface provides a new idea for further enhancing the SNR of MRI. By resonating at the working frequency point of magnetic resonance, the metasurface greatly enhances the radio frequency magnetic field in the region of interest, thereby amplifying the nuclear magnetic resonance signal and further enhancing the signal-to-noise ratio of magnetic resonance images. The metasurface with a traditional fixed configuration has been verified to be feasible in improving the magnetic resonance signal-to-noise ratio. The wearable metasurface can be as close as possible to the surface of the measured target and adapt to the irregular structure of the human body part. Compared with the metasurface with a fixed configuration, it can theoretically further improve the SNR.

[0051] The existing multi-channel phased array magnetic resonance radio frequency receiving coil receives MR signals through multiple single-loop radio frequency coils at the same time, and each coil covers a different anatomical region. These coils can work in different phases, collect nuclear magnetic signals at the same time, and then synthesize the data of each channel into a single image to achieve the acquisition of magnetic resonance images.

[0052] This method needs to be connected to the magnetic resonance system through cables. The multi-channel phased array coil technology has encountered bottlenecks. The increase in the number of channels will bring problems such as increased cost, overweight and oversize, and complex decoupling. Moreover, with the increase in the number of channels, the signal-to-noise ratio basically no longer increases.

[0053] The existing technical solutions also use a metasurface with a fixed configuration, which is composed of a metal wire array. The metasurface can resonate at the working frequency point of magnetic resonance, amplify the radio frequency magnetic field in the region, and enhance the signal-to-noise ratio of the image. However, due to this fixed configuration, it cannot be close to the surface of the measured target, so it cannot maximize the signal-to-noise ratio of the image and fails to fully utilize the signal-to-noise ratio enhancement performance of the metasurface. The flexible attachment characteristic of the wearable metasurface can maximize the signal-to-noise ratio of the image.

[0054] To solve at least one of the above problems existing in the prior art, an embodiment of the present application provides a wearable metasurface device for magnetic resonance imaging. Figure 1 This is a schematic diagram of a wearable metasurface device for magnetic resonance imaging according to an embodiment of the present application. As Figure 1 shown, the wearable metasurface device for magnetic resonance imaging includes:

[0055] A plurality of first electrodes 1;

[0056] A plurality of second electrodes 2, the plurality of first electrodes 1 and the plurality of second electrodes 2 are arranged in one-to-one correspondence; the first electrode 1 and the second electrode 2 are attached and can slide relative to each other to form a variable structure capacitor;

[0057] At least one annular connecting portion 3, the plurality of first electrodes 1 and the plurality of second electrodes 2 are arranged on the annular connecting portion 3 in a circular array.

[0058] In Figure 1In it, the positions of the first electrode plate 1 and the second electrode plate 2 overlap at least partially in the vertical direction, that is, the first electrode plate 1 can be partially located above the second electrode plate 2 (the two need to be attached), or can be located below the second electrode plate 2 to form the upper and lower electrode plates of the variable-structure capacitor. It can be understood that the variable-structure capacitor in the above embodiment is a sliding variable capacitor, which changes the capacitance by sliding the upper and lower electrode plates (the first electrode plate and the second electrode plate) to change the facing area between the upper and lower electrode plates.

[0059] The inventor found that due to the size differences of the measured targets, when the wearable metasurface is worn on the surfaces of different measured targets, its configuration size will change, so that the equivalent inductance of the entire structure will change, resulting in the resonance frequency shifting, the performance of radiofrequency magnetic resonance enhancement decreasing, and further affecting the image signal-to-noise ratio of magnetic resonance imaging.

[0060] Specifically, as Figure 2 shown, when the metasurface is worn on the surface of a larger target, its size will be stretched, resulting in an increase in the equivalent inductance. According to the resonance frequency calculation formula of the metasurface (see the following formula), when the equivalent inductance increases, the resonance frequency of the metasurface will decrease, resulting in a decrease in the performance of radiofrequency magnetic resonance enhancement at the magnetic resonance resonance point of the metamaterial.

[0061]

[0062] Among them, ω is the resonance frequency of the metasurface, L is the equivalent inductance of the metasurface, and C is the equivalent capacitance of the metasurface.

[0063] And through the wearable metasurface device for magnetic resonance signal imaging described in the above embodiments of the present application, while achieving the beneficial effect of stretchability during the realization of the wearable metasurface, the resonance frequency of the wearable metasurface device after stretching is also compensated.

[0064] Specifically, when the wearable metasurface device undergoes stretching, relative sliding occurs between the first electrode plate and the second electrode plate, resulting in a decrease in the equivalent capacitance of the overall structure. By preset calculation to determine the relationship between the change in the relative sliding area between the first electrode plate and the second electrode plate and the change in the equivalent inductance of the overall structure before and after stretching, the product of the equivalent capacitance and the equivalent inductance of the wearable metasurface device before and after stretching can be kept unchanged, thereby keeping the resonance frequency of the wearable metasurface device unchanged, and thus ensuring the image signal-to-noise ratio of magnetic resonance imaging.

[0065] In some embodiments of the present application, when the number of the annular connecting parts 3 is 1, it is located at the middle position between the first electrode plate 1 and the second electrode plate 2 to relatively fix the first electrode plate 1 and the second electrode plate 2 preferably.

[0066] Further, referring to Figure 1 , when the number of the annular connecting parts 3 is two, the multiple first electrode plates 1 and the multiple second electrode plates 2 are arranged in a circumferential array between the two annular connecting parts 3, that is, the two annular connecting parts 3 are located at both ends of the first electrode plates 1 and the second electrode plates 2 (at this time, the annular connecting parts can also be called end rings).

[0067] In some embodiments of the present application, referring to Figure 3 , any one of the second electrode plates 2 (taking the middle second electrode plate 2 as an example here, which is the upper electrode plate in the figure and can also be used as the lower electrode plate, and the present application is not limited thereto) is electrically connected to the first electrode plate 1 corresponding to one of the two second electrode plates 2 adjacent to it ( Figure 3 taking the first electrode plate 1 on the left side of the middle second electrode plate 2 as an example in

[0068] Figure 3 , and the present application is not limited thereto);

[0069] In some embodiments of the present application, referring to Figure 4 , the first electrode plate 1 includes: a first substrate 111 and a first conductive layer 112; the second electrode plate 2 includes: a second substrate 221 and a second conductive layer 222; wherein, the second conductive layer 222 is attached to the first substrate 111 (as shown in Figure 4 , that is, the first electrode plate 1 serves as the lower electrode and the second electrode plate 2 serves as the upper electrode); or

[0070] the first conductive layer 112 is attached to the second substrate 221 ( Figure 4 not shown in

[0071] Figure 4 , and in this embodiment, the first electrode plate 1 serves as the upper electrode and the second electrode plate 2 serves as the lower electrode).

[0072] Further, the first substrate 111 and the second substrate 221 are radio frequency loss substrates, that is, material substrates with relatively low radio frequency loss, preferably at least one of FR4, 400C, Rogers substrates, and polytetrafluoroethylene plastics in PCB technology.

[0073] In some embodiments of the present application, the annular connecting portion is composed of a plurality of elastic connecting members, and the first electrode plate and the corresponding second electrode plate are disposed on one elastic connecting member. It can be understood that for the same annular connecting portion, the elastic connecting members, the first electrode plates connected thereto, and the second electrode plates are in one-to-one correspondence.

[0074] In some embodiments of the present application, referring to Figure 1 , when the number of the annular connecting portions 3 is 2, the plurality of first electrode plates 1 and the plurality of second electrode plates 2 are arranged in a circumferential array between the two annular connecting portions 3, that is, the two annular connecting portions 3 are located at both ends of the first electrode plates 1 and the second electrode plates 2 (at this time, the annular connecting portion can also be referred to as an end ring).

[0075] Referring to Figure 1 , the annular connecting portion 3 includes: a plurality of chute fixing seats 4 (shown by the red dotted line frame in the figure) having the same number as the first electrode plates 1;

[0076] At least one of the first electrode plate 1 and the second electrode plate 2 slides inside the chute fixing seat 4.

[0077] In some embodiments of the present application, referring to Figure 4 and Figure 5 , the chute fixing seat 4 includes an elastic reset member 24 for resetting at least one of the first electrode plate 1 and the second electrode plate 2 after sliding. Preferably, referring to Figure 4 and Figure 5 , the elastic reset member 24 is an elastic cord or a tension spring.

[0078] In some embodiments of the present application, the second electrode plate 2 has a different length from the first electrode plate 1, and the second electrode plate 2 is disposed inside the chute fixing seat 4. Preferably, the length of the second electrode plate 2 is less than the length of the chute fixing seat, that is, the second electrode plate 2 is only disposed in the corresponding part of the annular connecting portion 3. Further, the width of the second electrode plate 2 may also be unequal to the width of the first electrode plate 1. It can be understood that this setting can further increase the ductility of the wearable metasurface device. In this embodiment (the second electrode plate 2 is only disposed inside the chute fixing seat 4, the first electrode plate 1 is the upper electrode, the second electrode plate 2 is the lower electrode, and the two annular connecting portions 3 are end rings), assuming that the length of the first electrode plate 1 is L 1 , its effective length is L 11 , the length of the second electrode plate 2 is L 2 , then L 11 is equal to the difference between the length of the first electrode plate 1 and the lengths of the two second electrode plates 2, that is: L 11 = L 1 - 2L 2 , for a single first electrode plate 1, its resonance frequency is related to the effective length L11 The capacitance C of the parallel - plate capacitor has the following relationship:

[0079]

[0080]

[0081] Among them, ω is the resonance frequency, ε is the dielectric constant of the intermediate dielectric layer, S is the facing area between the upper and lower plates, k is the electrostatic constant, d is the distance between the upper and lower plates, λ is the wavelength of the electromagnetic wave at resonance, W is the wave impedance of the first plate, and X is the capacitive reactance of the parallel - plate capacitor. During the stretching and shrinking process of the wearable metasurface, S will change passively, thus changing the capacitance value of the structure, and further realizing the passive adaptive compensation of the resonance frequency of the metasurface.

[0082] In some embodiments of the present application, referring to Figure 1 , there are pores between multiple first plates 1, and there are pores between the first plate 1 and its adjacent second plate 2. It should be noted that the statement "there are pores between multiple first plates 1" means that when the wearable metasurface device is in the initial state, there are pores between multiple first plates 1, and there are pores between the first plate 1 and its adjacent second plate 2; and after the wearable metasurface device is stretched, there are still pores between multiple first plates 1, and there are still pores between the first plate 1 and its adjacent second plate 2.

[0083] In some embodiments of the present application, the number of the first plates is an even number.

[0084] It should be pointed out that the concept of the wearable metasurface device for magnetic resonance imaging proposed in the present application is not limited to the extension of the wearable metasurface device. Specifically, when the person (or part) to be detected is relatively slender, the wearable metasurface device for magnetic resonance imaging proposed in the present application can also be tightened. For example, a tightening and stretching is set on a certain chute fixing seat to pull at least one of the first plate and the second plate, so that the perimeter of the ring - shaped connecting part becomes smaller, or at least one first plate and its corresponding second plate and chute fixing seat are removed (similar to the way of shortening a watch chain), so as to achieve the purpose of making the perimeter of the ring - shaped connecting part smaller, and further making the wearable metasurface as close as possible to the surface of the measured target.

[0085] As can be seen from the above description, an embodiment of the present invention provides a wearable metasurface device for magnetic resonance signal imaging, including: a plurality of first electrode plates; a plurality of second electrode plates, the plurality of first electrode plates and the plurality of second electrode plates are arranged in one-to-one correspondence; the first electrode plate and the second electrode plate are attached and can slide relative to each other to form a variable structure capacitor; at least one annular connecting portion, the plurality of first electrode plates and the plurality of second electrode plates are arranged in a circular array on the annular connecting portion.

[0086] An embodiment of the present invention provides a wearable metasurface device for magnetic resonance signal imaging, aiming to solve the problem that when the wearable metasurface undergoes tensile deformation, the resonance frequency shifts, resulting in a decrease in the magnetic resonance signal-to-noise ratio enhancement performance, so as to achieve efficient signal transmission and enhancement in magnetic resonance imaging (MRI).

[0087] To further illustrate the solution, the present invention takes a specific application scenario of a wearable metasurface device for magnetic resonance signal imaging as an example to provide a specific application example of a wearable metasurface device for magnetic resonance signal imaging.

[0088] First, refer to Figure 6 , the position shown in Figure 5 is the position where the wearable metasurface device for magnetic resonance signal imaging is located, which surrounds the target to be measured and adheres to the surface of the target to be measured as closely as possible (simply wear the wearable metasurface device on the part to be measured (wrist, knee, etc.), and use a suitable receiving coil to receive (including but not limited to a spine coil, a body coil, an abdominal coil, etc.)). Figure 6 In, 6 is a mobile hospital bed (which can move the human body to the optimal position according to the detection requirements), 7 is a radio frequency transmitting coil (body coil), 8 is a gradient coil, and 9 is a main magnet coil.

[0089] To solve the related technical problems in the prior art, the present application adds a deformation-responsive structural capacitor to the end ring of the metasurface. The structural capacitor is composed of an upper and a lower electrode plate and a medium in the middle. The upper and lower electrode plates can slide relative to each other, and the facing area between the upper and lower electrode plates determines the size of its equivalent capacitance.

[0090] It can be understood that after introducing this structure into the metasurface, when the size of the metasurface increases, the size of the end ring will also increase, and the upper and lower electrode plates of the structural capacitor will slide relative to each other under the action of force, resulting in a decrease in the facing area, and thus a decrease in the structural capacitor. According to the resonance frequency calculation formula of the aforementioned metasurface, at this time, the resonance frequency of the metasurface will increase, thereby correcting the decrease in the resonance frequency caused by the increase in the equivalent inductance.

[0091] Ideally, when the product LC of the equivalent inductance and the equivalent capacitance remains constant, the resonant frequency of the metasurface will remain unchanged. In practice, when the current frequency is corrected to be within 1% of the frequency of the magnetic resonance imaging system, the degradation of the signal-to-noise ratio enhancement performance is acceptable.

[0092] Specifically, as shown in the metasurface Figure 1 The structure is formed by arranging a plurality of first electrode plates 1 and corresponding second electrode plates 2 in a circular array, and all the first electrode plates 1 and the corresponding second electrode plates 2 are array-connected by an annular connecting portion 3 (end ring) to form a resonating metasurface. The first electrode plate 1 is composed of a first substrate 111 (low-loss substrate) and a first conductive layer 112. The first electrode plate 1 extends along the length direction to the end ring, is fixedly connected to the chute fixing seat 4 on the end ring, intersects with the end ring, and the overlapping part with the end ring serves as the upper electrode plate of the structural capacitor.

[0093] The upper electrode plate (second electrode plate 2) of the structural capacitor is composed of a second substrate 221 (low-loss substrate) and a second conductive layer 222, and can slide relative to the first electrode plate 1 along the circumferential direction of the end ring within the chute fixing seat 4, and together with the first electrode plate 1, it forms a variable structural capacitor.

[0094] On the other hand, an elastic reset member (elastic rope or tension spring) 24 elastically restricts the second electrode plate 2 on the chute fixing seat 4 to limit the position of the second electrode plate 2 relative to the chute fixing seat 4. The first electrode plate 1 is fixedly arranged in the groove of the chute fixing seat 4; thus, the variable structural capacitors are arranged in a circular array to form an end ring. During this process, any one of the second electrode plates 2 (is electrically connected to the first electrode plate 1 corresponding to one of the two second electrode plates 2 adjacent to it; the first electrode plate 1 corresponding to any one of the second electrode plates 2 is electrically connected to the other second electrode plate among the two second electrode plates 2 adjacent to any one of the second electrode plates 2. Thus far, a variable structural capacitor is formed by connecting a plurality of first electrode plates 1 and a plurality of second electrode plates 2 in series.

[0095] Next, according to the variable structural capacitor calculation formula C = εS / 4πkd, the initial capacitance value of the variable structural capacitor can be determined by the dielectric constant ε and thickness d of the first substrate 111. Changing the relative area S can linearly change the magnitude of the structural capacitance value.

[0096] In the present invention, when the metasurface is worn on the surface of different objects, the change in size will be reflected in the change in the size of the end ring. And the variable structural capacitor will be passively changed under the action of deformation, achieving the effect of passive self-adaptation of the resonant frequency.

[0097] Furthermore, the first electrode plate and the second electrode plate are made of a PCB board. A PCB board (Printed Circuit Board) is used to physically support and electrically connect electronic components. Electronic components are fixed on the board and their electrical functions are achieved through circuit connections. A PCB consists of an insulating substrate (such as FR4) and a conductive layer (usually copper) covering it. The main components of a PCB are as follows:

[0098] Substrate: Provides physical support for the PCB. Common ones include FR4 (glass fiber-reinforced epoxy resin), CEM1, CEM3, etc.

[0099] Conductive layer: Usually copper, used to form the conductive path of the circuit. It can be a single-sided board (with a copper layer on only one side), a double-sided board (with copper layers on both sides), or a multi-layer board (alternating layers of multiple copper layers and insulating layers).

[0100] Copper-clad layer: Used to protect the copper circuit, avoiding oxidation and corrosion.

[0101] Pad: The point for soldering electronic components.

[0102] Via hole: A hole providing electrical connection between different layers.

[0103] Silk screen layer: Used to identify the positions of components, markings, and other indication information.

[0104] The first substrate and the second substrate are made of materials with relatively low radio frequency loss, and copper is coated on them to form the conductive layer. The upper and lower electrode plates of the adjustable capacitor are composed of two FPCs, and FR4 reinforcement is carried out in the overlapping area. While forming the structural capacitor, it can be bent to form an end ring. The upper electrode plate of the current structural capacitor is composed of metal wires in the part of the end ring and extends along the circumferential direction, connecting to the lower electrode plate of the previous structural capacitor, while the lower electrode plate of the current structural capacitor extends and connects to the upper base of the next structural capacitor. The cyclic array of structural capacitors forms the entire capacitor. To ensure that the upper and lower electrode plates can fit and slide relative to the intermediate dielectric layer, the lower electrode plate is fixedly connected to the intermediate dielectric layer and fixed on a chute fixing seat (capacitor seat). The capacitor seat is designed with a chute for the upper electrode plate to slide. The capacitor seat can be made by 3D printing or machining.

[0105] Preferably, referring to Figure 7 , the surface of the wearable metasurface device for magnetic resonance imaging can be coated with an elastic fabric 10 or other elastic materials to encapsulate the metasurface. The elastic material contacts the surface of the object to be measured and can be stretched.

[0106] As can be seen from the above description, a specific application example of the present invention provides a wearable metasurface device for magnetic resonance imaging, including: a plurality of first electrode plates; a plurality of second electrode plates, wherein the plurality of first electrode plates and the plurality of second electrode plates are arranged in one-to-one correspondence; the first electrode plates and the second electrode plates are attached and can slide relative to each other to form a variable structure capacitor; at least one annular connecting portion, and the plurality of first electrode plates and the plurality of second electrode plates are arranged on the annular connecting portion in a circumferential array.

[0107] A specific application example of the present invention provides a wearable metasurface device for magnetic resonance imaging, aiming to solve the problem that when the wearable metasurface undergoes tensile deformation, the resonance frequency shifts, resulting in a decline in the performance of enhancing the magnetic resonance signal-to-noise ratio, so as to achieve efficient signal transmission and enhancement in magnetic resonance imaging (MRI).

[0108] In the description of this specification, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, so it cannot be understood as a limitation to the present invention. In addition, terms such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first", "second", etc. may explicitly or implicitly include one or more of such features. In the description of the present invention, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0109] The description referring to terms such as "an embodiment", "a specific embodiment", "some embodiments", "for example", "example", "specific example", or "some examples", etc. means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. The order of steps involved in each embodiment is used to schematically illustrate the implementation of the present invention, and the order of steps is not limited and can be adjusted appropriately as needed.

[0110] In the description of the present invention, it should be noted that unless otherwise clearly defined and limited, the terms "installed", "connected", and "coupled" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0111] The embodiments in this specification are all described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and the differences between each embodiment and other embodiments are emphasized. In particular, for the system embodiments, since they are basically similar to the method embodiments, they are described relatively simply, and the relevant parts can be referred to the description of the method embodiments. In the description of this specification, the description with reference to terms such as "one embodiment", "some embodiments", "example", "specific example", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of this specification. In this specification, the schematic expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0112] The above are only the embodiments of the embodiments of this specification and are not used to limit the embodiments of this specification. For those skilled in the art, various changes and modifications can be made to the embodiments of this specification. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the embodiments of this specification shall be included within the scope of the claims of the embodiments of this specification.

Claims

1. A wearable metasurface device for magnetic resonance imaging, characterized in that: include: a plurality of first plates; A plurality of second electrode plates, wherein the plurality of first electrode plates and the plurality of second electrode plates are arranged in one-to-one correspondence; The first electrode plate and the second electrode plate are fitted and can slide relative to each other to form a variable structure capacitor; At least one annular connecting portion, the plurality of first electrode plates and the plurality of second electrode plates are arranged in a circular array on the annular connecting portion.

2. The wearable metasurface device according to claim 1, characterized in that: Any second electrode plate is electrically connected to a first electrode plate corresponding to one of the two adjacent second electrode plates; The first electrode plate corresponding to any one of the second electrode plates is electrically connected to the other second electrode plate of the two second electrode plates adjacent to the any one of the second electrode plates.

3. The wearable metasurface device according to claim 1, characterized in that: The first electrode plate includes: a first substrate and a first conductive layer; The second electrode plate comprises: a second substrate and a second conductive layer; wherein the first conductive layer is bonded to the second substrate; or The second conductive layer is attached to the first substrate.

4. The wearable metasurface device according to claim 1, characterized in that: The first electrode plate and the second electrode plate are flexible circuit boards.

5. The wearable metasurface device according to claim 1, characterized in that: The annular connecting portion is composed of a plurality of elastic connecting members, and the first electrode plate and the corresponding second electrode plate are arranged on an elastic connecting member.

6. The wearable metasurface device according to claim 1, characterized in that: The number of the annular connecting parts is two, and the plurality of first electrode plates and the plurality of second electrode plates are arranged in a circular array between the two annular connecting parts; The annular connecting portion includes: a plurality of slide slot fixing seats having the same number as the first pole plate; At least one of the first pole plate and the second pole plate slides inside the slide groove fixing seat.

7. The wearable metasurface device according to claim 6, characterized in that: The slide groove fixing seat includes an elastic reset component, which is used to reset at least one of the first pole plate and the second pole plate after sliding.

8. The wearable metasurface device according to claim 6, characterized in that: The second pole plate has a different length from the first pole plate, and the second pole plate is arranged inside the slide slot fixing seat.

9. The wearable metasurface device according to claim 1, characterized in that: There are gaps between the plurality of first electrode plates, and there are gaps between the first electrode plate and the second electrode plate adjacent thereto.

10. The wearable metasurface device according to any one of claims 1 to 9, characterized in that: The number of the first pole plates is an even number.

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