Magnetic field enhancement component and magnetic field enhancement device

Abstract

The present application relates to a magnetic field enhancement component and a magnetic field enhancement device. The magnetic field enhancement component includes a first dielectric layer, a first electrode layer, a second electrode layer and a fourth control circuit. The first dielectric layer has a first surface. The first dielectric layer has a first end and a second end that are arranged opposite to each other. The first electrode layer is arranged on the first surface and is arranged close to the second end. The second electrode layer is arranged on the first surface and is spaced apart from the first electrode layer and is arranged close to the first end. One end of the fourth control circuit is connected to an end of the second electrode layer away from the first end. The other end of the fourth control circuit is connected to an end of the first electrode layer away from the second end. The fourth control circuit is used to control the first electrode layer and the second electrode layer to be disconnected in the radio frequency transmission stage and connected in the radio frequency reception stage.

Description

Technical Field

[0001] The present application relates to the technical field of magnetic resonance imaging, and in particular to a magnetic field enhancement component and a magnetic field enhancement device. Background Art

[0002] MRI (Magnetic Resonance Imaging) is a non-invasive detection method and an important basic diagnostic technology in the fields of medicine, biology, and neuroscience. The signal strength transmitted by traditional MRI equipment mainly depends on the strength of the static magnetic field B0. The use of high magnetic field or even ultra-high magnetic field system can improve the signal-to-noise ratio, resolution and shorten the scanning time of the image. However, the increase in the static magnetic field strength will bring the following three problems: 1) The non-uniformity of the radio frequency (RF) field increases, and the tuning difficulty increases; 2) The heat generation of human tissue increases, which brings safety hazards, and patients are also prone to adverse reactions such as dizziness and vomiting; 3) The purchase cost increases significantly, which is a burden for most small-scale hospitals. Therefore, how to use the smallest static magnetic field strength while obtaining high imaging quality has become a crucial issue in MRI technology.

[0003] Among them, the introduction of plate or columnar dielectric resonators with high dielectric constants in MRI to increase the intensity of the radio frequency magnetic field and reduce the specific absorption rate, thereby achieving the effect of improving imaging resolution and reducing the signal-to-noise ratio, is a new trend that can effectively improve MRI characteristics. The emergence of metamaterials provides a novel and more effective method to improve the quality and efficiency of MRI imaging. Metamaterials have many special properties that natural materials do not have. Through the interaction between electromagnetic waves and the metal or dielectric elements of metamaterials and the coupling effect between elements, the control of the electromagnetic wave propagation path and the electromagnetic field intensity distribution can be achieved. Among them, the specific working principle is to use the electromagnetic resonance in the structure formed by the metamaterial to achieve the adjustment of electromagnetic parameters such as anisotropy and gradient distribution. In addition, by designing parameters such as the geometric size, shape and dielectric constant of the metamaterial, the resonance enhancement of different frequency points can be achieved.

[0004] In a nuclear magnetic resonance system, there are two RF stages: an RF transmission stage and an RF reception stage. The RF fields in the RF transmission stage and the RF reception stage have the same resonant frequency. Therefore, the structure formed by the metamaterial will greatly increase the RF transmission field while enhancing the RF reception field. At this time, after the RF transmission field is enhanced, the MRI image quality will be reduced. However, the traditional magnetic field enhancement component includes a dielectric plate and a first electrode and a second electrode located on the front and back of the dielectric plate, respectively. The orthographic projection of the second electrode on the dielectric plate is located at both ends of the orthographic projection of the first electrode on the dielectric plate to form a parallel plate capacitor. At this time, the structure of the traditional magnetic field enhancement component only has frequency selectivity, which makes the magnetic field enhancement component present a linear response characteristic, which will simultaneously enhance the RF transmission field and the RF reception field, resulting in a reduction in MRI image quality. Summary of the invention

[0005] Based on this, in order to solve the above problems, it is necessary to provide a magnetic field enhancement component and a magnetic field enhancement device.

[0006] The present application provides a magnetic field enhancement component. The magnetic field enhancement component includes a first dielectric layer, a first electrode layer, a second electrode layer and a fourth control circuit. The first dielectric layer has a first surface. The first dielectric layer has a first end and a second end that are arranged opposite to each other. The first electrode layer is arranged on the first surface and is arranged close to the second end. The second electrode layer is arranged on the first surface and is spaced apart from the first electrode layer and is arranged close to the first end. One end of the fourth control circuit is connected to an end of the second electrode layer away from the first end, and the other end of the fourth control circuit is connected to an end of the first electrode layer away from the second end. The fourth control circuit is used to control the first electrode layer and the second electrode layer to be disconnected in the radio frequency transmission stage and connected in the radio frequency reception stage.

[0007] In the above-mentioned magnetic field enhancement component and magnetic field enhancement device, the second electrode layer and the first electrode layer can serve as the transmission line of the magnetic field enhancement component. The fourth control circuit controls the connection or disconnection of the second electrode layer and the first electrode layer. The magnetic field enhancement component introduces a nonlinear control structure through the fourth control circuit, so that the resonant circuit formed by the multiple magnetic field enhancement components also has nonlinear response characteristics, and can be applied to all clinical sequences including fast spin echo sequences. The resonance of the structure formed by the multiple magnetic field enhancement components is LC resonance. In LC resonance, the inductance comes from the transmission line itself formed by the first electrode layer and the second electrode layer, which can be equivalent to an inductor and a resistor. The capacitance in LC resonance comes from the structural capacitance formed between any two electrode layers and the dielectric.

[0008] In the RF transmission stage, the fourth control circuit controls the first electrode layer to be disconnected from the second electrode layer. The resonant circuit formed by the multiple magnetic field enhancement components is in a disconnected state, presenting a detuned state. In addition, there is no induced current in the resonant circuit formed by the multiple magnetic field enhancement components, and thus no induced magnetic field that interferes with the RF is generated, thereby eliminating the influence of the magnetic field enhancement components on the RF transmission stage.

[0009] In the RF receiving stage, the fourth control circuit controls the connection between the first electrode layer and the second electrode layer. The resonant circuit formed by the multiple magnetic field enhancement components is in a connected state, which can present a resonant state and greatly enhance the signal field. The fourth control circuit controls the first electrode layer and the second electrode layer to be disconnected in the RF transmitting stage and connected in the RF receiving stage, so that the magnetic field enhancement component can only enhance the RF receiving field, and will not enhance the RF transmitting field, thereby improving the image signal-to-noise ratio. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the conventional technology, the drawings required for use in the embodiments or the conventional technology descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0011] Figure 1 A side view of a magnetic field enhancement assembly in one embodiment provided in the present application;

[0012] Figure 2 A side view of a magnetic field enhancement assembly in one embodiment provided in the present application;

[0013] Figure 3 A side view of a magnetic field enhancement assembly in one embodiment provided in the present application;

[0014] Figure 4 Provided for this application Figure 3 A schematic structural diagram of a magnetic field enhancement assembly in an embodiment;

[0015] Figure 5 Provided for this application Figure 3 A top view of a magnetic field enhancement assembly in an embodiment;

[0016] Figure 6 A schematic structural diagram of the overlapping portion of the first electrode layer and the third electrode layer in an embodiment provided in the present application;

[0017] Figure 7 A schematic structural diagram of the overlapping portion of the first electrode layer and the third electrode layer in an embodiment provided in the present application;

[0018] Figure 8 A side view of a magnetic field enhancement assembly in one embodiment provided in the present application;

[0019] Fig. 9 A side view of a magnetic field enhancement assembly in one embodiment provided in the present application;

[0020] Fig.10 A schematic diagram of the overall structure of the magnetic field enhancement device provided in this application;

[0021] Fig.11 A schematic diagram of the exploded structure of the magnetic field enhancement device provided in this application;

[0022] Fig.12 It is the resonant performance of the magnetic field enhancement device in the RF transmission stage and the RF reception stage.

[0023] Description of reference numerals:

[0024] Magnetic field enhancement component 10, first dielectric layer 100, first electrode layer 110, second electrode layer 120, fourth control circuit 600, first surface 101, second surface 102, first end 103, second end 104, first depletion-type MOS transistor 231, second depletion-type MOS transistor 232, third depletion-type MOS transistor 233, fourth depletion-type MOS transistor 234, second surface 102, third electrode layer 130, second structure capacitor 302, fourth electrode layer 140, third structure capacitor 303, fifth electrode layer 141, fifth control circuit 610, sixth control circuit 620, sixth electrode layer 121, first opening 401, second opening 402, third opening 403, fourth opening 404, magnetic field enhancement device 20, cylindrical support structure 50, magnetic field enhancement component 10, first annular conductive sheet 510, second annular conductive sheet 520, third end 51, fourth end 53. DETAILED DESCRIPTION

[0025] In order to facilitate understanding of the present application, the present application will be described more fully below with reference to the relevant drawings. Embodiments of the present application are provided in the drawings. However, the present application can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present application more thorough and comprehensive.

[0026] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application.

[0027] It is understood that the terms "first", "second", etc. used in this application may be used herein to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish a first element from another element. For example, without departing from the scope of this application, a first resistor may be referred to as a second resistor, and similarly, a second resistor may be referred to as a first resistor. Both the first resistor and the second resistor are resistors, but they are not the same resistor.

[0028] It can be understood that the “connection” in the following embodiments should be understood as “electrical connection”, “communication connection”, etc. if the connected circuits, modules, units, etc. have electrical signals or data transmission between each other.

[0029] When used herein, the singular forms "a", "an", and "said / the" may also include plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms "include / comprise" or "have" and the like specify the presence of stated features, wholes, steps, operations, components, parts, or combinations thereof, but do not exclude the possibility of the presence or addition of one or more other features, wholes, steps, operations, components, parts, or combinations thereof. At the same time, the term "and / or" used in this specification includes any and all combinations of the relevant listed items.

[0030] See also Figure 1 The present application provides a magnetic field enhancement component 10. The magnetic field enhancement component 10 includes a first dielectric layer 100, a first electrode layer 110, a second electrode layer 120 and a fourth control circuit 600. The first dielectric layer 100 has a first surface 101. The first dielectric layer 100 has a first end 103 and a second end 104 that are oppositely arranged. The first electrode layer 110 is arranged on the first surface 101. The first electrode layer 110 is arranged close to the second end 104. The second electrode layer 120 is arranged on the first surface 101. The second electrode layer 120 is arranged spaced apart from the first electrode layer 110. The second electrode layer 120 is arranged close to the first end 103.

[0031] One end of the fourth control circuit 600 is connected to an end of the second electrode layer 120 away from the first end 103. The other end of the fourth control circuit 600 is connected to an end of the first electrode layer 110 away from the second end 104. The fourth control circuit 600 is used to control the first electrode layer 110 and the second electrode layer 120 to be disconnected in the RF transmission stage and connected in the RF reception stage.

[0032] In this embodiment, the second electrode layer 120 and the first electrode layer 110 can serve as the transmission line of the magnetic field enhancement component 10. The fourth control circuit 600 controls the connection or disconnection of the second electrode layer 120 and the first electrode layer 110. The magnetic field enhancement component 10 introduces a nonlinear control structure through the fourth control circuit 600, so that the resonant circuit formed by the multiple magnetic field enhancement components 10 also has a nonlinear response characteristic, which can be applied to all clinical sequences including fast spin echo sequences. The resonance of the structure formed by the multiple magnetic field enhancement components 10 is LC resonance. In LC resonance, the inductance comes from the transmission line itself formed by the first electrode layer 110 and the second electrode layer 120, which can be equivalent to an inductor and a resistor. The capacitance in LC resonance comes from the structural capacitance formed between any two electrode layers and the dielectric.

[0033] In the RF transmission stage, the fourth control circuit 600 controls the first electrode layer 110 to be disconnected from the second electrode layer 120. The resonant circuit formed by the multiple magnetic field enhancement components 10 is in a disconnected state, presenting a detuned state. In addition, there is no induced current in the resonant circuit formed by the multiple magnetic field enhancement components 10, and thus no induced magnetic field that interferes with the RF is generated, thereby eliminating the influence of the magnetic field enhancement components 10 on the RF transmission stage.

[0034] In the RF receiving stage, the fourth control circuit 600 controls the connection between the first electrode layer 110 and the second electrode layer 120. The resonant circuit formed by the multiple magnetic field enhancement components 10 is in a connected state, which can present a resonant state and greatly enhance the signal field. The fourth control circuit 600 controls the first electrode layer 110 and the second electrode layer 120 to be disconnected in the RF transmitting stage and connected in the RF receiving stage, so that the magnetic field enhancement component 10 can only enhance the RF receiving field, and will not enhance the RF transmitting field, thereby improving the image signal-to-noise ratio.

[0035] The magnetic field enhancement component 10 is a nonlinear response MRI image enhancement metasurface device based on MOS tubes. The nonlinear response MRI image enhancement metasurface device based on MOS tubes controls the first electrode layer 110 and the second electrode layer 120 to be disconnected in the RF transmission stage and connected in the RF reception stage through the fourth control circuit 600. The first electrode layer 110 and the second electrode layer 120 are disconnected in the RF transmission stage and connected in the RF reception stage, so that the magnetic field enhancement component 10 can only enhance the RF reception field, and will not enhance the RF transmission field. The nonlinear response MRI image enhancement metasurface device based on MOS tubes exhibits the characteristics of nonlinear response and will not enhance the RF transmission field and the RF reception field at the same time.

[0036] In one embodiment, the fourth control circuit 600 includes a first depletion-mode MOS transistor 231 and a second depletion-mode MOS transistor 232. The source of the first depletion-mode MOS transistor 231 is connected to the second electrode layer 120. The gate and drain of the first depletion-mode MOS transistor 231 are connected. The gate and drain of the second depletion-mode MOS transistor 232 are connected. The gate and drain of the second depletion-mode MOS transistor 232 are connected to the gate and drain of the first depletion-mode MOS transistor 231. The source of the second depletion-mode MOS transistor 232 is connected to the first electrode layer 110.

[0037] In this embodiment, the first depletion-type MOS tube 231 and the second depletion-type MOS tube 232 are connected in reverse series, which can control the first electrode layer 110 and the second electrode layer 120 to be disconnected in the RF transmission stage and connected in the RF reception stage. By connecting the first depletion-type MOS tube 231 and the second depletion-type MOS tube 232 in reverse series, it can adapt to the AC environment in the MRI equipment. The first depletion-type MOS tube 231 and the second depletion-type MOS tube 232 are connected in reverse series, which can ensure that one of the first depletion-type MOS tube 231 and the second depletion-type MOS tube 232 is cut off in the RF transmission stage, so that the first electrode layer 110 and the second electrode layer 120 are disconnected and not connected.

[0038] The first depletion MOS transistor 231 and the second depletion MOS transistor 232 have the characteristics of being turned on at low voltage and turned off at high voltage. In addition, the first depletion MOS transistor 231 and the second depletion MOS transistor 232 have a pinch-off voltage of about 1V at room temperature, and a disconnection time and a recovery time are both in nanoseconds.

[0039] The RF transmission stage and the RF reception stage in the MRI device have a time sequence difference of tens of milliseconds to thousands of milliseconds, which can quickly realize the conduction and disconnection of the first depletion-type MOS tube 231 and the second depletion-type MOS tube 232. The RF power in the RF transmission stage and the RF reception stage differs by three orders of magnitude. The induced voltage in the coil in the RF transmission stage is between a few V and several hundred V, and the specific value is related to the selected sequence and flip angle.

[0040] In the RF transmission stage, the induced voltage is relatively large, the first depletion-type MOS tube 231 and the second depletion-type MOS tube 232 are in a disconnected state, and the resonant circuit formed by the multiple magnetic field enhancement components 10 is in a disconnected state, presenting a detuned state. In addition, there is no current in the magnetic field enhancement component 10, and no induced magnetic field that will interfere with the RF is generated. In the RF reception stage, the first depletion-type MOS tube 231 and the second depletion-type MOS tube 232 are turned on, and the resonant circuit formed by the multiple magnetic field enhancement components 10 is in a connected state, which can present a resonant state, greatly enhance the signal field, and enhance the image signal-to-noise ratio.

[0041] The materials of the first electrode layer 110, the second electrode layer 120, the third electrode layer 130 and the fourth electrode layer 140 may be non-magnetic metals such as copper, silver, gold, etc. The material of the first dielectric layer 100 may be a material with a flame retardant grade of FR4, a high temperature resistant thermoplastic resin such as polyphenylene oxide (PPE), or Rogers 4003C material, etc. In one embodiment, the materials of the first electrode layer 110, the second electrode layer 120, the third electrode layer 130 and the fourth electrode layer 140 are the same, which are copper foils.

[0042] In one embodiment, the first dielectric layer 10 has a width of 15 mm, a thickness of 0.51 mm, and a length of 250 mm.

[0043] See also Figure 2 In one embodiment, the fourth control circuit 600 further includes a third depletion-mode MOS transistor 233 and a fourth depletion-mode MOS transistor 234. The source of the third depletion-mode MOS transistor 233 is connected to the source of the first depletion-mode MOS transistor 231. The gate and drain of the third depletion-mode MOS transistor 233 are connected. The gate and drain of the fourth depletion-mode MOS transistor 234 are connected. The gate and drain of the fourth depletion-mode MOS transistor 234 are connected to the gate and drain of the third depletion-mode MOS transistor 233. The source of the fourth depletion-mode MOS transistor 234 is connected to the source of the second depletion-mode MOS transistor 232.

[0044] In this embodiment, in the RF receiving stage, the first depletion-mode MOS tube 231 and the second depletion-mode MOS tube 232 are turned on and are equivalent to a resistor. The third depletion-mode MOS tube 233 and the fourth depletion-mode MOS tube 234 are turned on and are equivalent to a resistor. The first depletion-mode MOS tube 231 and the second depletion-mode MOS tube 232 are connected in reverse series. The third depletion-mode MOS tube 233 and the fourth depletion-mode MOS tube 234 are connected in reverse series and are connected in parallel with the first depletion-mode MOS tube 231 and the second depletion-mode MOS tube 232. At this time, in the RF receiving stage, two resistors are connected in parallel between the second electrode layer 120 and the first electrode layer 110, so that the overall resistance value is reduced, which is more conducive to the magnetic field enhancement component 10 to form a uniform magnetic field, thereby improving the MRI image quality.

[0045] In one embodiment, along the direction from the first end 103 to the second end 104, the second electrode layer 120 and the first electrode layer 110 are symmetrically arranged with respect to the fourth control circuit 600. That is, the second electrode layer 120 and the first electrode layer 110 have the same length.

[0046] In this embodiment, the fourth control circuit 600 is arranged in the middle position of the first dielectric layer 100. The second electrode layer 120 and the first electrode layer 110 can be equivalent to inductors, and the magnetic field strength is relatively large. The second electrode layer 120 and the first electrode layer 110 are distributed on both sides of the fourth control circuit 600, so that the structure of the magnetic field enhancement component 10 is symmetrical. The structure of the magnetic field enhancement component 10 is symmetrical, so that the distribution of the magnetic field enhanced by the magnetic field enhancement component 10 is symmetrical. In the RF receiving stage, the fourth control circuit 600 controls the first electrode layer 110 to be connected to the second electrode layer 120, so that the distribution of the magnetic field enhanced by the magnetic field enhancement component 10 is more uniform, thereby improving the MRI image quality.

[0047] See also Figure 3 and Figure 4 In one embodiment, the first dielectric layer 100 further includes a second surface 102. The second surface 102 is arranged opposite to the first surface 101. The magnetic field enhancement assembly 10 further includes a third electrode layer 130 and a fourth electrode layer 140. The third electrode layer 130 is arranged on the second surface 102. The third electrode layer 130 covers a portion of the second surface 102. The third electrode layer 130 is arranged near the second end 104. The fourth electrode layer 140 is arranged on the second surface 102. The fourth electrode layer 140 covers a portion of the second surface 102. The fourth electrode layer 140 is arranged near the first end 103.

[0048] The orthographic projection of the third electrode layer 130 on the first dielectric layer 100 overlaps with the orthographic projection of the first electrode layer 110 on the first dielectric layer 100 to form a second structural capacitor 302. In the overlapped portion, the first electrode layer 110, the first dielectric layer 100 and the third electrode layer 130 form the second structural capacitor 302. The orthographic projection of the fourth electrode layer 140 on the first dielectric layer 100 overlaps with the orthographic projection of the second electrode layer 120 on the first dielectric layer 100 to form a third structural capacitor 303. In the overlapped portion, the second electrode layer 120, the first dielectric layer 100 and the fourth electrode layer 140 form the third structural capacitor 303.

[0049] The second electrode layer 120 between the third structure capacitor 303 and the fourth control circuit 600 can form a first transmission line. The first electrode layer 110 between the fourth control circuit 600 and the second structure capacitor 302 can form a second transmission line. The third structure capacitor 303, the fourth control circuit 600 and the second structure capacitor 302 are connected in series through the first transmission line and the second transmission line. Therefore, by connecting the third structure capacitor 303, the fourth control circuit 600 and the second structure capacitor 302 in series, the resonant frequency of the resonant circuit formed by the multiple magnetic field enhancement components 10 can be adjusted, shortening the adjustment time of the multiple magnetic field enhancement components 10 after being placed in the nuclear magnetic resonance imaging system.

[0050] The magnetic field enhancement component 10 generates an induced voltage in a magnetic field environment. The transmission line portion formed by the first electrode layer 110 and the second electrode layer 120 forms a parasitic capacitor. The parasitic capacitor is in parallel with the second structure capacitor 302 and the third structure capacitor 303. In the RF receiving stage, the third structure capacitor 303 and the second structure capacitor 302 form a capacitor series structure, which divides the induced voltage into multiple parts, thereby reducing the voltage division of the third structure capacitor 303 and the second structure capacitor 302.

[0051] Furthermore, the third structure capacitor 303 and the second structure capacitor 302 form a capacitor series structure, which can reduce the voltage on the parasitic capacitor. The voltage on the parasitic capacitor is reduced, which reduces the harm of the parasitic capacitor, thereby reducing the load effect. The load effect of the magnetic field enhancement component 10 is reduced, so that the resonant frequency of the resonant circuit formed by the multiple magnetic field enhancement components 10 is not easily affected by the measured object, thereby improving the enhancement performance of the magnetic field enhancement component 10 and enhancing the stability of the resonant frequency.

[0052] In one embodiment, the overlap length is related to the overlap area in the overlapped portion corresponding to the third structure capacitor 303. The third structure capacitor 303 and the second structure capacitor 302 both have a suitable facing area, which means that the structure capacitor formed by the second electrode layer 120 and the fourth electrode layer 140 has a suitable value, so that the resonant circuit formed by the plurality of magnetic field enhancement components 10 has the same operating frequency as the MRI system.

[0053] The resonant frequency of the resonant circuit formed by the plurality of magnetic field enhancement components 10 is determined by the following formula: Wherein, L and C are the equivalent inductance and equivalent capacitance of the resonant circuit formed by the plurality of magnetic field enhancement components 10, respectively. The value of the equivalent capacitance is determined by the structural capacitance Cs of each unit. The relationship between the structural capacitance Cs and the area S facing the two electrode plates is: Among them, ε 0 is the vacuum dielectric constant, ε is the relative dielectric constant of the first dielectric layer 100. d is the distance between the two electrode plates (or the thickness of the first dielectric layer 100). Therefore, the purpose of the appropriate facing area is to make the resonant circuit formed by the multiple magnetic field enhancement components 10 have a target resonant frequency, that is, to have the same operating frequency as the MRI system.

[0054] In one embodiment, in the overlapped portion corresponding to the third structure capacitor 303, the overlapped length of the second electrode layer 120 and the fourth electrode layer 140 is 35 mm. In the overlapped portion corresponding to the second structure capacitor 302, the overlapped length of the first electrode layer 110 and the third electrode layer 130 is 35 mm.

[0055] In one embodiment, the length of the second electrode layer 120 between the third structure capacitor 303 and the fourth control circuit 600 is the same as the length of the first electrode layer 110 between the second structure capacitor 302 and the fourth control circuit 600. That is, in the direction from the first end 103 to the second end 104, the lengths of the first transmission line and the second transmission line are the same.

[0056] In this embodiment, the second electrode layer 120 between the third structure capacitor 303 and the fourth control circuit 600 can form the first transmission line. The first electrode layer 110 between the second structure capacitor 302 and the fourth control circuit 600 can form the second transmission line. The first transmission line and the second transmission line can be equivalent to inductance and resistance. At this time, the effective magnetic field is distributed between the third structure capacitor 303 and the fourth control circuit 600 and between the second structure capacitor 302 and the fourth control circuit 600. That is, the effective magnetic field is distributed between the first transmission line and the second transmission line. The effective magnetic field between the second structure capacitor 302 and the fourth control circuit 600 forms a first detection area. The effective magnetic field between the third structure capacitor 303 and the fourth control circuit 600 forms a second detection area. The first detection area is the same as the second detection area. The area formed by the effective magnetic field is used as the detection area to detect the detection part. In this embodiment, the magnetic field enhancement component 10 forms two identical detection areas on the left and right sides of the fourth control circuit 600, which is more conducive to the magnetic field enhancement component 10 to form a uniform magnetic field and improve the MRI image quality.

[0057] See also Figure 5 In one embodiment, the width of the second electrode layer 120 between the third structure capacitor 303 and the fourth control circuit 600 is smaller than the width of the second electrode layer 120 corresponding to the third structure capacitor 303. The width of the first electrode layer 110 between the second structure capacitor 302 and the fourth control circuit 600 is smaller than the width of the first electrode layer 110 corresponding to the second structure capacitor 302. That is, the width of the first transmission line in the direction perpendicular to the first end 103 to the second end 104 is smaller than the width of the second electrode layer 120 corresponding to the third structure capacitor 303. The width of the second transmission line is smaller than the width of the first electrode layer 110 corresponding to the second structure capacitor 302.

[0058] In this embodiment, the third structure capacitor 303 is connected to the fourth control circuit 600 through the first transmission line. The second structure capacitor 302 is connected to the fourth control circuit 600 through the second transmission line. However, the relative arrangement between the electrode layers corresponding to the transmission lines will form stray capacitance. The width of the second electrode layer 120 between the third structure capacitor 303 and the fourth control circuit 600 becomes smaller, which will reduce the width of the first transmission line, and further reduce the relative area between the electrode layers. The width of the first electrode layer 110 between the second structure capacitor 302 and the fourth control circuit 600 becomes smaller, which will reduce the width of the second transmission line, and further reduce the relative area between the electrode layers.

[0059] By setting the width of the first transmission line and the width of the second transmission line, when the first transmission line and the second transmission line are opposite to other electrode layers, the facing area becomes smaller, thereby reducing the stray capacitance formed. The width of the first transmission line is smaller than the width of the second electrode layer 120 corresponding to the third structure capacitor 303, which not only ensures that the third structure capacitor 303 fully utilizes the area of ​​the second electrode layer 120 to form a structure capacitor, but also reduces the stray capacitance. The width of the second transmission line is smaller than the width of the first electrode layer 110 corresponding to the second structure capacitor 302, which not only ensures that the second structure capacitor 302 fully utilizes the area of ​​the first electrode layer 110 to form a structure capacitor, but also reduces the stray capacitance. Therefore, without affecting the formation of the first structure capacitor 301 and the second structure capacitor 302, and without affecting the connection between the two, the stray capacitance is reduced, which is more conducive to the uniform distribution of the magnetic field and improves the quality of MRI images.

[0060] See also Figure 6 In one embodiment, the first electrode layer 110 corresponding to the second structure capacitor 302 is provided with a first opening 401. The third electrode layer 130 corresponding to the second structure capacitor 302 is provided with a second opening 402. The orthographic projections of the first opening 401 and the second opening 402 on the first dielectric layer 100 coincide. That is, the first opening 401 and the second opening 402 are relatively arranged on two opposite surfaces of the first dielectric layer 100.

[0061] The orthographic projections of the first opening 401 and the second opening 402 on the first dielectric layer 100 overlap, and the overlapping portion forms a comb-tooth shape with one opening, which can further optimize the local magnetic field distribution and improve the detection effect at a specific position of the detection site.

[0062] See also Figure 7In one embodiment, the first electrode layer 110 corresponding to the second structure capacitor 302 is provided with a third opening 403. The third opening 403 is spaced apart from the first opening 401. The third electrode layer 130 corresponding to the second structure capacitor 302 is provided with a fourth opening 404. The fourth opening 404 is spaced apart from the second opening 402. The orthographic projections of the third opening 403 and the fourth opening 404 on the first dielectric layer 100 overlap. The orthographic projections of the first opening 401 and the second opening 402 on the first dielectric layer 100 overlap. Through the first opening 401, the second opening 402, the third opening 403 and the fourth opening 404, the overlapping part of the orthographic projection forms a comb-shaped shape with two openings, which can further optimize the local magnetic field distribution and improve the detection effect of a specific position of the detection part.

[0063] In one embodiment, the structure of the second electrode layer 120 corresponding to the third structure capacitor 303 is the same as the structure of the first electrode layer 110 corresponding to the second structure capacitor 302. The structure of the fourth electrode layer 140 corresponding to the third structure capacitor 303 is the same as the structure of the third electrode layer 130 corresponding to the second structure capacitor 302. The structure of the third structure capacitor 303 is the same as the structure of the second structure capacitor 302, forming a symmetrical structure.

[0064] See also Figure 8 In one embodiment, the magnetic field enhancement component 10 further includes a fifth electrode layer 141 and a fifth control circuit 610. The fifth electrode layer 141 is spaced apart from the first electrode layer 110 and is disposed on the first surface 101. And the fifth electrode layer 141 is disposed between the first electrode layer 110 and the second electrode layer 120. One end of the fourth control circuit 600 is connected to one end of the second electrode layer 120. The other end of the fourth control circuit 600 is connected to one end of the fifth electrode layer 141. One end of the fifth control circuit 610 is connected to the other end of the fifth electrode layer 141. The other end of the fifth control circuit 610 is connected to one end of the first electrode layer 110.

[0065] In this embodiment, the fifth control circuit 610 is the same as the fourth control circuit 600, and includes the first depletion-type MOS transistor 231 and the second depletion-type MOS transistor 232 connected in reverse series. The fifth control circuit 610 and the fourth control circuit 600 jointly control the first electrode layer 110, the fifth electrode layer 141, and the second electrode layer 120 to be disconnected in the RF transmission stage and connected in the RF reception stage.

[0066] See also Fig. 9In one embodiment, the magnetic field enhancement component 10 further includes a fifth electrode layer 141, a sixth control circuit 620, and a sixth electrode layer 121. The fifth electrode layer 141 is spaced apart from the first electrode layer 110 and arranged on the first surface 101. And the fifth electrode layer 141 is arranged between the first electrode layer 110 and the second electrode layer 120. One end of the fourth control circuit 600 is connected to the other end of the fifth electrode layer 141. The other end of the fourth control circuit 600 is connected to one end of the first electrode layer 110. One end of the sixth control circuit 620 is connected to one end of the fourth electrode layer 140. The sixth electrode layer 121 is spaced apart from the third electrode layer 130 and arranged on the second surface 102. And the sixth electrode layer 121 is arranged between the fourth electrode layer 140 and the third electrode layer 130. The other end of the sixth control circuit 620 is connected to one end of the sixth electrode layer 121. The orthographic projection of the sixth electrode layer 121 on the first dielectric layer 100 partially overlaps with the orthographic projection of the fifth electrode layer 141 on the first dielectric layer 100 to form a first structural capacitor 301 .

[0067] In this embodiment, the sixth control circuit 620 is the same as the fourth control circuit 600, including the first depletion-type MOS transistor 231 and the second depletion-type MOS transistor 232 connected in reverse series. The sixth control circuit 620 and the fourth control circuit 600 jointly control the first electrode layer 110, the fifth electrode layer 141, the sixth electrode layer 121 and the fourth electrode layer 140 to be disconnected in the RF transmission stage and connected in the RF reception stage.

[0068] The fourth electrode layer 140 between the third structure capacitor 303 and the sixth control circuit 620 forms a third transmission line. The sixth electrode layer 121 between the sixth control circuit 620 and the first structure capacitor 301 forms a fourth transmission line. The fifth electrode layer 141 between the first structure capacitor 301 and the fourth control circuit 600 forms a fifth transmission line. The first electrode layer 110 between the fourth control circuit 600 and the second structure capacitor 302 forms a sixth transmission line. The third structure capacitor 303, the sixth control circuit 620, the first structure capacitor 301, the fourth control circuit 600 and the second structure capacitor 302 are connected in series through the third transmission line, the fourth transmission line, the fifth transmission line and the sixth transmission line. The magnetic field enhancement component 10 includes a plurality of structure capacitors connected in series.

[0069] In the RF receiving stage, the third structure capacitor 303, the first structure capacitor 301 and the second structure capacitor 302 form a capacitor series structure, which divides the induced voltage into multiple parts, thereby reducing the divided voltage of the third structure capacitor 303, the first structure capacitor 301 and the second structure capacitor 302.

[0070] Further, the third structure capacitor 303, the first structure capacitor 301 and the second structure capacitor 302 form a capacitor series structure, which reduces the voltage on the parasitic capacitor connected in parallel therewith. The voltage on the parasitic capacitor is reduced, which reduces the harm of the parasitic capacitor, thereby reducing the load effect. The load effect of the magnetic field enhancement component 10 is reduced, so that the resonant frequency of the resonant circuit formed by the multiple magnetic field enhancement components 10 is not easily affected by the object under test, thereby improving the enhancement performance of the magnetic field enhancement component 10 and enhancing the stability of the resonant frequency.

[0071] See also Fig.10 and Fig.11 In one embodiment, the present application provides a magnetic field enhancement device 20. The magnetic field enhancement device 20 includes a cylindrical support structure 50, a plurality of magnetic field enhancement components 10, a first annular conductive sheet 510, and a second annular conductive sheet 520. The cylindrical support structure 50 has two spaced-apart third ends 51 and a fourth end 53. The plurality of magnetic field enhancement components 10 are spaced apart from each other on the cylindrical support structure 50. The plurality of magnetic field enhancement components 10 extend along the third end 51 toward the fourth end 53. The first annular conductive sheet 510 is disposed on the cylindrical support structure 50. The first annular conductive sheet 510 is close to the third end 51. The first annular conductive sheet 510 is connected to the second electrode layer 120 of each magnetic field enhancement component 10. The second annular conductive sheet 520 is disposed on the cylindrical support structure 50. The second annular conductive sheet 520 is close to the fourth end 53. The second annular conductive sheet 520 is connected to the first electrode layer 110 of each magnetic field enhancement component 10.

[0072] In one embodiment, the first annular conductive sheet 510 is connected to the second electrode layer 120 of each magnetic field enhancement component 10 . The second annular conductive sheet 520 is connected to the first electrode layer 110 of each magnetic field enhancement component 10 .

[0073] In one embodiment, the first annular conductive sheet 510 and the second annular conductive sheet 520 may be made of metal materials such as gold, silver, and copper.

[0074] In one embodiment, the first annular conductive sheet 510 is connected to the fourth electrode layer 140 of each magnetic field enhancement assembly 10 . The second annular conductive sheet 520 is connected to the third electrode layer 130 of each magnetic field enhancement assembly 10 .

[0075] The cylindrical support structure 50 has an inner surface and an outer surface that are relatively spaced apart. The inner surface of the cylindrical support structure 50 can surround a detection space 509. The detection space 509 can be used to accommodate a detection part. The detection part can be an arm, a leg, an abdomen, etc. The equal distances between the multiple magnetic field enhancement components 10 can improve the uniformity of the local magnetic field.

[0076] A plurality of magnetic field enhancement assemblies 10 may be arranged at equal intervals on the outer surface of the cylindrical support structure 50. The first annular conductive sheet 510 and the second annular conductive sheet 520 are respectively arranged at opposite ends of the cylindrical support structure 50 and are arranged around the axis 504 of the cylindrical support structure 50.

[0077] Both ends of each magnetic field enhancement component 10 are respectively connected to the first annular conductive sheet 510 and the second annular conductive sheet 520. Multiple magnetic field enhancement components 10 are connected through the first annular conductive sheet 510 and the second annular conductive sheet 520. The first annular conductive sheet 510 and the second annular conductive sheet 520 are respectively connected end to end, so that the entire structure of the magnetic field enhancement device 20 is isotropic and the magnetic field uniformity is improved.

[0078] The first annular conductive sheet 510 and the second annular conductive sheet 520 can be respectively disposed around the axis 504 of the cylindrical support structure 50 , that is, the first annular conductive sheet 510 and the second annular conductive sheet 520 are both annular structures.

[0079] In one embodiment, a plurality of limiting structures 530 are arranged at intervals around the outer surface of the cylindrical support structure 50. In the direction from the third end 51 to the fourth end 53, each of the magnetic field enhancement components 10 corresponds to the limiting structure 530 of the third end 51 and the limiting structure 530 of the fourth end 53. One magnetic field enhancement component 10 is fixed by the limiting structures 530 at both ends of the third end 51 and the fourth end 53, and then the magnetic field enhancement component 10 is fixed to the outer surface of the cylindrical support structure 50.

[0080] In one embodiment, the limiting structure 530 may be a through slot. The through slot may be used to insert the magnetic field enhancement component 10. The two through slots respectively limit the two ends of the magnetic field enhancement component 10. The magnetic field enhancement component 10 may be fixed to the outer surface of the cylindrical support structure 50 through the limiting structure 530.

[0081] In one embodiment, the magnetic field enhancement device 20 may include 12 magnetic field enhancement components 10 equidistantly arranged on the outer surface of the cylindrical support structure 50 around the axis 504 .

[0082] See also Fig.12 , Fig.12 The resonant performance of the magnetic field enhancement device 20 in the RF transmission stage and the RF reception stage is shown. Fig.12 It can be seen that the magnetic field enhancement device 20 has a good resonant frequency in the RF receiving stage, can greatly enhance the RF receiving field, and improve the image signal-to-noise ratio. In the RF transmitting stage of the magnetic field enhancement device 20, the magnetic field enhancement component 10 is disconnected by the fourth control circuit 600, so that the resonant circuit formed by the multiple magnetic field enhancement components 10 is disconnected. The magnetic field enhancement device 20 does not have a resonant performance, and there is no current, and will not induce a magnetic field, ensuring that the RF magnetic field strength after adding the magnetic field enhancement device 20 is the same as before adding. Therefore, the first electrode layer 110 and the second electrode layer 120 are controlled by the fourth control circuit 600 to be disconnected in the RF transmitting stage and connected in the RF receiving stage, so that the magnetic field enhancement component 10 can only enhance the RF receiving field, and will not enhance the RF transmitting field, thereby improving the image signal-to-noise ratio.

[0083] In the description of this specification, the description with reference to the terms "some embodiments", "other embodiments", "ideal embodiments", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example.

[0084] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0085] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A magnetic field enhancement component, characterized in that: The magnetic field enhancement component comprises: A first dielectric layer (100) having a first surface (101), wherein the first dielectric layer (100) has a first end (103) and a second end (104) arranged opposite to each other; A first electrode layer (110) is disposed on the first surface (101) and is disposed close to the second end (104); A second electrode layer (120) is disposed on the first surface (101), is spaced apart from the first electrode layer (110), and is disposed close to the first end (103); a fourth control circuit (600), one end of the fourth control circuit (600) being connected to an end of the second electrode layer (120) away from the first end (103), and the other end of the fourth control circuit (600) being connected to an end of the first electrode layer (110) away from the second end (104); The fourth control circuit (600) is used to control the first electrode layer (110) and the second electrode layer (120) to be disconnected in a radio frequency transmission phase and connected in a radio frequency reception phase; The fourth control circuit (600) comprises: a first depletion-type MOS transistor (231), the source of the first depletion-type MOS transistor (231) being connected to the second electrode layer (120), and the gate and drain of the first depletion-type MOS transistor (231) being connected; a second depletion-type MOS transistor (232), the gate and drain of the second depletion-type MOS transistor (232) being connected and connected to the gate and drain of the first depletion-type MOS transistor (231), and the source of the second depletion-type MOS transistor (232) being connected to the first electrode layer (110); Wherein, along the direction from the first end (103) to the second end (104), the second electrode layer (120) and the first electrode layer (110) are symmetrically arranged with respect to the fourth control circuit (600).

2. The magnetic field enhancement assembly according to claim 1, characterized in that: The fourth control circuit (600) further includes: A third depletion-type MOS transistor (233), wherein the source of the third depletion-type MOS transistor (233) is connected to the source of the first depletion-type MOS transistor (231), and the gate and drain of the third depletion-type MOS transistor (233) are connected; A fourth depletion-type MOS transistor (234), wherein the gate and drain of the fourth depletion-type MOS transistor (234) are connected and connected to the gate and drain of the third depletion-type MOS transistor (233), and the source of the fourth depletion-type MOS transistor (234) is connected to the source of the second depletion-type MOS transistor (232).

3. The magnetic field enhancement assembly according to claim 1, characterized in that: The first dielectric layer (100) has a second surface (102) arranged opposite to the first surface (101), and the magnetic field enhancement component further comprises: A third electrode layer (130) is disposed on the second surface (102), covers a portion of the second surface (102), and is disposed close to the second end (104); The orthographic projection of the third electrode layer (130) on the first dielectric layer (100) partially overlaps with the orthographic projection of the first electrode layer (110) on the first dielectric layer (100), forming a second structural capacitor (302); A fourth electrode layer (140) is disposed on the second surface (102), covers a portion of the second surface (102), and is disposed close to the first end (103); The orthographic projection of the fourth electrode layer (140) on the first dielectric layer (100) partially overlaps with the orthographic projection of the second electrode layer (120) on the first dielectric layer (100), forming a third structural capacitor (303).

4. The magnetic field enhancement assembly according to claim 3, characterized in that: In the direction from the first end (103) to the second end (104), the length of the second electrode layer (120) between the third structure capacitor (303) and the fourth control circuit (600) is the same as the length of the first electrode layer (110) between the second structure capacitor (302) and the fourth control circuit (600).

5. The magnetic field enhancement assembly according to claim 3, characterized in that: The width of the second electrode layer (120) between the third structure capacitor (303) and the fourth control circuit (600) is smaller than the width of the second electrode layer (120) corresponding to the third structure capacitor (303); The width of the first electrode layer (110) between the second structure capacitor (302) and the fourth control circuit (600) is smaller than the width of the first electrode layer (110) corresponding to the second structure capacitor (302).

6. The magnetic field enhancement assembly according to claim 3, characterized in that: The first electrode layer (110) corresponding to the second structure capacitor (302) is provided with a first opening (401), and the third electrode layer (130) corresponding to the second structure capacitor (302) is provided with a second opening (402), and the orthographic projections of the first opening (401) and the second opening (402) on the first dielectric layer (100) overlap.

7. The magnetic field enhancement assembly according to claim 6, characterized in that: The first electrode layer (110) corresponding to the second structure capacitor (302) is provided with a third opening (403), and the third opening (403) is spaced apart from the first opening (401); The third electrode layer (130) corresponding to the second structure capacitor (302) is provided with a fourth opening (404), and the fourth opening (404) is spaced apart from the second opening (402); The orthographic projections of the third opening (403) and the fourth opening (404) on the first dielectric layer (100) overlap.

8. The magnetic field enhancement assembly according to claim 3, characterized in that: The first electrode layer (110), the second electrode layer (120), the third electrode layer (130) and the fourth electrode layer (140) are made of the same material, which is copper foil.

9. The magnetic field enhancement assembly according to claim 1, characterized in that: The first dielectric layer (100) has a width of 15 mm, a thickness of 0.51 mm and a length of 250 mm.

10. A magnetic field enhancement device, characterized in that: include: A cylindrical support structure (50) having two spaced-apart opposite third ends (51) and fourth ends (53); A plurality of magnetic field enhancement components (10), each of the magnetic field enhancement components (10) comprising: A first dielectric layer (100) having a first surface (101), wherein the first dielectric layer (100) has a first end (103) and a second end (104) arranged opposite to each other; A first electrode layer (110) is disposed on the first surface (101) and is disposed close to the second end (104); A second electrode layer (120) is disposed on the first surface (101), spaced apart from the first electrode layer (110), and disposed close to the first end (103); a fourth control circuit (600), one end of the fourth control circuit (600) being connected to an end of the second electrode layer (120) away from the first end (103), and the other end of the fourth control circuit (600) being connected to an end of the first electrode layer (110) away from the second end (104); The fourth control circuit (600) is used to control the first electrode layer (110) and the second electrode layer (120) to be disconnected in a radio frequency transmission phase and connected in a radio frequency reception phase; The plurality of magnetic field enhancement assemblies (10) are arranged at intervals on the cylindrical support structure (50) and extend along the third end (51) to the fourth end (53); a first annular conductive sheet (510) disposed on the cylindrical support structure (50) and close to the third end (51), the first annular conductive sheet (510) being connected to the second electrode layer (120) of each of the magnetic field enhancement components (10); and a second annular conductive sheet (520) disposed on the cylindrical support structure (50) and close to the fourth end (53), the second annular conductive sheet (520) being connected to the first electrode layer (110) of each of the magnetic field enhancement components (10); The fourth control circuit (600) comprises: a first depletion-type MOS transistor (231), the source of the first depletion-type MOS transistor (231) being connected to the second electrode layer (120), and the gate and drain of the first depletion-type MOS transistor (231) being connected; a second depletion-type MOS transistor (232), the gate and drain of the second depletion-type MOS transistor (232) being connected and connected to the gate and drain of the first depletion-type MOS transistor (231), and the source of the second depletion-type MOS transistor (232) being connected to the first electrode layer (110); Wherein, along the direction from the first end (103) to the second end (104), the second electrode layer (120) and the first electrode layer (110) are symmetrically arranged with respect to the fourth control circuit (600).

Images