CN114910840B

CN114910840B - Magnetic field enhancement assembly and magnetic field enhancement device

Info

Publication number: CN114910840B
Application number: CN202110183918.4A
Authority: CN
Inventors: 赵乾; 池中海; 孟永钢; 郑卓肇
Original assignee: Tsinghua University; Beijing Tsinghua Changgeng Hospital
Current assignee: Tsinghua University; Beijing Tsinghua Changgeng Hospital
Priority date: 2021-02-10
Filing date: 2021-02-10
Publication date: 2024-04-23
Anticipated expiration: 2041-02-10
Also published as: CN114910840A

Abstract

The application relates to a magnetic field enhancement assembly and a magnetic field enhancement device. The magnetic field enhancement assembly includes a first dielectric layer, a first electrode layer, a second electrode layer, a third electrode layer, and an output matching circuit. The first electrode layer is arranged on the first surface of the first electrode layer. The second electrode layer and the third electrode layer are oppositely arranged on the second surface of the first electrode layer at intervals. The second electrode layer partially overlaps the first electrode layer. The third electrode layer partially overlaps the first electrode layer. The output matching circuit is connected between the first electrode layer and the second electrode layer. The output matching circuit is also used for being connected with the signal acquisition device. The output matching circuit is used for adjusting the impedance value and resonance frequency of two ends of the signal acquisition device so as to directly take out the detection signal, reduce coupling artifacts and noise caused by matching with other coils, and have higher detection signal quality and higher image quality.

Description

Magnetic field enhancement assembly and magnetic field enhancement device

Technical Field

The application relates to the technical field of detection, in particular to a magnetic field enhancement assembly and a magnetic field enhancement device.

Background

The radio frequency coil of the traditional MRI collects human body feedback signals in a coil resonance mode. The strength of the human body feedback signal influences the quality of the signal acquired by the radio frequency coil. So that the strength of the human feedback signal can affect the signal-to-noise ratio and resolution of the MRI image. The signal-to-noise ratio and resolution of MRI images affect the diagnosis of late lesions.

The conventional magnetic field enhancement device cannot directly take out the detection signal and can only be used as a signal field enhancement device. The conventional magnetic field enhancement device needs to be matched with the signal receiving coil to take out the detection signal. Coupling effect can be generated between the magnetic field enhancement device and the signal receiving coil, so that artifacts are formed, and the quality of a detected image is reduced.

Disclosure of Invention

In view of this, it is necessary to provide a magnetic field enhancing assembly and a magnetic field enhancing device for the problem of how to improve the quality of a detected image.

A magnetic field enhancement assembly includes a first dielectric layer, a first electrode layer, a second electrode layer, a third electrode layer, and an output matching circuit. The first dielectric layer has opposite first and second ends. The first dielectric layer also includes opposing first and second surfaces.

The first electrode layer is arranged on the first surface. The first electrode layer extends from the first end to the second end.

The second electrode layer and the third electrode layer are oppositely arranged on the second surface at intervals. The second electrode layer is disposed proximate the first end and the third electrode layer is disposed proximate the second end. The orthographic projection of the second electrode layer on the first dielectric layer is overlapped with the orthographic projection part of the partial electrode, close to the first end, of the first electrode layer on the first dielectric layer. The second electrode layer, the first dielectric layer and a portion of the first electrode layer near the first end form a second structural capacitance. The orthographic projection of the third electrode layer on the first dielectric layer is overlapped with the orthographic projection part of the partial electrode, close to the second end, of the first electrode layer on the first dielectric layer. And the third electrode layer, the first dielectric layer and a part of the electrode, close to the second end, of the first electrode layer form a third structure capacitor.

One end of the output matching circuit is connected with a part of the electrode, close to the first end, of the first electrode layer. The other end of the output matching circuit is connected with the second electrode layer. The output matching circuit is also used for being connected with the signal acquisition device. The output matching circuit is used for adjusting the impedance value and resonance frequency of the two ends of the signal acquisition device.

The magnetic field enhancement component provided by the embodiment of the application forms a second structure capacitor through the partial electrode, which is close to the first end, of the first electrode layer, the first dielectric layer and the second electrode layer. And a part of the electrode, which is close to the second end, of the first electrode layer, the first dielectric layer and the third electrode layer form a third structure capacitor. The second structure capacitor is connected with the third structure capacitor to form an LC oscillating circuit. The output matching circuit and the signal acquisition device form a circuit for detecting the signal output side. The output matching circuit can adjust the impedance values of the two ends of the signal acquisition device so as to enable the output impedance of the output matching circuit to be matched with the output impedance of the output side cable. The magnetic field enhancement component can adjust the resonant frequency of the output side circuit through the output matching circuit so as to enable the resonant frequency of the output side circuit to be equal to the target frequency and improve the intensity of an output detection signal. Therefore, the magnetic field enhancement component can be matched with output impedance and increase signal intensity through the output matching circuit, the output matching circuit can directly take out detection signals, coupling artifacts and noise caused by matching with other coils are reduced, the quality of the detection signals is higher, and the image quality is higher. Further, the magnetic field enhancement assembly is proximate to the detection site and is relatively close to the detection site. The transmission distance of the feedback signal is closer, the detection sensitivity is higher, and the detected signal obtains a clearer image.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments or the conventional techniques of the present application, the drawings required for the descriptions of the embodiments or the conventional techniques will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to the drawings without inventive effort for those skilled in the art.

FIG. 1 is a circuit diagram of a magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 2 is a top view of a magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 3 is a bottom view of a magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 4 is a circuit diagram of the magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 5 is a circuit diagram of the magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 6 is a circuit diagram of the magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 7 is a circuit diagram of the magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 8 is a circuit diagram of the magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 9 is a schematic diagram of the magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 10 is a schematic diagram of the magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 11 is a schematic diagram of the magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 12 is a circuit diagram of the magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 13 is a circuit diagram of the magnetic field enhancement assembly provided in one embodiment of the present application;

FIG. 14 is a circuit diagram of the magnetic field enhancement device provided in one embodiment of the present application;

FIG. 15 is a schematic diagram of an exploded structure of the magnetic field enhancing device of FIG. 12;

FIG. 16 is a schematic end view of the magnetic field enhancement device provided in another embodiment of the present application;

Fig. 17 is an S parameter of the magnetic field enhancing device of fig. 16.

Reference numerals:

A magnetic field enhancing assembly 10; a first dielectric layer 100; a first surface 101; a second surface 102; a first end 103; a second end 104; a third end 51; a fourth end 53; a first electrode layer 110; a second electrode layer 120; a third electrode layer 130; a fourth electrode layer 140; a third inductance 243; a second structural capacitance 302; a third structure capacitance 303;

An output matching circuit 640; a matching capacitor 641; tuning capacitor 642; an output interface 643; a second switching circuit 650; a first switching element 651; a first depletion MOS transistor 652; a second depletion MOS transistor 653;

A first resonant circuit 60; a switch control circuit 430; a first diode 431; a second diode 432; an external capacitor 440; a third external capacitor 443; a fifth external capacitor 445;

A second resonant circuit 70; a third depletion MOS tube 231; a fourth depletion MOS transistor 232; a third capacitor 223; a first inductor 241; a first switch circuit 631; a third diode 213; a fourth diode 214;

A cylindrical support structure 50; a first annular conductive sheet 510; a second annular conductive sheet 530.

Detailed Description

In order that the above objects, features and advantages of the application will be readily understood, a more particular description of the application will be rendered by reference to the appended drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. The application may be embodied in many other forms than described herein and similarly modified by those skilled in the art without departing from the spirit or scope of the application, which is therefore not limited to the specific embodiments disclosed below.

The numbering of the components itself, e.g. "first", "second", etc., is used herein only to divide the objects described, and does not have any sequential or technical meaning. The term "coupled" as used herein includes both direct and indirect coupling (coupling), unless otherwise indicated. In the description of the present application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present application and simplifying the description, and do not indicate or imply that the device or element in question must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present application.

In the present application, unless expressly stated or limited otherwise, a first feature "up" or "down" a second feature may be the first and second features in direct contact, or the first and second features in indirect contact via an intervening medium. Moreover, a first feature being "above," "over" and "on" a second feature may be a first feature being directly above or obliquely above the second feature, or simply indicating that the first feature is level higher than the second feature. The first feature being "under", "below" and "beneath" the second feature may be the first feature being directly under or obliquely below the second feature, or simply indicating that the first feature is less level than the second feature.

Referring to fig. 1,2 and 3, a magnetic field enhancement assembly 10 is provided according to an embodiment of the present application, and includes a first dielectric layer 100, a first electrode layer 110, a second electrode layer 120, a third electrode layer 130 and an output matching circuit 640. The first dielectric layer 100 has opposite first and second ends 103, 104. The first dielectric layer 100 further includes opposing first and second surfaces 101, 102.

The first electrode layer 110 is disposed on the first surface 101. The first electrode layer 110 extends from the first end 103 to the second end 104.

The second electrode layer 120 and the third electrode layer 130 are disposed on the second surface 102 at opposite intervals. The second electrode layer 120 is disposed proximate the first end 103 and the third electrode layer 130 is disposed proximate the second end 104. The orthographic projection of the second electrode layer 120 on the first dielectric layer 100 overlaps with the orthographic projection of the portion of the electrode of the first electrode layer 110 near the first end 103 on the first dielectric layer 100. The second electrode layer 120, the first dielectric layer 100 and a portion of the first electrode layer 110 near the first end 103 form a second structural capacitance 302. The orthographic projection of the third electrode layer 130 on the first dielectric layer 100 overlaps with the orthographic projection of the portion of the electrode of the first electrode layer 110 near the second end 104 on the first dielectric layer 100. The third electrode layer 130, the first dielectric layer 100 and a portion of the first electrode layer 110 near the second end 104 form a third structural capacitance 303.

One end of the output matching circuit 640 is connected to a portion of the electrode of the first electrode layer 110 near the first end 103. The other end of the output matching circuit 640 is connected to the second electrode layer 120. The output matching circuit 640 is also used for connecting with a signal acquisition device. The output matching circuit 640 is used for adjusting the impedance value and resonance frequency of the two ends of the signal acquisition device.

The first dielectric layer 100 may function to support the first electrode layer 110, the second electrode layer 120, and the third electrode layer 130. The first dielectric layer 100 may be an insulating material. The first dielectric layer 100 may have a rectangular plate-like structure. The first dielectric layer 100 may be an insulating material. In one embodiment, the material of the first dielectric layer 100 may be a glass fiber epoxy plate. The first electrode layer 110, the second electrode layer 120, and the third electrode layer 130 may be composed of a conductive non-magnetic material. In one embodiment, the materials of the first electrode layer 110, the second electrode layer 120, and the third electrode layer 130 may be metal materials such as gold, silver, copper, and the like. The first electrode layer 110, the second electrode layer 120 and the third electrode layer 130 formed by the above materials have good conductivity and are convenient to process and manufacture, and in addition, the above materials are non-magnetic materials, so that the method is suitable for a nuclear magnetic resonance imaging system.

The output matching circuit 640 is connected to an output side cable to output signals in the loop in which the magnetic field enhancement assembly 10 is located.

In one embodiment, the length of the first dielectric layer 100 ranges from 200 millimeters to 300 millimeters. In one embodiment, the first dielectric layer 100 has a length of 250 millimeters. The first dielectric layer 100 has a width of 10mm to 30 mm. In one embodiment, the width of the first dielectric layer 100 is 15 millimeters. In one embodiment, the first dielectric layer 100 has a thickness of 0.2 mm to 2 mm. In one embodiment, the thickness of the first dielectric layer 100 is 0.51 millimeters.

The first electrode layer 110 extends from the first end 103 to the second end 104, and the length of the first electrode layer 110 is the same as the length of the first dielectric layer 100. The width of the first electrode layer 110 is the same as the width of the first dielectric layer 100.

The magnetic field enhancement assembly 10 according to the embodiment of the present application forms the second structural capacitor 302 by the partial electrode of the first electrode layer 110 near the first end 103, the first dielectric layer 100 and the second electrode layer 120. The portion of the first electrode layer 110 adjacent to the second end 104, the first dielectric layer 100 and the third electrode layer 130 form a third structural capacitance 303. The second structure capacitor 302 is connected to the third structure capacitor 303 to form an LC oscillating circuit. The output matching circuit 640 and the signal acquisition device constitute a circuit for detecting the output side of the signal. The output matching circuit 640 may adjust the impedance values of the two ends of the signal acquisition device, so that the output impedance of the output matching circuit 640 matches the output impedance of the cable to reduce reflection. Typical coaxial lines have an output impedance of 50 ohms or 75 ohms. The loop in which the magnetic field enhancement component 10 is located can adjust the resonant frequency of the output side circuit through the output matching circuit 640, so that the resonant frequency of the output side circuit is equal to the target frequency, and the intensity of the output detection signal is improved. Therefore, the magnetic field enhancement component 10 can match the output impedance and increase the signal strength through the output matching circuit 640, the output matching circuit 640 can directly take out the detection signal, reduce the coupling artifacts and noise caused by matching with other coils, and the quality of the detection signal is higher and the image quality is higher. Further, the loop in which the magnetic field enhancement assembly 10 is located is proximate to the detection site and is relatively close to the detection site. The transmission distance of the feedback signal is closer, the detection sensitivity is higher, and the detected signal obtains a clearer image.

The detection device in which the magnetic field enhancement assembly 10 is located is an MRI receive coil based on a super-structured surface. The super-structured surface based MRI receive coil may match output impedance and increase signal strength through the output matching circuit 640. The MRI receiving coil based on the super-structured surface can directly take out detection signals, and reduces coupling artifacts and noise caused by matching with other coils. The detection signal quality of the loop where the MRI receiving coil based on the super-constructed surface is located is higher, and the image quality is higher.

In one embodiment, the output matching circuit 640 includes a matching capacitor 641 and a tuning capacitor 642. One end of the matching capacitor 641 is connected to a portion of the electrode of the first electrode layer 110 near the first end 103. The tuning capacitor 642 is connected between the other end of the matching capacitor 641 and the second electrode layer 120. The two ends of the tuning capacitor 642 are connected to the signal acquisition device. The tuning capacitor 642 is connected in parallel with the signal acquisition device, and the tuning capacitor 642 is mainly used for adjusting the resonant frequency of the signal output end circuit so that the resonant frequency of the output side where the signal acquisition device is located is equal to the target resonant frequency. During the radio frequency receiving stage, the output matching circuit 640 at the output side and the signal acquisition device resonate, the strength of the detection signal is enhanced, and the detection signal is conveniently output.

The matching capacitor 641 is connected in series with the tuning capacitor 642 and in series with the signal acquisition device. The matching capacitor 641 can adjust the impedance of the output matching circuit 640 at the output side by adjusting its capacitance impedance so that the output impedance of the output matching circuit 640 matches the output impedance of the cable to reduce reflection. Typical coaxial lines have an output impedance of 50 ohms or 75 ohms. The matching capacitor 641 and the tuning capacitor 642 may be tunable capacitors.

In one embodiment, the output matching circuit 640 further includes an output interface 643. The output interface 643 is connected in parallel with the tuning capacitor 642. The output interface 643 is used for connecting with a signal acquisition device. The output interface 643 may be a terminal or a socket, etc.

The output matching circuit 640 is connected to an output side cable through the output interface 643 to output signals in the loop in which the magnetic field enhancement assembly 10 is located.

In one embodiment, the output matching circuit 640 further includes an amplifying circuit. The amplifying circuit is connected to the output interface 643, and is configured to amplify the detection signal output by the output interface 643.

Referring also to fig. 4, in one embodiment, the magnetic field enhancement assembly 10 further includes a second switching circuit 650. The second switch circuit 650 is connected between the output matching circuit 640 and a portion of the first electrode layer 110 near the first end 103, and the second switch circuit 650 is configured to be turned on during a radio frequency receiving stage. The matching capacitor 641 is electrically connected to a portion of the first electrode layer 110 adjacent to the first end 103. The output matching circuit 640 resonates and a detection signal can be output to the signal acquisition device.

In one embodiment, the second switching circuit 650 includes a first switching element 651. The first switching element 651 is connected between the output matching circuit 640 and a portion of the first electrode layer 110 near the first end 103. The first switching element 651 is configured to be turned on during the rf reception phase. The first switching element 651 is also turned off during the radio frequency transmission phase.

The first switching element 651 may be controlled by a control circuit. In one embodiment, the first switching element 651 includes an implement terminal and a control terminal. The execution end is connected between the output matching circuit 640 and a portion of the first electrode layer 110 near the first end 103. The two connection points of the executing terminal are respectively connected with the matching capacitor 641 and a part of the electrode of the first electrode layer 110 near the first end 103. The execution terminal is connected in series with the matching capacitor 641. The control end is connected with an external control device. The control end is used for receiving a closing command and an opening command. In the radio frequency receiving stage, the control device outputs a closing command to the control end. When the control terminal receives a close command, the execution terminal is closed, and the matching capacitor 641 and a part of the first electrode layer 110 close to the first terminal 103 are conducted. The output matching circuit 640 resonates and a detection signal can be output to the signal acquisition device.

And in the radio frequency transmitting stage, the control device outputs a disconnection command to the control end. And when the control end receives a disconnection command, the execution end is disconnected. The matching capacitor 641 is disconnected from a portion of the first electrode layer 110 near the first end 103. The output matching circuit 640 does not pass current, and the detection signal cannot be output to the signal acquisition device.

The signal acquisition device has the function of actively acquiring detection signals. The output of the detection signal can be controlled by controlling the signal acquisition time and frequency of the signal acquisition device. The second switching circuit 650 may cooperate with the signal acquisition device. During the rf transmission phase, the second switch circuit 650 is turned off, no current flows through the output matching circuit 640, no additional magnetic field is formed, and the influence of the magnetic field of the output matching circuit 640 on the rf signal during the transmission phase is reduced.

In one embodiment, the first switching element 651 comprises a first depletion MOS transistor 652 and a second depletion MOS transistor 653 in anti-series connection. The first depletion MOS transistor 652 and the second depletion MOS transistor 653 are connected in series between the output matching circuit 640 and a portion of the first electrode layer 110 near the first end 103. The gate and drain of the first depletion MOS transistor 652 are connected to an end of the matching capacitor 641 remote from the tuning capacitor 642. The source of the first depletion MOS transistor 652 is connected to the source of the second depletion MOS transistor 653. The gate and drain of the second depletion MOS transistor 653 are connected to a portion of the electrode of the first electrode layer 110 near the first end 103.

The first depletion MOS transistor 652 and the second depletion MOS transistor 653 are configured to be alternately turned on when in a radio frequency receiving phase. The first depletion MOS transistor 652 and the second depletion MOS transistor 653 are also configured to be turned off during the RF transmit phase.

The loop in which the magnetic field enhancement assembly 10 is located is applied to an MRI system to enhance the magnetic field strength of a human feedback signal during the radio frequency reception phase. The magnetic field during the radio frequency transmission phase of the MRI system is mainly the radio frequency magnetic field transmitted by the radio frequency device. The magnetic field in the receiving stage is mainly the magnetic field generated by the human body feedback signal. The magnetic field energy in the transmitting phase is more than 1000 times of the magnetic field energy in the receiving phase. The induced voltage of the loop in which the magnetic field enhancing assembly 10 is located during the transmit phase is between tens of volts and hundreds of volts. The induction voltage of the loop in which the magnetic field enhancement assembly 10 is located in the receiving phase is less than 1V.

In the rf receiving stage, the first depletion MOS transistor 652 and the second depletion MOS transistor 653 are connected in reverse series, so that the first depletion MOS transistor 652 and the second depletion MOS transistor 653 can be ensured to be alternately turned on, and the current in the output matching circuit 640 continuously flows.

In the rf receiving stage, the voltages at the two ends of the first depletion MOS transistor 652 and the second depletion MOS transistor 653 are smaller than the pinch-off voltage, and the source and drain of the first depletion MOS transistor 652 or the second depletion MOS transistor 653 are turned on. The matching capacitor 641 is electrically connected to a portion of the first electrode layer 110 adjacent to the first end 103. The output matching circuit 640 resonates and a detection signal can be output to the signal acquisition device.

In one embodiment, the first depletion MOS transistor 652 and the second depletion MOS transistor 653 are the same model. The pinch-off voltages of the first depletion MOS transistor 652 and the second depletion MOS transistor 653 are the same, so that the detection signal can be continuously output to the signal acquisition device in the radio frequency receiving stage.

Referring also to fig. 5, in one embodiment, the magnetic field enhancement assembly 10 further includes a first resonant circuit 60. One end of the first resonant circuit 60 is connected to a portion of the first electrode layer 110 near the first end 103. The other end of the first resonant circuit 60 is connected to the second electrode layer 120. The first resonant circuit 60 is configured to resonate the loop in which the magnetic field enhancement assembly 10 is located during the rf receiving phase, so as to increase the magnetic field strength of the feedback signal of the human body. The first resonant circuit 60 is configured to detune the circuit in which the magnetic field enhancement assembly 10 is located when the circuit is in a radio frequency transmission phase, so that the circuit in which the magnetic field enhancement assembly 10 is located does not have a function of enhancing a magnetic field.

In one embodiment, the first resonant circuit 60 includes a switch control circuit 430. Both ends of the switch control circuit 430 are respectively connected to a portion of the electrode of the first electrode layer 110 near the first end 103 and the second electrode layer 120. The switch control circuit 430 is configured to be turned on during a radio frequency transmission phase and turned off during a radio frequency reception phase.

The switch control circuit 430 is connected in parallel with the second structural capacitance 302. Therefore, when the switch control circuit 430 is turned on, a portion of the first electrode layer 110 near the first end 103 is electrically connected to the second electrode layer 120. When the switch control circuit 430 is turned off, a portion of the first electrode layer 110 near the first end 103 is disconnected from the second electrode layer 120. The turn-on voltage of the switch control circuit 430 may be greater than 1 volt. That is, the switch control circuit 430 is turned on when the voltage difference between the partial electrode of the first electrode layer 110 near the first end 103 and the two ends of the second electrode layer is greater than 1 volt. The switch control circuit 430 is turned off when the voltage difference between the portion of the first electrode layer 110 near the first end 103 and the second electrode layer 120 is less than 1 volt.

During the rf transmission phase, the switch control circuit 430 is turned on due to the large voltage difference across the structure capacitance. A portion of the first electrode layer 110 adjacent to the first end 103 is electrically connected to the second electrode layer 120. At this time, the second structural capacitor 302 cannot be formed by the second electrode layer 120 and the partial electrode of the first electrode layer 110 near the first end 103. I.e. the loop in which the magnetic field enhancing assembly 10 is located does not have resonance properties. The loop in which the magnetic field enhancement assembly 10 is located cannot enhance the rf transmit field.

In the rf receiving stage, the voltage difference between the partial electrode of the first electrode layer 110 near the first end 103 and the second electrode layer 120 is smaller, the switch control circuit 430 is turned off, and the partial electrode of the first electrode layer 110 near the first end 103 is disconnected from the second electrode layer. At this time, the second structural capacitor 302 is formed by the second electrode layer 120 and a portion of the first electrode layer 110 near the first end 103. The loop in which the magnetic field enhancing assembly 10 is located has a good resonant frequency during the radio frequency reception phase. The loop in which the magnetic field enhancement assembly 10 is located has a nonlinear response characteristic. The loop in which the magnetic field enhancement assembly 10 is located can enhance the rf magnetic field formed by the feedback signal from the detection site.

Referring to fig. 6, in one embodiment, the first resonant circuit 60 further includes an external capacitor 440. Both ends of the external capacitor 440 are respectively connected to the partial electrode of the first electrode layer 110 near the first end 103 and the second electrode layer 120. The external capacitor 440 may be a tunable capacitor connected in parallel with a portion of the first electrode layer 110 near the first end 103 and the second electrode layer 120. The resonance performance of the loop in which the magnetic field enhancing component 10 is located can be adjusted by the structural capacitive cooperation of the external capacitor 440 and the partial electrode of the first electrode layer 110 near the first end 103, the second electrode layer and the first dielectric layer 100. In the radio frequency receiving stage, the external capacitor 440 is connected in parallel with the third structural capacitor 303, and the external capacitor 440 is disposed at the first end 103, and the third structural capacitor 303 is disposed at the second end 104, so that the magnetic field of the loop where the magnetic field enhancing component 10 is located in the extending direction can be balanced, the magnetic field is more uniform, the enhancement degree of the radio frequency magnetic field of the feedback signal is more uniform, and the quality of the detection signal is improved.

The external capacitor 440 may be a fixed capacitor or an adjustable capacitor. When the use condition of the magnetic field enhancing assembly 10 is determined, for example, the frequency of the radio frequency coil is determined, a suitable fixed capacitance may be selected, so that the fixed capacitance is matched with the structural capacitance formed by the first sub-electrode layer 110, the second electrode layer 120 and the first dielectric layer 100, so that the resonant frequency of the loop where the magnetic field enhancing device 10 is located is equal to the frequency of the radio frequency coil, and further the magnetic field enhancing effect is achieved. When the environment of the loop in which the magnetic field enhancement device 10 is located is not determined, for example, the frequency of the radio frequency coil is not determined, an adjustable capacitance may be used in the magnetic field enhancement device 10. The resonant frequency of the loop in which the first resonant circuit 60 is located can be adjusted by adjusting the adjustable capacitance so that the loop in which the magnetic field enhancing device 10 is located is adapted to different environments.

In one embodiment, the switch control circuit 430 includes a first diode 431 and a second diode 432. The anode of the first diode 431 is connected to a portion of the first electrode layer 110 near the first end 103. The cathode of the first diode 431 is connected to the second electrode layer. The anode of the second diode 432 is connected to a portion of the first electrode layer 110 near the first end 103, and the cathode of the second diode 432 is connected to the second electrode layer.

It is understood that the turn-on voltage of the first diode 431 and the second diode 432 may be between 0 volt and 1 volt. In one embodiment, the turn-on voltage of the first diode 431 and the second diode 432 may be 0.8V. The first diode 431 and the second diode 432 are respectively connected in series between the partial electrode of the first electrode layer 110 near the first end 103 and the second electrode layer, and the first diode 431 and the second diode 432 are reversely connected.

Due to the alternating nature of radio frequency. The induced voltage generated by the portion of the first electrode layer 110 near the first end 103 and the second electrode layer 120 is also an ac voltage. In the radio frequency emission phase, the turn-on voltage of the first diode 431 and the second diode 432 is already exceeded due to the voltage difference between the second electrode layer 120 and the part of the first electrode layer 110 close to the first end 103. Therefore, one of the first diode 431 and the second diode 432 is always in a conductive state, and a portion of the first electrode layer 110 near the first end 103 is electrically connected to the second electrode layer 120, so as not to form a capacitor structure. At this time, current flows through the first diode 431 or the second diode 432, and the external capacitor 440 is shorted. A portion of the first electrode layer 110 adjacent to the first end 103 is connected in series with the second electrode layer 120.

In the rf receiving stage, the voltage difference between the portion of the first electrode layer 110 near the first end 103 and the second electrode layer 120 is smaller than the turn-on voltage of the first diode 431 and the second diode 432. Therefore, the first diode 431 and the second diode 432 are both in a non-conductive state, and a portion of the first electrode layer 110 near the first end 103, the external capacitor 440 and the second electrode layer 120 are connected in series.

The change of the magnetic field intensity in the rf transmitting phase and the rf receiving phase changes the conducting state of the first diode 431 and the second diode 432, and thus changes the connection relationship between the elements of the magnetic field enhancing assembly 10, and changes the resonance performance of the LC oscillating circuit.

In one embodiment, the external capacitor 440 is an adjustable capacitor. In the rf receiving stage, the new energy of the circuit oscillation of the magnetic field enhancement assembly 10 can be changed by adjusting the capacitance value of the external capacitor 440, so as to change the resonant frequency of the loop formed by a plurality of magnetic field enhancement assemblies 10. Therefore, by adjusting the capacitance value of the external capacitor 440, the loop in which the magnetic field enhancing assembly 10 is located can be adapted to magnetic resonance systems with different operating frequencies.

Referring to fig. 7, in one embodiment, the first resonant circuit 60 further includes a third external capacitor 443. The external capacitor 440 and the third external capacitor 443 are connected in series between the second electrode layer 120 and a portion of the first electrode layer 110 near the first end 103, and the switch control circuit 430 is connected in parallel to two ends of the external capacitor 440. The switch control circuit 430 is configured to be turned on during a radio frequency transmission phase and turned off during a radio frequency reception phase.

The external capacitor 440 and the third external capacitor 443 may be adjustable capacitors, and in the rf emission stage, the switch control circuit 430 is turned on due to a larger voltage difference between a portion of the first electrode layer 110 near the first end 103 and the second electrode layer 120. Only the third external capacitor 443 is connected between the second electrode layer 120 and a portion of the first electrode layer 110 near the first end 103. The degree of detuning of the loop in which the magnetic field enhancement component 10 is located during the rf transmission phase can be adjusted by adjusting the third external capacitance 443. I.e. the degree of detuning of the loop in which the magnetic field enhancement component 10 is located during the radio frequency transmission phase, can be adjusted by the third external capacitor 443. The magnetic field of the detected region after being added into the loop where the magnetic field enhancing component 10 is located and the magnetic field strength before being added into the loop where the magnetic field enhancing component 10 is located can be the same by adjusting the third external capacitor 443 in the radio frequency transmission stage, and at this time, the detected region maintains the original magnetic field strength, so that the influence of the loop where the magnetic field enhancing component 10 is located on the radio frequency transmission stage can be eliminated, the loop where the magnetic field enhancing component 10 is located can be suitable for all clinical sequences, and the clinical practicability of the loop where the magnetic field enhancing component 10 is located is improved.

Referring also to FIG. 8, in one embodiment. The first resonant circuit 60 further includes a fifth external capacitor 445. The fifth external capacitor 445 and the switch control circuit 430 are connected in series between a portion of the first electrode layer 110 near the first end 103 and the second electrode layer 120. The circuit formed by the fifth external capacitor 445 and the switch control circuit 430 connected in series is connected in parallel with the external capacitor 440.

Therefore, when the switch control circuit 430 is turned on, the fifth external capacitor 445 and the external capacitor 440 are connected in parallel to the second electrode layer 120 and a portion of the first electrode layer 110 near the first end 103. When the total capacitance of the magnetic field enhancement assembly 10 is equal, the capacitance of the fifth external capacitor 445 and the external capacitor 440 in parallel is greater than the capacitance of the two capacitors in series, so that the required capacitance of the second structure capacitor 302 and the third structure capacitor 303 can be smaller, and thus the magnetic field enhancement assembly 10 has lower losses.

In the radio frequency transmission stage, the resonant frequency of the loop where the magnetic field enhancing assembly 10 is located deviates from the working frequency of the magnetic resonance system further, and by adjusting the fifth external capacitor 445 and the external capacitor 440, it can be ensured that the magnetic field strength of the magnetic field enhancing assembly 10 is the same in the radio frequency transmission stage of the magnetic resonance system. It will be appreciated that the linear response characteristics of the magnetic field enhancing assembly 10 determine that it has the same resonant properties during both the rf transmit and rf receive phases.

During the emission phase, the voltage difference between the portion of the first electrode layer 110 near the first end 103 and the second electrode layer 120 is larger, and the switch control circuit 430 is turned on. The external capacitor 440 and the fifth external capacitor 445 are connected in series between the second electrode layer 120 and a portion of the first electrode layer 110 near the first end 103.

And during the radio frequency receiving stage, the voltage difference between the part of the first electrode layer 110 near the first end 103 and the second electrode layer 120 is smaller, and the switch control circuit 430 is turned off. Only the external capacitor 440 is connected in series between the second electrode layer 120 and a portion of the first electrode layer 110 near the first end 103. By adjusting the external capacitor 440, the resonant frequency of the loop in which the magnetic field enhancing component 10 is located can be adjusted, so that the resonant frequency is equal to the frequency of the rf coil, thereby greatly enhancing the rf receiving field and improving the image signal-to-noise ratio.

The circuit formed by connecting the fifth external capacitor 445 and the external capacitor 440 in parallel may be connected to the second electrode layer 120 through a portion of the electrode of the first electrode layer 110 near the first end 103.

By adjusting the external capacitor 440 and the fifth external capacitor 445, the loop in which the magnetic field enhancing component 10 is located can have a good resonant frequency during the rf receiving phase. Eventually, the resonance frequency of the loop in which the magnetic field enhancing assembly 10 is located reaches the operating frequency of the magnetic resonance system during the receiving phase.

Referring to fig. 9, in one embodiment, the first electrode layer 110 includes a first sub-electrode layer 111, a second sub-electrode layer 112, and a first connection layer 190. The first sub-electrode layer 111 and the second sub-electrode layer 112 have the same width. The first sub-electrode layer 111 and the second sub-electrode layer 112 are disposed at a relative interval. One end of the first connection layer 190 is connected to the first sub-electrode layer 111. The other end of the first connection layer 190 is connected to the second sub-electrode layer 112. The width of the first connection layer 190 is smaller than the width of the first sub-electrode layer 111 or the second sub-electrode layer 112.

The second electrode layer 120 and the third electrode layer 130 are disposed on the second surface 102 at opposite intervals. The orthographic projection of the second electrode layer 120 on the first dielectric layer 100 overlaps with the orthographic projection of the first sub-electrode layer 111 on the first dielectric layer 100. The second electrode layer 120, the first dielectric layer 100 and the first sub-electrode layer 111 constitute a second structural capacitance 302. The orthographic projection of the third electrode layer 130 on the first dielectric layer 100 overlaps the orthographic projection of the second sub-electrode layer 112 on the first dielectric layer 100. The third electrode layer 130, the first dielectric layer 100 and the second sub-electrode layer 112 constitute a third structural capacitance 303.

One end of the matching capacitor 641 far from the tuning capacitor 642 is connected to the first sub-electrode layer 111, and one end of the tuning capacitor 642 far from the matching capacitor 641 is connected to the second electrode layer 120.

The second structural capacitance 302 and the third structural capacitance 303 in the magnetic field enhancement assembly 10 are connected by the first connection layer 190 to form a resonant circuit. The magnetic field enhancement component 10 covers the detection part and enhances the magnetic field of the feedback signal of the detection part in a resonance mode. However, the first electrode layer 110, the second electrode layer 120, and the second electrode layer 120 cover the detection portion to form a shielding layer, which affects the transmission of the feedback signal to the rf coil. The width of the first connection layer 190 in the magnetic field enhancement assembly 10 is smaller than the width of the first sub-electrode layer 111 or the second sub-electrode layer 112. The area of the detection part covered by the first sub-electrode layer 111 is reduced, the shielding effect of the first sub-electrode layer 111 is reduced, and the transmission capability of the feedback signal is enhanced. The radio frequency coil is easier to receive feedback signals, so that the quality of the received signals is improved, and the quality of images formed after the signals are processed is improved.

In addition, when a plurality of the magnetic field enhancement assemblies 10 are used in cooperation, the area of relative overlap between the first connection layers 190 in different magnetic field enhancement assemblies 10 is reduced, stray capacitance formed by the first connection layers 190 in different magnetic field enhancement assemblies 10 and air is reduced, coupling effect is reduced, and signal quality is improved.

The matching capacitor 641 is connected in series with the tuning capacitor 642 and in series with the signal acquisition device. The matching capacitor 641 can adjust the impedance of the output matching circuit 640 at the output side by adjusting its capacitance, so that the output impedance of the output matching circuit 640 is matched with the output impedance of the cable, thereby facilitating the output of the detection signal. The matching capacitor 641 and the tuning capacitor 642 may be tunable capacitors.

In one embodiment, the electrical loss of the first connection layer 190 is less than 1/2 of the overall electrical loss of the magnetic field enhancement assembly 10. The first connection layer 190 has a smaller electrical loss and a smaller heat generation amount. The main energy of the magnetic field enhancing device 20 is used for enhancing the magnetic field of the detection signal, and the enhancement effect of the magnetic field is good.

In one embodiment, the width of the first connection layer 190 is 1/5 to 1/2 of the width of the first sub-electrode layer 111. The width of the first connection layer 190 is 1/5 to 1/2 of the width of the first sub-electrode layer 111, so that the electrical loss of the first connection layer 190 in the magnetic field enhancement assembly 10 can be ensured to be less than 1/2 of the overall electrical loss. The first connection layer 190 has smaller electrical loss, smaller heating value and better magnetic field enhancement effect.

In one embodiment, the widths of the first sub-electrode layer 111 and the second sub-electrode layer 112 are 1mm to 30 mm. The first connection layer 190 is 1mm to 15mm. In one embodiment, the width of the first sub-electrode layer 111 and the second sub-electrode layer 112 is 15mm, and the width of the first connection layer 190 is 4 mm.

The width direction of the first sub-electrode layer 111 is a first direction a. The second direction b is directed from the first end 103 to the second end 104. The first direction a is perpendicular to the second direction b.

Referring to fig. 10, in one embodiment, an included angle between the extending direction of the first connection layer 190 and the first direction b is an acute angle or an obtuse angle. The first direction b is directed from the first end 103 to the second end 104. When the magnetic field enhancing device 20 comprises a cylindrical support structure 50, a first annular conductive sheet 510, a second annular conductive sheet 530 and a plurality of said magnetic field enhancing assemblies 10. When the cylindrical support structure 50 is a cylindrical structure, a plurality of the magnetic field enhancement assemblies 10 are disposed in parallel with each other at intervals on the cylindrical support structure 50, and a plurality of the magnetic field enhancement assemblies 10 are connected in parallel. In the magnetic field enhancement device 20, the first connection layers 190 in the two opposing magnetic field enhancement modules 10 are staggered, and the parallel overlapping portions are reduced. The stray capacitance formed by the first connection layer 190 and air in the two opposing magnetic field enhancement assemblies 10 is reduced, the coupling effect is reduced, and the signal quality is improved.

Referring to fig. 11, in one embodiment, an arc chamfer is disposed at the intersection of the sidewall of the first connection layer 190 and the sidewall of the first sub-electrode layer 111 or the second sub-electrode 112. The current flows through the first sub-electrode layer 111, the first connection layer 190, and the second electrode layer 120. The width of the first connection layer 190 is smaller than the width of the first sub-electrode layer 112. The current is collected at the junction of the first sub-electrode layer 111 and the first connection layer 190, and the current density increases. The intersection of the side wall of the first connection layer 190 and the side wall of the first sub-electrode layer 111 is provided with an arc chamfer, so that the first connection layer 190 and the first sub-electrode layer 111 are connected through a horn structure, abrupt change of current density is slowed down, and current density at the intersection of the side wall of the first connection layer 190 and the side wall of the first sub-electrode layer 111 is reduced. The current density at the junction of the first connection layer 190 and the first sub-electrode layer 111 is reduced, the heating value is reduced, and the service life of the magnetic field enhancing assembly 10 is prolonged.

Referring also to fig. 12, in one embodiment, the magnetic field enhancement assembly 10 includes a first dielectric layer 100, a first electrode layer 110, a second electrode layer 120, a third electrode layer 130, a fourth electrode layer 140, a second resonant circuit 70, and an output matching circuit 640.

The first electrode layer 110 and the fourth electrode layer 140 are disposed on the first surface 101 at intervals. The first electrode layer 110 is disposed proximate the first end 103. The fourth electrode layer 140 is disposed proximate the second end 104.

The second electrode layer 120 and the third electrode layer 130 are disposed on the second surface 102 at intervals. The second electrode layer 120 is disposed proximate the first end 103. A third electrode layer 130 is disposed proximate the second end 104. The front projection of the first electrode layer 110 on the first dielectric layer 100 overlaps the front projection of the second electrode layer 120 on the first dielectric layer 100. The first electrode layer 110, the first dielectric layer 100 and the second electrode layer 120 constitute a second structural capacitance 302. The orthographic projection of the fourth electrode layer 140 on the first dielectric layer 100 overlaps the orthographic projection of the third electrode layer 130 on the first dielectric layer 100. The fourth electrode layer 140, the first dielectric layer 100 and the third electrode layer 130 constitute a third structural capacitance 303. The second structure capacitor 302 is connected to the third structure capacitor 303. The first electrode layer 110 and the fourth electrode layer 140 are connected.

One end of the second resonant circuit 70 is connected to the first electrode layer 110. The other end of the second resonant circuit 70 is connected to the fourth electrode layer 140.

One end of the output matching circuit 640 is connected to the first electrode layer 110. The other end of the output matching circuit 640 is connected to the second electrode layer 120. The output matching circuit 640 is also used for connecting with a signal acquisition device. The output matching circuit 640 is used for adjusting the impedance value and resonance frequency of the two ends of the signal acquisition device.

The second resonant circuit 70 is configured to resonate the magnetic field enhancement assembly 10 when in a radio frequency receiving phase to increase the magnetic field strength of the human feedback signal. The second resonant circuit 70 is further configured to control the first electrode layer 110 to be disconnected from the fourth electrode layer 140 during a radio frequency transmission phase and connected during a radio frequency reception phase. During the rf receiving phase, the second resonant circuit 70 connects the first electrode layer 110 and the fourth electrode layer 140 to form an LC tank circuit. During the rf receiving phase, the second resonant circuit 70 disconnects the first electrode layer 110 from the fourth electrode layer 140, and cannot form an LC oscillating circuit.

In one embodiment, the second resonant circuit 70 includes a third depletion MOS transistor 231 and a fourth depletion MOS transistor 232. The source of the third depletion MOS 231 is electrically connected to the fourth electrode layer 140. The gate and the drain of the third depletion MOS tube 231 are electrically connected with the gate and the drain of the fourth depletion MOS tube 232. The source of the fourth depletion MOS transistor 232 is electrically connected to the first electrode layer 110.

The third depletion MOS transistor 231 is connected in series with the fourth depletion MOS transistor 232. In the radio frequency transmitting stage, the radio frequency coil transmits radio frequency transmitting signals, and the field intensity of the magnetic field is larger. The induced voltage generated by the magnetic field enhancing assembly 10 is relatively large. The voltage between the third depletion MOS tube 231 and the fourth depletion MOS tube 232 exceeds the pinch-off voltage between the third depletion MOS tube 231 and the fourth depletion MOS tube 232, and the source-drain electrode of the third depletion MOS tube 231 is not conducted and the source-drain electrode of the fourth depletion MOS tube 232 is not conducted. Almost no current flows between the second structural capacitor 302 and the third structural capacitor 303, and the magnetic field generated by the magnetic field enhancing component 10 is weakened, so that the influence of the magnetic field enhancing component 10 on the magnetic field in the radio frequency emission stage is reduced, thereby reducing the artifact of the detected image and improving the definition of the detected image.

In the radio frequency receiving stage, the detection part transmits a feedback signal, and the field intensity of the magnetic field is smaller. The magnetic field enhancing assembly 10 produces a small induced voltage. The voltage between the third depletion MOS tube 231 and the fourth depletion MOS tube 232 is smaller than the pinch-off voltage between the third depletion MOS tube 231 and the fourth depletion MOS tube 232, and the source-drain electrode of the third depletion MOS tube 231 is conducted and the source-drain electrode of the fourth depletion MOS tube 232 is conducted. The second structure capacitor 302 and the third structure capacitor 303 are connected to form an LC circuit, so as to enhance the magnetic field.

Referring to fig. 13, in one embodiment, the second resonant circuit 70 includes a third capacitor 223, a first inductor 241, and a first switch circuit 631. One end of the third capacitor 223 is connected to the first electrode layer 110. The other end of the third capacitor 223 is connected to the second electrode layer 120. One end of the first inductor 241 is connected to the second electrode layer 120. The first switch circuit 631 is connected between the other end of the first inductor 241 and the first electrode layer 110. The first switch circuit 631 is configured to be turned off during a radio frequency reception phase. The first switch circuit 631 is further configured to be turned on during a radio frequency transmission stage, so that the seventh control circuit 630 is in a high-impedance state.

The first switching circuit 631 in the magnetic field enhancing assembly 10 is configured to be turned off during a radio frequency receive phase. The second structure capacitor 302 and the third structure capacitor 303 are connected through the third capacitor 223. The first switching circuit 631 and the first inductor 241 do not participate in the circuit conduction. The first switch circuit 631 is further configured to be turned on during a radio frequency transmission stage, and the third capacitor 223 is connected in parallel with the first inductor 241, so that the seventh control circuit 630 is in a high-resistance state. The circuit is broken between the second structure capacitor 302 and the third structure capacitor 303. In the rf signal emission stage, almost no current flows between the second structural capacitor 302 and the third structural capacitor 303, and the magnetic field generated by the loop in which the magnetic field enhancing component 10 is located is weakened, so that the influence of the loop in which the magnetic field enhancing component 10 is located on the magnetic field in the rf signal emission stage is reduced, thereby reducing the artifact of the detected image and improving the definition of the detected image.

The first switching circuit 631 may be controlled by a control circuit. In one embodiment, the first switching circuit 631 includes a switching element and a control terminal. One end of the switching element is connected to one end of the first inductor 241 remote from the second electrode layer 120. The other end of the switching element is connected to the first electrode layer 110. The control end is connected with an external control device. The control terminal is used for receiving the closing and opening commands. And in the radio frequency transmitting stage, the control device outputs a closing command to the control end. When the control terminal receives a close command, the first inductor 241 is electrically connected to the first electrode layer 110. The first inductor 241 is connected in parallel with the third capacitor 223, and generates parallel resonance, and is in a high-resistance state; almost no current flows between the first electrode layer 110 and the second electrode layer 120.

In the radio frequency receiving stage, the control device outputs a closing command to the control end. When the control terminal receives a turn-off command, the first inductor 241 is turned off from the first electrode layer 110. The first electrode layer 110 and the third capacitor 223 are connected in series with the second electrode layer 120, and form a part of a resonant circuit.

In one embodiment, the first switching circuit 631 includes a third diode 213 and a fourth diode 214. The anode of the third diode 213 is connected to the first electrode layer 110. The cathode of the third diode 213 is connected to the other end of the first inductor 241. The anode of the fourth diode 214 is connected to the other end of the first inductor 241, and the cathode of the fourth diode 214 is connected to the first electrode layer 110.

The third diode 213 and the fourth diode 214 are connected in anti-parallel. In the radio frequency transmitting stage, the radio frequency coil transmits radio frequency transmitting signals, and the field intensity of the magnetic field is larger. The induced voltage generated by the loop in which the magnetic field enhancing assembly 10 is located is large. The voltages applied across the third diode 213 and the fourth diode 214 alternate in opposite directions. The applied voltage exceeds the turn-on voltage of the third diode 213 and the fourth diode 214, and the third diode 213 and the fourth diode 214 are turned on. The third capacitor 223 is connected in parallel with the first inductor 241, so that the seventh control circuit 630 is in a high-resistance state. In the radio frequency signal transmitting stage, almost no current flows between the second structural capacitor 302 and the third structural capacitor 303, and the magnetic field generated by the loop where the magnetic field enhancing component 10 is located is weakened, so that the influence of the loop where the magnetic field enhancing component 10 is located on the magnetic field in the radio frequency signal transmitting stage is reduced, thereby reducing the artifact of the detected image and improving the definition of the detected image.

In the radio frequency receiving stage, the detection part transmits a feedback signal, and the field intensity of the magnetic field is smaller. The loop in which the magnetic field enhancing assembly 10 is located produces a small induced voltage. The applied voltage cannot reach the turn-on voltage of the third diode 213 and the fourth diode 214, and the third diode 213 and the fourth diode 214 are not turned on. The second structure capacitor 302 and the third structure capacitor 303 are connected through the third capacitor 223, and the magnetic field enhancement device 20 formed by the magnetic field enhancement assemblies 10 is in a resonance state, so as to play a role in enhancing a magnetic field.

In one embodiment, the turn-on voltages of the third diode 213 and the fourth diode 214 are each between 0 and 1V. In one embodiment, the turn-on voltages of the third diode 213 and the fourth diode 214 are the same, so that the magnetic field strength is continuously increased during the rf receiving phase of the magnetic field enhancement device 20, and the stability of the feedback signal is improved. In one embodiment, the turn-on voltage of the third diode 213 and the fourth diode 214 is 0.8V.

In one embodiment, the third diode 213 and the fourth diode 214 have the same model, and the voltage drops after the third diode 213 and the fourth diode 214 are turned on are the same, so that the magnetic field strength of the magnetic field enhancement device 20 is increased by the same magnitude in the radio frequency receiving stage, and the stability of the feedback signal is further improved.

Referring to fig. 14 and 15 together, an embodiment of the present application provides a magnetic field enhancement device 20, which includes a cylindrical support structure 50, a plurality of magnetic field enhancement assemblies 10, an output matching circuit 640, a first annular conductive sheet 510 and a second annular conductive sheet 530. The cylindrical support structure 50 has two spaced-apart opposed third and fourth ends 51, 53. The plurality of magnetic field enhancing assemblies 10 are disposed in spaced relation to the cylindrical support structure 50. A plurality of the magnetic field enhancement assemblies 10 each extend along the third end 51 toward the fourth end 53.

The magnetic field enhancement assembly 10 includes a first dielectric layer 100, a first electrode layer 110, a second electrode layer 120, and a third electrode layer 130. The first dielectric layer 100 has opposite first and second ends 103, 104. The first dielectric layer 100 further includes opposing first and second surfaces 101, 102.

The first annular conductive sheet 510 is disposed on the cylindrical support structure 50 and is adjacent to the third end 51. The first annular conductive sheet 510 is electrically connected to portions of the electrodes of the first electrode layer 110 of the plurality of magnetic field enhancement assemblies 10 proximate the first end 103. The second annular conductive tab 530 is disposed on the cylindrical support structure 50 proximate the fourth end 53. The second annular conductive sheet 530 is electrically connected to the second electrode layers 120 of the plurality of magnetic field enhancement assemblies 10.

The magnetic field enhancement device 20 according to the embodiment of the present application forms the second structural capacitor 302 by the portion of the electrode of the first electrode layer 110 near the first end 103, the first dielectric layer 100, and the second electrode layer 120. The portion of the first electrode layer 110 adjacent to the second end 104, the first dielectric layer 100 and the third electrode layer 130 form a third structural capacitance 303. The second structure capacitor 302 is connected to the third structure capacitor 303 to form an LC oscillating circuit. The output matching circuit 640 and the signal acquisition device constitute a circuit for detecting the output side of the signal. The magnetic field enhancement device 20 can adjust the matching impedance of the two ends of the signal acquisition device through the output matching circuit 640, so that the output impedance of the output matching circuit 640 is matched with the output impedance of the cable. The magnetic field enhancement device 20 can also adjust the resonant frequency through the output matching circuit 640, so that the resonant frequency of the output matching circuit 640 and the signal acquisition device on the output side is equal to the target frequency, and the intensity of the output detection signal is improved. During the radio frequency receiving stage, the magnetic field enhancing device 20 resonates, and the magnetic field of the magnetic field enhancing device 20 is identical to the magnetic field generated by the human feedback signal. The magnetic field enhancement device 20 can match the output impedance and increase the signal strength by the output matching circuit 640, and can extract the detection signal. Further, the magnetic field enhancement device 20 can be closer to the detection site, the sensitivity of detection of the magnetic field enhancement device 20 is higher, and the detected image is clearer.

Referring to fig. 16, in one embodiment, the seventh control circuits 630 are two. The two seventh control circuits 630 are connected to the two magnetic field enhancement assemblies 10 in a one-to-one correspondence, and the included angle between the two magnetic field enhancement assemblies 10 in the circular array is 90 °. The two magnetic field enhancement assemblies 10 form an included angle of 90 degrees at the end faces. The detection signals output by the two output matching circuits 640 are different by 90 ° phase angle, and the detection signals received by the two output matching circuits 640 are orthogonal. The signals received by the two output matching circuits 640 are mutually orthogonal and independent, and the two orthogonal signals are subjected to correlation processing, so that the signal-to-noise ratio can be increased, and the definition of the detected image can be improved.

Fig. 16 is S-parameters of the magnetic field enhancing device 20 of fig. 17. S11 and S22 are the reflection coefficients of two orthogonally placed ports, respectively, and it can be seen that at a frequency of interest of 63.8MHz, both ports have good resonance performance and impedance matching (reflection coefficient less than-40 dB), can receive very strong signals and return to the machine for post-processing. S12 represents the energy passed from port 1 to port 2, S12 being equal to S21 for a reciprocal network. The isolation of the two ports can be reflected in the S12, and in order to achieve orthogonal reception of the two ports, the S12 is required to be smaller, that is, the signal independence degree is high. In this embodiment, S12 is less than-25 dB, which means that the isolation of the two ports is high, and quadrature reception can be achieved.

A plurality of the magnetic field enhancement assemblies 10 are distributed in a circular array over the cylindrical support structure 50. The cylindrical support structure 50 has symmetrical structure, uniform magnetic field distribution and consistent enhancement effect on the feedback signal. The magnetic field enhancement device 20 can be sleeved on the arm, leg, hand or other parts of the human body, and is closer to the detection part, thereby improving the detection sensitivity.

The cylindrical support structure 50 may be replaced with a flat support structure or a curved support structure. The first annular conductive sheet 510 and the second annular conductive sheet 530 may be replaced with linear conductive sheets or curved conductive sheets to accommodate flat or curved support structures.

In one embodiment, the magnetic field enhancing device 20 further comprises a plurality of fixation structures 930. The plurality of fixing structures 930 are disposed on the outer surface of the cylindrical supporting structure 50 and are arranged in a circular array. A plurality of the fixing structures 930 are used to fix the magnetic field enhancement assemblies 10 one by one. The magnetic field enhancing assembly 10 may be secured to the cylindrical support structure 50 by the securing structure 930.

The fixing structure 930 may be a strap, a buckle, or the like. The magnetic field enhancing assembly 10 is removably secured to the cylindrical support structure 50 by the securing structure 930.

In one embodiment, the securing structure 930 includes first and second securing members 931, 932 that are spaced apart. The first fixing member 931 is disposed near the third end 51. The second securing member 932 is disposed adjacent the fourth end 53. The first fixing member 931 is used to fix one end of the magnetic field enhancement assembly 10. The second fixing member 932 is configured to fix the other end of the magnetic field enhancement assembly 10. The first fixing member 931 and the second fixing member 932 are respectively used to fix two ends of the magnetic field enhancement assembly 10.

In one embodiment, the first fixing member 931 and the second fixing member 932 include a U-shaped buckle. The first fixing member 931 and the second fixing member 932 are fastened to the outer surface of the cylindrical support structure 50. The openings of the U-shaped spaces of the first fixing member 931 and the second fixing member 932 are directed toward the third end 51 or the fourth end 53. The U-shaped spaces of the first mount 931 and the second mount 932 are configured to penetrate the magnetic field enhancement assembly 10. If the magnetic field enhancement assembly 10 needs to be replaced, only the magnetic field enhancement assembly 10 needs to be drawn out of or inserted into the U-shaped spaces of the first fixing member 931 and the second fixing member 932.

The technical features of the above-described embodiments may be arbitrarily combined, and all possible combinations of the technical features in the above-described embodiments are not described for brevity of description, however, as long as there is no contradiction between the combinations of the technical features, they should be considered as the scope of the description.

The examples described above represent only a few embodiments of the present application and are not to be construed as limiting the scope of the application. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the application, which are all within the scope of the application. Accordingly, the scope of protection of the present application is to be determined by the appended claims.

Claims

1. A magnetic field enhancing assembly, comprising:

a first dielectric layer (100) having opposite first (103) and second (104) ends and comprising opposite first (101) and second (102) surfaces;

A first electrode layer (110) disposed on the first surface (101) and extending from the first end (103) to the second end (104);

A second electrode layer (120) and a third electrode layer (130) disposed on the second surface (102) at opposite intervals, the second electrode layer (120) being disposed adjacent to the first end (103), the third electrode layer (130) being disposed adjacent to the second end (104);

The front projection of the second electrode layer (120) on the first dielectric layer (100) overlaps with the front projection of the first electrode layer (110) near the first end (103) on the front projection of the first dielectric layer (100), the second electrode layer (120), the first dielectric layer (100) and the first electrode layer (110) near the first end (103) form a second structural capacitance (302), the front projection of the third electrode layer (130) on the first dielectric layer (100) overlaps with the front projection of the first electrode layer (110) near the second end (104) on the front projection of the first dielectric layer (100), and the third electrode layer (130), the first dielectric layer (100) and the first electrode layer (110) near the second end (104) form a third structural capacitance (303);

An output matching circuit (640) comprising a matching capacitor (641), a tuning capacitor (642) and an output interface (643), wherein one end of the matching capacitor (641) is connected with a part of the first electrode layer (110) close to the first end (103), the tuning capacitor (642) is connected between the other end of the matching capacitor (641) and the second electrode layer (120), the output interface (643) is connected with the tuning capacitor (642) in parallel, the output interface (643) is used for being connected with a signal acquisition device, and the output matching circuit (640) is used for adjusting impedance values and harmonic frequencies of two ends of the signal acquisition device;

The second switch circuit (650), including first depletion MOS pipe (652) and second depletion MOS pipe (653) of anti-series connection, the grid and the drain electrode of first depletion MOS pipe (652) with output matching circuit (640) are connected, one end that tuning capacitor (642) was kept away from to matching capacitor (641) is connected, the source electrode of first depletion MOS pipe (652) with the source electrode of second depletion MOS pipe (653) is connected, the grid and the drain electrode of second depletion MOS pipe (653) with first electrode layer (110) are close to the part of first end (103) is connected, first depletion MOS pipe (652) with second depletion MOS pipe (653) are used for switching on in turn at the radio frequency reception stage.

2. The magnetic field enhancement assembly of claim 1, further comprising:

-a first resonant circuit (60), one end of the first resonant circuit (60) being connected to a portion of the first electrode layer (110) close to the first end (103), the other end of the first resonant circuit (60) being connected to the second electrode layer (120), the first resonant circuit (60) being configured to resonate the magnetic field enhancing assembly (10) in a radio frequency receiving phase, the first resonant circuit (60) being configured to detune the magnetic field enhancing assembly (10) in a radio frequency transmitting phase.

3. The magnetic field enhancement assembly of claim 2, wherein the first resonant circuit (60) comprises a switch control circuit (430), both ends of the switch control circuit (430) being respectively connected to a portion of the first electrode layer (110) near the first end (103) and the second electrode layer (120), the switch control circuit (430) being configured to be turned on during a radio frequency transmission phase and turned off during a radio frequency reception phase.

4. A magnetic field enhancement assembly as claimed in claim 3, characterized in that the switch control circuit (430) comprises a first diode (431) and a second diode (432), an anode of the first diode (431) being connected to a part of the first electrode layer (110) near the first end (103), a cathode of the first diode (431) being connected to the second electrode layer, an anode of the second diode (432) being connected to a part of the first electrode layer (110) near the first end (103), a cathode of the second diode (432) being connected to the second electrode layer.

5. A magnetic field enhancement assembly according to claim 3, wherein the first resonant circuit (60) further comprises an external capacitor (440), both ends of the external capacitor (440) being connected to a portion of the electrode of the first electrode layer (110) adjacent to the first end (103) and to the second electrode layer (120), respectively.

6. The magnetic field enhancement assembly of claim 5, wherein the first resonant circuit (60) further comprises a third external capacitor (443), the external capacitor (440) and the third external capacitor (443) are connected in series between a portion of the electrode of the first electrode layer (110) proximate to the first end (103) and the second electrode layer (120), and the switch control circuit (430) is connected in parallel across the external capacitor (440).

7. The magnetic field enhancement assembly of claim 1, wherein the first electrode layer (110) comprises a first sub-electrode layer (111), a second sub-electrode layer (112) and a first connection layer (190), the first sub-electrode layer (111) and the second sub-electrode layer (112) being of the same width and being arranged in a relatively spaced apart relationship, one end of the first connection layer (190) being connected to the first sub-electrode layer (111), the other end of the first connection layer (190) being connected to the second sub-electrode layer (112), the first connection layer (190) having a width smaller than the width of the first sub-electrode layer (111);

The orthographic projection of the second electrode layer (120) on the first dielectric layer (100) is overlapped with the orthographic projection part of the first sub-electrode layer (111) on the first dielectric layer (100), the second electrode layer (120), the first dielectric layer (100) and the first sub-electrode layer (111) form a second structural capacitor (302), the orthographic projection of the third electrode layer (130) on the first dielectric layer (100) is overlapped with the orthographic projection part of the second sub-electrode layer (112) on the first dielectric layer (100), and the third electrode layer (130), the first dielectric layer (100) and the second sub-electrode layer (112) form a third structural capacitor (303);

One end of the matching capacitor (641) far away from the tuning capacitor (642) is connected with the first sub-electrode layer (111), and one end of the tuning capacitor (642) far away from the matching capacitor (641) is connected with the second electrode layer (120).

8. A magnetic field enhancing assembly, comprising:

A first electrode layer (110) and a third electrode layer (130) arranged on the first surface (101) at intervals, wherein the first electrode layer (110) is arranged close to the first end (103), and the third electrode layer (130) is arranged close to the second end (104);

A second electrode layer (120) and a fourth electrode layer (140), which are arranged on the second surface (102) at intervals, wherein the second electrode layer (120) is arranged close to the first end (103), the fourth electrode layer (140) is arranged close to the second end (104), the orthographic projection of the first electrode layer (110) on the first dielectric layer (100) is overlapped with the orthographic projection of the second electrode layer (120) on the first dielectric layer (100), the second electrode layer (110), the first dielectric layer (100) and the second electrode layer (120) form a second structure capacitor (302), the orthographic projection of the third electrode layer (130) on the first dielectric layer (100) is overlapped with the orthographic projection of the fourth electrode layer (140) on the first dielectric layer (100), and the third electrode layer (130), the first dielectric layer (100) and the fourth electrode layer (140) form a third structure capacitor (303);

The second resonant circuit (70) comprises a third depletion MOS tube (231) and a fourth depletion MOS tube (232), wherein a source electrode of the third depletion MOS tube (231) is electrically connected with the third electrode layer (130), a grid electrode and a drain electrode of the third depletion MOS tube (231) are electrically connected with a grid electrode and a drain electrode of the fourth depletion MOS tube (232), a source electrode of the fourth depletion MOS tube (232) is electrically connected with the first electrode layer (110), the third depletion MOS tube (231) and the fourth depletion MOS tube (232) are conducted in a radio frequency receiving stage, and the third depletion MOS tube (231) and the fourth depletion MOS tube (232) are in a high-resistance state in a radio frequency transmitting stage;

9. A magnetic field enhancing assembly, comprising:

A second resonant circuit (70) comprising:

a third capacitor (223), wherein one end of the third capacitor (223) is connected with the first electrode layer (110), and the other end of the third capacitor (223) is connected with the third electrode layer (130);

A first inductor (241), wherein one end of the first inductor (241) is connected with the third electrode layer (130);

A first switch circuit (631) connected between the other end of the first inductor (241) and the first electrode layer (110), the first switch circuit (631) being configured to be turned off during a radio frequency receiving phase, and the first switch circuit (631) being further configured to be turned on during a radio frequency transmitting phase, so as to enable the second resonant circuit (70) to be in a high-impedance state;

10. A magnetic field enhancing device, comprising:

a cylindrical support structure (50) having two spaced-apart opposed third (51) and fourth (53) ends;

A plurality of magnetic field enhancement assemblies (10), the interval set up in cylindric bearing structure (50), a plurality of magnetic field enhancement assemblies (10) all follow third end (51) to fourth end (53), magnetic field enhancement assembly (10) include:

a first electrode layer (110) disposed on the first surface (101), the first electrode layer (110) extending from the first end (103) to the second end (104);

a first annular conductive sheet (510) disposed on the cylindrical support structure (50) and proximate the third end (51); the first annular conductive sheet (510) is electrically connected to the second electrode layers (120) of a plurality of the magnetic field enhancement assemblies (10);

A second annular conductive sheet (530) disposed on the cylindrical support structure (50) and proximate the fourth end (53), the second annular conductive sheet (530) being electrically connected to the third electrode layers (130) of the plurality of magnetic field enhancement assemblies (10); and