Magnetic resonance self-decoupling coil based on double-split-ring reverse coupling mechanism

Abstract

The invention provides a magnetic resonance self-decoupling coil based on a double-split-ring reverse coupling mechanism, which comprises a dielectric substrate, an external annular metal wire and an internal annular metal wire, the external annular metal wire and the internal annular metal wire are fixed on the dielectric substrate and sleeved together, one end of the external annular metal wire is provided with an opening, and the opening is connected with an outer ring tuning capacitor. Two sides of the outer ring tuning capacitor are respectively provided with a matching metal wire, each matching metal wire is provided with an opening, the opening is connected with a matching capacitor, and the tail ends of the two matching metal wires are connected with an excitation port; the inner annular metal wire 3 is provided with an opening on the opposite side of the opening end of the outer annular metal wire, and the opening is connected with an inner ring tuning capacitor. According to the invention, mutual inductance between magnetic resonance self-decoupling coil units can be effectively reduced, and coupling between multi-channel coil units is reduced.

Description

Technical Field

[0001] This invention relates to the field of magnetic resonance imaging, and in particular to a magnetic resonance self-decoupling coil based on a double-open-loop reverse coupling mechanism. Background Technology

[0002] Magnetic resonance imaging (MRI) is a commonly used non-invasive diagnostic technique in clinical practice. Its principle involves using a radio frequency transmitting coil to emit radio frequency pulses at Larmor frequencies to disrupt the precession equilibrium of atomic nuclei within an external reinforced static magnetic field. After the radio frequency pulses cease, a radio frequency receiving coil, based on Faraday's law of electromagnetic induction, receives the magnetic resonance signal as the atomic nuclei return to their precession equilibrium, and then uses a computer to reconstruct the image.

[0003] An open-loop resonator (SRR) is an artificial electromagnetic structure. It typically consists of a metal ring with one or more openings, commonly square or circular in shape. In the radio frequency (RF) band, SRRs exhibit unique electromagnetic characteristics, which can be tuned by adjusting their fundamental dimensional parameters such as ring radius, linewidth, and opening gap. A dual open-loop resonator (DSRR) is a derivative structure of the SRR, constructed from two nested open-loop units. It utilizes the electromagnetic coupling between the two rings to achieve more flexible resonance characteristics and is widely used in RF devices and metamaterials.

[0004] Improving the signal-to-noise ratio (SNR) is of great significance in magnetic resonance imaging (MRI). Since the SNR is proportional to the static magnetic flux density, high-field (≥3T) MRI has the potential to achieve high SNR imaging. 1.5T MRI, due to its low cost and high safety, has been widely used in clinical diagnosis. However, its low field strength and shallow penetration depth result in low image clarity and long imaging time, which seriously affects image quality and patient comfort. Array design and parallel imaging techniques can improve the SNR and imaging speed of high-field 1.5T systems, while also meeting the needs of multi-site and multi-modal imaging.

[0005] However, the destructive electromagnetic coupling between multi-channel coils is a key challenge in their design and application. Excessive coupling strength can compromise channel independence, reduce SNR and energy transfer efficiency, and introduce image artifacts and SAR risks. The higher the channel density and field strength, the more pronounced the problem becomes. Therefore, reducing the coupling between multi-channel coil units is crucial for magnetic resonance imaging. Traditional multi-channel coil decoupling schemes include geometric decoupling, capacitive / inductive decoupling, and preamplifier decoupling. Their core drawbacks lie in limited decoupling effectiveness, narrow bandwidth, susceptibility to loss / noise, high design complexity, and difficulty in adapting to high-density arrays. Essentially, they are passive compensations or physical isolations of "mutual inductance-capacitance coupling," failing to fundamentally solve the complex coupling problems under multi-channel, high-field-strength conditions. Therefore, there is an urgent need to propose a multi-channel coil decoupling scheme to overcome the shortcomings of traditional decoupling methods and achieve superior decoupling performance. Summary of the Invention

[0006] This invention designs a magnetic resonance self-decoupling coil based on a double-open-loop reverse coupling mechanism. By adjusting the capacitance of the inner and outer loops in the magnetic resonance self-decoupling coil, the inner and outer loops are made to have different resonant frequencies, which work together to achieve inductive coupling resonance. By adjusting the resonant frequencies of the inner and outer loops, the reverse current operating mode generated by inductive coupling is made to operate at the operating frequency of the magnetic resonance system. Utilizing the reverse current characteristics of the inner and outer loops, the magnetic fields generated by the inner and outer loop currents outside the magnetic resonance self-decoupling coil unit cancel each other out, thereby effectively reducing the mutual inductance between the magnetic resonance self-decoupling coil units and achieving the purpose of reducing coupling between multi-channel coil units. The technical solution is as follows: A magnetic resonance self-decoupling coil based on a double-opening-ring reverse coupling mechanism includes a dielectric substrate and an outer ring metal wire 2 and an inner ring metal wire 3 fixed on the dielectric substrate and nested together. One end of the outer ring metal wire 2 is open, and the opening is connected to an outer ring tuning capacitor 5. A matching metal wire 4 is led out from both sides of the outer ring tuning capacitor 5. Each matching metal wire 4 is open, and a matching capacitor 7 is connected to the opening. The ends of the two matching metal wires 4 are connected to an excitation port 8. The inner ring metal wire 3 is open on the opposite side of the open end of the outer ring metal wire 2, and the opening is connected to an inner ring tuning capacitor 6.

[0007] Furthermore, the outer ring metal wire 2 and the inner ring metal wire 3 are concentric, and the matching metal wire 4 is a straight metal wire.

[0008] Furthermore, the inner ring tuning capacitor 6 or the outer ring tuning capacitor 5 is an adjustable capacitor. By tuning the adjustable capacitor, the magnetic resonance self-decoupling coil resonates at the operating frequency of the magnetic resonance imaging system.

[0009] Furthermore, the resonant frequencies of the outer ring metal wire 2 and the inner ring metal wire 3 are determined respectively. Based on the determined geometric parameters, the required capacitance values ​​of the inner ring tuning capacitor 6 or the outer ring tuning capacitor 5 are calculated so that both the inner ring resonant frequency and the outer ring resonant frequency are lower than the operating frequency, with the inner ring resonant frequency close to the operating frequency and the outer ring resonant frequency far from the operating frequency.

[0010] Furthermore, the matching capacitor 7 is an adjustable capacitor. Depending on the applied magnetic resonance imaging system, each adjustable capacitor is tuned so that the entire magnetic resonance self-decoupling coil resonates at the Larmor frequency corresponding to the magnetic resonance imaging system.

[0011] Furthermore, in the electromagnetic wave finite element simulation software, based on the required side length of the magnetic resonance self-decoupling coil, the remaining geometric parameters, including the linewidth and gap of the two types of toroidal metal wires, the distance between the outer and inner toroidal metal wires, and the capacitance values, are optimized to achieve the best decoupling performance.

[0012] Furthermore, the outer and inner annular metal wires can be square, circular, or other arbitrary polygons.

[0013] The preferred design is as follows: the ring-shaped metal wire is square, with an outer ring side length of 100mm, an inner ring side length of 80mm, a matching metal wire length of 13mm, a wire width of 3mm, and an opening gap of 3mm. The outer ring tuning capacitor is 47pF, the inner ring tuning capacitor is 34.5pF, and the matching capacitor is 22pF, ensuring that the magnetic resonance self-decoupling coil resonates at the operating frequency of 63.8MHz in the 1.5T magnetic resonance imaging system with good impedance matching.

[0014] This invention provides a magnetic resonance self-decoupling coil based on a double-open-loop reverse coupling mechanism. The magnetic resonance self-decoupling coil consists of a dielectric substrate and inner and outer double-open-loops fixed on the dielectric substrate. Capacitors are connected to the openings of the two loops to adjust the resonant frequency, ensuring that the magnetic resonance self-decoupling coil resonates at the operating frequency of the magnetic resonance system. The resonant frequencies of both the inner and outer loops are lower than the operating frequency, with the inner loop resonant frequency close to the operating frequency and the outer loop resonant frequency far from the operating frequency. When the inner and outer loops work together, induced coupling resonance occurs, and the reverse current generated by the induced coupling operates at the operating frequency of the magnetic resonance system. Because the inner and outer currents are reversed, and the inner loop current is stronger than the outer loop current, the magnetic fields generated by the currents on the inner and outer loops outside the magnetic resonance self-decoupling coil cancel each other out, effectively reducing mutual inductance with surrounding components. Therefore, when arranged in an array, the mutual inductance between the magnetic resonance self-decoupling coil units is significantly reduced, i.e., the coupling degree between multi-channel coil units is reduced. This magnetic resonance self-decoupling coil element does not require overlapping placement, increasing the coil utilization area and detection field of view; it eliminates the need for additional capacitors, inductors, or decoupling circuits, avoiding additional losses and noise; and it has outstanding advantages such as flexibility, low cost, and ease of fabrication. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a magnetic resonance self-decoupling coil structure based on a double-open-loop reverse coupling mechanism provided in an embodiment of the present invention; Figure 2 A graph showing the relationship between S-parameters and frequency of a magnetic resonance self-decoupling coil based on a double-open-loop reverse coupling mechanism, provided in an embodiment of the present invention. Figure 3 This is a configuration diagram for an experimental test of the isolation of a magnetic resonance self-decoupling coil based on a double-open-loop reverse coupling mechanism, provided in an embodiment of the present invention. Figure 4 Diagram showing the setup for a traditional surface coil isolation test experiment; Figure 5 A graph showing the relationship between S-parameters and frequency when magnetic resonance self-decoupling coils based on a double-open-loop reverse coupling mechanism with a d of 14 mm are placed side by side, according to an embodiment of the present invention. Figure 6 The graph shows the relationship between S-parameters and frequency when traditional surface coils with a d of 14 mm are placed side by side. Figure 7 This paper compares the resonant frequency shift of a magnetic resonance self-decoupling coil based on a double-open-loop reverse coupling mechanism and a conventional surface coil as a function of distance d, according to embodiments of the present invention.

[0016] In the picture: 1. Dielectric substrate; 2. External ring-shaped metal wire; 3. Internal ring-shaped metal wire; 4. Matching metal wire; 5. Outer ring tuning capacitor; 6. Inner ring tuning capacitor; 7. Matching capacitor; 8. Excitation port; 9. Magnetic resonance self-decoupling coil; 10. Plastic ruler; 11. Traditional surface coil; Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are all within the scope of protection of this invention.

[0018] In the described magnetic resonance self-decoupling coil, both the inner and outer loop resonant frequencies are lower than the operating frequency, with the inner loop resonant frequency close to the operating frequency and the outer loop resonant frequency far from the operating frequency. When the inner and outer loops work together, induced coupling resonance occurs, and the reverse current generated by this induced coupling operates at the magnetic resonance system's operating frequency. Because the inner and outer currents are opposite, and the inner loop current is stronger than the outer loop current, the magnetic fields generated by the currents on the inner and outer loops cancel each other out outside the magnetic resonance self-decoupling coil, effectively reducing mutual inductance with surrounding components. Therefore, when arranged in an array, the mutual inductance between the magnetic resonance self-decoupling coil units is significantly reduced, i.e., the coupling degree between multi-channel coil units is reduced.

[0019] The annular metal wire is square, circular, or any other arbitrary polygon in shape.

[0020] The magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism can be used in magnetic resonance imaging systems with different field strengths such as 0.7T, 1.5T, 3T and 7T by tuning the resonant frequency through a variable capacitor.

[0021] Figure 1 This is a schematic diagram of a magnetic resonance self-decoupling coil structure based on a double-opening-loop reverse coupling mechanism provided in an embodiment of the present invention. The present invention provides a magnetic resonance self-decoupling coil based on a double-opening-loop reverse coupling mechanism, comprising a dielectric substrate 1 and two concentric ring-shaped metal wires fixed on the dielectric substrate 1, namely an outer ring-shaped metal wire 2 and an inner ring-shaped metal wire 3. One end of the outer ring-shaped metal wire 2 is open, and an outer ring tuning capacitor 5 is connected to this opening. A matching metal wire 4 is led out from each of its two sides. The matching metal wires 4 are straight metal wires, each with an opening in the middle and connected to a matching capacitor 7. The ends of the two matching metal wires 4 are connected to an excitation port 8. The inner ring-shaped metal wire 3 is open on the opposite side of the open end of the outer ring-shaped metal wire 2, and an inner ring tuning capacitor 6 is connected to this opening. In this embodiment, the inner ring tuning capacitor 6 is an adjustable capacitor. By tuning the inner ring tuning capacitor 6, the magnetic resonance self-decoupling coil resonates at the operating frequency of magnetic resonance imaging.

[0022] The magnetic resonance self-decoupling coil based on a dual-open-loop reverse coupling mechanism provided in this embodiment is applied to a 1.5T magnetic resonance imaging system. The isolation performance of the magnetic resonance self-decoupling coil based on the dual-open-loop reverse coupling mechanism under no-load conditions is tested in this embodiment. The invention will be further described in detail below with reference to the accompanying drawings and specific embodiments: Step 1: The geometric dimensions of the magnetic resonance self-decoupling coil are determined based on imaging requirements and electromagnetic wave finite element simulation. In this embodiment, the annular metal wire is square, with an outer ring side length of 100mm, an inner ring side length of 80mm, a straight metal wire length of 13mm, a wire width of 3mm, and an opening gap of 3mm.

[0023] Step Two: Capacitors are connected to each opening of the magnetic resonance self-decoupling coil. Using computer calculations in electromagnetic wave finite element simulation software, suitable capacitance values ​​are calculated based on determined geometric parameters to ensure the magnetic resonance self-decoupling coil resonates at the target frequency. Taking a 1.5T magnetic resonance imaging system as an example, simulation calculations show that the required capacitances for the magnetic resonance self-decoupling coil to resonate at the operating frequency of 63.8MHz with good impedance matching are: outer ring tuning capacitor 5 = 47pF, inner ring tuning capacitor 6 = 34.5pF, and matching capacitor 7 = 22pF. At this point, the outer ring resonates at 37.3MHz, the inner ring resonates at 53.2MHz, and the inner and outer ring currents are in opposite directions. The magnetic fields generated outside the magnetic resonance self-decoupling coil can effectively cancel each other out, reducing the mutual inductance between the coils and achieving good decoupling performance.

[0024] Step 3: Based on the geometric parameters and capacitance values ​​of the magnetic resonance self-decoupling coil determined in steps one and two, a physical magnetic resonance self-decoupling coil was fabricated. The magnetic resonance self-decoupling coil uses an FR-4 dielectric substrate with a long side of 115mm and a short side of 102mm. The ring-shaped metal wire is square, with an outer ring side length of 100mm, an inner ring side length of 80mm, a straight metal wire length of 13mm, a wire width of 3mm, and an opening gap of 3mm. The outer ring tuning capacitor 5 is 47pF, the inner ring tuning capacitor 6 is 34.5pF, and the matching capacitor 7 is 22pF. The outer ring tuning capacitor 5 and the matching capacitor 7 are fixed capacitors, while the inner ring tuning capacitor 6 is an adjustable capacitor for easy tuning.

[0025] Step Four: Experimental tests were conducted using two physical magnetic resonance self-decoupling coils produced in step three.

[0026] Figure 2 The graph shows the relationship between the S-parameters and frequency of a magnetic resonance self-decoupling coil based on a double-open-loop reverse coupling mechanism, as provided in an embodiment of the present invention. Figure 2 As shown, the magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism provided in the embodiment resonates at 35.3MHz and 63.8MHz, respectively. 35.3MHz represents the unidirectional current mode, and 63.8MHz represents the reverse current mode, which are the resonance modes of the magnetic resonance self-decoupling coil at the operating frequency of the 1.5T magnetic resonance system. The inset diagrams at the resonant frequencies are schematic diagrams of the surface current distribution of the magnetic resonance self-decoupling coil in the unidirectional and reverse current modes, respectively.

[0027] Figure 3This diagram illustrates the experimental setup for testing the isolation of a magnetic resonance self-decoupling coil based on a double-open-loop reverse coupling mechanism, as provided in this embodiment of the invention. The setup includes a magnetic resonance self-decoupling coil 9, a vector network analyzer (VNA), and a plastic ruler 10. During testing, one magnetic resonance self-decoupling coil unit is first connected individually to the VNA. The inner loop tuning capacitor 6 is adjusted to achieve resonance at 63.8 MHz. After both magnetic resonance self-decoupling coil units are tuned, they are placed a certain distance *d* apart, with reference to the plastic ruler 10. Here, *d* is the distance between the two closest edges of the two coils. The S-parameter curves of the two magnetic resonance self-decoupling coil units are measured using the VNA at different distances *d*.

[0028] Figure 4 This diagram shows the setup for a traditional surface coil isolation test experiment. Its configuration is similar to... Figure 3 The configurations shown are identical. The conventional surface coil 11 uses an FR-4 dielectric substrate with a long side of 115mm, a short side of 102mm, a ring side length of 100mm, a matching metal wire length of 13mm, and a line width of 3mm. A 17pF adjustable capacitor is connected to one open end of the ring for tuning, and a 5pF fixed capacitor is connected to the middle open end of the matching metal wire for impedance matching. The gap between the openings is 3mm. The S-parameter curves of the conventional surface coil 13 are tested using the same method as those used for magnetic resonance self-decoupling coils.

[0029] Figure 5 This is a graph showing the relationship between S-parameters and frequency when magnetic resonance self-decoupling coils based on a double-open-loop reverse coupling mechanism with a coil diameter (d) of 14 mm are placed side-by-side, according to an embodiment of the present invention. Figure 5 As shown, when two magnetic resonance self-decoupling coil units are placed side by side, the operating frequency remains unaffected and maintains its original resonant frequency. When the two are 14mm apart, the S21 parameter value at 63.8MHz is only -29.9dB, which indicates that the magnetic resonance self-decoupling coil units have good isolation.

[0030] Unlike the magnetic resonance self-decoupling coil based on a double-open-loop reverse coupling mechanism provided in this invention, existing conventional surface coils are typically toroidal coils, consisting of only one loop and several tuning and matching capacitors. Conventional surface coils have only one resonant mode and cannot control the magnetic field generated outside their own coil, resulting in strong mutual inductance between coil units. Therefore, conventional surface coils exhibit strong coupling without additional decoupling components or circuits.

[0031] Figure 6 This is a graph showing the relationship between S-parameters and frequency when conventional surface coils with a diameter (d) of 14 mm are placed side-by-side. (Example:) Figure 6As shown, when two conventional surface coils are placed side by side, the resonant peaks split due to strong coupling between the coil units, shifting to 62.5MHz and 65.1MHz respectively. When the two coils are 14mm apart, the S21 parameter value at 62.5MHz is -8.24dB and the S21 parameter value at 65.1MHz is -9.52dB, indicating that there is strong coupling between the two conventional surface coils.

[0032] Combination Figure 5 and Figure 6 It can be concluded that for traditional surface coils, when two or more coils are placed side by side, the single-loop structure cannot control the magnetic field generated outside the coil, resulting in strong mutual inductance between coil units. Therefore, without additional decoupling components or circuits, the coupling between coil units is strong and the isolation is poor. However, for the magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism provided by this invention, by tuning the double-loop structure, a reverse current operating mode is introduced. The inner and outer loop currents are in opposite directions, and the inner loop current is stronger than the outer loop current. Therefore, the magnetic fields generated outside the magnetic resonance self-decoupling coil by the currents on the inner and outer loops cancel each other out, effectively reducing the mutual inductance between the magnetic resonance self-decoupling coil units and improving the isolation.

[0033] Figure 7 This paper compares the resonant frequency shift of a magnetic resonance self-decoupling coil based on a double-open-loop reverse coupling mechanism provided in this embodiment of the invention with that of a conventional surface coil, as a function of distance d. Figure 7 As shown, the magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism never exhibits resonance peak splitting. In contrast, for traditional surface coils, there is no resonance peak splitting at a distance of 60mm, but it occurs at distances less than 60mm. Furthermore, as the distance decreases, the frequency shift of the split resonance peak relative to the single-coil resonance peak gradually increases. This demonstrates that the magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism provided in this embodiment of the invention offers a significant improvement in decoupling performance compared to traditional surface coils.

[0034] Based on the above results, the magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism utilizes the principle of double-loop mutual inductance coupling resonance and the characteristics of reverse current mode to control the magnetic field generated by the magnetic resonance self-decoupling coil. This has strong feasibility and effectiveness in reducing the coupling between multi-channel coil array elements and improving isolation in magnetic resonance imaging applications.

[0035] Matters not covered in this invention are common knowledge.

[0036] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A magnetic resonance self-decoupling coil based on a double-opening ring reverse coupling mechanism, comprising a dielectric substrate and an outer ring metal wire (2) and an inner ring metal wire (3) fixed on the dielectric substrate and nested together. One end of the outer ring metal wire (2) is open and connected to an outer ring tuning capacitor (5). A matching metal wire (4) is led out from both sides of the outer ring tuning capacitor (5). Each matching metal wire (4) is open and connected to a matching capacitor (7) at the opening. The ends of the two matching metal wires (4) are connected to an excitation port (8). The inner ring metal wire (3) is open on the opposite side of the open end of the outer ring metal wire (2) and connected to an inner ring tuning capacitor (6) at the opening.

2. The magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism according to claim 1, characterized in that, The outer ring metal wire (2) and the inner ring metal wire (3) are concentric, and the matching metal wire (4) is a straight metal wire.

3. The magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism according to claim 1, characterized in that, The inner ring tuning capacitor (6) or the outer ring tuning capacitor (5) is an adjustable capacitor. By tuning the adjustable capacitor, the magnetic resonance self-decoupling coil resonates at the operating frequency of the magnetic resonance imaging system.

4. The magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism according to claim 3, characterized in that, Determine the resonant frequencies of the outer ring metal wire (2) and the inner ring metal wire (3) respectively. Calculate the required inner ring tuning capacitor (6) or outer ring tuning capacitor (5) based on the determined geometric parameters, so that the inner ring resonant frequency and the outer ring resonant frequency are both lower than the working frequency, and the inner ring resonant frequency is close to the working frequency, while the outer ring resonant frequency is far from the working frequency.

5. The magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism according to claim 3, characterized in that, The matching capacitor is an adjustable capacitor. Depending on the magnetic resonance imaging system being used, each adjustable capacitor is tuned so that the entire magnetic resonance self-decoupling coil resonates at the Larmor frequency corresponding to the magnetic resonance imaging system.

6. The magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism according to claim 1, characterized in that, In the electromagnetic wave finite element simulation software, based on the required side length of the magnetic resonance self-decoupling coil, the remaining geometric parameters, including the linewidth and gap of the two types of toroidal metal wires, the distance between the outer and inner toroidal metal wires, and the capacitance values, are optimized to achieve the best decoupling performance.

7. The magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism according to claim 1, characterized in that, The outer and inner annular metal wires can be square, circular, or other arbitrary polygons.

8. The magnetic resonance self-decoupling coil based on the double-open-loop reverse coupling mechanism according to claim 1, characterized in that, The ring-shaped metal wire is square, with an outer ring side length of 100mm and an inner ring side length of 80mm. The matching metal wire is 13mm long, 3mm wide, and has a 3mm gap. The outer ring tuning capacitor is 47pF, the inner ring tuning capacitor is 34.5pF, and the matching capacitor is 22pF, enabling the magnetic resonance self-decoupling coil to resonate at the operating frequency of 63.8MHz in the 1.5T magnetic resonance imaging system with good impedance matching.

Images