CN110557127B

CN110557127B - Multi-coil antenna system and implantable medical device

Info

Publication number: CN110557127B
Application number: CN201910927975.1A
Authority: CN
Inventors: 肜新伟; 于峰崎; 吴天准
Original assignee: Shenzhen Institute of Advanced Technology of CAS
Current assignee: Shenzhen Institute of Advanced Technology of CAS
Priority date: 2019-09-27
Filing date: 2019-09-27
Publication date: 2021-09-07
Anticipated expiration: 2039-09-27
Also published as: CN110557127A

Abstract

The invention discloses a multi-coil antenna system, which comprises a first communication device and a second communication device for bidirectional wireless communication. The first communication device is arranged outside the body and comprises a first conformal antenna formed by a first coil and a third coil, and the second communication device is arranged inside the body and comprises a second conformal antenna formed by a second coil and a fourth coil and has biocompatibility. The first coil is coupled with the corresponding second coil to form an energy channel, the third coil is coupled with the corresponding fourth coil to form a signal channel, and noise reduction processing is performed twice on the signal channel. The first communication device transmits radio frequency energy and communication signals to the second communication device through the energy channel and the signal channel respectively, the second communication device receives the radio frequency energy and the communication signals, and corresponding feedback signals are output to the first communication device through the signal channel according to the radio frequency energy and the communication signals. The invention further discloses an implantable medical device comprising the multi-coil antenna system.

Description

Multi-coil antenna system and implantable medical device

Technical Field

The invention relates to the field of medical treatment, in particular to a multi-coil antenna system and implantable medical equipment.

Background

With the development of medical technical means and equipment, great convenience is brought to people, the treatment modes of diseases are greatly enriched, and implantable medical equipment is one of the medical equipment.

The implantable medical device can realize the transmission of radio frequency energy and bidirectional wireless communication between the external device and the implantable device in the body in a wireless mode. In order to realize the radio frequency energy transmission and the bidirectional wireless communication of the implanted medical device, the prior art generally adopts: (1) single frequency multiple coil systems, e.g., 13.56MHz single frequency dual coil or multiple coil systems; (2) a dual-frequency multi-coil system, such as a dual-frequency tri-coil system.

However, in the existing processing method, neither a single-frequency multi-coil system nor a dual-frequency multi-coil system solves the problems of high-efficiency radio frequency energy transmission and high-speed bidirectional wireless communication. The main difficulties are that due to the volume limitation of the implanted body coil, the radio frequency energy can cause serious interference to the signal coil, the micro-motion of the body coil can cause mismatch, and the wireless communication rate after simple modulation is not high.

Disclosure of Invention

The invention aims to provide a multi-coil antenna system and an implanted medical device, which can realize high-efficiency radio frequency energy transfer and high-speed bidirectional wireless communication through coil conformal, dual noise reduction and closed-loop control methods.

In one embodiment of the present invention, a multi-coil antenna system is provided, which includes a first communication device and a second communication device, wherein the first communication device is disposed outside a body, and the second communication device is disposed inside the body and wirelessly communicates with the first communication device in a two-way manner; wherein the first communication device includes at least a first coil and a third coil, the first coil and the third coil constituting a first conformal antenna, the second communication device includes at least a second coil and a fourth coil having biocompatibility, the second coil and the fourth coil constituting a second conformal antenna, the first coil is coupled with the corresponding second coil to form an energy channel and perform quality factor matching, the third coil is coupled with the corresponding third coil to form a signal channel and perform quality factor broadband matching, and noise reduction processing is performed twice within the signal channel, the first communication device transmits radio frequency energy and a communication signal to the second communication device through the energy channel and the signal channel, respectively, the second communication device receives the radio frequency energy and the communication signal transmitted by the first communication device, and outputting a corresponding feedback signal to the first communication device from the signal channel according to the radio frequency energy and the communication signal.

In an embodiment of the invention, an implantable medical device is provided, which includes the above multi-coil antenna system.

Compared with the prior art, the implementation case of the invention realizes the high-efficiency transmission of the radio frequency energy after the quality factor matching of the circuit is carried out by preferentially adopting a proper capacitor or matching a proper inductor in the first matching circuit and the second matching circuit. After the third matching circuit and the fourth matching circuit preferentially adopt proper capacitors or match proper inductors to carry out quality factor broadband matching of the circuits, high-speed transmission of communication signals and feedback signals is realized. Meanwhile, the interference of radio frequency energy to communication signals and feedback signals is reduced by adopting a dual noise reduction technology, and the normal transmission of the communication signals and the feedback signals is ensured. The dual noise reduction includes a first noise reduction and a second noise reduction. The noise is reduced for the first time, the magnetic flux cancellation principle of the coil is mainly used, and the interference of radio frequency energy on communication signals and feedback signals during transmission in a transmission channel is reduced through a special coil winding mode. And the second noise reduction is carried out, and the radio frequency energy radiated to the in-vitro communication unit and the in-vivo communication unit is attenuated under the action of the trap circuit, so that the interference of the radio frequency energy to communication signals and feedback signals in the transmission process is reduced. In addition, the multi-coil antenna system adjusts for changes in the transmission of radio frequency energy caused by the presence of a micromotion of the second communication device in the body based on the closed loop formed by the first communication device and the second communication device.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a block circuit diagram of a multi-coil antenna system in accordance with an embodiment of the present invention;

FIG. 2 is a schematic diagram of a first communication device of the multi-coil antenna system of FIG. 1;

fig. 3 is a schematic diagram of a second communication device of the multi-coil antenna system of fig. 1;

FIG. 4 is a schematic diagram of a transmission channel of the multi-coil antenna system of FIG. 1;

fig. 5 is a schematic view of the structure of the coil of the first communication device shown in fig. 2;

fig. 6 is a schematic diagram of the structure of the coil of the second communication device shown in fig. 3;

FIG. 7 is a schematic diagram of a trap circuit according to an embodiment of the present invention;

FIG. 8 is a schematic diagram of an energy matching circuit according to an embodiment of the present invention;

FIG. 9 is a schematic diagram of another energy matching circuit according to an embodiment of the present invention;

FIG. 10 is a flow chart of coil fine adjustment for the multi-coil antenna system of FIG. 1;

FIG. 11 is a graph of a test of the attenuation of the notch circuit of FIG. 7 at a signal frequency;

fig. 12 is a return loss test graph of a signal antenna at three different frequency points.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

The following describes the circuit structure and the operation process of the multi-coil antenna system in the implantable medical device in detail with reference to the accompanying drawings.

Please refer to fig. 1, which is a circuit block diagram of a multi-coil antenna system according to an embodiment of the present invention. As shown in fig. 1, the multi-coil antenna system 10 includes a first communication device 100 and a second communication device 200.

The first communication apparatus 100 is placed outside the body, and serves as an extracorporeal device that wirelessly transmits radio frequency energy and a communication signal to the second communication apparatus 200 and receives a feedback signal of the second communication apparatus 200.

The second communication device 200 is placed in the body and functions as an implanted device to wirelessly receive the radio frequency energy and communication signals of the first communication device 100 and to transmit feedback signals to the first communication device 100.

For example, in the retina implantation system for the blind, the first communication device 100 can provide video information collected outside the body as a communication signal and provide radio frequency energy required for the operation of the second communication device 200 inside the body, and the two signals are transmitted in a wireless manner. The second communication device 200 in the body can trigger the corresponding retinal cell according to the received radio frequency energy and communication signal, so as to achieve the purpose of acquiring the visual information. Meanwhile, due to the influence of eyeball rotation, the second communication device 200 located in the body slightly moves to cause the change of the radio frequency energy transmitted to the second communication device 200, and the second communication device 200 can transmit a feedback signal to the first communication device 100 outside the body according to the change of the displacement, so that the first communication device 100 can adjust the radio frequency energy and the transmitting power of the communication signal in real time, thereby reducing the power change of the device in the body, and realizing the bidirectional wireless communication between the external equipment and the implanted equipment in the body. When the eyeball rotates, mismatch of magnetic flux cancellation in the body is caused, interference is improved, and the interference of energy is reduced through the circuit part with double noise reduction.

In the embodiment of the present invention, the first communication device 100 can wirelessly transmit the rf energy and the communication signal to the second communication device 200, so that the second communication device 200 can output the corresponding trigger signal to the internal body tissue according to the received rf energy and communication signal. The in vivo tissue may be, for example, retinal cells located in the eye to trigger the in vivo tissue to produce a response. Meanwhile, when the displacement of the second communication device 200 inside the body changes, for example, when the position of the second communication device 200 slightly moves, the rf energy transmitted to the second communication device 200 also changes, and the second communication device 200 can transmit a feedback signal to the first communication device 100 outside the body according to the change, so that the first communication device 100 can adjust the rf energy and the transmission power of the communication signal, thereby reducing the power change of the inside device. Thereby realizing efficient energy transmission and high-speed bidirectional wireless communication.

Specifically, as shown in fig. 1, the first communication device 100 includes an external circuit control unit 101, an external energy unit 102, and an external communication unit 103.

The external circuit control unit 101 is configured to control the external energy unit 102 and the external communication unit 103 to output preset radio frequency energy and communication signals. Specifically, the external circuit control unit 101 outputs an energy control signal to the external energy unit 102 to control the external energy unit 102 to output a preset radio frequency energy; the extracorporeal circuit control unit 101 outputs a communication control signal to the extracorporeal communication unit 103 to control the extracorporeal communication unit 103 to output a preset communication control signal. The extracorporeal circuit control unit 101 may also adjust the output power of the radio frequency energy and the communication signal in real time according to the received feedback signal.

The external energy unit 102 is electrically connected to the external circuit control unit 101, and is configured to receive an energy control signal output by the external circuit control unit 101, and output radio frequency energy according to the action of the energy control signal.

The external communication unit 103 is electrically connected to the external circuit control unit 101, and is configured to receive the communication control signal output by the external circuit control unit 101 and output a communication signal according to the action of the communication control signal. Meanwhile, the external communication unit 103 is also configured to receive the feedback signal output by the second communication device 200 and transmit the feedback signal to the external circuit control unit 101.

In an embodiment, the second communication device 200 comprises an in-vivo circuit control unit 201, an in-vivo energy unit 202 and an in-vivo communication unit 203. Wherein, the in-vivo energy unit 202 and the in-vivo communication unit 203 are both electrically connected with the in-vivo circuit control unit 201.

The internal energy unit 202 receives the rf energy output by the external energy unit 102 in a wireless manner, matches the rf energy to improve the transmission efficiency of the rf energy, and then rectifies and filters the rf energy and transmits the rf energy to the internal circuit control unit 201.

The in-vivo communication unit 203 receives the communication signal output by the in-vitro communication unit 103 in a wireless manner, matches the communication signal to improve the transmission rate of the communication signal, attenuates the radio frequency energy radiated into the in-vivo communication unit 203 to reduce the interference of the radio frequency energy to the communication signal, modulates and demodulates the radio frequency energy, and transmits the radio frequency energy to the in-vivo circuit control unit 201. Meanwhile, the internal communication unit 203 is also configured to receive the response signal output by the internal circuit control unit 201, and output a feedback signal to the external communication unit 103 of the first communication device 100 according to the action of the response signal, so that high-rate bidirectional wireless communication between the first communication device 100 and the second communication device 200 is realized.

The in-vivo circuit control unit 201 is configured to receive the rf energy transmitted by the in-vivo energy unit 202 and the communication signal transmitted by the in-vivo communication unit 203, and output a corresponding trigger signal to the in-vivo tissue according to the rf energy and the communication signal. Meanwhile, when the second communication device 200 is displaced to change the rf energy, the in-vivo circuit control unit 201 also outputs a response signal to the in-vivo communication unit 203.

In the embodiment of the present invention, the multi-coil antenna system 10 realizes high-efficiency transmission of radio frequency energy through the external energy unit 102 and the internal energy unit 202, and realizes high-rate transmission of communication signals and feedback signals, i.e., high-rate bidirectional wireless communication, through the external communication unit 103 and the internal communication unit 203.

Specifically, please refer to fig. 2, which is a schematic structural diagram of the first communication device of the multi-coil antenna system shown in fig. 1 in fig. 2. As shown in fig. 2, the extracorporeal energy unit 102 includes an energy radio frequency unit 1021, a first matching circuit 1022, and a first coil L1. The energy rf unit 1021, the first matching circuit 1022 and the first coil L1 are electrically connected in sequence.

The energy control signal output by the extracorporeal circuit control unit 101 enables the energy rf unit 1021 to emit rf energy. The first matching circuit 1022 improves the transmission efficiency of the rf energy by preferentially adopting a proper capacitor or matching with a proper inductor for high-quality factor matching of the circuit, and transmits the rf energy to the in-vivo energy unit 202 in a wireless manner through the first coil L1.

The external communication unit 103 includes a communication radio frequency unit 1031, a first trap circuit 1032, a third matching circuit 1033, and a third coil L3. The rf communication unit 1031, the first trap circuit 1032, the third matching circuit 1033, and the third coil L3 are electrically connected in sequence.

Wherein, the communication control signal outputted by the extracorporeal circuit control unit 101 makes the communication rf unit 1031 transmit the corresponding communication signal. When receiving the communication signal, first notch circuit 1032 can attenuate the radio frequency energy radiated to external communication section 103, thereby reducing interference of the radio frequency energy with the communication signal. And the third matching circuit 1033 improves the bandwidth and transmission rate of the communication signal by performing low-quality-factor broadband matching of the circuit using an appropriate capacitance or inductance, and transmits the communication signal to the in-vivo communication unit 203 wirelessly through the third coil L3.

In addition, the feedback signal is also received wirelessly by the third coil L3 and is transmitted to the extracorporeal circuit control unit 101 via the third matching circuit 1033, the first trap circuit 1032, and the communication radio frequency unit 1031.

Specifically, please refer to fig. 3, which is a schematic structural diagram of a second communication device of the multi-coil antenna system shown in fig. 1. As shown in fig. 3, the in-vivo energy unit 202 includes a second coil L2, a second matching circuit 2021, and a rectifying-filtering unit 2022. The second coil L2, the second matching circuit 2021 and the rectifying and filtering unit 2022 are electrically connected in sequence.

The second coil L2 wirelessly receives the rf energy output from the external energy unit 102 and transmits the rf energy to the second matching circuit 2021. The second matching circuit 2021 performs high quality factor matching of the circuit by using a suitable capacitor or inductor, thereby improving the transmission efficiency of the rf energy, and transmits the rf energy to the in-vivo circuit control unit 201 after the rf energy is rectified and filtered by the rectifying and filtering unit 2022, thereby providing energy for the second communication device 200.

Intra-body communication section 203 includes fourth coil L4, fourth matching circuit 2031, second notch circuit 2032, and modem section 2033. The fourth coil L4, the fourth matching circuit 2031, the second notch circuit 2032, and the modem unit 2033 are electrically connected in sequence.

Among them, the communication signal output from the external communication unit 103 is received wirelessly by the fourth coil L4 and transmitted to the fourth matching circuit 2031. The fourth matching circuit 2031 performs low quality factor wideband matching of the circuit by using a suitable capacitor or inductor, increases the transmission rate of the communication signal, attenuates the radio frequency energy radiated into the in-vivo communication unit 203 by the second notch circuit 2032, reduces interference of the radio frequency energy on the communication signal, performs modulation and demodulation processing on the communication signal by the modulation and demodulation unit 2033, and transmits the communication signal to the in-vivo circuit control unit 201.

The feedback signal may be transmitted via modem section 2033, second notch circuit 2032, and fourth matching circuit 2031, and then wirelessly transmitted to external communication section 103 via fourth coil L4.

In the embodiment of the present invention, the multi-coil antenna system 10 performs high-quality-factor matching of the circuit by preferentially using a proper capacitor or matching with a proper inductor by using the first matching circuit 1022 and the second matching circuit 2021, so as to achieve high-efficiency transmission of radio frequency energy, performs low-quality-factor broadband matching of the circuit by using a proper capacitor or inductor by using the third matching circuit 1033 and the fourth matching circuit 2031, so as to achieve high-speed transmission of a communication signal and a feedback signal, and reduces interference of the radio frequency energy on the communication signal and the feedback signal by using the first notch circuit 1032 and the second notch circuit 2032.

Further, please refer to fig. 4, which is a schematic structural diagram of a transmission channel of the multi-coil antenna system shown in fig. 1. As shown in fig. 4, the two-way wireless transmission of the rf energy, the communication signal and the feedback signal between the first communication apparatus 100 and the second communication apparatus 200 is realized by the transmission channel formed by the first coil L1, the second coil L2, the third coil L3 and the fourth coil L4, so as to realize the high efficiency rf energy transfer and the high speed two-way wireless communication between the external device and the implanted device inside the body. That is, the first coil L1 and the second coil L2 form an energy channel to transmit radio frequency energy, and the third coil L3 and the fourth coil L4 form a signal channel to transmit communication signals and feedback signals. Meanwhile, an energy relay coil L5 may be optionally added to improve efficiency, which is not specifically limited in the embodiments of the present invention.

In the embodiment of the invention, in the transmission process of signals, the coils are coupled with each other, and the coupling relationship is shown in table 1:

TABLE 1 coil coupling relation table

As shown in table 1, the coil coupling coefficients K13, K14, K24 and K32 interfere with the transmission of the communication signal and the feedback signal, while the coil coupling coefficient K12 represents the transmission efficiency of the radio frequency energy, and K34 represents the transmission efficiency of the communication signal and the feedback signal. Therefore, in order to improve the signal transmission efficiency of the multi-coil antenna system, it is necessary to reduce the coil coupling coefficients K13, K14, K24 and K32 while increasing the coil coupling coefficient K12 as much as possible and making the value of K34 moderate.

Further, in the embodiment of the present invention, when the distance between the first communication apparatus 100 and the second communication apparatus 200 is determined, the second coil L2 is located at the projection center of the first coil L1 in a manner that the first coil L1 corresponds to the front of the second coil L2, so as to increase the coil coupling coefficient K12, and in this case, the K34 is located within a reasonable coupling coefficient range.

Meanwhile, the coil coupling coefficients K13, K14, K24 and K32 are reduced by means of a magnetic flux cancellation method, so that interference of radio frequency energy to communication signals and feedback signals in a transmission process is reduced.

In order to solve the problems of the implanted medical device, high-efficiency energy transfer from the outside of the body to the inside of the body, high-speed bidirectional wireless communication and reduction of the interference of energy to the wireless communication, particularly to the interference to the wireless communication in the body, the invention needs at least 4 coils, matching circuits and trap circuits, wherein 2 coils are arranged outside the body and 2 coils are arranged in the body; l1 is an external energy transmitting coil, L2 is an internal energy receiving coil, L3 is an external wireless communication coil, L4 is an internal wireless communication coil, and an energy-selective relay coil L5 can be installed outside or inside the body and is not generally used in order to reduce the structural complexity, the technical implementation complexity and the operation complexity. It is understood that in other embodiments, the first coil L1, the second coil L2, the third coil L3 and the fourth coil L4 may be a coil set formed by connecting a plurality of sub-coils in series.

Specifically, please refer to fig. 5, which is a schematic structural diagram of the coil of the first communication device shown in fig. 2. As shown in fig. 5, the coils in the first communication device 100 include a first coil L1 and a third coil L3, wherein the thick line is a first coil L1, the thin line is a third coil L3, both of which are wound with multiple turns, and the third coil L3 is on the periphery of the first coil L1. Meanwhile, the first coil L1 and the third coil L3 conform to the structure of the first communication device 100, constituting a first conformal antenna. Here, the first conformal antenna means that the first coil L1 is located near the center of the first communication device 100, and the third coil L3 is wound along the periphery of the first communication device 100. Further, since the first communication device 100 has a certain curved surface, the first coil L1 and the third coil L3 are also provided as a curved-surface coil structure having a certain arc as a whole according to the structure of the extracorporeal product. The coil is conformal with the structure, make full use of packaging structure's effective part, be favorable to the improvement of signal coil inductance value, the high quality factor of energy coil has the load to match stably to constitute conformal antenna.

The first coil L1 is a ferromagnetic wire made of a plurality of metallic (usually copper, silver, alloy, etc.) thin wires having good electrical conductivity, and the diameter of the thin metallic wires is determined by the operating frequency. In one embodiment, the metal thin wires are covered with an insulating material.

The first coil L1 is usually wound in a regular shape or other shape and requires that the value of the quality factor be as high as possible at the frequency of operation. And a layer of magnetic material with small magnetic loss and proper magnetic conductivity is selectively attached to the first coil L1 to improve the directivity of the radio frequency energy antenna, so that the wireless transmission efficiency of the radio frequency energy is improved.

The third coil L3 is made of a material similar to the first coil L1, and has a configuration designed according to the structural design of the first communication device 100, a size larger than the first coil L1, and an inner portion having a partial area overlapping with the first coil L1.

Further, in the transmission path formed by the first coil L1, the second coil L2, the third coil L3, and the fourth coil L4, during normal operation, the first coil L1 and the second coil L2 generate magnetic fluxes L1c + and L2c + in the positive directions at the overlapping area of the third coil L3. Meanwhile, the first coil L1 generates opposite magnetic fluxes L1 a-and L1 b-at the non-overlapping area of the third coil L3, and the second coil L2 generates opposite magnetic fluxes L2 a-and L2 b-at the non-overlapping area of the third coil L3.

The embodiment of the present invention adjusts the size of the overlapping area by adjusting the distance d between the upper and lower two ferromagnetic wires of the third coil L3 or the position of the moving coil, so that the difference between the forward magnetic flux generated by the first coil L1 and the second coil L2 on the third coil L3 and the reverse magnetic flux generated by the first coil L1 and the second coil L2 on the third coil L3 is within a predetermined range. Namely, the sum of L1c + and L2c + and the sum of L1a-, L1b-, L2 a-and L2 b-are subjected to difference operation, and the obtained result is in a preset range, so that the aim of magnetic flux cancellation is fulfilled, and the coil coupling coefficients K13 and K23 are further reduced. In this embodiment, the predetermined range is-0.01 to 0.01, and this embodiment is not limited.

Please refer to fig. 6, which is a schematic structural diagram of the coil of the second communication device shown in fig. 3. As shown in fig. 6, the coils in the second communication device 200 include a second coil L2 and a fourth coil L4, wherein the thick line is the second coil L2, the thin line is the fourth coil L4, both of which are wound with multiple turns, and the fourth coil L4 is on the periphery of the second coil L2. Meanwhile, the second coil L2 and the fourth coil L4 conform to the structure of the second communication device 200, constituting a second conformal antenna. Here, the second conformal antenna refers to a second coil L2 close to the package of the second communication device 200, and the fourth coil L4 is wound along the edge of the second communication device 200. In addition, since the second communication device 200 has a certain curved surface, the second coil L2 is also configured as a curved coil structure having a certain curvature as a whole according to the structure of the second communication device 200, and the fourth coil L4 needs to be able to perform twisting and bending according to the structure. The coil is conformal with the structure, makes full use of the effective part of the packaging structure, is favorable for improving the inductance value of the signal coil particularly under the condition that the internal space is limited, and has high quality factor and stability under load matching, thereby forming a conformal antenna.

The second coil L2 is a ferromagnetic wire made of a single-stranded wire or multiple-stranded wires made of a biocompatible metal material (such as gold, platinum, alloy, etc.), each of the multiple-stranded wires needs to be coated with a biocompatible insulating layer or a composite insulating layer (such as Parylene, PTFE, SiO2, etc. or a composite coating), and since the second communication device 200 has a small volume, the second coil L2 has a small volume and weight, which are determined by the in-vivo installation position, and the quality factor of the wound coil in the operating frequency band is as high as possible.

The fourth coil L4 is made of a material, insulating property, biocompatibility, and a processing technique similar to the second coil L2, and has a shape designed according to a structure, a contour conforming to the structure, and a winding number fixed to increase an outer surrounding area as much as possible, thereby increasing an inductance value, and has a size larger than that of the second coil L2, and a partial area inside the second coil L1 overlaps the second coil L3526.

Further, in the transmission path formed by the first coil L1, the second coil L2, the third coil L3 and the fourth coil L4, during normal operation, the first coil L1 and the second coil L2 generate forward magnetic fluxes L1d + and L2c + at the overlapping area of the fourth coil L4, meanwhile, the second coil L2 generates reverse magnetic fluxes L2 a-and L2 b-at the non-overlapping area of the fourth coil L4, and due to the large size of the external coil, the fourth coil L4 is substantially within the projection range of the first coil L1, so that the first coil L1 generates forward magnetic fluxes L1e + and L1f + at the non-overlapping area of the fourth coil L4.

In the embodiment of the invention, by means of other methods such as adjusting the distance d1 between the upper and lower two magnet wires of the fourth coil L4 or moving the position of the coil, the size of the overlapping area is adjusted, so that the obtained result after the difference operation between the forward magnetic flux generated by the first coil L1 and the second coil L2 on the fourth coil L4 and the reverse magnetic flux generated by the second coil L2 on the fourth coil L4 is within a predetermined range, namely the obtained result after the difference operation between the sum of L1d +, L2c +, L1e + and L1f + and the sum of L2 a-L2 b-is within a predetermined range, the purpose of magnetic flux cancellation is achieved, and the coil coupling coefficients K14 and K24 are further reduced. In this embodiment, the predetermined range is-0.01 to 0.01, and this embodiment is not limited.

The coil winding manner and the coil position design shown in fig. 5 and fig. 6 are applied to the coils of the first communication device 100 and the second communication device 200, specifically, the first coil L1 and the third coil L3 are conformal to the first communication device 100, and the second coil L2 and the fourth coil L4 are conformal to the second communication device 200, so that the structural space in the first communication device 100 and the second communication device 200 is fully utilized, the utilization rate of the internal space of the product is improved, on the basis, the magnetic flux cancellation is realized through the proper coil position design, and the interference of radio frequency energy to communication signals and feedback signals during transmission in a transmission channel is reduced.

The interference to the communication signal and the feedback signal also includes the radio frequency energy radiated to the external communication unit 103 and the internal communication unit 203, and the embodiment of the present invention attenuates such interference by providing the first notch circuit 1032 and the second notch circuit 2032.

Specifically, please refer to fig. 7, which is a schematic structural diagram of a trap circuit according to an embodiment of the present invention. As shown in fig. 7, the circuit includes a fifth capacitor C5, a sixth capacitor C6, a seventh capacitor C7, a sixth inductor L6, a third node C, a fourth node D, a signal path first connection terminal L, a signal path second connection terminal N, a signal matching circuit first connection terminal M, and a signal matching circuit second connection terminal Q.

One end of the fifth capacitor C5 is electrically connected to the first connection end L of the signal channel, and the other end of the fifth capacitor C5 is electrically connected to the third node C.

The signal channel second connection end N is electrically connected to the fourth node D, and the signal matching circuit second connection end Q is electrically connected to the fourth node D.

One end of the sixth capacitor C6 is electrically connected to the third node C, and the other end of the sixth capacitor C6 is electrically connected to the first connection end M of the signal matching circuit.

One end of the seventh capacitor C7 is electrically connected to the third node C, the other end of the seventh capacitor C7 is electrically connected to one end of the sixth inductor L6, and the other end of the sixth inductor L6 is electrically connected to the fourth node D.

In the embodiment of the present invention, the first notch circuit 1032 and the second notch circuit 2032 include notch circuits shown in fig. 7, and reduce interference of radio frequency energy on communication signals and feedback signals during transmission by attenuating the radio frequency energy radiated into the external communication unit 103 and the internal communication unit 203.

Further, the notch circuit applied in the embodiment of the present invention is not limited to the one shown in fig. 7, for example, a new notch circuit may be formed by interchanging positions of the seventh capacitor C7 and the sixth inductor L6, or a new notch circuit may be formed by changing a topology structure into a differential structure, or the notch circuit shown in fig. 7 may be modified to a notch circuit built by an active device, a multi-step notch circuit built by a passive device, or a circuit variation such as increasing the number of notches may be applied to the first notch circuit 1032 and the second notch circuit 2032.

The embodiment of the invention reduces the interference of the radio frequency energy to the communication signal and the feedback signal by adopting a double noise reduction technology, and ensures the normal transmission of the communication signal and the feedback signal, namely, the noise reduction processing of the radio frequency energy is carried out twice in a signal channel. The dual noise reduction technique includes a first and a second re-noise reduction. The first noise reduction is realized by mainly using the magnetic flux cancellation principle of the coil and reducing the interference of radio frequency energy on communication signals and feedback signals when the radio frequency energy is transmitted in a transmission channel in a special coil winding mode. And in the second noise reduction step, the trap circuit is used for attenuating the radio frequency energy radiated to the external communication unit 103 and the internal communication unit 203, so that the interference of the radio frequency energy to the communication signal and the feedback signal in the transmission process is reduced.

The embodiment of the present invention implements high-efficiency transmission of radio frequency energy by using appropriate capacitors (preferred capacitors) or inductors in the first matching circuit 1022 and the second matching circuit 2021 for high-quality factor matching of the circuits. And high-rate transmission of communication signals and feedback signals is achieved after low-q broadband matching of the circuits is performed by using appropriate capacitances or inductances in the third matching circuit 1033 and the fourth matching circuit 2031.

Specifically, please refer to fig. 8, which is a schematic structural diagram of an energy matching circuit according to an embodiment of the present invention. As shown in fig. 8, the energy matching circuit includes a first capacitor C1, a second capacitor C2, a first node a, a first connection terminal X for rf energy, a second connection terminal Y for rf energy, a first connection terminal G for energy coil, and a second connection terminal H for energy coil.

One end of the first capacitor C1 is electrically connected to the first connection terminal X of rf energy, and the other end of the first capacitor C1 is electrically connected to the first node a.

The radio frequency energy second connection end Y is electrically connected to the first node A, and the energy coil second connection end H is electrically connected to the first node A.

One end of the second capacitor C2 is electrically connected to the first connection end X of the rf energy, and the other end of the second capacitor C2 is electrically connected to the first connection end G of the energy coil.

Please refer to fig. 9, which is a schematic structural diagram of another energy matching circuit according to an embodiment of the present invention. As shown in fig. 9, the energy matching circuit includes a third capacitor C3, a fourth capacitor C4, a second node B, a first connection terminal X for rf energy, a second connection terminal Y for rf energy, a first connection terminal G for energy coil, and a second connection terminal H for energy coil.

One end of the fourth capacitor C4 is electrically connected to the first rf energy connection terminal X, and the other end of the fourth capacitor C4 is electrically connected to the second node B.

The radio frequency energy second connection end Y is electrically connected to the second node B, and the energy coil second connection end H is electrically connected to the second node B.

One end of the third capacitor C3 is electrically connected to the first rf energy connection terminal X, and the other end of the third capacitor C3 is electrically connected to the first energy coil connection terminal G.

In the embodiment of the present invention, the first matching circuit 1021 and the second matching circuit 2021 include the energy matching circuit shown in fig. 8 or fig. 9, and the first coil L1 and the second coil L2 are close to the rf energy transfer frequency F1 by a narrowband high-quality-factor matching method, so as to improve the transfer efficiency of the rf energy.

Further, in the embodiment of the present invention, the communication bandwidth is calculated according to the data rate, the coding and the modulation method, the value of the load quality factor is calculated according to the data communication frequency F2, and finally the matching method with the low quality factor is applied to the third matching circuit 1033 and the fourth matching circuit 2031 according to the load, so as to realize the high-rate and bidirectional communication of the communication signal and the feedback signal transmission.

In the process of signal transmission between the first communication device 100 and the second communication device 200, the second communication device 200 located inside the body may have a slight position change, which may further affect the transmission of the radio frequency energy, and the embodiment of the present invention adjusts the radio frequency energy change caused by the coil micro-motion according to the closed loop formed by the first communication device 100 and the second communication device 200.

Specifically, please refer to fig. 10, which is a flowchart illustrating the coil fine-tuning of the communication circuit shown in fig. 1. As shown in fig. 10, when the second communication device 200 is jogged, the rf energy output by the rectifying and filtering unit 2022 changes accordingly, and based on this, the embodiment of the present invention implements coil jogging adjustment through the closed-loop control loop formed by the first communication device 100 and the second communication device 200, and the adjusting step includes:

s501, the implantable medical device is started.

In an embodiment of the present invention, when the implantable medical device receives the input activation command, the implantable medical device is activated.

And S502, recording the numerical value of the radio frequency energy output by the rectifying and filtering unit.

The value of the radio frequency energy received by the in-vivo circuit control unit 201 is recorded.

S503, judging whether the change of the radio frequency energy exceeds a threshold value.

In the embodiment of the present invention, when it is determined that the change of the radio frequency energy exceeds the threshold, step S504 is executed, and the in-vivo circuit control unit 201 in the second communication device 200 records the change.

In the embodiment of the invention, when the change of the radio frequency energy is judged not to exceed the threshold value, the inching adjustment step is ended.

S504, the internal circuit control unit 201 records the change amount.

And S505, responding to the variable quantity to generate a corresponding feedback signal, and transmitting the feedback signal to an extracorporeal circuit control unit.

Specifically, in the embodiment of the present invention, the internal circuit control unit 201 outputs a response signal to the internal communication unit 203 according to the variation, and then the internal communication unit 203 outputs a corresponding feedback signal to the external communication unit 103 according to the response signal, and the external communication unit 103 transmits the feedback signal to the external circuit control unit 101.

S506, the external circuit control unit 101 adjusts the rf power.

The extracorporeal circuit control unit 101 adjusts the magnitude of the energy control signal and the communication control signal according to the received feedback signal, thereby achieving the purpose of adjustment and reducing the internal power change. Then, the next detection is performed on the change in the rf energy, and it is determined whether the change in the rf energy exceeds the threshold, that is, step S503 is continuously performed.

The embodiment of the invention sets a specific experiment to verify the actual effect of the multi-coil antenna system 10.

The embodiment of the invention uses a demagnetizing wire consisting of 6 enameled wires with the thickness of 0.13mm on the first coil L1 and the third coil L3, wherein the inside of each enameled wire is oxygen-free copper, or single crystal copper, or silver-plated copper wire. High-purity gold wires of 0.13mm are used on the second coil L2 and the fourth coil L4, and a 6-micron Parylene polymer film coating and 2-micron SiO are wrapped on the outer layer₂The coating meets the sterility standard and long-term reliability of medical devices.

Wherein the first coil L1 is wound with 40 turns, the third coil L3 is wound with 10 turns, the single-layer winding method is preferred, and the second double-layer winding method is preferred. The second coil L2 is wound in 5 layers with 70 turns and the fourth coil L4 is wound in 2 layers with 10 turns. And the total surface area of the second coil L2 and the fourth coil L4 is about 120 square millimeters.

Specifically, when the rf energy transfer frequency F1 is 1MHz, the inductance values of the first coil L1 and the second coil L2 range from 80uH to 120uH, the quality factor value of the first coil L1 is greater than 100, and the quality factor value of the second coil L2 is greater than 50.

When the data communication frequency F2 of the communication signal and the feedback signal is 13.56MHz, the inductance values of the third coil L3 and the fourth coil L4 range from 2uH to 7uH, the quality factor value thereof ranges from 6 to 12, the channel bandwidth is 3MHz, and the air communication rate 2MBPS is modulated and demodulated using a 30% ASK/OOK modulation and demodulation method.

Further, in the trap circuit shown in fig. 7, the capacitance of the fifth capacitor C5 and the sixth capacitor C6 is 180pF, the capacitance of the seventh capacitor C7 is 37pF, and the inductance of the sixth inductor is 650 nH.

On the basis of the structure setting and data design of the multi-coil antenna system, experimental tests are carried out in the embodiment of the invention to prove the excellence of the multi-coil antenna system, including the test of data transmission rate, the test of radio frequency energy transmission efficiency, the attenuation test of a trap circuit to signal frequency and the return loss test under different data transmission frequencies.

The data transmission rate is measured by centering on a data transmission frequency of 13.56MHz, measuring a channel bandwidth of 3MHz, and measuring a data transmission rate of 2MBPS by using a 30% ASK/OOK modulation and demodulation method.

The efficiency of rf energy transfer was tested by using the first communication device 100 and the second communication device 200 with an air gap of 10 mm to complete coil pairing, and the efficiency of rf energy transfer between the antennas was 90% under the condition that the depth of the second communication device 200 was 8 mm. After the coil pairing is completed with the distance between the pig eye surface and the eyeball between the first communication device 100 and the second communication device 200 being 13mm, the radio frequency energy transfer efficiency can still reach 24%, and the temperature change in the pig eye sphere is less than 1 ℃.

Please refer to fig. 11, which is a graph illustrating the attenuation test of the notch circuit shown in fig. 7 for the signal frequency. As shown in fig. 11, the attenuation test of the notch circuit to the signal frequency includes the attenuation test to the rf energy transfer frequency F1 and the data communication frequency F2, wherein the attenuation test to the rf energy transfer frequency F1 is greater than 40dB, and the attenuation test to the data communication frequency F2 is less than 1dB, so that the interference of the rf energy to the data transmission process is reduced.

Please refer to fig. 12, which is a graph illustrating a return loss test at three different frequencies. As shown in FIG. 12, the data communication frequency F2 is 13.56MHz, and the return loss is-19.207 dB. At the data transmission frequency F2 of 12.56MHz, its return loss is-7.3375 dB. At the data communication frequency F2 of 14.56MHz, its return loss is-11.487 dB. Of these three different frequencies, the return loss at the data communication frequency F2 of 13.56MHz is the smallest, and performs best compared to the other two.

Compared with the prior art, the embodiment of the invention realizes high-efficiency transmission of radio frequency energy after the first matching circuit 1022 and the second matching circuit 2021 preferentially adopt proper capacitors or match proper inductors for high-quality factor matching of the circuits. After low-quality-factor broadband matching of the circuits is performed in the third matching circuit 1033 and the fourth matching circuit 2031 by using appropriate capacitors or inductors, high-speed transmission of communication signals and feedback signals is realized. Meanwhile, the interference of radio frequency energy to communication signals and feedback signals is reduced by adopting a dual noise reduction technology, and the normal transmission of the communication signals and the feedback signals is ensured. The noise is reduced for the first time, the magnetic flux cancellation principle of the coil is mainly used, and the interference of radio frequency energy on communication signals and feedback signals during transmission in a transmission channel is reduced through a special coil winding mode. And the second noise reduction is carried out, and radio frequency energy radiated to the external communication unit 103 and the internal communication unit 203 is attenuated through the action of the trap circuit, so that the interference of the radio frequency energy to communication signals and feedback signals in the transmission process is reduced. In addition, the multi-coil antenna system 10 adjusts the change of the signal transmission efficiency caused when the second communication device 200 in the body is moved slightly according to the closed loop formed by the first communication device 100 and the second communication device 200.

The multi-coil antenna system and the implantable medical device provided by the embodiment of the present invention are described in detail above, and the principle and the embodiment of the present invention are explained in detail herein by applying specific examples, and the description of the above embodiments is only used to help understanding the method and the core idea of the present invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, there may be variations in the specific embodiments and the application scope, and in summary, the content of the present specification should not be construed as a limitation to the present invention.

Claims

1. A multi-coil antenna system comprising a first communication device disposed outside a body and a second communication device disposed inside the body and in bidirectional wireless communication with the first communication device; wherein the first communication device includes at least a first coil and a third coil, the first coil and the third coil constituting a first conformal antenna, the second communication device includes at least a second coil and a fourth coil having biocompatibility, the second coil and the fourth coil constituting a second conformal antenna, the first coil is coupled with the corresponding second coil to form an energy channel and perform quality factor matching, the third coil is coupled with the corresponding third coil to form a signal channel and perform quality factor broadband matching, and noise reduction processing is performed twice within the signal channel, the first communication device transmits radio frequency energy and a communication signal to the second communication device through the energy channel and the signal channel, respectively, the second communication device receives the radio frequency energy and the communication signal transmitted by the first communication device, and outputting a corresponding feedback signal to the first communication device from the signal channel according to the radio frequency energy and the communication signal, wherein the third coil has a first overlapping region and a first non-overlapping region, and a difference operation is performed between the magnetic flux generated in the first overlapping region and the magnetic flux generated in the first non-overlapping region to obtain a result within a predetermined range.

2. The multi-coil antenna system of claim 1, wherein the first conformal antenna comprises:

the first coil is located at the center of the structure of the first communication device, the third coil is located at the peripheral edge of the structure of the first communication device, and the third coil is located at the periphery of the first coil.

3. The multi-coil antenna system of claim 1, wherein the second conformal antenna comprises:

the second coil is located in the structural center of the second communication device, the fourth coil is located at the structural peripheral edge of the second communication device, and the fourth coil is located at the periphery of the second coil.

4. A multi-coil antenna system according to claim 1, wherein the second and fourth coils are each a ferromagnetic wire comprising a single-stranded or multi-stranded wire of a biocompatible metallic material, each wire being coated on its surface with a biocompatible or composite insulating layer.

5. The multi-coil antenna system as claimed in claim 3, wherein the fourth coil has a second overlapping area and a second non-overlapping area, and the difference between the magnetic flux generated in the second overlapping area and the magnetic flux generated in the second non-overlapping area is within the predetermined range.

6. The multi-coil antenna system as claimed in claim 1, wherein the first coil corresponds to a front surface of the second coil in a case where the first communication device and the second communication device are located at a distance from each other, such that the second coil is located at a center of projection of the first coil.

7. The multi-coil antenna system of claim 1, wherein the first, second, third and fourth coils are each a coil set consisting of a plurality of sub-coils connected in series.

8. The multi-coil antenna system of claim 1, wherein the first communication device comprises an external circuit control unit, an external energy unit, and an external communication unit, wherein,

the external circuit control unit is used for controlling the external energy unit and the external communication unit to output preset radio frequency energy and communication signals, and the external circuit control unit adjusts the output power of the radio frequency energy and the communication signals according to the received feedback signals;

the in-vitro energy unit is electrically connected with the in-vitro circuit control unit and used for receiving the energy control signal output by the in-vitro circuit control unit and outputting the radio frequency energy according to the action of the energy control signal;

the external communication unit is electrically connected with the external circuit control unit and used for receiving the communication control signal output by the external circuit control unit and outputting the communication signal according to the action of the communication control signal;

the external communication unit is also used for receiving the feedback signal output by the second communication device and transmitting the feedback signal to the external circuit control unit.

9. The multi-coil antenna system of claim 8, wherein the external energy unit comprises an energy radio frequency unit, a first matching circuit, and a first coil, wherein the energy radio frequency unit, the first matching circuit, and the first coil are electrically connected in sequence,

the energy control signal output by the external circuit control unit enables the energy radio frequency unit to emit the radio frequency energy, and after the first matching circuit performs the quality factor matching, the radio frequency energy is transmitted to the internal energy unit in a wireless mode through the first coil.

10. The multi-coil antenna system of claim 9, wherein the external communication unit comprises a communication rf unit, a first notch circuit, a third matching circuit, and a third coil, wherein the communication rf unit, the first notch circuit, the third matching circuit, and the third coil are electrically connected in sequence, and the first co-formed antenna and the first notch circuit cooperate to form two noise reduction processes on rf energy;

the communication control signal output by the external circuit control unit enables the communication radio frequency unit to transmit a communication signal, the first trap circuit receives the communication signal and is used for attenuating radio frequency energy radiated into the external communication unit, and the third matching circuit is used for transmitting the communication signal to the internal communication unit in a wireless mode through the third coil after quality factor broadband matching is carried out;

the third coil receives the feedback signal in a wireless mode and transmits the feedback signal to the extracorporeal circuit control unit through the third matching circuit, the first trap circuit and the communication radio frequency unit.

11. The multi-coil antenna system of claim 10, wherein the second communication device comprises an in-vivo circuitry control unit, an in-vivo energy unit, and an in-vivo communication unit, wherein,

the in-vivo energy unit receives the radio frequency energy in a wireless mode and transmits the radio frequency energy to the in-vivo circuit control unit;

the in-vivo communication unit receives the communication signal in a wireless mode and transmits the communication signal to the in-vivo circuit control unit;

the in-vivo communication unit is used for receiving the response signal output by the in-vivo circuit control unit and outputting a feedback signal according to the action of the response signal;

the in-vivo circuit control unit is used for receiving the radio frequency energy transmitted by the in-vivo energy unit and the communication signal transmitted by the in-vivo communication unit, and outputting a trigger signal to in-vivo tissues according to the radio frequency energy and the communication signal so as to trigger the in-vivo tissues to generate reactions;

when the second communication device generates micro-motion to cause the change of the radio frequency energy, the in-vivo circuit control unit outputs the response signal to the in-vivo communication unit.

12. The multi-coil antenna system of claim 11, wherein the in-vivo energy unit comprises a second coil, a second matching circuit, and a rectifying-filtering unit, wherein the second coil, the second matching circuit, and the rectifying-filtering unit are electrically connected in sequence,

the second coil receives radio frequency energy output by the in-vitro energy unit in a wireless mode and transmits the radio frequency energy to the second matching circuit, the second matching circuit performs quality factor matching and then carries out rectification filtering processing on the radio frequency energy through the rectification filtering unit, and the radio frequency energy is transmitted to the in-vivo circuit control unit to provide energy for the second communication device.

13. The multi-coil antenna system of claim 11, wherein the in-vivo communication unit comprises a fourth coil, a fourth matching circuit, a second notch circuit, and a modem unit, wherein the fourth coil, the fourth matching circuit, the second notch circuit, and the modem unit are electrically connected in sequence, and the second conformal antenna and the second notch circuit work together to perform two noise reduction processes on the rf energy;

the fourth coil receives the radio frequency energy output by the external communication unit in a wireless mode and transmits the radio frequency energy to the fourth matching circuit, the second trap circuit attenuates the radio frequency energy radiated into the internal communication unit after the fourth matching circuit executes the quality factor broadband matching, and the modem unit transmits the communication signal to the internal circuit control unit after carrying out the modem processing on the communication signal;

after the feedback signal is transmitted through the modem unit, the second notch circuit, and the fourth matching circuit, the fourth coil wirelessly transmits the feedback signal to the extracorporeal communication unit.

14. The multi-coil antenna system of claim 12, wherein the first matching circuit and the second matching circuit each comprise a first fundamental matching circuit comprising a first capacitor, a second capacitor, a radio frequency energy first connection, a radio frequency energy second connection, an energy coil first connection, and an energy coil second connection, wherein,

one end of the first capacitor is electrically connected to the radio frequency energy first connecting end, and the other end of the first capacitor is electrically connected to a first node;

the radio frequency energy second connecting end is electrically connected to the first node, and the energy coil second connecting end is electrically connected to the first node;

one end of the second capacitor is electrically connected to the radio frequency energy first connection end, and the other end of the second capacitor is electrically connected to the energy coil first connection end.

15. The multi-coil antenna system of claim 12, wherein the first matching circuit and the second matching circuit are formed by a second basic matching circuit comprising a third capacitor, a fourth capacitor, a radio frequency energy first connection, a radio frequency energy second connection, an energy coil first connection, and an energy coil second connection, wherein,

one end of the fourth capacitor is electrically connected to the radio frequency energy first connecting end, and the other end of the fourth capacitor is electrically connected to the second node;

the radio frequency energy second connecting end is electrically connected to the second node, and the energy coil second connecting end is electrically connected to the second node;

one end of the third capacitor is electrically connected to the first radio frequency energy connecting end, and the other end of the third capacitor is electrically connected to the first energy coil connecting end.

16. The multi-coil antenna system of claim 13, wherein the electrical parameters of the third matching circuit and the fourth matching circuit are set according to data transmission rate, coding, modulation scheme, data transmission frequency, and load.

17. The multi-coil antenna system of claim 13, wherein the first and second notch circuits each comprise a first fundamental notch circuit comprising a fifth capacitor, a sixth capacitor, a seventh capacitor, a sixth inductor, a signal path first connection, a signal path second connection, a signal matching circuit first connection, and a signal matching circuit second connection, respectively,

one end of the fifth capacitor is electrically connected to the first connection end of the signal channel, and the other end of the fifth capacitor is electrically connected to the third node;

the second connecting end of the signal channel is electrically connected to a fourth node, and the second connecting end of the signal matching circuit is electrically connected to the fourth node;

one end of the sixth capacitor is electrically connected to the third node, and the other end of the sixth capacitor is electrically connected to the first connection end of the signal matching circuit;

one end of the seventh capacitor is electrically connected to the third node, the other end of the seventh capacitor is electrically connected to one end of the sixth inductor, and the other end of the sixth inductor is electrically connected to the fourth node.

18. The multi-coil antenna system of claim 13, wherein the first and second notch circuits each comprise a second fundamental notch circuit comprising a fifth capacitor, a sixth capacitor, a seventh capacitor, a sixth inductor, a signal path first connection, a signal path second connection, a signal matching circuit first connection, and a signal matching circuit second connection, respectively,

one end of the sixth inductor is electrically connected to the third node, the other end of the sixth inductor is electrically connected to one end of the seventh capacitor, and the other end of the seventh capacitor is electrically connected to the fourth node.

19. The multi-coil antenna system of claim 17, wherein the first fundamental trap circuit comprises a multi-order trap circuit formed from passive components.

20. The multi-coil antenna system of claim 17, wherein the first fundamental trap circuit comprises a trap circuit formed from active devices.

21. The multi-coil antenna system of claim 1, wherein the in-vivo circuit control unit records the value of the radio frequency energy after the multi-coil antenna is powered on and started;

the in-vivo circuit control unit judges whether the change of the radio frequency energy exceeds a threshold value;

if the change of the radio frequency energy exceeds a threshold value, the in-vivo circuit control unit records the change quantity signal;

the in-vivo circuit control unit outputs a response signal to the in-vivo communication unit according to the variation signal, the in-vivo communication unit outputs a feedback signal to the in-vitro communication unit according to the response signal, and the in-vitro communication unit transmits the feedback signal to the in-vitro circuit control unit;

and the external circuit control unit adjusts the power of the output energy control signal and the communication control signal according to the feedback signal.

22. An implantable medical device comprising a multi-coil antenna system according to any one of claims 1 to 21.