An induction coil assembly

Abstract

There us provided herein an induction coil assembly for a wireless transceiver. The induction coil assembly including a transmitter coil assembly for transmitting power and data. The transmitter coil assembly is arranged so as to substantially surround an inner coil assembly area. The induction coil assembly also includes a receiver coil assembly for receiving data. The receiver coil has a first receiver coil sub-assembly being positioned inside the inner coil assembly area, and a second receiver coil sub-assembly being arranged to surround the inner coil assembly area. The transmitter coil assembly is substantially null-coupled to the receiver coil assembly.

Description

An Induction Coil AssemblyRelated Application[1] This application claims priority from Australian Application No. 2023904047 filed on 14 December 2023, the contents of which are to be taken as incorporated herein by this reference.Technical Field[2] The present invention relates to an induction coil assembly. Embodiments of the invention may include a wireless transceiver incorporating such an induction coil assembly. The wireless transceiver may be configured for inductive coupling to an implantable microelectronic medical device.Background of Invention[3] In biomedical applications, implantable electronic medical devices may be used for real-time patient monitoring, diagnosis, and treatment of certain medical conditions. Wireless inductive links can be used to wirelessly power the implantable medical device and to enable data communications between the implantable medical device and the external world via a wireless inductive transceiver. Wireless power transmission and data communication using an inductive link can be used in relation to various biomedical applications, including visual prosthesis, cochlear implants, neuromuscular and nerve stimulators, cardiac pacemakers or defibrillators, deep brain stimulators, spinal cord stimulators, brain-machine interfaces, gastrointestinal microsystems and capsule endoscopy.[4] In some applications such as neuromuscular stimulators, cochlear implants and visual prosthesis, the implantable medical device may be battery-less and therefore require continuous power from an external battery, or have miniature rechargeable batteries that require inductive charging on a regular basis. In addition, implantable medical devices that provide sensory information such as vision and hearing may also require large amounts of real-time information to be transferred between the implantable medical device(s) and external artificial sensors such a camera or microphone.[5] Using wireless inductive links for powering and enable communications for implantable medical devices can eliminate the need for subcutaneous and percutaneous wiring which can lead to increased risk of injury, infection and premature failure of the implanted devices. However, one practical issue is that wireless inductive links can be very sensitive to misalignment. The performance of wireless inductive systems can greatly depend on how well a transmitter and receiver are aligned. In some scenarios, it is also necessary for the wireless inductive system to support multiple implantable medical devices. Moreover, it may be necessary for the wireless inductive system to accommodate a large separation distance between the external and implanted induction coils due to thickness of hair, skin, bone and other bodily tissues.[6] Typically, a relatively large external inductive coil is employed in an external wireless transceiver and a relatively small implant coil is adopted in the implantable medical device. Such an arrangement can result in low magnetic coupling between external inductive coil(s) of the transceiver and the implanted coil(s) of the one or more implanted device(s). As such, uplink communication signals received by the external wireless transceiver from implanted devices are typically orders of magnitude weaker than downlink data and power transmission signals transmitted from the external wireless transceiver. This can undesirably cause problems with noise and crosstalk between the downlink and uplink communications between the wireless transceiver and the implantable medical device.[7] Embodiments of the invention may provide an inductive coil assembly, a wireless transceiver incorporating the inductive coil assembly and an inductive system which overcomes or ameliorates one or more of the disadvantages or problems described above, or which at least provides the consumer with a useful choice.[8] A reference herein to a patent document or any other matter identified as prior art, is not to be taken as an admission that the document or other matter was known or that the information it contains was part of the common general knowledge as at the priority date of any of the claims.Summary of Invention[9] According to one aspect of the invention, there is provided an induction coil assembly for a wireless transceiver, the induction coil assembly including a transmitter coil assembly for transmitting power and data, the transmitter coil assembly being arranged so as to substantially surround an inner coil assembly area, and a receiver coil assembly for receiving data, the receiver coil having a first receiver coil sub-assembly being positioned inside the inner coil assembly area, and a second receiver coil sub-assembly being arranged to surround the inner coil assembly area, wherein the transmitter coil assembly is substantially null-coupled to the receiver coil assembly.

[0010] A null-coupled wireless inductive link can advantageously provide simultaneous power transfer and bidirectional communications with one or more implantable medical devices whilst reducing the effects of crosstalk between downlink and uplink communications, and also enabling downlink and uplink communications to operate in the same frequency band.

[0011] When used herein, the terms 'null coupling' or 'null coupled' refer to substantially null-coupling or near null-coupling between coil assemblies such that perfect null coupling is not required, and that any residual magnetic flux may be considered negligible in the effective operation of the induction coil assembly according to embodiments of the invention.

[0012] The transmitter coil assembly may include a transmitter induction coil arranged in a circular configuration so as to define the inner coil assembly area. The transmitter coil assembly may include any suitable number of individual coils. In one embodiment, the transmitter coil assembly includes a single coil of wire (also referred to herein as the transmitter coil) wound around the inner coil assembly area. The transmitter coil may include any suitable number of turns. In some embodiments, the transmitter coil may include about 2 to 25 turns. Typically, the operating frequency of the induction coil assembly may be about 0.1 to 20MHz. In some embodiments, the transmitter coil may include about 4 to 8 turnswhen the operating frequency is about 5MHz. For operating frequencies lower than 5MHz, the transmitter coil may include more than 4 to 8 turns as the tolerance for inductance, parasitic capacitance and skin effect resistance is generally higher at lower transmission frequencies. Conversely, the transmitter coil may include less than 4 to 8 turns for operating frequencies higher than 5MHz.

[0013] The first receiver coil sub-assembly may include an inner receiver induction coil arranged in a circular configuration. The first receiver coil sub-assembly may include any suitable number of individual coils. In one embodiment, the first receiver coil sub-assembly includes a single coil of wire (herein referred to as a first receiver coil) such that a central axis of the first receiver coil corresponds with a central axis of the transmitter coil. The first receiver coil may include any suitable number of turns. In some embodiments, the first receiver coil may include about 1 to 15 turns. In one embodiment, the first receiver coil includes 7 turns when an operating frequency of 1.25MHz is used. Typically, the operating frequency range is about 0.1MHz to 20MHz. Receiver coil tuning frequency is limited by the self-inductance and parasitic capacitance of the receiver coil, therefore, in some embodiments the first receiver coil may include a lower number of turns to allow resonant tuned operation of the induction coil assembly at a higher operating frequency. Alternatively, the first receiver coil may include a higher number of turns while operating the receiver coil assembly at a lower frequency and with increased receiver sensitivity.

[0014] The second receiver coil sub-assembly may include a first outer receiver induction coil arranged in a circular configuration and a second outer receiver induction coil arranged in a circular configuration. The first and second outer receiver induction coils may be concentric circular coils. Moreover, a central axis of the first and second outer receiver induction coils may correspond with a central axis of the transmitter coil. Each of the first and second outer receiver induction coils may include any suitable number of turns. In some embodiments, first outer receiver induction coils may include about 5 to 30 turns, and the second outer receiver induction coils may include about 5 to 30 turns. Typically, each of the first and second outer receiver induction coils includes more turns than the inner receiver induction coil. This allows the first and second outer receiver induction coils to be reduced in diameter compared to the diameters required to achieve null coupling with equal turns on all coils, thereby reducing the overall induction coil assembly footprint.

[0015] The inner receiver induction coil, first and second outer receiver induction coils may be concentric circular coils, in which the first outer receiver induction coil surrounds the inner receiver induction coil, and the second outer receiver induction coil surrounds the first outer receiver induction coil.

[0016] The inner receiver induction coil and the second outer receiver induction coil may be arranged in phase. Moreover, the first outer receiver induction coil may be arranged out of phase with the inner receiver induction coil and the second outer receiver induction coil.

[0017] The number of turns in each of the inner receiver induction coil, the first outer receiver induction coil and the second outer receiver induction coil may be different. For example, the inner receiver induction coil may include about 2 to 15 turns, the first outer receiver induction coil may include about 5 to 30 turns, and the second outer receiver induction coil may include about 5 to 30 turns. In some embodiments, a ratio between the number of turns between the inner receiver induction coil, the first outer receiver induction coil and the second outer receiver induction coil may be about 1:3:3.

[0018] In another embodiment, the first receiver coil sub-assembly may include an inner receiver induction coil arranged in a circular configuration. The second receiver coil subassembly may include one or more outer enclosed coils surrounding the inner coil assembly area. The first receiver coil sub-assembly may include any suitable number of individual coils. In one embodiment, the first receiver coil sub-assembly includes a single coil of wire (herein referred to as a first receiver coil) such that a central axis of the first receiver coil corresponds with a central axis of the transmitter coil. The first receiver coil may include any suitable number of turns. In some embodiments, first receiver coil may include about 5 to 15 turns.

[0019] The second receiver coil sub-assembly may include a single outer enclosed coil surrounding the inner coil assembly area. The single outer enclosed coil may be generally C- shaped, in which a centre of the C- shape generally corresponds to a centre of the inner coil assembly area. The single outer enclosed coil may include any suitable number of turns. In one embodiment, the single outer enclosed coil includes about 5 to 30 turns.

[0020] In some embodiments, the second receiver coil sub-assembly includes a plurality of outer enclosed coils arranged radially around the inner coil assembly area. Preferably, thesecond receiver coil sub-assembly includes a sufficient number of enclosed coils such that magnetic fields generated from the enclosed coils adequately provide continuous or near continuous coverage of a peripheral area surrounding the inner coil assembly area such that sufficient null coupling between the transmitter coil assembly and the receiver coil assembly can be achieved. Each enclosed coil can have any suitable shape or configuration. In one embodiment, six outer enclosed coils may be arranged radially around the inner coil assembly area. Each enclosed coil may be wound about an axis that is parallel to a central axis of the transmitter coil. Each enclosed coil may include any suitable number of turns. In one embodiment, each enclosed coil includes about 5 to 30 turns.

[0021] The second receiver coil sub-assembly may include a plurality of outer enclosed coils. The outer enclosed coils may be arranged in phase with one another.

[0022] In one embodiment, the one or more outer enclosed coils may include an array of circular coils arranged radially around the inner coil assembly area. Any suitable number of circular coils may be provided. In one embodiment, sixteen circular coils are provided.Typically, a central axis of each circular coil may be parallel with a central axis of the transmitter coil. The circular coils may be arranged in phase. Each circular coil may include any suitable number of turns. In some embodiments, each circular coil may include about 5 to 30 turns.

[0023] The first receiver coil sub-assembly and the second receiver coil sub-assembly may be arranged in phase.

[0024] The wireless transceiver may be configured to provide wireless power transfer to, and data communications with, one or more implantable medical devices. In addition, the transmitter coil assembly may be configured to transmit power and data to the one or more implantable medical devices. Furthermore, the receiver coil assembly may be configured to receive data from the one or more implantable medical devices.

[0025] According to another aspect of the invention, there is provided a wireless transceiver having an induction coil assembly, the induction coil assembly including a transmitter coil assembly for transmitting power and data, the transmitter coil assembly being arranged so as to substantially surround an inner coil assembly area, anda receiver coil assembly for receiving data, the receiver coil having a first receiver coil sub-assembly being positioned inside the inner coil assembly area, and a second receiver coil sub-assembly being arranged to surround the inner coil assembly area, wherein the transmitter coil assembly is substantially null-coupled to the receiver coil assembly.

[0026] According to another aspect of the invention, there is provided a wireless transceiver having an induction coil assembly as described herein.

[0027] The wireless transceiver may be configured for inductive coupling with one or more implantable medical devices to provide continuous wireless power to, and wireless data communications with, the one or more implantable medical devices via a modulated electromagnetic field.

[0028] The wireless transceiver may further include a controller coupled to the transmitter coil assembly and the receiver coil assembly. The controller may be configured to enable transmission of power and data via the transmitter coil assembly and receipt of data via the receiver coil assembly simultaneously over the same frequency band.

[0029] The wireless transceiver may further include an interface to allow user selection of communication frequency.

[0030] The wireless transceiver may further include an output module for providing data and / or control output based on data received via the receiver coil assembly.

[0031] The wireless transceiver may further include one or more transceiver sensors for obtaining input from a physical environment associated with the wireless transceiver. The controller may be configured to selectively generate data signals for communication with the implantable medical device based on input from the one or more transceiver sensors.

[0032] The wireless transceiver may be wearable. For example, the wireless transceiver may include straps or any suitable fasteners for holding the wireless transceiver against aportion of a body such that the induction coil assembly is generally aligned with one or more implantable medical devices within the body.

[0033] The wireless transceiver may further include a power supply. Alternatively, the wireless transceiver may be configured for coupling to an external power supply.

[0034] According to a further aspect of the invention, there is provided a system comprising a wireless transceiver as described herein, and an implantable medical device, wherein the wireless transceiver is configured for inductive coupling with implantable medical device to provide continuous wireless power to, and wireless data communications with, the implantable medical device via a modulated electromagnetic field.

[0035] According to a yet another aspect of the invention, there is provided a system comprising an implantable medical device, and a wireless transceiver having an induction coil assembly, the induction coil assembly including a transmitter coil assembly for transmitting power and data, the transmitter coil assembly being arranged so as to substantially surround an inner coil assembly area, and a receiver coil assembly for receiving data, the receiver coil having a first receiver coil sub-assembly being positioned inside the inner coil assembly area, and a second receiver coil sub-assembly being arranged to surround the inner coil assembly area, wherein the transmitter coil assembly is substantially null-coupled to the receiver coil assembly, and wherein the wireless transceiver is configured for inductive coupling with implantable medical device to provide continuous wireless power to, and wireless data communications with, the implantable medical device via a modulated electromagnetic field.

[0036] The implantable medical device may include an implant coil assembly for inductive coupling with the inductive coil assembly of the wireless transceiver.

[0037] The implantable medical device may include a load-shift-keying switch configured to facilitate transmission of uplink data from the implant coil assembly to the receiver coil assembly via backscattering of energy from a downlink carrier signal transmitted from the transmitter coil assembly.

[0038] The implantable medical device may include an amplifier configured to amplify an uplink data signal from the implant coil assembly to the receiver coil assembly, the uplink data signal being transmitted on a separate carrier signal to that of a downlink carrier signal from the transmitter coil assembly to the implantable medical device.

[0039] In order that the invention may be more readily understood and put into practice, one or more preferred embodiments thereof will now be described, by way of example only, with reference to the accompanying drawings.

[0040] It will be appreciated that for simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the figures to indicate corresponding or analogous elements.Brief Description of Drawings

[0041] FIGURE 1 is a schematic diagram illustrating a wireless induction system.

[0042] FIGURE 2 is a schematic diagram illustrating an induction coil assembly according to one embodiment of the invention.

[0043] FIGURE 3 is a schematic diagram illustrating another induction coil assembly according to one embodiment of the invention.

[0044] FIGURE 4 is a schematic diagram illustrating a further induction coil assembly according to one embodiment of the invention.

[0045] FIGURES 5A and 5B are schematic diagrams illustrating yet another induction coil assembly according to one embodiment of the invention.

[0046] FIGURE 5C illustrates an example implementation of the transmitter coil assembly according to the induction coil assembly shown in Figures 5A to 5B.

[0047] FIGURE 5D illustrates an example implementation of the receiver coil assembly according to the induction coil assembly shown in Figures 5A to 5B.

[0048] FIGURE 6 is a functional block diagram of a wireless induction system including a wireless transceiver and an implantable medical device.

[0049] FIGURE 7 is a cross-sectional view illustrating an implantable medical device of the wireless induction system according to an embodiment of the invention.

[0050] FIGURE 8 is a schematic diagram illustrating an example physical implementation of a wireless induction system in the form of a cortical prosthesis with an external camera and a tactile interface.

[0051] FIGURE 9 is a schematic diagram illustrating an example physical implementation of a wireless induction system in the form of a cortical prosthesis interfaced with an electronic prosthetic limb.

[0052] FIGURE 10 is a schematic diagram illustrating an example physical implementation of a wireless induction system in the form of deep brain stimulation and recording system with a tactile interface.

[0053] FIGURE 11 is a schematic diagram illustrating an example physical implementation of a wireless induction system incorporated into a sacral neuromodulation system with a tactile interface.

[0054] FIGURE 12 is a schematic diagram illustrating an example physical implementation of a wireless induction system as a spinal cord interface.Detailed Description

[0055] Figure 1 illustrates a wireless induction system 100 including an external wireless transceiver 102 inductively coupled to an implantable medical device 108 such that the system 100 enables full-duplex communications between the transceiver 102 and theimplantable device 108. In some embodiments, the wireless transceiver 102 can be coupled to a plurality of implantable devices 108.

[0056] The wireless transceiver 102 includes an induction coil assembly 112 (also referred to herein interchangeably as a transceiver coil assembly 112) comprising a transmitter coil assembly 104 and a receiver coil assembly 106. The implantable device 108 includes an implant coil 110 configured for inductive coupling with the transmitter coil assembly 104 and the receiver coil assembly 106. The transmitter coil assembly 104 is configured to transmit power and data from the external transceiver 102 to the implantable device 108 via the implant coil 110. Data transmitted from the transceiver 102 to the implantable device 108 is herein referred to as downlink data and a carrier signal for transferring the downlink data is referred herein as a downlink carrier signal. The receiver coil assembly 106 is configured to receive data from the implantable device 108 via the implant coil 110. Data transmitted from the implantable device 108 to the transceiver 102 is herein referred to as uplink data (also known as reverse telemetry data) and a carrier signal for transferring the uplink data is referred herein as an uplink carrier signal.

[0057] In accordance with embodiments of the invention, and as described in further detail below with reference to Figures 2 to 5C, the transmitter coil assembly 104 and the receiver coil assembly 106 of the external transceiver 102 is substantially null coupled. It is desirable to minimise coupling between the transmitter coil assembly 104 and the receiver coil assembly 106, and maximise coupling between the transceiver coil assembly 112 and the implant coil 110. When the coupling between the transmitter coil assembly 104 and the receiver coil assembly 106 (K12) is zero or near zero, the effects of crosstalk between downlink and uplink communications can be reduced. This also enables downlink and uplink communications to operate in the same frequency band. In some embodiments, reverse telemetry data from the implant coil 110 to the receiver coil assembly 106 is transmitted by load shift keying (backscatter). This will be described in further detail below with reference to Figure 6.

[0058] If K12 is non-zero, the downlink carrier signal transmitted via the transmitter coil assembly 104 may prevent receiving the relatively much weaker backscattered uplink carrier signal transmitted from the implant coil 110. In particular, the sidebands of the downlinkcarrier signal may reduce the signal to noise ratio (SNR) of the uplink carrier signal and the downlink carrier signal may overload and / or clip the uplink receiver frontend associated with the receiver coil assembly 106, and / or increase the severity of non-linear components which can be difficult to filter out. Embodiments of the present invention therefore provides null- coupled transceiver coil assembly 112 configured for use in an external wireless transceiver 102, which may overcome or ameliorate one or more of these problems.

[0059] A null coupled induction coil assembly 200 for a wireless transceiver 102 according to one embodiment of the invention is illustrated in Figure 2. The induction coil assembly 200 includes a transmitter coil assembly 202 for transmitting power and data to an implant coil 110 of an implantable device 108. The transmitter coil assembly 202 includes a generally circular transmitter coil 202 defining an inner coil assembly area 206 within the perimeter of the circular transmitter coil 202. The coil assembly 200 further includes a receiver coil assembly 208 for receiving reverse telemetry data from the implant coil 110. The receiver coil assembly 208 includes a first receiver coil sub-assembly 210. The first receiver coil sub-assembly 210 includes a generally circular inner receiver coil 210 positioned inside the inner coil assembly area 206. The receiver coil assembly 208 further includes a second receiver coil sub-assembly 212. The second receiver coil sub-assembly 212 includes a pair of concentric circular outer receiver coils 214, 216 (also referred to herein as first and second outer receiver coils 214, 216) arranged to surround the inner coil assembly area 206.

[0060] In coil assembly 200 shown, the transmitter coil assembly 202 is substantially null coupled to the receiver coil assembly 208. The transmitter coil 202, the inner and outer receiver coils 210, 214, 216 are circular concentric coils. In one embodiment, the coil loop diameters may be about 20 to 80mm for the transmitter coil 202, 15 to 60mm for the inner receiver coil 210, and 20 to 80mm and 25 to 100mm for the pair of outer receiver coils 212. The overall diameter of the coil assembly 200 may be defined by the diameter of the second outer receiver coil 216, being about 25 to 100mm.

[0061] As shown by the arrows in Figure 2, the inner receiver coil 210 and the second outer receiver coil 216 are arranged such that a current passing through the coils 210, 216 is in phase. In addition, the first outer receiver coil 214 is wound such that a current passingthrough the first outer receiver coil 214 is out of phase with the current passing through the inner receiver coil 210 and the second outer receiver coil 216.

[0062] The number of turns on each of the three coils 210, 214, 216 of the receiver coil assembly 208 may be unequal to one another so as to optimize coupling with the implant coil 110 and / or to minimise the overall physical footprint of the induction coil assembly 200.

[0063] A null coupled induction coil assembly 300 for a wireless transceiver 102 according to another embodiment of the invention is illustrated in Figure 3. The induction coil assembly 300 includes a transmitter coil assembly 302 for transmitting power and data to an implant coil 110 of an implantable device 108. The transmitter coil assembly 302 includes a generally circular transmitter coil 302 defining an inner coil assembly area 306 within the perimeter of the circular transmitter coil 302. The coil assembly 300 further includes a receiver coil assembly 308 for receiving reverse telemetry data from the implant coil 110. The receiver coil assembly 308 includes a first receiver coil sub-assembly in the form of a generally circular inner receiver coil 310 positioned inside the inner coil assembly area 306. The receiver coil assembly 308 further includes a second receiver coil sub-assembly 312. The second receiver coil sub-assembly 312 includes a plurality of outer enclosed coils in the form of an array of circular coils 312 surrounding the inner coil assembly area 306.

[0064] In coil assembly 300 shown, the transmitter coil assembly 302 is substantially null coupled to the receiver coil assembly 308. In one embodiment, the coil loop diameters may be about 20 to 80mm for the transmitter coil 302, 15 to 60mm for the inner receiver coil 310, and 5 to 20mm for each of the outer circular coils 312.

[0065] In this embodiment, the inner receiver coil 310 and the outer circular coils 312 are wound in the same direction (or in-phase) such that a current circulates in the same direction in each of the coils 310, 312 (e.g. in a clockwise direction as illustrated by the arrows in Figure 3). Moreover, the transmitter coil 302 is arranged such that the voltage and / or current induced in inner receiver coil 310, due to the magnetic field emitted by transmitter coil 302, is equal and opposite in phase to the sum of voltages and / or currents induced in outer circular coils 312, therefore achieving null coupling between transmitter coil 302 and receiver coil assembly 308.

[0066] As illustrated by the arrows in Figure 3, the direction of current passing through a mid-section of each circular coil 312 in closest proximity to a respective mid-section of an adjacent circular coil 312 is opposite to the direction of current passing through the respective mid-section of the adjacent circular coil 312. As such, the magnetic flux generated by the mid-sections of each circular coil 312 is effectively cancelled by the magnetic flux generated by the respective mid-sections of each adjacent circular coil 312. Accordingly, induction coil assembly 300 of Figure 3 is magnetically equivalent to the induction coil assembly 200 as shown in Figure 2. However, the induction coil assembly 300 presents a manufacturing advantage over the induction coil assembly 200. In particular, the relative positions of the outer circular coils 312 can be conveniently adjusted so as to vary a distance between the second receiver coil sub-assembly 312 and the transmitter coil 302, thereby also adjusting a distance between the second receiver coil-assembly 312 and the inner receiver coil 310. This ability to allow adjustment of the relative positions of the coils advantageously enables the induction coil assembly 300 to be fine-tuned after manufacturing, for example, to more closely achieve null coupling, or near null coupling between the transmitter coil 302 and the receiver coil assembly 308. The ability for adjustment and fine-tuning post manufacturing allows for manufacturing tolerances in the coil diameters. In some cases, it may be difficult to provide precise coil diameters during manufacturing. Moreover, coil diameters cannot easily be altered post-manufacturing. As the diameter of coils affect the coupling between the coils, it is advantageous to allow fine-tuning post manufacturing to allow for manufacturing tolerances in the coil diameters.

[0067] A null coupled induction coil assembly 400 for a wireless transceiver 102 according to a further embodiment of the invention is illustrated in Figure 4. The induction coil assembly 400 includes a transmitter coil assembly 402 for transmitting power and data to an implant coil 110 of an implantable device 108. The transmitter coil assembly 402 includes a generally circular transmitter coil 402 defining an inner coil assembly area 406 within the perimeter of the circular transmitter coil 402. The coil assembly 400 further includes a receiver coil assembly 408 for receiving reverse telemetry data from the implant coil 110. The receiver coil assembly 408 includes a first receiver coil sub-assembly in the form of a generally circular inner receiver coil 410 positioned inside the inner coil assembly area 406. The receiver coil assembly 408 further includes a second receiver coil sub-assembly 412. Thesecond receiver coil sub-assembly 412 includes a plurality of outer enclosed coils 412 surrounding the inner coil assembly area 306. Whilst six enclosed coils 412 are illustrated in Figure 4, it is understood that any suitable number of enclosed coils 412 can be provided.

[0068] In the coil assembly 400 shown, the transmitter coil assembly 402 is substantially null coupled to the receiver coil assembly 408. In one embodiment, the coil loop diameters may be about 20 to 80mm for the transmitter coil 402, 15 to 60mm for the inner receiver coil 410. Each of the enclosed coils 412 may have a width W of approximately between 5 to 20mm. An overall diameter of the coil assembly 400 may be about 30 to 120mm.

[0069] In this embodiment, the inner receiver coil 410 and the outer enclosed coils 412 are arranged such that a current passing through the coils 410, 412 is in phase. Moreover, the transmitter coil 402 is arranged such that the voltage and / or current induced in inner receiver coil 410, due to the magnetic field emitted by transmitter coil 402, is equal and opposite in phase to the sum of voltages and / or currents induced in outer circular coils 412, therefore substantially achieving null coupling between transmitter coil 402 and receiver coil assembly 408.

[0070] Similar to the induction coil assembly 300 as shown in Figure 3, the induction coil assembly 400 as shown in Figure 4 can be fine-tuned after manufacturing by adjusting the relative positions of the outer enclosed coils 412, to better achieve null coupling, or near null coupling between the transmitter coil 402 and the receiver coil assembly 408.

[0071] A further null coupled induction coil assembly 500 for a wireless transceiver 102 according to yet another embodiment of the invention is illustrated in Figures 5A to 5B. The induction coil assembly 500 functions in a similar manner to the induction coil assembly 400 described above with reference to Figure 4, in which like features refer to those previously described.

[0072] In particular, the induction coil assembly 500 includes a transmitter coil assembly 502 for transmitting power and data to an implant coil 110 of an implantable device 108. The transmitter coil assembly 502 includes a generally circular transmitter coil 502 defining an inner coil assembly area 506 within the perimeter of the circular transmitter coil 502. The coil assembly 500 further includes a receiver coil assembly 508 for receiving reverse telemetrydata from the implant coil 110. The receiver coil assembly 508 includes a first receiver coil sub-assembly in the form of a generally circular inner receiver coil 510 positioned inside the inner coil assembly area 506. The receiver coil assembly 508 further includes a second receiver coil sub-assembly 512. The second receiver coil sub-assembly 512 includes a plurality of outer enclosed coils 512 surrounding the inner coil assembly area 506.

[0073] In coil assembly 500 shown, the transmitter coil assembly 502 is substantially null coupled to the receiver coil assembly 508. In one embodiment, the coil loop diameters may be about 20 to 80mm for the transmitter coil 502, 15 to 60mm for the inner receiver coil 510. Each of the enclosed coils 512 may have a width W of approximately between 5 to 20mm. An overall diameter D of the induction coil assembly 500 (Figure 5B) may be approximately between 30 to 120mm.

[0074] The outer enclosed coils 512 have a slightly different shape to those of induction coil assembly 400 as shown in Figure 4. In particular, each of the outer enclosed coils 512 of the coil assembly 500 include a straight portion 514 to facilitate manufacturing of the coils by enabling construction by tightly winding flexible wire around rigid bobbins, as opposed to concave portion 414 which may preclude said manufacturing method. As more clearly shown in Figure 5D, the inner receiver coil 510 can be wound around an inner receiver bobbin 518, and each of the outer enclosed coils 512 can be wound around a respective outer receiver bobbin 520. The transmitter coil 502 can be wound around a transmitter coil bobbin 522. The transmitter coil bobbin 522 can be mounted to the receiver bobbins 518, 520 such that the transmitter coil 502 is placed generally between the inner receiver coil 510 and the outer enclosed coils 512. A slotted mounting plate 524, slots in the inner receiver bobbin 518 and outer receiver bobbins 520 facilitate alignment between the transmitter coil 502, inner receiver coil 510, and the outer enclosed coils 512, to fine tune the coupling between the coils to better achieve null coupling or near null coupling. Fasteners may be inserted into the slotted holes to semi permanently fix all components of coil assembly 500 together while a tuning process is conducted, thereafter adhesive may be used to permanently fix all components in place allowing fasteners to be removed.

[0075] The transmitter coil 502, and receiver coils 508 may include flexible coils which are made self-supporting by the application of a curing polymer, allowing the bobbins 518,520, 522 to be removed. Alternatively, the coils 502, 508 may be manufactured by deposition or etching of a conductive layer on an insulative substrate. The induction coil assemblies 200 to 400 may be manufactured in a similar manner to that described herein with reference to Figures 5A to 5D.

[0076] Similar to the coil assembly 400 as shown in Figure 4, the inner receiver coil 510 and the outer enclosed coils 512 of the coil assembly 500 are arranged such that a current passing through the coils 510, 512 is in phase. Moreover, the transmitter coil 502 is arranged such that the voltage and / or current induced in inner receiver coil 510, due to the magnetic field emitted by transmitter coil 502, is equal and opposite in phase to the sum of voltages and / or currents induced in outer circular coils 512, therefore achieving null coupling between transmitter coil 502 and receiver coil assembly 508.

[0077] In each embodiment of the inductive coil assembly (200, 300, 400, 500) as described above with reference to Figures 2 to 5D, null coupling between the transmitter coil assembly 202, 302, 402, 502 and the respective receiver coil assembly 208, 308, 408, 508 may be achieved by arranging the individual coils such that the coupling between each transmitter coil assembly 202, 302, 402, 502 and the respective inner receiver coil 210, 310, 410, 510 is about equal and opposite to the total coupling between each transmitter coil assembly 202, 302, 402, 502 and the respective outer receiver coil assemblies 212, 312, 412, 512.

[0078] In the example embodiment shown in Figures 5A to 5D, the mean magnetic field from the transmitter coil 502 acting on the inner receiver coil 510 is in the opposite polarity to the mean magnetic field from the transmitter coil 502 acting on the outer enclosed coils 512. The former couple mostly with fields inside the perimeter of the transmitter coil 502 and the latter couple mostly with fields outside the perimeter of the transmitter coil 502. As such, the voltage induced on the receiver coil 510 is nulled by the sum of the voltages induced on outer enclosed coils 512. The sum of the voltages induced on outer enclosed coils 512 could be considered to 'buck' the voltage induced on the inner receiver coil 510 down to zero, or vice versa.

[0079] The fraction of the magnetic flux produced by the current in one coil that couples with another coil can be defined by the coefficient of coupling 'K'. If the inductance of innerreceiver coil 510 is equal to the total inductance of outer enclosed coils 512, and the coefficient of coupling between the transmitter coil 502 and the inner receiver coil 510 (Kinner) is equal and opposite to the sum of the coefficients of coupling between the transmitter coil 502 and each of the outer enclosed coils 512 (Sum(K0Uter)), then total coefficient of coupling between the transmitter coil 502 and the receiver coils 510, 512 (Ktotai) is zero:If, Kjnner=Sum(Kouter), then Ktotai = o

[0080] As previously mentioned, the outer enclosed coils 512 can be positioned radially closer or further from the transmitter coil 502 to alter the coupling to more closely achieve null coupling between the transmitter coil 502 and receiver coils 508 to allow for variations in manufacturing and relative alignment of the inner receiver coil 510. Additionally, the inner receiver coil 510 can be manufactured with a different number of turns (ninner, typically fewer) than the number of turns for the outer enclosed coils 512 (nouter). Thus: njnnerxKjnner—OouterlxKouterl + outer2xKouter2 + OouterSxKouterS + Oouter4xKouter4 + nouter5xKouter5 + OouterSxKouterS

[0081] The straight portions 514 of the outer enclosed coils 512 can aid manufacturing of the coils by allowing winding of flexible wire around a rigid bobbin as described above with reference to Figure 5D. In the embodiment of the induction coil assembly 400 as shown in Figure 4, the outer enclosed coils 512 include concave segments 414. Providing concave segments 414 instead of straight portions 514 in the outer enclosed coils 412 results in less coupling of the magnetic field from the outer enclosed coils 412 inside the perimeter of the transmitter coil 402, which is in-phase with the field coupled to the inner receiver coil 410. This could allow the outer diameter of the outer enclosed coils 412 to be reduced when a same number of turns is used, thereby minimising the footprint of the overall induction coil assembly 400 and the overall inductance of the receiver coil assembly 408. This may be desirable in some embodiments, as the resonant tuning capacitance of the receive circuit can be proportionally increased, which in turn reduces the effect of capacitive coupling between receiver coil assembly 408, the transmitter coil 402 and / or external sources, and increases the self-resonant frequency of the receiver coil assembly 408 allowing a higher tuningfrequency to be achieved. In practice, concave segments 414 of the outer enclosed coils 412 may be defined by traces on a printed circuit board.

[0082] In all embodiments of the inductive coil assembly (200, 300, 400, 500) as described above with reference to Figures 2 to 5D, the coils may be electrically connected in series, parallel or series-parallel combination. Moreover, all transmitter and receiver coils may be manufactured on a common two-dimensional plane or offset from a plane to suit manufacturing or to optimise coupling. In some embodiments, the two-dimensional plane may be intentionally distorted to approximate the contours of the human body.

[0083] Moreover, in all embodiments of the inductive coil assembly (200, 300, 400, 500) as described above with reference to Figures 2 to 5D, magnetic null coupling between the respective transmitter coil assembly (202, 302, 402, 502) and the receiver coil assembly (208, 308, 408, 508) can be effectively achieved. The magnetically null-coupled arrangement of the coils advantageously allows downlink and uplink wireless communications to operate simultaneously over the same frequency band at high data rates without crosstalk.

[0084] The geometry and arrangement of the coils also establishes a single effective area below the wireless transceiver 102 where one or more implantable devices 108 can receive continuous power and full-duplex communications. In particular, by arranging the coils such that an inner receiver coil sub-assembly (210, 310, 410, 510) is placed inside the transmitter coil (202, 302, 402, 502), and an outer receiver coil sub-assembly (212, 312, 412, 512) is placed outside or substantially outside the transmitter coil (202, 302, 402, 502), the wireless transmitter 102 can provide a relatively large effective area (for example, effective area 516 as shown in Figure 5B) over which power transfer and bi-directional communications with the implantable device 108 can be effectively and consistently achieved across the entire footprint of the inductive coil assembly 500. Providing a large effective area 516 allows the wireless transceiver 102 to effectively couple to the implantable device 108 whilst permitting a greater level of movement and positioning flexibility for the wireless transceiver 102. This can be particularly useful in scenarios where it may be difficult to perfectly align the implantable device 108 with a specific useable region of the wireless transceiver 102, or if the wireless transceiver 102 is coupled to a plurality of different implantable devices 108.

[0085] A functional block diagram of a wireless induction system 600 comprising a wireless transceiver 602 inductively coupled to an implantable medical device 700 via a modulated electromagnetic field is shown in Figure 6. Whilst a single implantable device 700 is shown, it is understood that the wireless transceiver 602 can be coupled to a plurality of implantable devices 700.

[0086] The wireless transceiver 602 includes a null coupled induction coil assembly 606 in accordance with any one of the induction coil assemblies 200, 300, 400, 500 as described herein with reference to Figures 2 to 5D. The induction coil assembly 606 includes a transmitter coil assembly 608 for transmission of power and downlink data to the implantable device 700 via implant coil 702, and a receiver coil assembly 612 for receiving uplink data from the implantable device 700 via the implant coil 702.

[0087] The induction coil assembly 606 is coupled to an electronics module 630 for controlling operations of the induction coil assembly 606. The electronics module 630 includes a controller 614, for example in the form of a microcontroller, FPGA or the like. Any suitable controller 614 may be used. The controller 614 is coupled to the transmitter coil assembly 608 via transmitter 616 and the receiver coil assembly 612 via receiver 618. The receiver 618 is configured to demodulate uplink carrier signals transmitted from the implant coil 702 and received by the receiver coil assembly 612. The controller 614 is configured to decode the received uplink data. Uplink data may include downlink command acknowledgements from the implantable device 700. The command acknowledgements may be generated by an implant controller 708 of the implantable device 700. The transceiver controller 614 may be configured to determine an operational status and / or operating errors of the implantable device 700 based on the command acknowledgements.

[0088] Typically, the transceiver controller 614 is configured to enable transmission of power and data via the transmitter coil assembly 618 to the implantable device 700 and receipt of data via the receiver coil assembly 606 from the implantable device 700 simultaneously over the same frequency band. The transmitter coil assembly 608 is substantially null coupled with the receiver coil assembly 612 such that there is no or negligible magnetic interaction between the two coil assemblies 608, 612. The null coupled arrangement between the transmitter coil assembly 608 and receiver coil assembly 612allows uplink and downlink carrier signals to operate over the same frequency band without interference or with negligible interference. In this arrangement, the magnetic coupling between the transmitter coil assembly 608 and the implant coil 702, and the magnetic coupling between the receiver coil assembly 612 and the implant coil 702 is sought to be maximized.

[0089] The transceiver controller 614 may also be configured to store data from the implantable device 700. One or more implant sensors 710 may collect sensor data for transmission to the transceiver controller 614 via uplink carrier signals. The sensor data can be stored in memory of the transceiver controller 614 for inspection by a clinician, output to an external system via an output module 620 or processed in order to be used as feedback for the control of stimulation via one or more stimulators 712 of the implantable device 700 as described in further detail below.

[0090] The wireless transceiver 602 further includes a user interface 626 to allow user selection of the communication frequency and data rate. The user interface 626 may also be configured to enable input of other operating parameters of the transceiver 602 and / or the implantable device 700 by a user. For example, the user interface 626 can also be configured to allow user selection of a desired intensity or patterning of stimulation via stimulators 712 of the implantable device 700 as discussed in further detail below.

[0091] The wireless transceiver 602 further includes an output module 620 for providing data and / or control output based on uplink data received via the receiver coil assembly 612.

[0092] The wireless transceiver 602 may further include one or more transceiver sensors 622 for obtaining input from a physical environment associated with the wireless transceiver 602. In some embodiments, the transceiver controller 614 is configured to selectively generate data signals for communication with the implantable medical device 700 based on input from the one or more transceiver sensors 622. The transceiver sensors 622 may be used in combination with user interface 626 to alter a frequency, intensity or patterning of stimulation via the implantable device 700 as discussed in further detail below.

[0093] In some embodiments, one or more of the transceiver sensors 622, output module 620 and user interface 626 may be provided on board the electronics module 630.Alternatively or in combination, one or more of transceiver sensors 622, output module 620 and user interface 626 may be provided externally to the electronics module 630.

[0094] The wireless transceiver 602 further includes a power supply 628 for powering the wireless transceiver 602. The power supply 628 may consist of a rechargeable energy storage device such as lithium polymer electrochemical battery cells, voltage regulation and battery charging / management circuitry.

[0095] The wireless transceiver 602 is inductively coupled to the implant coil 702 of a wireless implantable medical device 700

[0096] Typically, the implantable device 700 comprises a hermetically sealed body. The implant coil 702 may have any suitable shape or configuration. For example, the implant coil 702 may be circular, square or any other closed shape.

[0097] The implantable medical device 700 includes a hermetically sealed body. In the implantable medical device 700, the implant coil 702 is coupled to an electronic module 718 configured to control and manage operation of the implantable device 700. The implant coil 702 is coupled to a power rectification and regulation module 704, which is configured to harvest power from the plant coil 702 and provide a voltage regulated power supply for the implantable medical device 700. In some embodiments, the power rectification and regulation module 704 may include a rechargeable battery and / or storage capacitor. The implant coil 702 is also coupled to a data receiver 706 for demodulating data from a downlink carrier signal received by the implant coil 702. The data receiver 706 is coupled to an implant controller 708 configured to decode the demodulated data from the data receiver 706. The implant controller 708 also receives sensor data from one or more implant sensors 710 and generates controls signals to one or more stimulators 712 based on the demodulated data from the downlink carrier signal and / or request sensor data from the one or more implant sensors 710.

[0098] The implant controller 708 may be configured with a unique hardware address. In an embodiment in which more than one implantable device 700 is inductively coupled to the wireless transceiver 602, the transceiver controller 614 can independently communicate with each implantable device 700 by appending a respective unique hardware address to awireless command signal. Alternatively, the transceiver controller 614 may simultaneously communicate with all coupled implantable devices 700 by generating a wireless command signal and appending a predetermined unique broadcast hardware address to which all implant controllers 708 decode and process irrespective of their own unique hardware address.

[0099] In one embodiment, the implant controller 708 may be programmed to selectively control operation of the one or more stimulators 712 and implant sensors 710 continuously or intermittently. In some embodiments, the transceiver controller 614 may be configured to generate a continuous stream of control signals to wirelessly control operation of the one or more stimulators 712 and / or implant sensors 710.

[0100] The implant controller 708 may be configured to assume a safe operating state (e.g. in which the stimulator(s) 712 are turned off) in the event that power received from the transceiver 602 becomes insufficient to maintain operation of the implantable device 700, or when the implantable device 700 is initially transitioning from an unpowered state.Moreover, the implant controller 708 may be configured to perform data error checking and correction to ensure any errors in the decoded wireless downlink data does not result in unsafe or unexpected operation of the implantable device 700.

[0101] The implantable medical device 700 may further include a body interface 714 coupled to the one or more implant sensors 710 and stimulators 712. The body interface 714 may be configured to establish a connection between body fluids and tissues and each of the implant sensors 710 and / or stimulators 712. In some embodiments, this interface may be achieved via any one or more of electrical, thermal, optical, mechanical, or fluidic transfer. Each implant sensor 710 may be configured to convert sensed quantities into electrical voltages, which may be quantised into digital data by the implant controller 708. The implantable device 700 may further include a load-shift-keying switch. Sensor data from the one or more implant sensors 710 may be digitally signal processed and / or compressed by the implant controller 708 before being wirelessly transmitted over an uplink carrier signal via the implant coil 702. Transmission of uplink data via the implant coil 702 may be performed by backscattering of energy from the downlink carrier signals with a load-shift-keying switch 716. The load-shift keying switch 716 may be configured to modulate implanted powerusage by means of an electronic dummy load. Alternatively, uplink data may be transmitted on via superimposing a separate signal on implant coil 702 by means of a transmitting power amplifier 716. Accordingly, the implantable device 700 may transmit uplink data on a subcarrier signal of the power and data downlink carrier signal, or a separate modulated carrier signal.

[0102] Figure 7 depicts a cross-sectional view of the implantable medical device 700. In the particular embodiment shown, the implantable device 700 is equipped with multiple different types of biological body interface modules 714a, 714b, 714c, 714d, 714e, 714f, 714g. A practical implementation of an implantable device 700 may employ any one or more types of body interface modules 714a, 714b, 714c, 714d, 714e, 714f, 714g as illustrated in Figure 7 and described herein, in any suitable combination.

[0103] For example, one or more electrically conductive penetrating electrodes 714a and one or more electrically conductive surface electrodes 714b may be provided by the implantable device 700 to electrically interface with neural tissue, to provide electrical neural recording (sensing) and stimulation. One or more vessels 714c for transporting bodily fluids from a remote location to an electronic fluid sensor for fluid monitoring may be provided by the implantable device 700. One or more nerve cuff electrodes 714d for electrical recording and / or stimulating from peripheral nerves may also be provided by the implantable device 700. One or more electro-mechanical cuffs 714e may be provided by the implantable device 700 to mechanically modulate flow through tubular organs. One or more light emitter or light sensors 714f may be provided by the implantable device 700 to perform optogenetic neural stimulation and / or recording. One or more connectors 714g may be provided by the implantable device 700 to interface with an electrode assembly such as a deep brain stimulator (DBS) electrode.

[0104] As discussed above, an implantable device 700 may provide any one or more type of the body interface modules 714a to 714g described herein in any suitable combination. Moreover, an implantable device may include a plurality of a single type or several different types of a body interface module. When multiple implantable devices 700 are coupled to the wireless transceiver 600 in a wireless inductive system 600, each implantable device 700 may be equipped with different body interface modules 714a to 714g. In some embodiments, thebody interface modules 714 may be located externally (and in some cases remotely) from the hermetic body of the implantable device 700 and coupled to the implantable device 700 via flexible wires or tubes. Alternatively, the external body interface modules 714 may be rigidly mounted directly to the hermetic body. In some embodiments, the body interface modules 714 may be used to mechanically anchor the implantable device 700 within the body.

[0105] Some example medical applications of the wireless induction system 600 will now be described with reference to Figures 8 to 12.

[0106] Figure 8 illustrates an implementation of the wireless induction system 600 as a visual prosthesis 800 with head-worn wireless transceiver 602. The wireless transceiver 602 includes the electronic module 630 and the induction coil assembly 606. The wireless transceiver 602 is mounted to a patient's head 802, for example via mounting straps (not shown). The electronic module 630 is coupled to a transceiver sensor 622 in the form of a head worn camera 622 for visual imaging of the surrounding environment. The implantable medical device 700 includes a plurality of cortica lly implanted wireless devices 700 equipped with penetrating electrodes 714a and / or surface electrodes 714b electrodes.

[0107] In this particular physical implementation, the transceiver controller 614 is configured to process imagery from the camera 622 and recorded neural activity from electrodes 714a, 714b and determine an optimal pattern of stimulation 712 of the electrodes 714a, 714b to give the patient 802 a visual perception of the surrounding environment. A tactile based user interface 626 is configured to allow the patient 802 to optimise processing by the transceiver controller 614 to improve stimulation 712 efficacy in real time or near real time to adapt to changes in the surrounding environment and task.

[0108] Figure 9 illustrates a physical implementation of the wireless induction system 600 as a motor prosthesis 900. The motor prosthesis 900 includes the head-worn wireless transceiver 602 including the electronic module 630 and induction coil assembly 606. The electronic module 630 is coupled an electro-mechanical prosthetic limb 902. The prosthetic limb 902 implements mechanical outputs (output module 620) and tactile sensing (transceiver sensor 622). The wireless transceiver 602 is coupled to a plurality of cortica I ly implanted wireless devices 700. Each implant device 700 is equipped with penetrating electrodes 714a, surface electrodes 714b or light emitters / light sensors 714f. The transceivercontroller 614 is configured to stimulate 712 in the motor cortex to deliver tactile sensations detected by sensors 622. Neural recordings via implant sensor(s) 710 are transmitted to and processed by transceiver controller 614 to control mechanical movements 620 of the limb prosthesis 902.

[0109] Figure 10 illustrates a physical implementation of the wireless induction system 600 as a deep brain stimulator 1000. The wireless induction system 600 includes a head-worn wireless transceiver 602, the transceiver 602 including the electronic module 630 and the induction coil assembly 606. The transceiver 602 is coupled to one or more implanted medical devices 700, each device 700 being equipped with connectors to interface with deep brain electrodes assemblies 714g, for example in the form of electrode shank assemblies. Each electrode shank assembly 714g may contain multiple electrodes, allowing simultaneous stimulation 712 and recording 710 from multiple locations in the brain. Multiple electrode assemblies 714g may also be employed. Applications for deep brain stimulators include memory prosthetics and treatment of epilepsy. The transceiver controller 614 may be configured to process neural recordings captured by implant sensor(s) 710 and determine the appropriate frequency and patterning of stimulation via stimulator(s) 712. For treatment of epilepsy, the transceiver controller 614 may be configured to detect the onset of an epileptic fit via analysis of neural recordings and generate control signals for appropriate stimulation so as to mitigate the epileptic fit. For a memory prosthesis, the transceiver controller 614 may be configured to process neural activity recorded from the hippocampus via implant sensors 710 and generate control signals for appropriate stimulation via stimulator(s) 712 at another location in the hippocampus to restore memory function impacted by neurodegeneration. The electronic module 630 may be coupled to an external tactile based user interface 626 configured to allow a user to optimize processing by the transceiver controller 614 to improve stimulation efficacy.

[0110] Figure 11 illustrates a physical implementation of a wireless induction system 600 as a sacral neuromodulation system 1100. The wireless induction system 600 includes a body-worn wireless transceiver 602, the transceiver 602 including the electronic module 630 and the induction coil assembly 606. The transceiver 602 is inductively coupled to one or more implanted wireless devices 700, each device 700 being equipped with cuff electrodes 714d placed on the sacral nerves 1102. Stimulation 712 is delivered to the sacral nerves 1102to restore normal bladder or bowel function. The electronic module 630 is coupled to a tactile user interface 626 configured to allow a user to alter / optimize the operation of the sacral neuromodulation system 1100 by the transceiver controller 614.

[0111] Figure 12 illustrates a physical implementation of a wireless induction system 600 as a spinal stimulation system 1200. The wireless induction system 600 includes a body-worn wireless transceiver 602, the transceiver 602 including the electronic module 630 and the induction coil assembly 606. The transceiver 602 is inductively coupled to one or more implanted wireless devices 700, each device 700 being equipped with electrodes 714b placed on the spinal cord 1202. Stimulation 712 is delivered to restore lost bodily functions due to neurodegeneration or to relieve pain. The transceiver controller 614 may be configured to process neural recordings transmitted via implant sensors 710 to general control signals to improve stimulation, or to implement a feedback path between multiple electrodes 714b in the spinal stimulation system 1200, such as could be utilised to transmit neural signals across a damaged section of the spinal cord by performing stimulation 712 in a remote location.Interpretation

[0112] This specification, including the claims, is intended to be interpreted as follows:

[0112] Embodiments or examples described in the specification are intended to be illustrative of the invention, without limiting the scope thereof. The invention is capable of being practised with various modifications and additions as will readily occur to those skilled in the art. Accordingly, it is to be understood that the scope of the invention is not to be limited to the exact construction and operation described or illustrated, but only by the following claims.

[0113] The mere disclosure of a method step or product element in the specification should not be construed as being essential to the invention claimed herein, except where it is either expressly stated to be so or expressly recited in a claim.

[0114] The terms in the claims have the broadest scope of meaning they would have been given by a person of ordinary skill in the art as of the relevant date.

[0115] The terms "a" and "an" mean "one or more", unless expressly specified otherwise.

[0116] Neither the title nor the abstract of the present application is to be taken as limiting in any way as the scope of the claimed invention.

[0117] Where the preamble of a claim recites a purpose, benefit or possible use of the claimed invention, it does not limit the claimed invention to having only that purpose, benefit or possible use.

[0118] It should be noted that terms of degree such as "generally", "substantially", "about" and "approximately" as used herein mean a reasonable amount of deviation of the modified term such that the end result is not significantly changed. These terms of degree should be construed as including a deviation of the modified term if this deviation would not negate the meaning of the term it modifies.

[0119] In the specification, including the claims, the term "comprise", and variants of that term such as "comprises" or "comprising", are used to mean "including but not limited to", unless expressly specified otherwise, or unless in the context or usage an exclusive interpretation of the term is required.

[0120] Furthermore, the recitation of any numerical ranges by endpoints herein includes all numbers and fractions subsumed within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.90, 4, and 5). It is also to be understood that all numbers and fractions thereof are presumed to be modified by the term "about" which means a variation up to a certain amount of the number to which reference is being made if the end result is not significantly changed.

[0121] As used herein, the wording "and / or" is intended to represent an inclusive-or. That is, "X and / or Y" is intended to mean X or Y or both, for example. As a further example, "X, Y, and / or Z" is intended to mean X or Y or Z or any combination thereof.

[0122] The disclosure of any document referred to herein is incorporated by reference into this patent application as part of the present disclosure, but only for purposes of written description and enablement and should in no way be used to limit, define, or otherwise construe any term of the present application where the present application, without such incorporation by reference, would not have failed to provide an ascertainable meaning. Anyincorporation by reference does not, in and of itself, constitute any endorsement or ratification of any statement, opinion or argument contained in any incorporated document.

Claims

The claims defining the invention are as follows1. An induction coil assembly for a wireless transceiver, the induction coil assembly including a transmitter coil assembly for transmitting power and data, the transmitter coil assembly being arranged so as to substantially surround an inner coil assembly area, and a receiver coil assembly for receiving data, the receiver coil having a first receiver coil sub-assembly being positioned inside the inner coil assembly area, and a second receiver coil sub-assembly being arranged to surround the inner coil assembly area, wherein the transmitter coil assembly is substantially null-coupled to the receiver coil assembly.

2. The induction coil assembly of claim 1, wherein the transmitter coil assembly includes a transmitter induction coil arranged in a circular configuration so as to define the inner coil assembly area.

3. The induction coil assembly according to any one of the preceding claims, wherein the first receiver coil sub-assembly includes an inner receiver induction coil arranged in a circular configuration, and the second receiver coil sub-assembly includes a first outer receiver induction coil arranged in a circular configuration and a second outer receiver induction coil arranged in a circular configuration, the first and second outer receiver induction coils being concentric circular coils.

4. The induction coil assembly of claim 3, wherein the inner receiver induction coil, first and second outer receiver induction coils are concentric circular coils, in which the first outer receiver induction coil surrounds the inner receiver induction coil, and the second outer receiver induction coil surrounds the first outer receiver induction coil.

5. The induction coil assembly of claim 4, whereinthe inner receiver induction coil and the second outer receiver induction coil are in phase, and the first outer receiver induction coil is out of phase with the inner receiver induction coil and the second outer receiver induction coil.

6. The induction coil assembly according to any one of claims 3 to 5, wherein the number of turns in each of the inner receiver induction coil, the first outer receiver induction coil and the second outer receiver induction coil are different.

7. The induction coil assembly of claim 1 or 2, wherein the first receiver coil sub-assembly includes an inner receiver induction coil arranged in a circular configuration, and the second receiver coil sub-assembly includes one or more outer enclosed coils surrounding the inner coil assembly area.

8. The induction coil assembly of claim 7, wherein the one or more outer enclosed coils include an array of circular coils arranged radially around inner coil assembly area.

9. The induction coil assembly according to claim 7 or 8, wherein the second receiver coil sub-assembly includes a plurality of outer enclosed coils, the outer enclosed coils being in phase.

10. The induction coil assembly according to any one of claims 7 to 9, wherein the first receiver coil sub-assembly and the second receiver coil sub-assembly are in phase.

11. The induction coil assembly according to any one of the preceding claims, wherein the wireless transceiver is configured to provide wireless power transfer to, and data communications with, one or more implantable medical devices, and wherein the transmitter coil assembly is configured to transmit power and data to the one or more implantable medical devices, and the receiver coil assembly is configured to receive data from the one or more implantable medical devices.

12. A wireless transceiver having an induction coil assembly according to any one of claims 1 to 10.

13. The wireless transceiver of claim 12, wherein the wireless transceiver is configured for inductive coupling with one or more implantable medical devices to provide continuous wireless power to, and wireless data communications with, the one or more implantable medical devices via a modulated electromagnetic field.

14. The wireless transceiver of claim 13, further including a controller coupled to the transmitter coil assembly and the receiver coil assembly, wherein the controller is configured to enable transmission of power and data via the transmitter coil assembly and receipt of data via the receiver coil assembly simultaneously over the same frequency band.

15. The wireless transceiver of claim 14, further including an interface to allow user selection of communication frequency.

16. The wireless transceiver according to any one of claims 13 to 15, further including an output module for providing data and / or control output based on data received via the receiver coil assembly.

17. The wireless transceiver according to claim 14 or 15, further including one or more transceiver sensors for obtaining input from a physical environment associated with the wireless transceiver, the controller being configured to selectively generate data signals for communication with the implantable medical device based on input from the one or more transceiver sensors.

18. The wireless transceiver of any one of claims 12 to 14, wherein the wireless transceiver is wearable.

19. The wireless transceiver according to any one of claims 12 to 18, further including a power supply.

20. A system comprising a wireless transceiver according to any one of claims 12 to 19, andan implantable medical device, wherein the wireless transceiver is configured for inductive coupling with implantable medical device to provide continuous wireless power to, and wireless data communications with, the implantable medical device via a modulated electromagnetic field.

21. The system of claim 20, wherein the implantable medical device includes an implant coil assembly for inductive coupling with the inductive coil assembly of the wireless transceiver.

22. The system of claim 21, wherein the implantable medical device includes a load-shift- keying switch configured to facilitate transmission of uplink data from the implant coil assembly to the receiver coil assembly via backscattering of energy from a downlink carrier signal transmitted from the transmitter coil assembly.

23. The system of claim 21 or 22, wherein the implantable medical device includes an amplifier configured to amplify an uplink data signal from the implant coil assembly to the receiver coil assembly, the uplink data signal being transmitted on a separate carrier signal to that of a downlink carrier signal from the transmitter coil assembly to the implantable medical device.

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