CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY
[001] This patent application does not claim priority from any application.

TECHNICAL FIELD
[002] The present subject matter described herein, in general, relates to an antenna for wireless power transfer. More particularly to an antenna for a wireless power transfer in a cochlear implant.

BACKGROUND
[003] In a medical implant domain, a Cochlear implant is a type of an implantable prosthesis device. A system of the cochlear implant uses an external component and an internal component. The external component senses surrounding sounds and generates stimulation signals that are transmitted to the internal component. As there is no permanent power for the internal component, the power is supplied by the external component. To transmit stimulation signals and the power, a set of coils are provided, wherein one coil is placed in the internal component and another coil in the external component.
[004] The set of coils are planar in geometry and are magnetically coupled. The set of coils are positioned parallel to each other so that the stimulation signals and the power is transferred. The set of coils use resonant inductive coupling to transmit the stimulation signals and the power. An efficiency of the power transfer between the set of coils depends on various factors including but not limited to number of turns of the coil, length of the coil, shape of the coil, an operating frequency, magnetic permeability of the coil, a distance between the set of coils.

SUMMARY
[005] Before the present apparatus of an antenna is described, it is to be understood that this application is not limited to the particular machine or an apparatus, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related to an antenna for wireless power transfer in a cochlear implant. The aspects are further elaborated below in the detailed description. This summary is not intended to identify essential features of the proposed subject matter nor is it intended for use in determining or limiting the scope of the proposed subject matter.
[006] In one implementation, an antenna for wireless power transfer in a cochlear implant is disclosed. The antenna may comprise of a coil. The shape of the coil may be a quadrilateral. The coil may further comprise one or more coil windings. An at least one step may be displaced on each side of the one or more coil windings. A width of the at least one step on an innermost coil may be greater than twice of a distance between a side of the innermost coil winding and the side of a subsequent coil winding. Further, the width of the at least one step on the innermost coil may be less than a length of the side. Furthermore, a width of the at least one step of the subsequent coil winding may be greater than the width of the at least one step of the innermost coil winding.

BRIEF DESCRIPTION OF THE DRAWINGS
[007] The foregoing summary, as well as the following detailed description of embodiments, is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the disclosure, there is shown in the present document example constructions of the disclosure, however, the disclosure is not limited to the specific methods and apparatus disclosed in the document and the drawings:
[008] The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer like features and components.
[009] Figure 1 illustrates one embodiment of an antenna having a rectangular outline for wireless power transfer of a cochlear implant, in accordance with an embodiment of the present subject matter.
[0010] Figure 2 illustrates one more embodiment of an antenna having a square outline for wireless power transfer of a cochlear implant, in accordance with an embodiment of the present subject matter.
[0011] Figure 3(a) illustrates an S-parameter graph of power transfer between a set of coils having a rectangular outline, wherein the set of coils are prior art with respect to the present subject matter.
[0012] Figure 3(b) illustrates an S-parameter graph of power transfer between a set of coils, wherein each coil has rectangular outline in accordance with an embodiment of the present subject matter.
[0013] The figures depict various embodiments of the present disclosure for purposes of illustration only. One skilled in the art will readily recognize from the following discussion that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.

DETAILED DESCRIPTION
[0014] Some embodiments of this disclosure, illustrating all its features, will now be discussed in detail. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items or meant to be limited to only the listed item or items. Although any systems similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, systems and methods are now described. The disclosed embodiments are merely exemplary of the disclosure, which may be embodied in various forms.
[0015] Various modifications to the embodiment of an antenna for a wireless power transfer in a cochlear implant will be readily apparent to those skilled in the art and the generic principles herein may be applied to other embodiments. However, one of ordinary skill in the art will readily recognize that the present disclosure is not intended to be limited to the embodiments illustrated but is to be accorded the widest scope consistent with the principles and features described herein.
[0016] As described earlier, an efficiency of power transfer between a set of coils in a cochlear implant may depend on several factors. One of the several factors include a shape of the set of coils. In the prior art, a set of coils for the power transfer comprises a set of planar coils. No design modifications of the set of coils are adhered in the prior art.
[0017] The present invention discloses an antenna for wireless power transfer in a cochlear implant. The shape of the antenna may be in a quadrilateral form. The antenna comprises one or more coil windings. At least one step may be displaced of one or more coil windings. The at least one step may be displaced on each side of the one or more coil windings. As the coil may be a quadrilateral, a number of sides on a coil winding is four. The at least one step may indicate an indentation on each side. The dimensions of the at least one step may have a width and a depth. The width may be a length of the at least one step that is measured parallelly to each step of the one or more coil windings. The height may indicate the length of the indentation. The indentation may lie in a perpendicular direction with respect to each side.
[0018] The width of the at least one step of an innermost coil may be greater than twice of a pitch of the one or more coil windings. The pitch indicates a distance between a side of the innermost coil winding and the side of the subsequent coil winding. Further, the width of the at least on the innermost coil may be less than a length of the side. The width of the at least one step of the subsequent coil winding may be greater than the width of the at least one step of the innermost coil winding.
[0019] In one embodiment, the coil may operate for a dual frequency in an Industrial, Scientific and Medical (ISM) band. Further, the coil may enhance the efficiency of power coupling between a set of coils. The set of coils may be used as a pair in a cochlear implant.
[0020] Now referring to figure 1, a schematic diagram of an antenna having a rectangular outline is disclosed in accordance with an embodiment. The antenna may be used for wireless power transfer in a cochlear implant. The antenna may comprise a coil 100. The coil 100 may further comprise of one or more coil windings. At least one step 104 may be displaced on each side 102 of the one or more coil windings. The at least one step 104 may be an indentation displaced on each side 102 of the one or more coil windings. The indentation on each side 102 may lie in the same plane of the one or more coil windings. The at least one step 104 may have a width and a height. The width may be a length of the at least one step 104 that is measured parallelly to each side 102 of the one or more coil windings. The height may indicate the length of the indentation. The height may lie in a perpendicular direction to each side 102.
[0021] In the embodiment, two steps 104 may be displaced on each side 102 of the one or more coil windings. A width of the at least one step 104 of the innermost coil winding 106 may be greater than twice a pitch of the one or more coil windings. The pitch of the one or more coil windings may indicate a distance between two nearest coil windings. For example, the width of the at least one step on the innermost coil 106 may be greater than twice of the pitch. The pitch for the innermost coil winding 106 may indicate a distance between a side 102 of the innermost coil winding 106 and that of a subsequent coil winding 108. The width of the at least one step 104 of the innermost coil winding 106 may be less than a length of the side of the innermost coil winding 106.
[0022] The width of the at least one step 104 of each coil winding may be greater than the width of the at least one step 104 of the innermost coil winding 106. The width of the at least one step 104 of each coil winding may be increased proportionately with regards to the distance between each side 102 of each coil winding and the side 102 of the innermost coil winding. The maximum width of the at least one step 104 may be less than the maximum length of the side 102 of an outermost coil winding. For example, consider the width of the at least one step 104 on the innermost coil to be five millimeters. Further the width of the at least one step 104 of the subsequent coil 108 may be eight millimeters. Furthermore, the width of the at least one step 104 of the coil winding after the subsequent coil winding may be eleven millimeters. In the example, it may be noticed that the width of the at least one step 104 is increased proportionately with regards to the distance between the side 104 of the innermost coil 106 and the side 104 of each coil winding. Further in the example, the width of the at least one step 104 of the one or more coil windings may not exceed the length of the side 102 of the outermost coil winding.
[0023] In another embodiment, the at least one step 104 may be displaced symmetrically on each coil winding. In the figure 1, it may be noted that two steps 104 are placed symmetrically on each side 102 of each coil winding. The width of the two steps 104 may be equal for each winding coil. For example, the width of the two steps 104 on the innermost coil winding 106 may be five millimeters for each side 102 associated to the innermost coil winding 106.
[0024] In one implementation, the one or more coil windings may be made from at least one of a wire or a trace. The wire may be made from conducting material. Further, the trace may be made on a printed circuit board. A trace may be formed by longitudinally cutting the wire. The longitudinal cutting may be made on a top plane and a bottom plane of the wire. The top plane and the bottom plane may lie parallel to a horizontal plane passing through the centre of the wire. Further, the top plane and the bottom plane may be equidistant from the horizontal plane passing through the centre of the wire.
[0025] In one aspect, a set of coils having the design as depicted in figure 1 may be used for power coupling. The set of coils may be operated for dual frequency in an Industrial, Scientific and Medical (ISM) band. For example, the set of coils may be coupled for 13.56 Megahertz and 27.12 Megahertz. The distance between the set of coils for magnetic coupling may be five millimeters. The coil 100 may be preferred due to its suitability at frequencies below 100 Megahertz. The coil 100 may have an air core medium for magnetic coupling.
[0026] Now referring to figure 2, a schematic diagram of an antenna having a square outline is disclosed in accordance with an embodiment. The antenna may be used for wireless power transfer in a cochlear implant. The cochlear implant may comprise of a set of antennas to perform power coupling operation. The power coupling operation indicates magnetic coupling of the set of antennas to transmit signals. The antenna may be in a form of a coil 200. The coil 200 may have a planar geometry. The coil further comprises one or more coil windings. Referring to the figure 2, one step 104 may be displaced on each side 102 of the one or more coil windings. The one step 104 may be an indentation on each side 102 of the one or more coil windings. The at least one step 104 may lie in the same plane as the one or more coil windings. The one step 104 may have a width and a height. The width may be a length of the at least one step 104 that is measured parallelly to each edge 102 of the one or more coil windings. The height may indicate the length of the indentation. The height may lie in a perpendicular direction to each edge 102.
[0027] A width of the one step 104 of the innermost coil winding 106 may be at least twice a pitch of the one or more coil windings. The pitch of the one or more coil windings may indicate a distance between two nearest coil windings. For example, the width of the at least one step on the innermost coil winding 106 may be greater than twice the pitch. The pitch associated to the innermost coil winding 106 may indicate a distance between a side 102 of the innermost coil winding 106 and the subsequent coil winding 108. Further the width of the one step 104 of the innermost coil winding 106 may be less than a length of the side of the innermost coil winding 106.
[0028] The width of the one step 104 on each side of the subsequent coil windings may be greater than the width of the one step 104 of the innermost coil windings. The subsequent coil windings may indicate one or more coil windings that surround the innermost coil winding 106. The width of the one step 104 one each side 102 may be increased proportionately. The proportionate increase may be with regards to the distance between each side 102 of each coil winding and the side 102 of innermost coil winding. The maximum width of the one step 104 may be less than the maximum length of the side 102 of an outermost coil winding.
[0029] For example, consider the width of the one step 104 on the innermost coil to be five millimeters. Further the width of the one step 104 of the subsequent coil 108 may be eight millimeters. Furthermore, the width of the at least one step 104 of the coil winding after the subsequent coil winding may be eleven millimeters. In the example, it may be noticed that the width of the at least one step 104 is increased proportionately with regards to the distance between the side 104 of the innermost coil 106 and the side 104 of each coil winding. Further in the example, the width of the at least one step 104 of the one or more coil windings may not exceed the length of the side 102 of the outermost coil winding.
[0030] In another embodiment, the one step 104 may be displaced symmetrically on each coil winding. In the figure 1, it may be noted that one step 104 may be placed symmetrically on each side 102 of each coil winding. The width of the one step 104 may be equal for each winding coil. For example, the width of the one step 104 on the innermost coil winding 106 may be three millimeters for each side 102 associated to the innermost coil winding 106.
[0031] In one implementation, the one or more coil windings may be made from at least one of a wire or a trace. The wire may be made from a conducting material. Further, the trace may be made on a printed circuit board. A trace may be formed by longitudinally cutting the wire. The longitudinal cutting may be made on a top plane and a bottom plane of the wire. The top plane and the bottom plane may lie parallel to a horizontal plane passing through the centre of the wire. Further, the top plane and the bottom plane may be equidistant from the horizontal plane passing through the centre of the wire. In one example, a height of the trace may be thirty five micron.
[0032] In one aspect, a set of coils having the design as depicted in figure 2 may be used for power coupling. The set of coils may be operated for dual frequency in an Industrial, Scientific and Medical (ISM) band. For example, the set of coils may be coupled for 13.56 Megahertz and 27.12 Megahertz. The coil 200 may be preferred due to its suitability at frequencies below 100 Megahertz. The coil 200 may have an air core medium for magnetic coupling.
[0033] In another example, consider the set of coils without the steps. The set of coils may be used for power coupling in the cochlear implant. Each coil may have dimensions 60 millimeters by 70 millimeters. The pitch between one or more coil windings of each coil may be 3 millimeters. The distance between the set of coils may be 5 millimeters. A number of turns for each coil is three. A table 1 as mentioned below represents an experimental data indicating the efficiency of power transfer between the set of coils. The experiment may be performed for a set of frequencies that includes 13.56 Megahertz (Mhz) and 27.12 Mhz. Fig 3(a) represents Scattering (S) parameters chart for the experiment performed for 13.56 Mhz and 27.12 Mhz. An insertion loss (IL) of -5.6 dB and -8.56 dB may be anticipated at 13.56 Mhz and 27.12 respectively. Further a return loss of -1.39 and -0.65 may be anticipated at 13.56 Mhz and 27.12 Mhz respectively. The efficiency of power coupling for 13.56 Mhz and 27.12 Mhz may be 27.54 percent and 13.93 percent respectively.
Table 1:
Frequency (Megahertz) Insertion Loss (IL) (dB) Return Loss (RL) (dB) DC Resistance (Rdc) (ohm) Inductance (L) (uF) Efficiency (%)
13.56 -5.6 -1.39 11.66 0.8 27.54
27.12 -8.56 -0.65 14.69 0.76 13.93

[0034] From the table 1, the set of coils shows an efficiency of 27.54 percent for 13.56 Megahertz (Mhz). Further the efficiency is 13.93 percent for the set of coils operating at 27.12 Mhz. The experiment may be further carried out for the set of coils having steps. In the experiment, each coil may have a design as elaborated for coil 100. For the purpose of experiment, the coil 100 may have the dimensions as 60 millimeters by 70 millimeters. The diameter of the wire for the coil may be one millimeter. The gap between each turn may be 3 millimeters and the distance between the set of coils may be 5 millimeters. A below table 2 represents an experimental data indicating the efficiency of power transfer between the set of coils wherein each coil has the design of coil 100. The experiment may be performed for a set of frequencies that includes 13.56 Megahertz (Mhz) and 27.12 Mhz. Fig 3(b) represents Scattering (S) parameters chart for the experiment performed for 13.56 Mhz and 27.12 Mhz. An insertion loss (IL) of -4.66 dB and -6.56 dB may be anticipated at 13.56 Mhz and 27.12 respectively. Further a return loss of -1.81 and -1.08 may be anticipated at 13.56 Mhz and 27.12 Mhz respectively. The efficiency of power coupling for 13.56 Mhz and 27.12 Mhz may be 34.19 percent and 22.08 percent respectively. It may be observed that there may be increase in efficiency of power coupling by adding steps to the set of coils.
Table 2:
Frequency (Megahertz) Insertion Loss (IL) (dB) Return Loss (RL) (dB) DC Resistance (Rdc) (ohm) Inductance (L) (uH) Efficiency (%)
13.56 MHz -4.66 -1.81 11.57 0.641 34.19
27.12 MHz -6.56 -1.08 15.86 0.588 22.08

[0035] Referring to table 1 and table 2, it may be noticed that there is an increase in the efficiency of the power coupling. The increase in efficiency may be associated to the steps 104 provided in the set of coils. (Rdc)
[0036] Exemplary embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features.
[0037] Some embodiments of the antenna enable enhancement in the power transfer efficiency between the set of coils.
[0038] Some embodiments of the antenna enable a shorter battery charge cycle for the cochlear implant.
[0039] Although implementations the antenna for wireless power transfer in a cochlear implant have been described in language specific to structural features and/or methods, it is to be understood that the appended claims are not necessarily limited to the specific features or methods described. Rather, the specific features and methods are disclosed as examples of implementations of the antenna for wireless power transfer in a cochlear implant.

Claims:
1. An antenna for wireless power transfer in a cochlear implant, the antenna comprising:
a coil (100), wherein the coil (100) is a quadrilateral, and wherein the coil comprises
one or more coil windings;
at least one step (104) displaced on each side (102) of the one or more coil windings, wherein a width of the at least one step (104) displaced on an innermost coil winding (106) is greater than twice of a distance between a side (102) of the innermost coil winding (106) and the side (102) of a subsequent coil winding (108), and wherein the width of the at least one step (104) displaced on the innermost coil winding (106) is less than a length of the side (102) of the innermost coil winding (106); and
the width of the at least one step (104) of the subsequent coil winding (108) is greater than the width of the at least one step (104) of the innermost coil winding (106).
2. The antenna of claim 1, wherein the coil (100) is one of a square or a rectangle.
3. The antenna of claim 1, wherein the coil (100) made of at least one of (a) a wire and (b) a trace disposed on a printed circuit board.
4. The antenna of claim 1, wherein increasing the width of the at least one step (104) of each coil winding is directly proportional to the distance between the side (102) of each coil winding and the innermost coil winding (106), and wherein the width is increased with respect to the at least one step (104) of the innermost coil winding (106).
5. The antenna of claim 1, wherein the one or more coil windings is made of a conducting material.
6. The antenna of claim 1, wherein maximum size of the width of the at least one step (104) on the coil (100) is based on a length of an outer diameter of the coil (100).
7. The antenna of claim 1, wherein the at least one step (104) is displaced symmetrically on one or more coil windings.
8. The antenna of claim 1, wherein a number of the one or more coil windings is based on an outer diameter of the coil (100).
9. The antenna of claim 1, wherein a number of steps on the side is based on a length of an outer diameter of the quadrilateral, a number of one or more coil windings and a length of the side.
10. The antenna of claim 3, wherein the trace is made by longitudinal cutting a top portion and a bottom portion of the wire, wherein longitudinal cutting is made at a plane parallel to a horizontal plane passing through the center of the wire.