ANTENNA MODULE AND ELECTRONIC DEVICE HAVING THE SAME

An antenna module includes an insulating substrate; and communications wiring disposed on opposite surfaces of the insulating substrate and including a spiral wiring formed by a first spiral wiring disposed on a first surface of the insulating substrate and a second spiral wiring disposed on a second surface of the insulating substrate, wherein the spiral wiring includes a plurality of coil strands spaced apart from each other and not electrically connected to each other within the spiral wiring, and the communications wiring further includes a connecting part electrically connecting the plurality of coil strands to each other outside the spiral wiring.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Application No. 10-2018-0018720 filed on Feb. 14, 2018, in the Korean Intellectual Property Office, the entire disclosure of which is incorporated herein by reference for all purposes.

BACKGROUND

This application relates to an antenna module and an electronic device having the same.

2. Description of Related Art

Portable terminals have recently been implemented with the capability of performing various functions such as wireless power reception for wirelessly receiving power to charge batteries of the portable terminals, radio frequency identification (RFID), near-field communication (NFC), and magnetic secure transmission (MST).

Such functions are performed using an antenna having a coil shape. Different functions use different antennas, and as a result, a plurality of antennas are mounted in the portable terminal to perform the different functions.

However, there is also a demand for decreasing the thickness of a portable terminal, and as the thickness of the portable terminal decreases, it becomes more and more difficult to mount the plurality of antennas in the portable terminal while maintaining a high efficiency of the plurality of antennas.

SUMMARY

In one general aspect, an antenna module includes an insulating substrate; and communications wiring disposed on opposite surfaces of the insulating substrate and including a spiral wiring formed by a first spiral wiring disposed on a first surface of the insulating substrate and a second spiral wiring disposed on a second surface of the insulating substrate, wherein the spiral wiring includes a plurality of coil strands spaced apart from each other and not electrically connected to each other within the spiral wiring, and the communications wiring further includes a connecting part electrically connecting the plurality of coil strands to each other outside the spiral wiring.

The communications wiring may further include a connection pad; and a lead wiring connecting an outer end portion of the spiral wiring to the connection pad, and the connecting part may be disposed within the lead wiring.

The coil strands of the first spiral wiring and the coil strands of the second spiral wiring may be respectively connected to each other through interlayer connection conductors disposed in the insulating substrate.

The coil strands of the first spiral wiring and the coil strands of the second spiral wiring may be connected to each other in opposite order in a diameter direction of the spiral wiring.

A coil strand disposed in an innermost position in each turn of the first spiral wiring among the coil strands of the first spiral wiring may be connected to a coil strand disposed in an outermost position of each turn of the second spiral wiring among the coil strands of the second spiral wiring.

The coil strands of an innermost turn of the first spiral wiring and an innermost turn of the second spiral wiring may be dispersed on the first surface and the second surface of the insulating substrate.

One or more of the coil strands of the innermost turns may be disposed on both the first surface and the second surface of the insulating substrate and may be connected to each other in parallel.

A line width of the coil strands connected to each other in parallel may be narrower than a line width of remaining ones of the coil strands.

An overall width of the first spiral wiring may be equal to an overall width of the second spiral wiring.

The antenna module may further include a magnetic portion disposed on one surface of the insulating substrate, and the connecting part may be disposed in a position that does not face the magnetic portion.

One or more turns of the first spiral wiring and one or more turns of the second spiral wiring may be connected to each other in parallel.

An innermost turn of the first spiral wiring and an innermost turn of the second spiral wiring may be connected to each other in parallel, and an outermost turn of the first spiral wiring and an outermost turn of the second spiral wiring may be connected to each other in parallel.

A line width of the coil strands of the turns of the first spiral wiring and the second spiral wiring connected to each other in parallel may be narrower than a line width of the coil strands of remaining turns of the first spiral wiring and the second spiral wiring.

In another general aspect, an electronic device includes a wiring portion including communications wiring disposed on opposite surfaces of an insulating substrate; and a magnetic portion coupled to one surface of the wiring portion, wherein the communications wiring includes a spiral wiring including a plurality of coil strands spaced apart from each other; and a connecting part electrically connecting the coil strands to each other and disposed at a position where the connecting part does not face the magnetic portion.

The spiral wiring may be formed by a first spiral wiring disposed on a first surface of the insulating substrate and a second spiral wiring disposed on a second surface of the insulating substrate, an inner end portion of the first spiral wiring and an inner end portion of the second spiral wiring may be connected to each other through an interlayer connection conductor disposed in the insulating substrate, and the communications wiring may further include a first connection pad; a second connection pad; a first lead wiring connecting an outer end portion of the first spiral wiring to the first connection pad; and a second lead wiring connecting an outer end portion of the second spiral wiring to the second connection pad.

An innermost turn of the first spiral wiring and an innermost turn of the second spiral wiring may connected to each other in parallel.

In another general aspect, an antenna module includes an insulating substrate; and a plurality of coil strands forming a spiral wiring on the insulating substrate beginning on a first surface of the insulating substrate and ending on a second surface of the insulating substrate, the plurality of coil strands not being electrically connected to each other within the spiral wiring and being electrically connected to each other outside the spiral wiring.

The spiral wiring may include a first spiral wiring disposed on the first surface of the insulating substrate; and a second spiral wiring disposed on the second surface of the insulating substrate, the antenna module may further include interlayer connection conductors disposed in the insulating substrate and electrically connecting inner end portions of the plurality of coil strands of the first spiral wiring to inner end portions of the plurality of coil strands of the second spiral wiring; a first connection pad; a second connection pad; a first lead wiring electrically connecting outer end portions of the plurality of coil strands of the first spiral wiring to the first connection pad; and a second lead wiring electrically connecting outer end portions of the plurality of coil strands of the second spiral wiring to the second connection pad, wherein either the first connection pad may electrically connect the plurality of coil strands of the first spiral wiring to each other, and the second connection pad may electrically connect the plurality of coil strands of the second spiral wiring to each other, or the first lead wiring may include a first connecting part electrically connecting the plurality of coil strands of the first spiral wiring to each other in the first lead wiring, and the second lead wiring may include a second connecting part electrically connecting the plurality of coil strands of the second spiral wiring to each other in the second lead wiring.

A number of turns of the first spiral wiring may equal to a number of turns of the second spiral wiring, an outer periphery of the first spiral wiring may align with an outer periphery of the second spiral wiring through the insulating substrate, and an inner periphery of the first spiral wiring may align with an inner periphery of the second spiral wiring through the insulating substrate.

The antenna module may further include a magnetic portion disposed on the first surface or the second surface of the insulating substrate or facing the first surface or the second surface of the insulating substrate, and the plurality of coil strands may be electrically connected to each other outside the spiral wiring at a position that does not face the magnetic portion.

DETAILED DESCRIPTION

An electronic device described in this application may be a cellular phone or a smartphone. However, the electronic device is not limited thereto, but may be any electronic device that may be carried and has the capability of performing wireless communications, such as a notebook, a tablet PC, or a wearable device.

FIG. 1is a perspective view schematically illustrating an example of an electronic device, andFIG. 2is a cross-sectional view taken along a line I-I′ ofFIG. 1.

Referring toFIGS. 1 and 2, the electronic device may be a wireless charging device20that wirelessly transmits power, or a portable terminal10that wirelessly receives the power and charges a battery of the portable terminal10with the received power.

The portable terminal10includes a terminal body15, a cover11, a battery12, and an antenna module100. The antenna module110includes a magnetic portion102, an adhesive part104, and a wiring portion110.

The cover11, which is a rear cover coupled to the terminal body15to complete the portable terminal10, may be a battery cover that can be separated from the terminal body15when the battery is replaced. However, the cover11is not limited thereto, and may also be an integral cover that is difficult to separate from the terminal body15.

The battery12may be a secondary battery that can be repeatedly charged and discharged, and may be attached to and detached from the portable terminal10, but is not limited thereto.

The antenna module100is disposed between the terminal body15and the cover11, and charges the battery12by receiving power transmitted from the wireless charging device20and supplying the received power to the battery12. The antenna module100may be directly attached to an inner surface of the cover11, or may be disposed as close as possible to the inner surface of the cover11.

The charging device20is provided to charge the battery12of the portable device10. To this end, the charging device20includes a voltage converting part22and a power transmitter200in a case21.

The voltage converting part22converts household alternating current (AC) power supplied from an external power source into direct current (DC) power, and then converts the DC power into an AC voltage having a particular frequency and supplies the AC voltage having the particular frequency to the power transmitter200.

When the AC voltage is applied to the power transmitter200, a magnetic field around the power transmitter200changes as the AC voltage changes. As a result, a voltage is induced in a wiring portion110of the portable terminal10disposed adjacent to the power transmitter200according to the change in the magnetic field, and this voltage charges the battery12.

The power transmitter200may be configured in a manner similar to the antenna module100described above. Therefore, a detailed description of the power transmitter200will be omitted.

Hereinafter, the antenna module100will be described in detail.

FIG. 3is a plan view schematically illustrating a first surface of an example of an antenna module, andFIG. 4is a plan view schematically illustrating a second surface of the antenna module illustrated inFIG. 3.

Referring toFIGS. 3 and 4, the antenna module100includes a wiring portion110and a magnetic portion102. The wiring portion110includes an insulating substrate11and communications wiring130. The communications wiring130includes spiral wirings131aand131bhaving a coil shape, lead wirings132aand132b, connecting parts133aand133b, and connection pads134. The connection pads134include a first connection pad134aand a second connection pad134b.

The magnetic portion102has a flat plate shape (or a sheet shape), and is disposed on one surface of the wiring portion110and coupled to the wiring portion110. The magnetic portion102is provided to efficiently form a magnetic path for a magnetic field generated by the communications wiring130of the wiring portion110. To this end, the magnetic portion102is formed of a material capable of easily forming the magnetic path, such as a ferrite sheet, but is not limited thereto.

Although not illustrated, a metal sheet may also be added between the magnetic portion102and the battery12to shield the battery12from electromagnetic waves or leakage magnetic flux as needed. The metal sheet may be formed of aluminum, for example, but a material of the metal sheet is not limited thereto.

In addition, the antenna module100has the adhesive part104interposed between the wiring portion110and the magnetic portion102so that the wiring portion110and the magnetic portion102are firmly fixed and bonded to each other.

The adhesive part104is disposed between the wiring portion110and the magnetic portion102and bonds the magnetic portion102and the wiring portion110to each other. The adhesive part104may be formed of an adhesive sheet or an adhesive tape, or may be formed by coating a surface of the wiring portion110or the magnetic portion102with an adhesive or a resin having adhesive properties.

In addition, the adhesive part104may contain ferrite powder particles, causing the adhesive part104to have magnetic properties similar to the magnetic portion102.

The magnetic portion102is disposed to face the spiral wirings131aand131b. In addition, the magnetic portion102is disposed to face portions of the lead wirings132aand132badjacent to the spiral wirings131aand131b, but is disposed not to face the connecting parts133aand133b.

The wiring portion110has a form of a substrate. In more detail, the wiring portion110includes the insulating substrate111and the communications wiring130formed on opposite surfaces of the insulating substrate111.

The insulating substrate111is a substrate on which circuit wiring may be formed on one surface or opposite surfaces thereof, and may be, for example, an insulating film (e.g., a polyimide film). In this example, the wiring portion110has a form of a flexible printed circuit board (PCB). However, the insulating substrate111is not limited thereto, and various kinds of substrates (e.g., a printed circuit board, a ceramic substrate, a glass substrate, an epoxy substrate, and a flexible substrate) may be selectively used as long as the circuit wiring may be formed on one surface or opposite surfaces thereof.

In the example illustrated inFIGS. 3 and 4, the communications wiring130is formed on the opposite surfaces of the insulating substrate111.

The communications wiring130is formed on the opposite surfaces of the insulating substrate111and have, for example, a form of a circuit wiring formed of a copper foil, but is not limited thereto.

The communications wiring130may be manufactured by patterning a double-sided copper-clad laminate (CCL). Alternatively, the communications wiring130may be formed on the opposite surfaces of a flexible insulating substrate such as a film by a photolithography method, and may be manufactured, for example, using a flexible PCB (FPCB) having a double-sided structure.

Accordingly, the wiring portion110has a very small thickness. However, the wiring portion110may also be manufactured as a multilayer substrate, or in a form of a printed circuit board (PCB) having rigidity, as needed.

The communications wiring130is formed of a metal layer of a thin film, and includes the spiral wirings131aand131bhaving a coil shape, the lead wirings132aand132b, the connecting parts133aand133b, and the connection pad134.

The connection pad134is a contact point that can be electrically connected to other components. Therefore, the connection pad134is connected to both end portions of the spiral wirings131aand131bthrough the lead wirings132aand132b, and is exposed to the outside of the antenna module100so that it may be physically connected to an external component.

The spiral wirings131aand131bare disposed on the opposite surfaces of the insulating substrate111to face each other. Accordingly, the spiral wirings131aand131bare a first spiral wiring131aformed on a first surface of the insulating substrate111and a second spiral wiring131bformed on a second surface of the insulating substrate111. In addition, an overall width (or an outer diameter) of the first spiral wiring131ais equal to an overall width (or an outer diameter) of the second spiral wiring131b.

In this example, the first spiral wiring131aand the second spiral wiring131bhave spirals formed in the same direction. That is, as illustrated inFIGS. 3 and 4, the first spiral wiring131aand the second spiral wiring131bhave spirals formed in the same direction (e.g., a clockwise direction in the example illustrated inFIGS. 3 and 4).

When a current flows in the wiring portion110, the current flows in the same direction in the first spiral wiring131aand the second spiral wiring131bwhen the first spiral wiring131aand the second spiral wiring131bare viewed from the same side of the wiring portion110. This is because the current in the wiring portion110flows from the outermost turn to the innermost turn of the first spiral wiring131a, and then flows from the innermost turn to the outermost turn of the second spiral wiring131b, or vice versa. This causes a magnetic field generated by the current flowing in the first spiral wiring131aand a magnetic field generated by the current flowing in the second spiral wiring131bto reinforce each other, a power reception efficiency is improved.

The first spiral wiring131aand the second spiral wiring131bare connected to each other by interlayer connection conductors137at inner end portions of the first spiral wiring131aand the second spiral wiring131b.

The interlayer connection conductors137are disposed in the insulating substrate111so that they penetrate through the insulating substrate111and electrically connect the first spiral wiring131aand the second spiral wiring131bto each other.

In the example illustrated inFIGS. 3 and 4, a plurality of interlayer connection conductors137are disposed in a line. However, the interlayer connection conductors are not limited thereto, but may be disposed in other arrangements as long as they connect the first spiral wiring131aand the second spiral wiring131bto each other.

The interlayer connection conductors137may be formed by forming through holes in the insulating substrate111and then filling the through holes with a conductive material, but are not limited thereto.

The lead wirings132aand132bare wirings that connect outer end portions of the spiral wirings131aand131bto the connection pad134. Therefore, the lead wirings132aand132binclude a first lead wiring132adisposed on the first surface of the insulating substrate111and connecting the outer end portion of the first spiral wiring131ato the first connection pad134a, and a second lead wiring132bdisposed on the second surface of the insulating substrate111and connecting the outer end portion of the second spiral wiring131ato the second connection pad134b.

The first spiral wiring131aand the second spiral wiring131bare connected to each other through the interlayer connection conductors137at the inner end portions of the first spiral wiring131aand the second spiral wiring131b. Therefore, the lead wirings132aand132bextend from the outer end portions of the first spiral wiring131aand the second spiral wiring131bto the first connection pad134aand the second connection pad134b.

Accordingly, the communications wiring130includes the first connection pad134a, the first lead wiring132a, the first spiral wiring131a, the interlayer connection conductors137, the second spiral wiring131b, the second lead wiring132b, and the second connection pad134connected to each other in series in the order listed to form one coil wiring.

Although not illustrated, an protective insulating layer may be formed on the communications wiring130. The protective insulating layer may be provided to protect the communications wiring130from damage and insulate the communications wiring130from contacting external elements. The connection pad134is provided to contact an external component and be electrically connected to the external component. Therefore, the protective insulating layer disposed on the communications wiring130is not disposed on the connection pad134, or is removed from the connection pad134if it is disposed on the connection pad134, so that the connection pad134is exposed so that it can be electrically connected to the external component.

In the example illustrated inFIGS. 3 and 4, the communications wiring130protrudes from the insulating substrate111. However, the communications wiring130is not limited thereto, but may be modified in various ways. For example, at least a portion of the communications wiring130may be embedded in the insulating substrate111.

The overall contour of the first spiral wiring131aand the second spiral wiring131bis an annular shape (or a ring shape). Therefore, a region (hereinafter, referred to as a central region) in which the communications wiring130is not formed is formed in the centers of the first spiral wiring131aand the second spiral wiring131b. Hereinafter, the central region refers to an inner region of the spiral wiring in which the communications wiring130is not formed.

When a current flows in a conductor, the current does not flow through the entire cross-sectional area of the conductor, but rather flows through an outer portion of the cross-sectional area due to the ‘skin effect.’ The skin effect is a phenomenon in which the current flows only near the surface of the conductor such as a metal when a high frequency current is applied to the conductor. The skin effect is caused by a counter-electromotive force generated inside the conductor due to a rapid change of the current flowing through the conductor, thereby making it difficult for the current to flow in the central portion of the conductor. The higher the frequency of the current, the closer the current flows to the surface of the conductor.

In addition, the current flowing in the conductor is affected by a proximity effect, which is a phenomenon in which the current does not evenly flow in the conductor, but is biased to one side of the conductor, due to eddy currents induced in the conductor by a current flowing in an adjacent conductor.

FIG. 14AandFIG. 14Bare graphs illustrating examples of simulations of current density in a spiral wiring.FIG. 14Aillustrates an example of a simulation of current density in a single wiring, that is, a wiring in which each turn is formed by a single conductor, andFIG. 14Billustrates an example of a simulation of current density in a divided wiring, that is, a wiring in which each turn is formed by a plurality of conductors or coil strands.

InFIGS. 14A and 14B, the X axis indicates a radial distance measured from an inner diameter of the spiral wiring. Therefore, as X increases, a position in the spiral wiring moves from the inner diameter of the spiral wiring to an outer diameter side of the spiral wiring. The Y axis indicates a current density in the spiral wiring.

Referring toFIG. 14A, it may be seen that the current density in each of turns t1to t11is not constant and is mostly biased to one side. As can be seen fromFIG. 14A, the current density in turns t1to t8is biased toward an inner side of the single conductor forming each turn, and the current density in turns t9to t11is biased toward an outer side of single conductor.

Thus, in a spiral wiring in which each turn is formed by a single conductor, the current flowing in each turn does not evenly flow along a surface of the conductor, but is biased to one side of the conductor.

Since the current does not flow evenly along the surface of the conductor, an amount of current that can flow in the conductor is limited and a resistance value of the conductor is increased, thereby reducing power reception efficiency.

Therefore, in the examples disclosed in this application, to prevent the power reception efficiency from being reduced due to the above-mentioned factors, each of the turns t1to t11of the communications wiring130is divided into a plurality of coil strands S1, S2, and S3as illustrated inFIG. 14B. As a result, the communications wiring130in the examples disclosed in this application are structurally formed in a form of a Litz wire.

As can be seen fromFIG. 14B, the current density is almost uniform in each coil strand when compared toFIG. 14A.

As described above, if one wiring is divided into a plurality of coil strands, the skin effect and the bias phenomenon of the current produced by the proximity effect are mitigated. However, as the number of divided coil strands increases, an interval between the coil strands also increases. As a result, a DC resistance also increases. Therefore, when the wiring is divided into an excessively large number of coil strands, the power reception efficiency may be reduced.

Therefore, in the example illustrated inFIGS. 3 and 4, the communications wiring130includes three coil strands S1, S2, and S3. However, the communications wiring130is not limited thereto, but may include two coil strands or four or more coil strands.

For convenience of explanation, in the drawings, the three coil strands of the first spiral wiring131aare denoted by S1, S2, and S3, and the three coil strands of the second spiral wiring131bare denoted by P1, P2, and P3. However, the coil strands S1, S2, and S3of the first spiral wiring131aare respectively connected to the coil strands P1, P2, and P3of the second spiral wiring131b, so the phrase ‘coil strands S1, S2, and S3’ refers to all of the coil strands S1, S2, and S3of the first spiral wiring131aand the coil strands P1, P2, and P3of the second spiral wiring131bconnected thereto, unless the coil strands are separately distinguished in the following description.

The coil strands S1, S2, and S3are spaced apart from each other by a same interval, and all have a same line width.

The three coil strands S1, S2, and S3are electrically connected to each other at one end of each of the lead wirings132aand132bconnected to the connection pad134. Therefore, the first lead wiring132aand the second lead wiring132binclude the connecting parts133aand133bat which the plurality of coil strands are electrically connected to each other.

The coil strands S1, S2, and S3are connected in parallel by the connecting parts133aand133b.

In the example illustrated inFIGS. 3 and 4, the connecting parts133aand133bare disposed positions where the lead wirings132aand132band the connection pad134are connected to each other. However, the connecting parts133aand133bare not limited thereto, but may be disposed at various positions of the lead wirings132aand132bas long as the positions do not face the magnetic portion102.

If the connecting parts133aand133bare disposed at positions facing the magnetic portion102, or are disposed within the spiral wirings131aand131b, the advantageous effects obtained by dividing the communications wiring130into the plurality of coil strands S1, S2, and S3are reduced.

Therefore, in the examples of the antenna module100disclosed in this application, the connecting parts133aand133bare disposed only outside the spiral wirings131aand131b, that is, on the lead wirings132aand132b. In addition, the connecting parts133aand133bare disposed only at positions of the lead wirings132aand132bthat do not face the magnetic portion102. Therefore, the plurality of coil strands S1, S2, and S3are not electrically connected to each other inside at positions within the spiral wirings131aand131b, or at positions facing the magnetic portion102.

In another example in which the coil strands S1, S2, and S3are directly connected to the connection pad134, the coil strands S1, S2, and S3are electrically connected to each other by the connection pad134. In this case, the connecting parts133aand133bare omitted.

The antenna module100described above provides the communications wiring130divided into the plurality of coil strands. As described above, when the communications wiring130is formed of the plurality of coil strands S1, S2, and S3, rather than one wiring, the size of the region in the conductor in which the current does not flow is reduced, and the phenomenon in which the current density is biased to one side of the wiring is reduced.

In addition, the divided coil strands S1, S2, and S3are not electrically connected to each other at positions within the spiral wirings131aand131bbut are electrically connected to each other at positions in the lead wirings132aand132bextending from the spiral wirings131aand131b.

Therefore, when the antenna module100described above is used for wireless charging, charging efficiency is increased compared to wireless charging using a conventional antenna module.

The antenna module100is not limited to the above-mentioned examples, but may be modified in various ways.

FIG. 5is a plan view schematically illustrating a first surface of another example of an antenna module, andFIG. 6is a plan view schematically illustrating a second surface of the antenna module illustrated inFIG. 5.

Referring toFIGS. 5 and 6, in the antenna module of this example, some turns of the spiral wirings131aand131bare connected to each other in parallel.

In this example, one turn (hereinafter referred to as the innermost turn) disposed at the inner diameter of each of the spiral wrings131aand131bare connected to each other in parallel. To this end, the antenna! module of this example includes a first interlayer connection conductor137aand a second interlayer connection conductor137b.

The first interlayer connection conductor137aconnects an inner end portion of the first spiral wiring131awith a point at which the innermost turn of the second spiral wiring131bstarts in the second spiral wiring131b. In addition, the second interlayer connection conductor137bconnects an inner end portion of the second spiral wiring131bwith a point at which the innermost turn of the first spiral wiring131astarts in the first spiral wiring131a.

By the configuration described above, the innermost turn of the first spiral wiring131aand the innermost turn of the second spiral wiring131bare connected to each other in parallel. Therefore, the first spiral wiring131aand the second spiral wiring131bare connected to each other in a series structure through a parallel structure in which the innermost turn of the first spiral wiring131aand the innermost turn of the second spiral wiring131bare connected to each other in parallel.

Since magnetic flux density is generally concentrated in the central region of the spiral coil, the current bias phenomenon due to a proximity effect is greatest in the wiring (e.g., the innermost turn) adjacent to the central region.

Therefore, in this example, additional electrical paths are provided by connecting the innermost of the first spiral wiring131aand the innermost turn of the second spiral wiring131bto each other in parallel. As result, since the current is dispersed and flows into the six coil strands of the innermost turns, the current density in each coil strand is decreased. As a result, the current bias phenomenon is also significantly reduced, thereby increasing power transmission efficiency.

Since the innermost turns of the communications wiring130are connected in parallel with each other, the innermost turns of the communications wiring130include twice as many coil strands (e.g., six coil strands) as the other turns. Therefore, although not illustrated, a line width of the innermost turns may be narrower than a line width of the other turns. For example, the line width of the innermost turns may be decreased to half of line width of the other turns. In this case, the phenomenon in which the current is biased to one side of the conductor is further reduced, and inner diameters of the spiral wirings131aand131bmay be increased.

FIG. 7is a plan view schematically illustrating a first surface of another example of an antenna module, andFIG. 8is a plan view schematically illustrating a second surface of the antenna module illustrated inFIG. 7.

Referring toFIGS. 7 and 8, the antenna module of this example is configured in a manner similar to the antenna module illustrated inFIGS. 5 and 6, except that one turn (hereinafter referred to as the outermost turn) disposed at the outer diameter of each of the spiral wirings131aand131bare also connected to each other in parallel.

In general, in a spiral coil, the current bias phenomenon due to the proximity effect is greatest at the innermost turn as discussed above in connection withFIGS. 5 and 6, and is next greatest at the outermost turn.

Therefore, in this example, additional electrical paths are provided by also connecting the outermost turns to each other in parallel. As a result, similar to the result obtained by connecting the innermost turns in parallel, since the current is dispersed and flows into six coil strands in the outermost turns, the current density in each coil strand in the outermost turns is decreased.

To connect the outermost turns in parallel, both ends of the outermost turn of the first spiral wiring131aare connected to both ends of the outermost turn of the second spiral wiring131bby a third interlayer connection conductor137cand a fourth interlayer connection conductor137d, thereby connecting the outermost turns in parallel.

To this end, the second spiral wiring131bseparately includes an expansion wiring131b1for forming the outermost turn of the second spiral wiring131bthat is connected in parallel with the outermost turn of the first spiral wiring131a. The expansion wiring131b1is not directly connected to the rest of the second spiral wiring131b, but is used only to form a parallel connection with the outermost turn of the first spiral wiring131a.

As described above, in the case in which the outermost turns of the spiral wirings131aand131bare connected in parallel, since the number of the coil strands S1, S2, and S3is increased in the outermost turns, the concentration of the current density in a specific region of the outermost turns is reduced.

Since the outermost turns are connected in parallel, the outermost turns include twice as many coil strands (e.g., six coil strands) as the other turns excluding the innermost turns. Therefore, although not illustrated, the line width of the outermost turns may be narrower than a line width of the other turns excluding the innermost turns. For example, the line width of the outermost turns may be decreased to half the line width of the other turns excluding the innermost turns. In this case, the phenomenon in which the current is biased to one side of the conductor is further reduced, and inner diameters of the spiral wirings131aand131bmay be increased.

In addition, in the example of the antenna module illustrated inFIGS. 7 and 8, outer peripheries of the spiral wirings131aand131bhave a quadrangular shape and inner peripheries thereof have a circular shape. In this example, the line width is increased in corner portions of the spiral wirings131aand131bto form the quadrangular shape. However, the configuration of the spiral wirings131aand131bis not limited thereto, and the shapes of one or both of the outer periphery and the inner periphery may be modified in various ways. For example, the outer periphery and the inner periphery may both have the quadrangular shape or may have an oval shape or another polygonal shape.

FIG. 9is a plan view schematically illustrating a first surface of another example of an antenna module, andFIG. 10is a plan view schematically illustrating a second surface of the antenna module illustrated inFIG. 9.

Referring toFIGS. 9 and 10, in this example, the order in which the coil strands S1, S2, and S3are disposed is changed when moving from the first spiral wiring131ato the second spiral wiring131b. This will be described in more detail as follows.

As in the examples described above, each turn of the spiral wirings131aand131bincludes the plurality of coil strands S1, S2, and S3. In this example, as illustrated inFIG. 9, each turn of the first spiral wiring131aincludes a first coil strand S1disposed at the innermost side of the turn, a third coil strand S3disposed at the outermost side of the turn, and a second coil strand S2disposed between the first coil strand S1and the third coil strand S3.

In this example, the first coil strand S1is always disposed at the innermost side of each turn of the first spiral wiring131a. In addition, the third coil strand S3is always disposed at the outermost side of each turn of the first spiral wiring131a. Therefore, in a case in which the first coil strand S1of the first spiral wiring131ais connected to the first coil strand P1of the second spiral wiring131band the third coil strand S3of the first spiral wiring131ais connected to the third coil strand P3of the second spiral wiring131b, total lengths of the coil strands S1, S2, and S3are different from each other. As a result, an impedance is concentrated on a specific coil strand.

Therefore, in order to solve the above-mentioned problem, in the communications wiring130of this example, the coil strands S1, S2, and S3included in the first spiral wiring131aand the coil strands P1, P2, and P3included in the second spiral wiring131bare connected to each other in opposite order in a diameter direction, thereby making the total lengths of the coil strands equal to each other.

Specifically, the first coil strand S1disposed at the innermost side of each turn of the first spiral wiring131ais connected to the third coil strand P3disposed at the outermost side of each turn of the second spiral wiring131bthrough an interlayer connection conductor137a1, and the third coil strand S3disposed at the outermost side of each turn of the first spiral wiring131ais connected to the first coil strand P1disposed at the innermost side of each turn of the second spiral wiring131bthrough an interlayer connection conductor137a3.

In addition, the second coil strand S2of the first spiral wiring131ais connected to the second coil strand P2of the second spiral wiring131bthrough an interlayer connection conductor137a2.

By configuring the communications wiring130as described above, since an average of distances from the centers of the spiral wirings131aand131bto the coil strands S1, S2, and S3is approximately uniform, the concentration of the impedance on the specific coil strand is reduced or eliminated.

In a case in which a total number of turns of the spiral wirings131aand131bis an even number (e.g., ten turns), since five turns are disposed on each of the opposite surfaces of the insulating substrate111, the innermost turn may be configured as in this example.

On the other hand, in a case in which the total number of turns of the spiral wirings131aand131bis an odd number (e.g., eleven turns), since 5.5 turns need to be disposed on each of the opposite surfaces of the insulating substrate111, the example ofFIGS. 9 and 10is modified in another example to be described below.

FIG. 11is a plan view schematically illustrating a first surface of another example of an antenna module,FIG. 12is a plan view schematically illustrating a second surface of the antenna module illustrated inFIG. 11, andFIG. 13is an enlarged view of portions A and B ofFIGS. 11 and 12.

Referring toFIGS. 11 through 13, the antenna module of this example is formed in a way similar to the antenna module of the example ofFIGS. 9 and 10, and differs only in a structure of the innermost turn.

The communications wiring130of the example illustrated inFIGS. 11 through 13has an odd number of turns (e.g., eleven turns). Accordingly, to dispose the spiral wirings131aand131bequally on the opposite surfaces of the insulating substrate111, coil strands of one turn (the innermost turn) are dispersed on the opposite surfaces of the insulating substrate111.

More specifically, the innermost turn of the first spiral wiring131adoes not include the first coil strand S1, but includes only a second coil strand S2′ and a third coil strand S3′. In addition, the innermost turn of the second spiral wiring131bdoes not include the first coil strand P1, but includes only a second coil strand P2′ and a third coil strand P3′.

The first coil strand S1of the second innermost turn of the first spiral wiring131ais connected to the third coil strand P3′ of the innermost turn of the second spiral wiring131bthrough an interlayer connection conductor137a1. Therefore, the third coil strand P3′ of the innermost turn of the second spiral wiring131bserves as the first coil strand of the innermost turn of the spiral wiring formed by the first spiral wiring131aand the second spiral wiring131b.

In addition, the third coil strand S3′ of the innermost turn of the first spiral wiring131ais connected to the first coil strand P1of the second innermost turn of the second spiral wiring131bthrough an interlayer connection conductor137a3. Therefore, the third coil strand S3′ of the innermost turn of the first spiral wiring131aserves as the third coil strand of the innermost turn of the spiral wiring formed by the first spiral wiring131aand the second spiral wiring131b.

In addition, the second coil strand S2′ of the innermost turn of the first spiral wiring131ais connected to the second coil strand P2of the second innermost turn of the second spiral wiring131bthrough an interlayer connection137a2′, and the second coil strand S2of the second innermost turn of the first spiral wiring131ais connected to the second coil strand P2′ of the innermost turn of the second spiral wiring131bthrough an interlayer connection conductor137a2.

In detail, the first coil strand of the innermost turns is formed as the third coil strand P3′ of the second spiral wiring131bon the second surface of the insulating substrate111. In addition, the third coil strand S3′ of the first spiral wiring131ais disposed on the first surface of the insulating substrate111. In addition, the second coil strands S2′ and P2′ of the innermost turns on the opposite surfaces of the insulating substrate111are connected to each other in parallel.

To this end, the interlayer connection conductors137a2and137a2′ are respectively disposed at a start point and an end point of the second coil strands S2′ and P2′ of the innermost turn, and the second coil strands S2′ and P2′ disposed on the opposite surfaces of the insulating substrate111are connected to each other in parallel. Since the parallel connection of the second coil strands S2′ and P2′ is similar to the parallel connection of the innermost turns in the example ofFIGS. 5 and 6described above and the parallel connection of the innermost turns and the parallel connection of the outermost turns in the example ofFIGS. 7 and 8described above, a detailed description thereof will be omitted.

In the example illustrated inFIGS. 11 through 13, line widths of the second coil strands S2′ and P2′ are narrower than line widths of the third coil strands S3′ and P3′. For example, the line width of the second coil strands S2′ and P2′ is half of the line widths of the third coil strands S3′ and P3′. However, the line width of the second coil strands S2′ and P2′ is not limited thereto.

In the example of the antenna module described above, even though the total number of the turns of the spiral wiring is an odd number, the antenna wirings are evenly dispersed on the first surface and the second surface of the insulating substrate.

In the example ofFIGS. 11 through 13described above, the communications wiring130includes the three coil strands S1, S2, and S3, and as a result, the second coil strands of the innermost turn are connected in parallel. However, in a case in which the number of coil strands is an even number (e.g., four coil strands), half (e.g., the first coil strand and the second coil strand) of the coil strands of the innermost turn may be included in the first spiral wiring131a, and the remaining half (e.g., the third coil strand and the fourth coil strand) may be included in the second spiral wiring131b.

Although the insulating substrate111in the examples described above includes only one communications wiring130that performs wireless charging, the insulating substrate111is not limited thereto, but may include a plurality of communications wirings130. For example, the insulating substrate111may include one or more communication wirings130that perform any one or any combination of any two or more of radio frequency identification (RFID), near-field communication (NFC), and magnetic secure transmission (MST) in addition to or in place of wireless charging.

Further, features of the examples described above may be combined with each other. For example, the parallel connection of the outermost turns of the antenna module illustrated inFIGS. 7 and 8may be applied to the outermost turns of the antenna module illustrated inFIGS. 9 and 10orFIGS. 11 and 12.

Further, although the example ofFIGS. 5 and 6described above illustrates a case in which only the innermost one turns are connected to each other in parallel, and the example of

FIGS. 7 and 8described above illustrates a case in which the innermost one turns are connected to each other in parallel and the outermost one turns are connected in parallel with each other, the turns that are connected in parallel with each other may be modified in various ways. For example, two or more turns, for example, the innermost two turns, may be connected in parallel with each other.

In the examples described above, since the communications wiring of the antenna module is formed with a plurality of coil strands for each turn of the spiral wiring, rather than with a single conductor for each turn of the spiral wiring, the region inside the coil strands in which the current does not flow is reduced, and an increase in a resistance of the spiral wiring due to the current flowing in the spiral wiring being biased to one side of the coil strands is suppressed.

In addition, the divided coil strands are not electrically connected to each other within the spiral wiring, but are electrically connected to each other in a lead wiring that extends away from the spiral wiring. Therefore, when the examples of the antenna module described above are used for wireless charging, the charging efficiency is increased compared to wireless charging performed using a conventional antenna module.