Patent Publication Number: US-2023140065-A1

Title: Wireless power transmission resonator using conducting wire with vertical rectangular cross-section

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of Korean Patent Application No. 10-2021-0149787 filed on Nov. 3, 2021, and Korean Patent Application No. 10-2022-0112603 filed on Sep. 6, 2022, in the Korean Intellectual Property Office, the entire disclosures of which are incorporated herein by reference for all purposes. 
     BACKGROUND 
     1. Field of the Invention 
     One or more example embodiments relate to a wireless power transmission resonator using a conducting wire with a vertical rectangular cross-section. 
     2. Description of Related Art 
     Wireless power transmission using an electric and magnetic field mixed coupling method may transmit power farther than wireless power transmission using a magnetic field coupling method and wireless power transmission using an electric field coupling method. Wireless power transmission using the electric and magnetic field mixed coupling method may transmit power farther and may improve transmission efficiency by inducing coupling of positives of an electric field and a magnetic field. In the electric and magnetic field mixed coupling method, a sum of an electric field coefficient and a magnetic coupling coefficient may be determined to be a total coupling coefficient. 
     SUMMARY 
     Example embodiments provide a wireless power transmission resonator using a conducting wire with a vertical rectangular cross-section to remove an electric field and a magnetic field, which intervene with coupling, and solve spreading of an edge current and a line of magnetic force generated by the wireless power transmission resonator in an electric and magnetic field mixed coupling method. 
     According to an aspect, there is provided a wireless power transmission resonator including a first element including a first element upper part arranged in an upper end of a resonator and a first element lower part arranged in a lower end of the resonator, wherein the first element upper part may include a spiral layer having a spiral structure that is wound to face a wide surface of a conducting wire including a vertical rectangular cross-section and the first element lower part may include a spiral layer having a spiral structure that is wound to face the wide surface of the conducting wire including the vertical rectangular cross-section, a second element arranged in a center of the resonator and between the first element upper part and the first element lower part and including a spiral layer having a spiral structure that is wound to face the wide surface of the conducting wire including the vertical rectangular cross-section, and a power supply connected to the first element or the second element and configured to provide power to the resonator. 
     The first element upper part and the first element lower part may include a laminating structure including a spiral layer including one or more layers, and the first element upper part may be connected to the first element lower part by one conducting wire including a vertical rectangular cross-section. 
     The spiral structure of the first element upper part and the spiral structure of the first element lower part may include at least one of a circular spiral structure, a quadrangular spiral structure, a hexagonal spiral structure, and an octagonal spiral structure, or a combination of two or more thereof. 
     The second element may include a laminating structure including a spiral layer including one or more layers and may be connected to the first element upper part and the first element lower part by one conducting wire including a vertical rectangular cross-section. 
     The spiral structure of the second element may include at least one of a circular spiral structure, a quadrangular spiral structure, a hexagonal spiral structure, and an octagonal spiral structure, or a combination of two or more thereof. 
     The conducting wire including the vertical rectangular cross-section may include at least one of a diagonal cross mesh pattern and a cross mesh pattern or a combination of two or more thereof. 
     The power supply may include at least one of an indirect power supply and a direct power supply or a combination of two or more thereof. 
     According to an aspect, there is provided a wireless power transmission resonator including a resonator upper part arranged in an upper end of a resonator and including a spiral layer having a spiral structure that is wound to face a wide surface of a conducting wire including a vertical rectangular cross-section, a resonator lower part arranged in a lower end of a resonator and including a spiral layer having a spiral structure that is wound to face the wide surface of the conducting wire including the vertical rectangular cross-section, and a power supply connected to the resonator upper part and the resonator lower part and configured to provide power to the resonator. 
     The resonator upper part and the resonator lower part may include a laminating structure including a spiral layer including one or more layers, and the resonator upper part may be connected to the resonator lower part by one conducting wire including a vertical rectangular cross-section. 
     The spiral structure of the resonator upper part and the spiral structure of the resonator lower part may include at least one of a circular spiral structure, a quadrangular spiral structure, a hexagonal spiral structure, and an octagonal spiral structure, or a combination of two or more thereof. 
     The wireless power transmission resonator may further include an element arranged in a center of the wireless power transmission resonator and between the resonator upper part and the resonator lower part, wherein the element may include a spiral layer having a spiral structure that is wound to face a wide surface of a conducting wire including a vertical rectangular cross-section and a laminating structure including a spiral layer including one or more layers. 
     The spiral structure of the element may include at least one of a circular spiral structure, a quadrangular spiral structure, a hexagonal spiral structure, and an octagonal spiral structure, or a combination of two or more thereof. 
     The conducting wire including the vertical rectangular cross-section may include at least one of a diagonal cross mesh pattern and a cross mesh pattern or a combination of two or more thereof. 
     The power supply may include at least one of an indirect power supply and a direct power supply or a combination of two or more thereof. 
     According to an aspect, there is provided a wireless power transmission resonator including a resonator upper part arranged in an upper end of a resonator and including a laminating structure including one or more spiral layers having a spiral structure that is wound to face a wide surface of a conducting wire including a vertical rectangular cross-section, a resonator lower part arranged in a lower end of a resonator, connected to the resonator upper part by one conducting wire, and including a laminating structure including one or more spiral layers having a spiral structure that is wound to face the wide surface of the conducting wire including the vertical rectangular cross-section, an element arranged in a center of the resonator and between the first resonator upper part and the resonator lower part, connected to the resonator upper part and the resonator lower part by one conducting wire, and including a laminating structure including one or more spiral layers having a spiral structure that is wound to face the wide surface of the conducting wire including the vertical rectangular cross-section, and a power supply connected to the element and configured to provide power to the resonator. 
     Additional aspects of example embodiments will be set forth in part in the description which follows and, in part, will be apparent from the description, or may be learned by practice of the disclosure. 
     According to example embodiments, a wireless power transmission resonator using a conducting wire including a vertical rectangular cross-section may reduce an occurrence of an edge current, may concentrate a line of magnetic force, and may remove an electric field and a magnetic field, which intervene with coupling. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and/or other aspects, features, and advantages of the invention will become apparent and more readily appreciated from the following description of example embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG.  1    is a diagram illustrating a characteristic of a magnetic field based on a cross-section of a conducting wire in a loop resonator according to an example embodiment; 
         FIG.  2    is a diagram illustrating a characteristic of an S 12  parameter based on a cross-section of a conducting wire in a loop resonator according to an example embodiment; 
         FIG.  3    is a diagram illustrating an electromagnetic distribution characteristic of a resonator according to an example embodiment; 
         FIG.  4    is a diagram illustrating a current distribution and a charge distribution of the resonator of  FIG.  3    according to an example embodiment; 
         FIG.  5    is a diagram illustrating a resonator for increasing a magnetic field coupling according to an example embodiment; 
         FIG.  6    is a diagram illustrating a current distribution and a charge distribution of the resonator of  FIG.  5    according to an example embodiment; 
         FIG.  7    is a diagram illustrating an electromagnetic distribution characteristic of the resonator of  FIG.  5    according to an example embodiment; 
         FIG.  8    is a diagram illustrating a resonator according to an example embodiment; 
         FIG.  9    is a diagram illustrating a current distribution and a charge distribution of the resonator of  FIG.  8    according to an example embodiment; 
         FIG.  10    is a diagram illustrating an electromagnetic distribution characteristic of the resonator of  FIG.  8    according to an example embodiment; 
         FIG.  11    is an example of implementing wireless power transmission using the resonator of  FIG.  8    according to an example embodiment; 
         FIG.  12    is a diagram illustrating an S parameter characteristic of the resonator of  FIG.  11    according to an example embodiment; 
         FIG.  13    is a diagram illustrating characteristics of spatial radiation loss and heat loss of the resonator of  FIG.  11    according to an example embodiment; 
         FIG.  14    is a diagram illustrating a resonator according to an example embodiment; 
         FIG.  15    is a diagram illustrating an S parameter characteristic of the resonator of  FIG.  14    according to an example embodiment; 
         FIG.  16    is a diagram illustrating characteristics of spatial radiation loss and heat loss of the resonator of  FIG.  14    according to an example embodiment; 
         FIG.  17    is a diagram illustrating a resonator according to an example embodiment; 
         FIG.  18    is a diagram illustrating a resonator according to an example embodiment; 
         FIG.  19    is a diagram illustrating a resonator including an indirect power supply according to an example embodiment; 
         FIG.  20    is a diagram illustrating a plurality of spiral structures according to an example embodiment; and 
         FIG.  21    is a diagram illustrating a pattern of a conducting wire that may be used in a resonator according to an example embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, examples will be described in detail with reference to the accompanying drawings. The scope of the right, however, should not be construed as limited to the example embodiments set forth herein. In the drawings, like reference numerals are used for like elements. 
     Various modifications may be made to the examples. Here, the examples are not construed as limited to the disclosure and should be understood to include all changes, equivalents, and replacements within the idea and the technical scope of the disclosure. 
     Although terms of “first” or “second” are used to explain various components, the components are not limited to the terms. These terms should be used only to distinguish one component from another component. For example, a first component may be referred to as a second component, and similarly the second component may also be referred to as the first component. 
     The terminology used herein is for the purpose of describing particular examples only and is not to be limiting of the examples. As used herein, the singular forms “a”, “an”, and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. As used herein, “A or B”, “at least one of A and B”, “at least one of A or B”, “A, B or C”, “at least one of A, B and C”, and “at least one of A, B, or C,” each of which may include any one of the items listed together in the corresponding one of the phrases, or all possible combinations thereof. It will be further understood that the terms “comprises/comprising” and/or “includes/including” when used herein, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof. 
     Unless otherwise defined, all terms including technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, such as those defined in commonly-used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     When describing the examples with reference to the accompanying drawings, like reference numerals refer to like constituent elements and a repeated description related thereto will be omitted. In the description of example embodiments, detailed description of well-known related structures or functions will be omitted when it is deemed that such description will cause ambiguous interpretation of the present disclosure. 
     Hereinafter, example embodiments will be described in detail with reference to the accompanying drawings. 
       FIG.  1    is a diagram illustrating a characteristic of a magnetic field based on a cross-section of a conducting wire in a loop resonator according to an example embodiment. 
       FIG.  1    illustrates a loop resonator  101  including a conducting wire with a square cross-section, a loop resonator  102  including a conducting wire with a vertical rectangular cross-section, and a loop resonator  103  including a conducting wire with a horizontal rectangular cross-section. 
     Each of the resonators may have the same weight and only the shapes of the cross-sections may be different. Each of the resonators may be connected to a power supply. A current may flow from a cathode to an anode. Therefore, the current may flow in a counterclockwise direction. A magnetic field may occur when the current flows. Referring to  FIG.  1   , according to Ampere&#39;s circuital law, a magnetic field may be generated in the counterclockwise direction. 
     A magnetic field  101 - 1  of a loop resonator including a conducting wire with a square cross-section may be generated in the counterclockwise direction and may have a circular shape of which a radius is the same as the radius from the center of the conducting wire. A magnetic field  102 - 1  of a loop resonator including a conducting wire with a vertical rectangular cross-section may be generated in the counterclockwise direction and may have a vertically long elliptical shape. A magnetic field  103 - 1  of a loop resonator including a conducting wire with a horizontal rectangular cross-section may be generated in the counterclockwise direction and may have a horizontally long elliptical shape. 
     Hereinafter, the efficiency of each of the loop resonators may be determined. 
       FIG.  2    is a diagram illustrating a characteristic of an S 12  parameter based on a cross-section of a conducting wire in a loop resonator according to an example embodiment. 
       FIG.  2    illustrates S 12  parameters according to a frequency when the loop resonators of  FIG.  1    have the same size. The S 12  parameter may be a ratio of power transmitted from a port  1 , which is a transmitter, to power received by a port  2 , which is a receiver. As S 12  increases, the efficiency of the resonator may increase. 
     Accordingly, the loop resonator  101  including a conducting wire with a square cross-section may have 63.8% efficiency at a resonant frequency f 0 . The loop resonator  102  including a conducting wire with a vertical rectangular cross-section may have 70.5% efficiency at the resonant frequency f 0 . The loop resonator  103  including a conducting wire with a horizontal rectangular cross-section may have 49.8% efficiency at the resonant frequency f 0 . The efficiency of the loop resonator  102  including a conducting wire with a vertical rectangular cross-section may be the greatest. 
     A current may flow in a wide range due to a skin effect and may generate a magnetic field while flowing on the surface of a conductor. Here, a magnetic field generated by the loop resonator  102  including a conducting wire with a vertical rectangular cross-section may be more centrally concentrated than a magnetic field generated by a loop resonator including other conducting wires. Accordingly, the efficiency of the loop resonator  102  including a conducting wire with a vertical rectangular cross-section may be the greatest. 
     Hereinafter, a double spiral resonator including a conducting wire with a vertical rectangular cross-section that may decrease an edge current by minimizing the surface perpendicular to a magnetic flux direction is described. 
       FIG.  3    is a diagram illustrating an electromagnetic distribution characteristic of a resonator according to an example embodiment, 
       FIG.  3    illustrates a resonator upper part  301 , a resonator lower part  302 , and a power supply  303 . 
     The resonator upper part  301  and the resonator lower part  302  may include a spiral structure that is wound to face the wide surface of the conducting wire including the cross-section having a vertical rectangular shape. The resonator upper part  301  and the resonator lower part  302  may be spaced apart by a distance H. The cathode of the power supply  303  may be connected to the resonator upper part  301 , and the anode of the power supply  303  may be connected to the resonator lower part  302 . Accordingly, as the distance H between the resonator upper part  301  and the resonator lower part  302  increases, a potential difference may increase. As the potential difference increases, an electric coupling force may increase. That is, as the distance between the resonator upper part  301  and the resonator lower part  302  increases, the electric coupling force may increase, and thus, power may be transmitted farther. 
     In addition, the potential difference may be greater when the resonator upper part  301  and the resonator lower part  302  are horizontally arranged compared to a case where the resonator upper part  301  and the resonator lower part  302  are vertically arranged. When the resonator upper part  301  and the resonator lower part  302  are vertically arranged, an electric field  330  with a large coupling force may be generated. The electric field  330  with the large coupling force may increase as the potential difference increases. Accordingly, when the resonator upper part  301  and the resonator lower part  302  are vertically arranged, power may be transmitted farther. 
     Two types of magnetic fields may be generated by a current flowing in the resonator. A magnetic field  310  with a large coupling force and a vertically polarized wave characteristic may be generated by a current  340  flowing in the resonator upper part  301  and the resonator lower part  302 . A magnetic field  320  with a low coupling force and a horizontally polarized wave characteristic may be generated by a current flowing in a conducting wire connected to the power supply  303 . 
     A loss due to an edge current may be minimized by minimizing a surface perpendicular to the magnetic field  310  with the large coupling force. Since the magnetic field  320  with the low coupling force has the horizontally polarized wave characteristic and does not affect coupling, the magnetic field  320  with the low coupling force may be a component that is not helpful to wireless power transmission. 
     Hereinafter, a current distribution and a charge distribution of the resonator of  FIG.  3    is described. 
       FIG.  4    is a diagram illustrating a current distribution and a charge distribution of the resonator of  FIG.  3    according to an example embodiment. 
     Referring to  FIG.  4   , the current distribution is the greatest around the power supply  303 , which is the center of the resonator. That is, around the power supply  303 , the intensity of the current may have the greatest distribution. 
     Since the resonator of  FIG.  3    is a double spiral resonator using a conducting wire including a vertical rectangular cross-section and shows the greatest efficiency in  FIG.  2   , the resonator of  FIG.  3    may have a greater transmission efficiency and may transmit power farther than a prior resonator. However, although the intensity of the current has the greatest distribution around the power supply  303 , unavailability of using this to increase coupling may be a loss. 
     Accordingly, hereinafter, a method of using a current around the power supply  303  to increase coupling is described. 
       FIG.  5    is a diagram illustrating a resonator for increasing a magnetic field coupling according to an example embodiment. 
       FIG.  5    illustrates a first element  501  and a second element  502 , wherein the first element  501  including a first element upper part  504  and a first element lower part  505 . A resonator  503  may include the first element  501  and the second element  502 . The second element  502  may be connected to a power supply. 
     The first element upper part  504  and the first element lower part  505  included in the first element  501  may include a spiral structure that is wound twice to face the wide surface of a conducting wire including a vertical rectangular cross-section. Each of the first element upper part  504  and the first element lower part  505  may include a single-layered spiral structure. That is, the first element upper part  504  and the first element lower part  505  may be single-layered and double-wound. The second element  502  may have a structure in which the central portion of the resonator where the power supply is located strongly generates magnetic field coupling. 
     The first element  501  may be an element in which electric coupling is strongly generated. The second element may be an element in which magnetic field coupling is strongly generated. 
     Since the first element  501  includes the spiral structure, the first element  501  may simultaneously generate electric coupling as well as magnetic field coupling due to current induction. 
     Hereinafter, a current distribution and a charge distribution of the resonator  503  of  FIG.  5    is described. 
       FIG.  6    is a diagram illustrating a current distribution and a charge distribution of the resonator of  FIG.  5    according to an example embodiment. 
     Referring to  FIG.  6   , in the resonator  503  of  FIG.  5   , the length of the second element  502 , in which magnetic field coupling is strongly generated, is wider than the resonator of  FIG.  3   . Thus, the resonator  503  of  FIG.  5    may transmit power farther than the resonator of  FIG.  3   . 
     By improving a structure of a resonator to increase magnetic field coupling using the high current distribution in the center of the resonator and increase electric coupling using the high charge distribution at both ends of the resonator, power may be transmitted farther. 
     Hereinafter, an electromagnetic distribution characteristic of the resonator  503  of  FIG.  5    is described. 
       FIG.  7    is a diagram illustrating an electromagnetic distribution characteristic of the resonator of  FIG.  5    according to an example embodiment. 
       FIG.  7    illustrates the first element  501  and the second element  502 , wherein the first element  501  includes the first element upper part  504  and the first element lower part  505 . The resonator may include the first element  501  and the second element  502 . 
     A magnetic field  510  with a large coupling force and a vertical polarized wave characteristic may be generated by a current flowing in the second element  502  as well as a current flowing in the first element upper part  504  and the first element lower part  505 . 
     The second element  502  in which magnetic field coupling is strongly generated may be configured in a single layer and may be connected to the power supply. An electric field may be generated from the cathode to the anode. Accordingly, the electric field  520  with a low coupling force generated by the power supply may be generated from the cathode to the anode. The element field  520  with a low coupling force may be generated in a direction perpendicular to a direction of the electric field  530  with a large coupling force generated by the first element upper part  504  and the first element lower part  505 . 
     When performing medium-range power transmission by vertically arranging transmission/reception resonators, power may be transmitted farther than the resonator of  FIG.  3    as a current flowing in the second element  502 , which is the center of the resonator  503  of  FIG.  5   , contributes to the magnetic field  510  with the large coupling force, however, the magnetic field  520  with the low coupling force that may not help power transmission may still exist. 
     When manufacturing a resonator by a conducting wire including a vertical rectangular cross-section, the current may flow on a wide surface, and thus, a resistive element may decrease. In addition, when arranging the resonator in a spiral structure to face the wide surface, an occurrence of an edge current may decrease as the magnetic field concentrates on the center and a vertical polarized wave element occurs in a direction perpendicular to an opening of the resonator. 
       FIG.  8    is a diagram illustrating a resonator according to an example embodiment. 
       FIG.  8    illustrates a resonator  803  including a first element  801  and a second element  802 , wherein the first element  801  includes a first element upper part  804  and a first element lower part  805 . 
     Each of the first element upper part  804  and the first element lower part  805  may include a double-wound spiral structure. Each of the first element upper part  804  and the first element lower part  805  may include a single-layered spiral structure. That is, the first element upper part  804  and the first element lower part  805  may be single-layered and double-wound. 
     The second element  802  may include a single-wound spiral structure. The second element  802  may include a double-layered spiral structure. That is, the second element  802  may be double-layered and single-wound. The second element  802  may be connected to a power supply. 
     The resonator  803  may include the first element  801  and the second element  802 . The second element  802  may be arranged in the center of the resonator. Both ends of the second element  802  may be connected to the first element upper part  804  and the first element lower part  805 , respectively. The first element upper part  804  of the first element  801  may be arranged in the upper part of the resonator  803 , and the first element lower part  805  may be arranged in the lower part of the resonator  803 . 
     The resonator  803  may be in a structure configured to remove a magnetic field and an electric field that may not help the coupling force, concentrate the magnetic flux on the center, and minimize an edge current. 
     Hereinafter, a current distribution and a charge distribution of the resonator  803  is described. 
       FIG.  9    is a diagram illustrating a current distribution and a charge distribution of the resonator of  FIG.  8    according to an example embodiment. 
     The resonator  803  of  FIG.  8    may be a resonator configured to couple a magnetic field generated by the second element  802  that is arranged in the center of the resonator  803  and has a high current element as much as possible. 
     Referring to  FIG.  9   , in the resonator  803  of  FIG.  8   , the length of the second element  802 , in which magnetic field coupling is strongly generated, is wider than the resonator  503  of  FIG.  5   . Thus, the resonator  803  of  FIG.  8    may transmit power farther than the resonator  503  of  FIG.  5   . 
     Hereinafter, an electromagnetic distribution characteristic of the resonator  803  of  FIG.  8    is described. 
       FIG.  10    is a diagram illustrating an electromagnetic distribution characteristic of the resonator of  FIG.  8    according to an example embodiment. 
     A magnetic field  810  with a large coupling force and a vertical polarized wave characteristic may be generated by a current flowing in the second element  802  as well as a current flowing in the first element upper part  804  and the first element lower part  805 . 
     Referring to  FIG.  10   , the electric field  520  of  FIG.  7    with the small coupling force decreases. Referring to  FIG.  10   , a power supply may be arranged in the center of the second element  802  and based on the power supply, a lower layer may be a cathode and an upper layer may be an anode. Accordingly, the electric field  520  with the small coupling force of  FIG.  7    may decrease and the decreased electric field may be generated in a same direction as the electric field  830  with the large coupling force. Thus, electric coupling may increase. 
     Here, when performing medium-range power transmission by vertically arranging transmission/reception resonators, power may be transmitted farther than the resonator  503  of  FIG.  5   . Hereinafter, wireless power transmission using the resonator  803  of  FIG.  8    is described. 
       FIG.  11    is an example of implementing wireless power transmission using the resonator of  FIG.  8    according to an example embodiment. 
       FIG.  11    illustrates a transmitter  1103  and a receiver  1101  using the resonator of  FIG.  8   . In the transmitter  1103 , a power supply  1104  may be connected to a second element. In the receiver  1101 , a load  1102  may be connected to the second element. The power supply  1104  may include any circuit and system configured to generate a power signal. The load  1104  may include a rectifying circuit configured to rectify an input radio frequency (RF) signal and a charging system. 
     The length of the largest side between the length side and the width side of openings of the transmitter  1103  and the receiver  1101  may be defined as W, and a distance between the transmitter  1103  and the receiver  1101  may be defined as D. 
     Hereinafter, an S parameter and a loss when the distance D between the receiver  1101  and the transmitter  1103  both including a copper wire is  10  W is described. 
       FIG.  12    is a diagram illustrating an S parameter characteristic of the resonator of  FIG.  11    according to an example embodiment. 
       FIG.  12    illustrates S 12  and S 11  parameters when the distance D between the transmitter  1103  and the receiver  1101  is 10 W. The S 11  parameter may be a reflection coefficient of a transmitter. The S 12  parameter may be a ratio of power transmitted from a transmitter to power received by a receiver. As S 12  increases, the efficiency of the resonator may increase. 
     At the resonant frequency of 10.82 MHz, the power transmission efficiency of the resonator may be 50% and the reflection coefficient may be 0.4%. That is, when the distance D is less than 10 W, the power transmission efficiency of the resonator may be greater than or equal to 50%. The reflection coefficient 0.4% may indicate that impedance matching is properly achieved. 
     In case of a resonator using traditional copper, it is known that implementing a resonator having 50% efficiency when the distance D is greater than or equal to 5 W is a difficult technique. The resonator of the present disclosure may have 50% efficiency when D is 10 W and thus may transmit power farther than the resonator using traditional copper. 
       FIG.  13    is a diagram illustrating characteristics of spatial radiation loss and heat loss of the resonator of  FIG.  11    according to an example embodiment, 
       FIG.  13    illustrates spatial radiation loss and heat loss characteristics when the distance D between the transmitter  1103  and the receiver  1101  is 10 W. 
     The spatial radiation loss may be maximized between 10.80 MHz and 10.82 MHz and may decrease as a frequency increases. The spatial radiation loss may be 24.4% at 10.82 MHz. The heat loss may be 24.9% at 10.82 MHz. 
     The frequency being used may change by adjusting the size of a resonator. Therefore,  FIG.  13    illustrates spatial radiation loss and heat loss characteristics based on a 10.82 MHz frequency. However, the frequency may be tuned to an industry-science-medical (ISM) band as 6.78 MHz or 13.56 MHz. Hence, the resonator in the present disclosure may be used in a field where spatial radiation is allowed, like the ISM band, or may be applied to various fields by allocating a separate frequency. 
       FIG.  14    is a diagram illustrating a resonator according to an example embodiment. 
       FIG.  14    illustrates a first element  1401  and a second element  1402 , wherein the first element  1401  includes a first element upper part  1404  and a first element lower part  1405 . A resonator  1403  may include the first element  1401  and the second element  1402 . The second element  1402  may be connected to a power supply. 
     The first element upper part  1404  and the first element lower part  1405  may include a spiral structure that is wound twice to face the wide surface of a conducting wire including a vertical rectangular cross-section. Each of the first element upper part  1404  and the first element lower part  1405  may include a single-layered spiral structure. That is, the first element upper part  1404  and the first element lower part  1405  may be single-layered and double-wound. 
     The second element  1402  may include a double-wound spiral structure. The second element  1402  may include a double-layered spiral structure. That is, the second element  1402  may be double-layered and double-wound. The second element  1402  may be connected to a power supply. 
     The resonator  1403  may include the first element  1401  and the second element  1402 . The second element  1402  may be arranged in the center of the resonator  1403 . Both ends of the second element  1402  may be connected to the first element upper part  1404  and the first element lower part  1405 , respectively. 
     Compared to the resonator  803  of  FIG.  8   , the resonator  1403  may include a wider area in which magnetic field coupling is strongly generated. Thus, the resonator  1403  may transmit power farther than the resonator  803  of  FIG.  8   . 
     Hereinafter, an S parameter, spatial radiation loss, and a heat loss of the resonator  1403  are described. 
       FIG.  15    is a diagram illustrating an S parameter characteristic of the resonator of  FIG.  14    according to an example embodiment. 
       FIG.  15    illustrates S 12  and S 11  parameters when the distance D between the transmitter and the receiver using the resonator of  FIG.  14    is 10 W. The S 11  parameter may be a reflection coefficient of a transmitter. The S 12  parameter may be a ratio of power transmitted from a transmitter to power received by a receiver. As S 12  increases, the efficiency of the resonator may increase. 
     At 7.04 MHz, the power transmission efficiency of the resonator may be 54.4%, and the reflection coefficient may be 0.7%. Since the power transmission efficiency of the resonator  1403  of  FIG.  14    is 54.4% and the power transmission efficiency of the resonator  803  of  FIG.  8    is 50%, the efficiency of the resonator  1403  of  FIG.  14    may be better. 
     In the resonator  1403 , the second element  1402  may be double-layered and double-wound and in the resonator  803 , the second element  802  may be single-layered and double-wound. Thus, as the number of windings of a resonator&#39;s conducting wire with a vertical rectangular cross-section increases, the power transmission efficiency may increase. 
     Compared to the resonator  803 , in the resonator  1403 , a resonant frequency may decrease as the total length of the conducting wire increases. 
       FIG.  16    is a diagram illustrating characteristics of spatial radiation loss and heat loss of the resonator of  FIG.  14    according to an example embodiment. 
       FIG.  16    illustrates spatial radiation loss and heat loss characteristics when the distance D of the resonator  1403  of  FIG.  14    is 10 W. 
     At the resonant frequency of 7.04 MHz, a heat loss may be 30.2%. At the resonant frequency of 7.04 MHz, a spatial radiation loss may be 14.7%. 
     The heat loss and the spatial radiation loss may be adjusted by changing a design dimension and a material of a resonator. By using a metal having a high conductivity, such as silver, as a conducting wire, the heat loss may decrease and the power transmission efficiency may increase. 
     Hereinafter, a generalized structure of a resonator based on the above descriptions is described. 
       FIG.  17    is a diagram illustrating a resonator according to an example embodiment. 
       FIG.  17    illustrates a first element including the first element upper part  1702  and the first element lower part  1704  and the second element  1703 . 
     The first element upper part  1702  may be arranged in the upper end of a resonator  1701 . The first element upper part  1702  may include a spiral layer having a spiral structure that is wound to face the wide surface of a conducting wire including a cross-section having a vertical rectangular shape. The first element upper part  1702  may have a laminating structure including a spiral layer including one or more layers. The first element upper part  1702  may include a spiral layer including N2 layers, which is a plurality of layers. As the number of layers of the first element upper part  1702  increases, the efficiency of wireless power transmission may increase. The first element upper part  1702  may include a spiral structure including M2 envelopes. As the number of envelopes of the first element upper part  1702  increases, the efficiency of wireless power transmission may increase. 
     The first element lower part  1704  may be arranged in the lower end of the resonator  1701 . The first element lower part  1704  may include a spiral layer having a spiral structure that is wound to face the wide surface of a conducting wire including a cross-section having a vertical rectangular shape. The first element lower part  1704  may have a laminating structure including a spiral layer including one or more layers. The first element lower part  1704  may include a spiral layer including N2 layers, which is a plurality of layers. As the number of layers of the first element lower part  1704  increases, the efficiency of wireless power transmission may increase. The first element lower part  1704  may include a spiral structure including M2 envelopes. As the number of envelopes of the first element lower part  1704  increases, the efficiency of wireless power transmission may increase. The first element lower part  1704  may be connected to the first element upper part  1701  by one conducting wire including a vertical rectangular cross-section. 
     The second element  1703  may be between the first element upper part  1702  and the first element lower part  1704 . The second element  1703  may be arranged in the center of the resonator  1701 . The second element  1703  may include a spiral layer having a spiral structure that is wound to face the wide surface of a conducting wire including a cross-section having a vertical rectangular shape. The second element  1703  may include a spiral layer including N1 layers, which is a plurality of layers. As the number of layers of the second element  1703  increases, the efficiency of wireless power transmission may increase. The second element  1703  may include a spiral structure including M1 envelopes. As the number of envelopes of second element  1703  increases, the efficiency of wireless power transmission may increase. 
     The resonator  1701  may include a power supply. The power supply may be a direct power supply that is directly connected to the resonator and provides power thereto. The power supply may be an indirect power supply that is indirectly connected to the resonator and provides power thereto. 
       FIG.  18    is a diagram illustrating a resonator according to an example embodiment. 
     Referring to  FIG.  18   , a resonator  1801  may include a resonator upper part  1802 , a resonator lower part  1803 , and a power supply  1804 . 
     The resonator upper part  1802  may be arranged in the upper end of the resonator  1801 . The resonator upper part  1802  may include a spiral layer having a spiral structure that is wound to face the wide surface of a conducting wire including a cross-section having a vertical rectangular shape. The resonator upper part  1802  may have a laminating structure including a spiral layer including one or more layers. The resonator upper part  1802  may include a spiral layer including N1 layers, which is a plurality of layers. As the number of layers of the resonator upper part  1802  increases, the efficiency of wireless power transmission may increase. The resonator upper part  1802  may include a spiral structure including M1 envelopes. As the number of envelopes of resonator upper part  1802  increases, the efficiency of wireless power transmission may increase. 
     The resonator lower part  1803  may be arranged in the lower end of the resonator  1801 . The resonator lower part  1803  may include a spiral layer having a spiral structure that is wound to face the wide surface of a conducting wire including a cross-section having a vertical rectangular shape. The resonator lower part  1803  may include a spiral layer including N1 layers, which is a plurality of layers. As the number of layers of the resonator lower part  1803  increases, the efficiency of wireless power transmission may increase. The resonator lower part  1803  may include a spiral structure including M1 envelopes. As the number of envelopes of the resonator lower part  1803  increases, the efficiency of wireless power transmission may increase. 
     The power supply  1804  may be connected to the resonator upper part  1802  and the resonator lower part  1803  and may provide power thereto. The power supply  1804  may include at least one of a direct power supply and an indirect power supply, or may be a combination of two or more thereof. 
     The resonator  1801  may further include an element arranged in the center of the resonator  1801 , which is between the resonator upper part  1802  and the resonator lower part  1803 . The element may include a spiral layer having a spiral structure that is wound to face the wide surface of a conducting wire including a cross-section having a vertical rectangular shape. The element may have a laminating structure including a spiral layer including one or more layers. 
       FIG.  19    is a diagram illustrating a resonator including an indirect power supply according to an example embodiment. 
     When the resonator described above functions as a transmitter of wireless power transmission, the resonator may be connected to a power supply. The power supply may be a direct power supply that is directly connected to the resonator and provides power thereto. The power supply may be an indirect power supply that is indirectly connected to the resonator and provides power thereto. 
     Referring to  FIG.  19   , as an example of an indirect power supply, a resonator  1901  connected to an electric dipole power supply and a resonator  1902  connected to a loop element are illustrated. Accordingly, the power supply may include at least one of a direct power supply and an indirect power supply, or may include a combination of two or more thereof. 
     The indirect power supply may be independent from adjustment of input impedance or output impedance. Thus, by using the indirect power supply, a resonator may be manufactured based on a load or impedance of the power supply. 
       FIG.  20    is a diagram illustrating a plurality of spiral structures according to an example embodiment. 
       FIG.  20    illustrates a spiral structure applicable to a resonator. The structure illustrated in  FIG.  20    may be a structure viewing the first element upper part, the first element lower part, and the second element, which are described above, from the top or the bottom. 
     Accordingly, the first element and the second element may include at least one of a circular spiral structure  2001 , a quadrangular spiral structure  2002 , a hexagonal spiral structure  2003 , and an octagonal spiral structure  2004 , or a combination of two or more thereof. 
     The first element and the second element may include other polygonal structures than the ones listed above. 
       FIG.  21    is a diagram illustrating a pattern of a conducting wire that may be used in a resonator according to an example embodiment. 
       FIG.  21    illustrates a diagonal cross mesh pattern  2101  and a cross mesh pattern  2102 . 
     A conducting wire included in the resonator of the present disclosure may have a tape shape of which a cross-section has a vertical rectangular shape. The conducting wire may include at least one of the diagonal cross mesh pattern  2101  and the cross mesh pattern  2102  or a combination of two or more thereof. When the conducting wire is a mesh pattern, the conducting wire may be less affected by wind and the weight of the resonator may decrease. 
     The components described in the example embodiments may be implemented by hardware components including, for example, at least one digital signal processor (DSP), a processor, a controller, an application-specific integrated circuit (ASIC), a programmable logic element, such as a field programmable gate array (FPGA), other electronic devices, or combinations thereof. At least some of the functions or the processes described in the example embodiments may be implemented by software, and the software may be recorded on a recording medium. The components, the functions, and the processes described in the example embodiments may be implemented by a combination of hardware and software. 
     The method according to example embodiments may be written in a computer-executable program and may be implemented as various recording media such as magnetic storage media, optical reading media, or digital storage media. 
     Various techniques described herein may be implemented in digital electronic circuitry, computer hardware, firmware, software, or combinations thereof. The implementations may be achieved as a computer program product, for example, a computer program tangibly embodied in a machine readable storage device (a computer-readable medium) to process the operations of a data processing device, for example, a programmable processor, a computer, or a plurality of computers or to control the operations. A computer program, such as the computer program(s) described above, may be written in any form of a programming language, including compiled or interpreted languages, and may be deployed in any form, including as a stand-alone program or as a module, a component, a subroutine, or other units suitable for use in a computing environment. A computer program may be deployed to be processed on one computer or multiple computers at one site or distributed across multiple sites and interconnected by a communication network. 
     Processors suitable for processing of a computer program include, by way of example, both general and special purpose microprocessors, and any one or more processors of any kind of digital computer. Generally, a processor will receive instructions and data from a read-only memory or a random-access memory, or both. Elements of a computer may include at least one processor for executing instructions and one or more memory devices for storing instructions and data. Generally, a computer also may include, or be operatively coupled to receive data from or transfer data to, or both, one or more mass storage devices for storing data, e.g., magnetic, magneto-optical disks, or optical disks. Examples of information carriers suitable for embodying computer program instructions and data include semiconductor memory devices, e.g., magnetic media such as hard disks, floppy disks, and magnetic tape, optical media such as compact disk read only memory (CD-ROM) or digital video disks (DVDs), magneto-optical media such as floptical disks, read-only memory (ROM), random-access memory (RAM), flash memory, erasable programmable ROM (EPROM), or electrically erasable programmable ROM (EEPROM). The processor and the memory may be supplemented by, or incorporated in special purpose logic circuitry. 
     In addition, non-transitory computer-readable media may be any available media that may be accessed by a computer and may include both computer storage media and transmission media. 
     Although the present specification includes details of a plurality of specific example embodiments, the details should not be construed as limiting any invention or a scope that can be claimed, but rather should be construed as being descriptions of features that may be peculiar to specific example embodiments of specific inventions. Specific features described in the present specification in the context of individual example embodiments may be combined and implemented in a single example embodiment. On the contrary, various features described in the context of a single embodiment may be implemented in a plurality of example embodiments individually or in any appropriate sub-combination. Furthermore, although features may operate in a specific combination and may be initially depicted as being claimed, one or more features of a claimed combination may be excluded from the combination in some cases, and the claimed combination may be changed into a sub-combination or a modification of the sub-combination. 
     Likewise, although operations are depicted in a specific order in the drawings, it should not be understood that the operations must be performed in the depicted specific order or sequential order or all the shown operations must be performed in order to obtain a preferred result. In specific cases, multitasking and parallel processing may be advantageous. In a specific case, multitasking and parallel processing may be advantageous. In addition, it should not be understood that the separation of various device components of the aforementioned example embodiments is required for all the example embodiments, and it should be understood that the aforementioned program components and apparatuses may be integrated into a single software product or packaged into multiple software products. 
     The example embodiments disclosed in the present specification and the drawings are intended merely to present specific examples in order to aid in understanding of the present disclosure, but are not intended to limit the scope of the present disclosure. It will be apparent to those skilled in the art that various modifications based on the technical spirit of the present disclosure, as well as the disclosed example embodiments, can be made.