Patent Publication Number: US-2019173180-A1

Title: Wireless communication device and antenna device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2017-233535, filed on Dec. 5, 2017, the entire contents of which are incorporated herein by reference. 
     FIELD 
     The embodiment discussed herein is related to a wireless communication device and an antenna device. 
     BACKGROUND 
     Up to now, a wireless communication device provided with a dielectric including one principal surface and another principal surface, a rectangular coil antenna which is formed on the one principal surface of this dielectric and to which an IC chip for the coil antenna is electrically connected, and a monopole antenna which is formed on the one principal surface or the other principal surface of the dielectric on an outer circumference of winding constituting this coil antenna and which is grounded by the coil antenna has been proposed. 
     The wireless communication device is further provided with an IC chip for the monopole antenna to which power is supplied by this monopole antenna and a winding bending portion which is part of the winding constituting the coil antenna and in which the winding constituting the coil antenna is bend onto an inner circumference side (for example, see Japanese Laid-open Patent Publication No. 2011-128956). 
     SUMMARY 
     According to an aspect of the embodiments, a wireless communication device includes a loop antenna that includes a first terminal and a second terminal, and a third terminal and a fourth terminal respectively corresponding to the first terminal and the second terminal, the loop antenna constituting a loop between the first terminal and the second terminal and the third terminal and the fourth terminal, and the loop antenna having a first inductance, a first communication circuit that is coupled between the first terminal and the third terminal and has a first impedance, the first communication circuit resonating at a first frequency with the loop antenna, a coil that is coupled between the second terminal and the fourth terminal and has a second inductance higher than the first inductance, a capacitance that is coupled between the second terminal and the fourth terminal in parallel to the coil and has an electrostatic capacitance having a complex conjugate relationship with a second inductance of the coil, and a second communication circuit that is coupled between the second terminal and the fourth terminal and has a second impedance lower than the first impedance, the second communication circuit performing a communication at a second frequency via the loop antenna. 
     The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  illustrates a wireless communication device according to an embodiment; 
         FIG. 2  illustrates a configuration in which a cover portion is removed from the wireless communication device illustrated in  FIG. 1 ; 
         FIG. 3  illustrates a configuration in which part of components is removed from the wireless communication device; 
         FIG. 4A  illustrates part of the components of the wireless communication device; 
         FIG. 4B  illustrates part of the components of the wireless communication device; 
         FIG. 5  illustrates an inlay; 
         FIG. 6  illustrates an element; 
         FIG. 7  illustrates an equivalent circuit of the wireless communication device as a radio frequency identifier (RFID) tag; 
         FIG. 8  illustrates an equivalent circuit of the wireless communication device as a Bluetooth Low Energy (BLE) communication device; 
         FIG. 9  illustrates a simulation model of the wireless communication device; 
         FIG. 10  is a Smith chart illustrates an impedance characteristic in a case where the wireless communication device functions as the RFID tag; 
         FIG. 11  is a Smith chart illustrates an impedance characteristic in a case where the wireless communication device functions as the BLE communication device; 
         FIG. 12  illustrates a wireless communication device according to a first modified example of the embodiment; and 
         FIG. 13  illustrates a wireless communication device according to a second modified example of the embodiment. 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     A wireless communication device in related art is compatible with both a radio frequency identifier (RFID) system in a low frequency (LF) band or a high frequency (HF) band and an RFID system in an ultra-high frequency (UHF) band. 
     Both the RFID system in the LF band or the HF band and the RFID system in the UHF band include an integrated circuit (IC) chip. That is, for example, an impedance of an antenna when viewed from a terminal for connecting the IC chip of the RFID system in the LF band or the HF band is connected is several thousands of Q, and the impedance of the antenna when viewed from a terminal to which the IC chip of the RFID system in the UHF band is connected is also several thousands of Q. 
     In this manner, since the impedances of the antennas used in the two RFID systems are close to each other, it is relatively easy to cause the single wireless communication device to be compatible with both the two RFID systems. 
     On the other hand, it is difficult to be compatible with both a function as an RFID tag and a function as a communication device based on Bluetooth Low Energy (BLE) (registered trademark), Wifi, or a low power wide area (LPWA). While the impedance of the antenna of the RFID tag several thousands of Ω, an inductance of the antenna of the communication device based on BLE, Wifi, or LPWA is 50Ω, and the impedances largely vary. 
     The above Japanese Laid-open Patent Publication No. 2011-128956 does not disclose a solution to a case where the impedances largely vary as described above. 
     Hereinafter, an embodiment of a technology with which a plurality of communications in which the impedances largely vary may be performed will be described. 
     Embodiment 
       FIG. 1  illustrates a wireless communication device  100  according to the embodiment. The wireless communication device  100  includes a base portion  101 , a sheet portion  105 , antenna elements  110  and  120 , an IC chip  130 , a coil  140 L, a capacitance  140 C, a matching circuit  150  (a coil  150 L and a capacitance  150 C), a communication portion  160 , a battery  170 , and a cover portion  180 . The wireless communication device may be referred to as a wireless communication tag. 
     Hereinafter, a configuration of the wireless communication device  100  will be described with reference to  FIG. 2  to  FIG. 6  in addition to  FIG. 1 . In  FIG. 1  to  FIG. 6 , a common XYZ coordinate system is defined. 
       FIG. 2  illustrates a configuration in which the cover portion  180  is excluded from the wireless communication device  100  illustrated in  FIG. 1 .  FIG. 3  illustrates a configuration in which the IC chip  130 , the coil  140 L, the capacitance  140 C, the matching circuit  150 , the communication portion  160 , the battery  170 , and the cover portion  180  are excluded from the wireless communication device  100  illustrated in  FIG. 1 .  FIG. 4A  and  FIG. 4B  illustrate the base portion  101 , the sheet portion  105 , the antenna elements  110  and  120 , the IC chip  130 , the coil  140 L, the capacitance  140 C, the matching circuit  150 , the communication portion  160 , and the battery  170 .  FIG. 4A  illustrates a configuration in which the cover portion  180  is excluded from the wireless communication device  100 , and  FIG. 4B  is a cross sectional view taken along an arrow line IVB-IVB of  FIG. 4A .  FIG. 5  illustrates an inlay  200 .  FIG. 6  illustrates an element  200 A in which the IC chip  130 , the coil  140 L, the capacitance  140 C, the matching circuit  150 , the communication portion  160 , and the battery  170  are excluded from the inlay  200  illustrated in  FIG. 5 . The element  200 A may be treated as an antenna device. 
     The inlay  200  is constituted by the sheet portion  105 , the antenna elements  110  and  120 , the IC chip  130 , the coil  140 L, the capacitance  140 C, the matching circuit  150 , the communication portion  160 , and the battery  170 . 
     Hereinafter, an entire configuration of the wireless communication device  100  will be illustrated with reference to  FIG. 1  to  FIG. 3 .  FIG. 1  to  FIG. 3  are transparently illustrated to easily comprehend an internal configuration. Detailed configurations of the antenna elements  110  and  120 , the IC chip  130 , the coil  140 L, the capacitance  140 C, the matching circuit  150 , the communication portion  160 , the battery  170 , the inlay  200 , and the like will be described with reference to  FIG. 4A ,  FIG. 4B ,  FIG. 5 , and  FIG. 6 . 
     A surface where the IC chip  130 , the coil  140 L, the capacitance  140 C, the matching circuit  150 , the communication portion  160 , and the battery  170  of the thin-plate like wireless communication device  100  are mounted will be referred to as a top surface, and a surface on an opposite side to the top surface will be referred to as a bottom surface. 
     The wireless communication device  100  is a hybrid-type tag having communication functions based on two different standards. The wireless communication device  100  is a tag having both a function as a radio frequency identifier (RFID) tag and a function as a Bluetooth Low Energy (BLE) (registered trademark) communication device. The function as the RFID tag of the wireless communication device  100  is a function as a passive-type RFID tag including no power source. The wireless communication device  100  performs a communication at 920 MHz as the RFID tag, for example. 
     The wireless communication device  100  performs a communication at 2.45 GHz as the BLE communication device, for example. A mode in which the wireless communication device  100  has the function as the BLE communication device will be described, for example, but the wireless communication device  100  may have the function as the communication device for performing the communication based on Wifi or low power wide area (LPWA) instead of BLE. 
     The wireless communication device  100  may perform the communications based on the two different standards while both the IC chip  130  and the communication portion  160  use a single loop antenna  190  constituted by the antenna elements  110  and  120 . 
     The base portion  101  is a thin plate like (rectangular parallelepiped shape) member as illustrated in  FIG. 1 ,  FIG. 2 ,  FIG. 3 ,  FIG. 4A , and  FIG. 4B . It is sufficient when the base portion  101  is made of a dielectric. For example, the base portion  101  may be manufactured by using ABS resin, polyethylene terephthalate (PET) resin, polycarbonate resin, polyvinyl chloride (PVC) resin, or the like. 
     As illustrated in  FIG. 1 , the inlay  200  (see  FIG. 5 ) is wound around the base portion  101  in an X-axis direction. With regard to the base portion  101 , a length in the X-axis direction is approximately 35 mm, a width in a Y-axis direction is approximately 25 mm, and a thickness in a Z-axis direction is approximately 1.2 mm. Both ends in the X-axis direction of the base portion  101  will be referred to as end portions  101 A and  101 B. 
     As illustrated in  FIG. 5 , the sheet portion  105  is a rectangular film in a plan view, and the antenna elements  110  and  120  are formed on one surface. The sheet portion  105  is an example of a sheet member. The sheet portion  105  is a PET film or a film-like member made of PET resin or paper, for example. 
     The antenna elements  110  and  120  are formed on one surface of the sheet portion  105 . In a state in which the IC chip  130 , the coil  140 L, the capacitance  140 C, the matching circuit  150 , the communication portion  160 , and the battery  170  are mounted, the sheet portion  105  is bonded to the base portion  101  while being wound. That is, for example, in a state in which the inlay  200  (see  FIG. 6 ) is completed and the IC chip  130 , the coil  140 L, the capacitance  140 C, the matching circuit  150 , the communication portion  160 , and the battery  170  are mounted, the sheet portion  105  is bonded while being wound around the base portion  101 . The coil  140 L, the capacitance  140 C, the matching circuit  150 , the communication portion  160 , and the battery  170  may also be bonded after the sheet portion  105  is wound around the base portion  101 . 
     As illustrated in  FIG. 5  and  FIG. 6 , the antenna element  110  is formed in an area corresponding to approximately a half of one surface of the sheet portion  105  in a longitudinal direction (X-axis direction). The antenna element  110  is an example of a first antenna element. 
     The antenna element  110  includes an element  111 , a protrusion portion  112 , a wiring portion  113 , and a protrusion portion  114 . The antenna element  110  and the antenna element  120  constitute the loop antenna  190 . The loop antenna  190  is arranged so as to be wound around the base portion  101  in the X-axis direction. With regard to the loop antenna  190 , a length in the X-axis direction is approximately 35 mm, a width in the Y-axis direction is approximately 23 mm, and a height in the Z-axis direction is approximately 1.2 mm. 
     It is sufficient when the antenna element  110  is made of a metal, and aluminum, copper, or the like may be used. The antenna element  110  may be manufactured by wet etching processing together with the antenna element  120 , for example. When a metallic foil such as a copper foil is arranged on one of the surfaces of the sheet portion  105  and the wet etching processing is performed, patterning of the antenna elements  110  and  120  may be performed. 
     A mask used when resist formed on the metallic foil is exposed with light by photolithography before the wet etching processing is performed have openings in accordance with shapes of the antenna elements  110  and  120 . 
     The element  111  is a rectangular radiant portion in a plan view. The protrusion portion  112  and the wiring portion  113  are connected to an end portion  111 A on an X-axis positive direction side. The protrusion portion  114  is connected to an end of the end portion  111 A on a Y-axis negative direction side. An end portion  111 B is arranged on an opposite side to the end portion  111 A. The element  111  is an example of a first base portion. 
     The element  111  is arranged from the end portion  111 A located on a top surface side of the base portion  101  to the end portion  111 B located on a bottom surface side of the base portion  101  and bent at the end portion  101 A of the base portion  101 . 
     As illustrated in  FIG. 4B , the end portion  111 B is overlapped with an end portion  121 B of an element  121  which will be described below on the bottom surface side of the base portion  101  in a state in which the inlay  200  is wound around the base portion  101 . 
     A portion where the end portion  111 B and the end portion  121 B are overlapped with each other in a plan view constitutes an overlapped portion  191 . In the overlapped portion  191 , the end portion  111 B and the end portion  121 B are insulated by the sheet portion  105 . 
     As illustrated in  FIG. 4A ,  FIG. 4B ,  FIG. 5 , and  FIG. 6 , the protrusion portion  112  extends from the end portion  111 A of the element  111  so as to protrude in an X-axis positive direction. Three protrusion portions  112  are arranged on a Y-axis positive direction side with respect to the wiring portion  113 , and three protrusion portions  112  are arranged on the Y-axis negative direction side with respect to the wiring portion  113 . Lengths in the X-axis direction of the six protrusion portions  112  are all equal to one another. The protrusion portion  112  is an example of a first protrusion portion. Since  FIG. 1  to  FIG. 3  are illustrated based on a simulation model which will be described below, 12 protrusion portions  112  are arranged. 
     Widths of the six protrusion portions  112  (widths in the Y-axis direction) are equal to one another and respectively have uniform widths (widths in the Y-axis direction) from a side to be connected to the element  111  to a tip on the X-axis positive direction side. The protrusion portion  112  and the protrusion portion  122  of the antenna element  120  are arranged in a nested manner in a plan view. 
     The protrusion portion  112 , the wiring portion  113 , the protrusion portion  122 , and the wiring portion  123  constitute an interdigital portion  192 . The interdigital portion  192  functions as a capacitor having a predetermined electrostatic capacitance. The interdigital portion  192  may be treated as a capacitor connected in parallel to the loop antenna  190  constituted by the antenna elements  110  and  120 . 
     Respective dimensions such as lengths in the X-axis direction, widths in the Y-axis direction, heights in the Z-axis direction, intervals in the X-axis direction, and intervals in the Y-axis direction of the protrusion portion  112 , the wiring portion  113 , the protrusion portion  122 , the wiring portion  123  may be set as appropriate values so as to set the electrostatic capacitance of the interdigital portion  192  as a desired value. 
     The wiring portion  113  extends from the end portion  111 A of the element  111  so as to protrude in the X-axis positive direction. The wiring portion  113  is an example of a first wiring portion. The width of the wiring portion  113  (width in the Y-axis direction) is uniform from the side connected to the element  111  to the tip on the X-axis positive direction side. The width of the wiring portion  113  is approximately twice as wide as the width of the protrusion portion  112 , for example. 
     Since a current flows through the wiring portion  113  at the time of the communication of the wireless communication device  100 , the width of the wiring portion  113  is preferably set to be thick so as to decrease a resistance value of the wiring portion  113 . For this reason, the width of the wiring portion  113  is set to be thicker than the protrusion portion  112  in the wireless communication device  100  according to the embodiment. The width of the wiring portion  113  is equal to the width of the wiring portion  123  connected via the IC chip  130 . 
     The wiring portion  113  is located between the three protrusion portions  112  and the three protrusion portions  112 . The wiring portion  113  includes a terminal  113 A on the tip, and the IC chip  130  is connected to the terminal  113 A. The wiring portion  113  is arranged on a central axis in parallel with an X axis of the antenna element  120 , for example. The terminal  113 A is an example of a first terminal. 
     In a state before the IC chip  130  is connected, as illustrated in  FIG. 6 , the wiring portion  113  is formed while a gap in the X-axis direction is prepared with a terminal  123 A on a tip of the wiring portion  123 . One of two terminals of the IC chip  130  is connected to the terminal  113 A by soldering or the like. As an example, a mode in which the wiring portion  113  is set to be shorter than the wiring portion  123 , and the IC chip  130  is offset on an X-axis negative direction side in a plan view of  FIG. 4A  and  FIG. 4B  will be described, but the wiring portion  113  may be longer than the wiring portion  123 , or the lengths may be equal to each other. A position in the X-axis direction of the IC chip  130  is determined in accordance with the lengths of the wiring portion  113  and the wiring portion  123 . 
     The protrusion portion  114  is connected to the end on the Y-axis negative direction side of the end portion  111 A. The protrusion portion  114  exists only on the top surface of the wireless communication device  100  and does not exist on a side surface (lateral face on the X-axis negative direction side) and the bottom surface of the wireless communication device  100  in a state in which the sheet portion  105  is wound around the base portion  101 . 
     The protrusion portion  114  is a portion arranged for the connection of the coil  140 L, the capacitance  140 C, the matching circuit  150 , and the communication portion  160 . One end of the coil  140 L, one end of the capacitance  140 C, one end of the capacitance  150 C of the matching circuit  150 , and a terminal  160 A of the communication portion  160  are connected to the protrusion portion  114 . 
     The portion in the protrusion portion  114  where the one end of the coil  140 L, the one end of the capacitance  140 C, the one end of the capacitance  150 C of the matching circuit  150 , and the terminal  160 A of the communication portion  160  are connected (portion corresponding to the end on the X-axis positive direction side of the protrusion portion  114  and extending in the Y-axis direction) is an example of a second terminal. 
     As illustrated in  FIG. 5  and  FIG. 6 , the antenna element  120  is formed in an area corresponding to approximately a half of one surface of the sheet portion  105  in a longitudinal direction. The antenna element  120  is an example of a second antenna element. 
     The antenna element  120  includes the element  121 , a protrusion portion  122 , a wiring portion  123 , and a protrusion portion  124 . The antenna element  120  constitutes the loop antenna  190  together with the antenna element  110 . 
     It is sufficient when the antenna element  120  is made of a metal, and aluminum, copper, or the like may be used. The antenna element  120  may be manufactured by the wet etching processing together with the antenna element  110 , for example. When the metallic foil such as the copper foil is arranged on one of the surfaces of the sheet portion  105  and the wet etching processing is performed, the patterning of the antenna elements  110  and  120  may be performed. 
     The element  121  is a rectangular radiant portion in a plan view. The protrusion portion  122  and the wiring portion  123  are connected to an end portion  121 A on the X-axis negative direction side, and the end portion  121 B is arranged on an opposite side to the end portion  121 A. The element  121  is an example of a second base portion. 
     The element  121  is arranged from the end portion  121 A located on the top surface side of the base portion  101  to the end portion  121 B located on the bottom surface side of the base portion  101  and bent on an end portion  101 B side of the base portion  101 . 
     The element  121  is overlapped with the element  111  in the end portion  121 B. 
     As illustrated in  FIG. 4B , the end portion  121 B is overlapped with the end portion  111 B of the element  111  on the bottom surface side of the base portion  101  in a state in which the inlay  200  is wound around the base portion  101 . 
     A portion where the end portion  121 B and the end portion  111 B are overlapped with each other in a plan view constitutes the overlapped portion  191 , and the end portion  121 B and the end portion  111 B are insulated by the sheet portion  105  in the overlapped portion  191 . 
     As illustrated in  FIG. 4A ,  FIG. 4B ,  FIG. 5 , and  FIG. 6 , the protrusion portion  122  extends so as to protrude from the end portion  121 A of the element  121  in the X-axis negative direction. Three protrusion portions  122  are arranged on the Y-axis positive direction side with respect to the wiring portion  123 , and three protrusion portions  122  are arranged on the Y-axis negative direction side with respect to the wiring portion  123 . All lengths in the X-axis direction of the six protrusion portions  122  are equal to one another. The protrusion portion  122  is an example of a second protrusion portion. Since  FIG. 1  to  FIG. 3  are illustrated based on the simulation model which will be described below, 12 protrusion portions  122  are arranged. 
     Widths of the six protrusion portions  122  (widths in the Y-axis direction) are equal to one another and respectively have uniform widths (widths in the Y-axis direction) from a side to be connected to the element  121  to a tip on the X-axis positive direction side. The width of the protrusion portion  122  is equal to the width of the protrusion portion  112 . The six protrusion portions  122  and the six protrusion portions  112  are arranged in a nested manner in a plan view. 
     The wiring portion  123  extends from the end portion  121 A of the element  121  so as to protrude in the X-axis negative direction. The wiring portion  123  is an example of a second wiring portion. 
     The width of the wiring portion  123  (width in the Y-axis direction) is uniform from the side to be connected to the element  121  to the tip on the X-axis negative direction side. The width of the wiring portion  123  is equal to the width of the wiring portion  113  and is approximately twice as wide as the width of the protrusion portion  122 . 
     Since a current flows through the wiring portion  123  at the time of the communication of the wireless communication device  100 , the width of the wiring portion  123  is preferably set to be thicker so as to decrease a resistance value of the wiring portion  123 . For this reason, the width of the wiring portion  123  is set to be thicker than the protrusion portion  122  in the wireless communication device  100  according to the embodiment. 
     The wiring portion  123  is located between the three protrusion portions  122  on the Y-axis positive direction side and the three protrusion portions  122  on the Y-axis negative direction side. The terminal  123 A is arranged on the tip of the wiring portion  123 . The IC chip  130  is connected to the terminal  123 A as illustrated in  FIG. 1 . The wiring portion  123  is arranged on a central axis in parallel with the X axis of the antenna element  120 , for example. The terminal  123 A is an example of a third terminal. 
     In a state before the IC chip  130  is connected, as illustrated in  FIG. 6 , the wiring portion  123  is formed while a gap in the X-axis direction is prepared with the terminal  113 A on the tip of the wiring portion  113 . The other one of the two terminals of the IC chip  130  is connected to the terminal  123 A by soldering or the like. 
     The above-mentioned wiring portion  123  constitutes the interdigital portion  192  together with the protrusion portion  122 , the protrusion portion  112 , and the wiring portion  113 . 
     The protrusion portion  124  is a portion connected to the tip of the protrusion portion  122  arranged at a farthest end on the negative side in the Y-axis direction and formed so as to bend from the tip of the protrusion portion  122  in the Y-axis negative direction. The other end of the coil  140 L, the other end of the capacitance  140 C, the other end of the capacitance  150 C of the matching circuit  150 , and one end of the coil  150 L of the matching circuit  150  are connected to the protrusion portion  124 . 
     A portion where the other end of the coil  140 L, the other end of the capacitance  140 C, the other end of the capacitance  150 C of the matching circuit  150 , and one end of the coil  150 L of the matching circuit  150  in the protrusion portion  124  is an example of a fourth terminal. 
     With regard to the loop antenna  190  constituted by the antenna elements  110  and  120 , the dimensions of the respective portions, inductances, the electrostatic capacitances, and the like are appropriately set such that a resonance frequency becomes 920 MHz. That is, for example, the loop antenna  190  is appropriately set in accordance with the state in which the wireless communication device  100  functions as the RFID tag. 
     A loop length of the loop antenna  190  (length of a loop from the terminal  113 A via the overlapped portion  191  to the terminal  123 A) is shorter than one wavelength at 920 MHz, and the loop antenna  190  is an antenna functioning as an inductor. The loop antenna  190  has a configuration in which the loop antenna  190  resonates at 920 MHz by the electrostatic capacitance of the interdigital portion  192 , the overlapped portion  191 , and the like. 
     The inductance of the loop antenna  190  is an example of the first inductance. 920 MHz corresponding to the resonance frequency at which the wireless communication device  100  functions as the RFID tag is an example of a first frequency. 
     The IC chip  130  is an IC chip for the RFID tag. The IC chip  130  includes two terminals  131  and  132  to be mounted onto the surface of the sheet portion  105 . The two terminals  131  and  132  of the IC chip  130  are respectively connected to the terminals  113 A and  123 A by soldering or the like. The IC chip  130  is electrically connected to the antenna elements  110  and  120  and stores data representing a unique identifier (ID) in an internal memory chip. 
     When a signal for reading a radio frequency (RF) band is received from a reader writer of the wireless communication device  100  via the antenna elements  110  and  120 , the IC chip  130  operates by power of the received signal and transmits the data representing the ID via the antenna elements  110  and  120 . As a result, the reader writer may read the ID of the wireless communication device  100 . 
     The IC chip  130  is an example of a first communication circuit. The impedance of the IC chip  130  is approximately 1700Ω to approximately 3800Ω and is an example of a first impedance. 
     The coil  140 L has two terminals, and the two terminals are connected to the protrusion portion  114  and the protrusion portion  124 . That is, for example, the coil  140 L is inserted between the protrusion portion  114  and the protrusion portion  124  in series. The coil  140 L is arranged on the surface of the sheet portion  105 . 
     The coil  140 L has an inductance sufficiently higher than the inductance of the loop antenna  190 . As an example, the inductance of the coil  140 L is preferably set to be higher than the inductance of the loop antenna  190  by approximately two orders of magnitude. For example, the inductance of the coil  140 L is preferably set to be 100 times as high as the inductance of the loop antenna  190 . 
     The coil  140 L is arranged to behave such that high frequency power at 920 MHz is interrupted, and the protrusion portion  114  and the protrusion portion  124  are disconnected (open) with respect to the power at 920 MHz when the wireless communication device  100  functions as the RFID tag and the loop antenna  190  receives the power at 920 MHz. The inductance of the coil  140 L is an example of a second inductance. 
     The capacitance  140 C and the capacitance  150 C are connected to the coil  140 L in parallel. An equivalent state is established in which, while the inductance of the coil  140 L is set as a sufficiently high value, the protrusion portion  114  and the protrusion portion  124  are open when a current at 920 MHz flows through the loop antenna  190 . 
     The matching circuit  150  is connected to the protrusion portion  114  and the protrusion portion  124  to connect the communication portion  160 . Since the matching circuit  150  is not used when the wireless communication device  100  functions as the RFID tag, the coil  140 L having the above-mentioned inductance is connected between the protrusion portion  114  and the protrusion portion  124  in series such that the matching circuit  150  is not visible from the terminals  113 A and  123 A. 
     The state in which the inductance of the coil  140 L is sufficiently higher than the inductance of the loop antenna  190  means that the inductance is high to such an extent that the equivalent state may be realized in which the protrusion portion  114  and the protrusion portion  124  are open when the current at 920 MHz flows through the loop antenna  190  as described above. 
     The capacitance  140 C has two terminals, and the two terminals are connected to the protrusion portion  114  and the protrusion portion  124 . The capacitance  140 C is connected to the coil  140 L in parallel. The capacitance  140 C is arranged on the surface of the sheet portion  105 . 
     The capacitance  140 C has an electrostatic capacitance having a complex conjugate relationship with the inductance of the coil  140 L. A reason why the electrostatic capacitance of the capacitance  140 C is set as the above-mentioned value is that an imaginary component of the impedance of the coil  140 L is to be cancelled. 
     The capacitance  140 C is arranged such that the coil  140 L is not visible when the matching circuit  150  side is viewed from the two terminals of the matching circuit  150  to be connected to two terminals  160 A and  160 B of the communication portion  160 . The state in which the coil  140 L is not visible from the two terminals of the matching circuit  150  means that the impedance in which the matching circuit  150  side is viewed from the two terminals of the matching circuit  150  does not include the impedance of the coil  140 L. In other words, for example, the state in which the coil  140 L is not visible from the two terminals of the matching circuit  150  is equivalent to a state in which the coil  140 L does not exist. 
     The capacitance  140 C is connected to the coil  140 L in parallel such that the coil  140 L becomes invisible from the two terminals of the matching circuit  150 . The capacitance  140 C has an electrostatic capacitance having a complex conjugate relationship with the inductance of the coil  140 L. 
     The matching circuit  150  includes the coil  150 L and the capacitance  150 C and is arranged on the surface of the sheet portion  105 . The coil  150 L has two terminals, and the two terminals are respectively connected to the protrusion portion  124  and the terminal  160 B of the communication portion  160 . The capacitance  150 C has two terminals, and the two terminals are connected to the protrusion portion  114  and the protrusion portion  124 . That is, for example, the coil  150 L is connected to the communication portion  160  in series, and the capacitance  150 C is connected to the communication portion  160  in parallel. 
     The impedance of the IC chip  130  for the RFID tag is approximately 1700Ω to approximately 3800Ω. In contrast, the impedance of the communication portion  160  for BLE is 50Ω. In this manner, the impedances of the IC chip  130  and the communication portion  160  largely vary. 
     The matching circuit  150  is arranged such that both the IC chip  130  and the communication portion  160  described above use the single loop antenna  190 . The impedance of the circuit including the matching circuit  150 , the loop antenna  190 , the IC chip  130 , the coil  140 L, and the capacitance  140 C appears to have 50Ω when viewed from the communication portion  160 . 
     Details with regard to an inductance of the coil  150 L and an electrostatic capacitance of the capacitance  150 C will be described below with reference to a Smith chart of  FIG. 11 . 
     The communication portion  160  is a communication portion that performs a communication based on BLE and is arranged on the surface of the sheet portion  105 . More specifically, for example, the communication portion  160  is a communication module that regularly outputs a BLE beacon having a unique identifier (ID). The communication portion  160  performs the communication in a frequency band at 2.45 GHz. 
     The communication portion  160  includes two terminals  160 A and  160 B connected to the loop antenna  190 . The terminal  160 A is connected to the protrusion portion  114 , and the terminal  160 B is connected to one end of the coil  150 L. The communication portion  160  is driven by power supplied from the battery  170  via a power supply line  170 A. When the communication portion  160  outputs the beacon, the beacon is radiated from the loop antenna  190 . 
     The impedance of the communication portion  160  is 50Ω, for example. That is, for example, the impedance of the communication portion  160  is much lower than the impedance of the IC chip  130  (approximately 1700Ω to approximately 3800Ω). The communication portion  160  is an example of a second communication circuit. The impedance of the communication portion  160  is an example of a second impedance. 2.45 GHz corresponding to the frequency band at which the communication portion  160  performs the communication is an example of a second frequency. 
     The battery  170  is arranged on the surface of the sheet portion  105  and connected to the communication portion  160  via the power supply line  170 A. The battery  170  supplies the power to the communication portion  160  via the power supply line  170 A. The battery  170  is realized by a button-type battery cell or the like. 
     The overlapped portion  191  is a portion where the end portion  111 B of the antenna element  110  and the end portion  121 B of the antenna element  120  are overlapped with each other. Since the high frequency current at 920 MHz flows through the antenna elements  110  and  120 , the overlapped portion  191  is connected in an alternating current manner, and the antenna elements  110  and  120  constitute the loop antenna  190 . 
     The overlapped portion  191  may be used to adjust the resonance frequency of the wireless communication device  100 . The electrostatic capacitance of the overlapped portion  191  is determined by an overlapped area between the end portions  111 B and  121 B and an interval between the end portions  111 B and  121 B. 
     The overlapped portion  191  includes a portion overlapped with the interdigital portion  192 . In this manner, when the overlapped portion  191  and the interdigital portion  192  are overlapped with each other in the Z-axis direction, the electrostatic capacitance may also be secured between the overlapped portion  191  and the interdigital portion  192 . When the resonance frequency of the wireless communication device  100  may also be adjusted by adjusting the above-mentioned electrostatic capacitance related to the overlapped portion  191 . 
     The interdigital portion  192  is constituted by the protrusion portion  112 , the wiring portion  113 , the protrusion portion  122 , and the wiring portion  123  arranged in a nested manner in parallel in a plan view. 
     The interdigital portion  192  is arranged to adjust the resonance frequency of the loop antenna  190  of the wireless communication device  100  by earning the electrostatic capacitance generated when the protrusion portion  112 , the wiring portion  113 , the protrusion portion  122 , and the wiring portion  123  are arranged so as to be adjacent to one another. The interdigital portion  192  is formed across the antenna elements  110  and  120 . 
       FIG. 7  illustrates an equivalent circuit of the wireless communication device  100  as the RFID tag. The loop antenna  190  constituted by the antenna elements  110  and  120  may be represented by a resistor Rap and an inductor Lap. Since the overlapped portion  191  and the interdigital portion  192  are arranged in the loop antenna  190  in the wireless communication device  100  according to the embodiment, in  FIG. 7 , a capacitor Cap is connected to the resistor Rap and the inductor Lap in parallel. The capacitor Cap is represented as a single capacitor while the overlapped portion  191  and the interdigital portion  192  are combined with each other. 
     The IC chip  130  of the wireless communication device  100  may be represented by a resistor Rcp and a capacitor Ccp. 
     That is, for example, the loop antenna  190  includes a resistance component and an inductance component, and also a capacitance component is connected to the loop antenna  190 . The IC chip  130  may be represented as the resistance component and the capacitance component. 
     The resistor Rap is a resistor having a resistance value Rap. The inductor Lap is an inductor in which an inductance is Lap. The capacitor Cap is a capacitor in which a capacitance is Cap. The resistor Rcp is a resistor having a resistance value Rcp. The capacitor Ccp is a capacitor in which a capacitance is Ccp. 
     For example, Rcp is 2000Ω, and Ccp is approximately 1.0 pF. These are average values obtained in a general-use IC chip. 
     The wireless communication device  100  performs the communication while the equivalent circuit illustrated in  FIG. 7  is caused to generate resonance. That is, for example, when the wireless communication device  100  receives the signal for reading and transmits the data representing the ID, a current based on the resonance flows through the IC chip  130  and the antenna elements  110  and  120 . 
     A resonance frequency of a resonance current is mainly determined by the electrostatic capacitance of the IC chip  130 , the inductances of the antenna elements  110  and  120 , the electrostatic capacitance of the overlapped portion  191 , and the electrostatic capacitance of the interdigital portion  192 . 
     The resonance frequency of the wireless communication device  100  is obtained by Expression (1). 
     
       
         
           
             
               
                 
                   
                     f 
                     0 
                   
                   = 
                   
                     1 
                     
                       2 
                        
                       π 
                        
                       
                         
                           Lap 
                            
                           
                             ( 
                             
                               Ccp 
                               + 
                               Cap 
                             
                             ) 
                           
                         
                       
                     
                   
                 
               
               
                 
                   ( 
                   1 
                   ) 
                 
               
             
           
         
       
     
     In Expression (1), Lap denotes the inductances Lap of the antenna elements  110  and  120 , Ccp denotes the capacitance Ccp of the IC chip  130 , and Cap denotes the capacitance Cap of the overlapped portion  191  and the interdigital portion  192 . 
     In this manner, the resonance frequency of the wireless communication device  100  is determined by not only the loop antenna  190  (the antenna elements  110  and  120 ) but also the loop antenna  190  (the antenna elements  110  and  120 ), the overlapped portion  191 , the interdigital portion  192 , and the IC chip  130 . 
     In this aspect, the loop antenna  190  included in the wireless communication device  100  is different from a so-called loop antenna that generates resonance by setting the loop length as a length of one wavelength at the resonance frequency. 
     The resonance frequency of the resonance current in the wireless communication device  100  according to the embodiment is a frequency (communication frequency) at which the wireless communication device  100  performs the communication and is set as 920 MHz, for example. The loop length of the loop antenna  190  constituted by the antenna elements  110  and  120  is approximately 70 mm and is set to be shorter than the wavelength at the resonance frequency. 
     As an example, in a case where the resonance frequency is 920 MHz, the wavelength at the resonance frequency is approximately 325 mm, and the loop length of the loop antenna  190  in the wireless communication device  100  is approximately 70 mm. 
     In this manner, since the loop length of the loop antenna  190  is shorter than the length of the one wavelength at the resonance frequency, unlike the so-called loop antenna that sets the loop length as the one wavelength at the resonance frequency, the antenna elements  110  and  120  constituting the loop antenna  190  function as the inductors. 
     The length (loop length) corresponding to the combination of the antenna elements  110  and  120  is relatively short as described above, and the inductances of the antenna elements  110  and  120  are in proportion to the length. Therefore, the inductance of the loop antenna  190  is relatively low. In the wireless communication device  100 , to compensate the low inductance, the resonance frequency is adjusted by arranging the overlapped portion  191  and the interdigital portion  192  in the loop antenna  190 . 
     The impedance of the antenna obtained by adding the overlapped portion  191  and the interdigital portion  192  to the loop antenna  190  constituted by the antenna elements  110  and  120  is determined by the resistance value (Rap) of the resistor Rap, the inductance (Lap) of the inductor Lap, and the capacitance (Cap) of the capacitor Cap illustrated in  FIG. 7 . 
     The impedance of the IC chip  130  is determined by the resistance value (Rcp) of the resistor Rcp and the capacitance (Ccp) of the capacitor Ccp. 
     To obtain satisfactory impedance matching between the loop antenna  190  and the IC chip  130 , the resistance value Rap and the resistance value Rcp may be adjusted in addition to the adjustment of the inductance Lap, the capacitance Cap, and the capacitance Ccp. 
       FIG. 8  illustrates an equivalent circuit of the wireless communication device  100  as the BLE communication device. Similarly as in  FIG. 7 , the loop antenna  190  is represented by the resistor Rap and the inductor Lap, and the capacitor Cap is connected to the loop antenna  190  in parallel. 
     An inductor Lp representing the coil  140 L, a capacitor Cp representing the capacitance  140 C, and the matching circuit  150  are connected to the resistor Rap, the inductor Lap, and the capacitor Cap in parallel, and the communication portion  160  is connected to the matching circuit  150 . The communication portion  160  may be represented by a resistor Rp. The resistor Rp is 50Ω. 
     Since the impedance appears to have 50Ω when viewed from the matching circuit  150  side from the two terminals of the matching circuit  150  to which the terminals  160 A and  160 B of the communication portion  160  are connected, the communication portion  160  may perform the communication based on BLE via the loop antenna  190 . 
       FIG. 9  illustrates the simulation model of the wireless communication device  100 . According to the simulation model of the wireless communication device  100 , the length in the X-axis direction of the loop antenna  190  is approximately 35 mm, the width in the Y-axis direction is approximately 23 mm, and the height in the Z-axis direction is approximately 1.2 mm. 
     The simulation model of the wireless communication device  100  does not include the matching circuit  150 , the communication portion  160 , and the battery  170 . 
     The 12 protrusion portions  112  and the 12 protrusion portions  122  are arranged in the interdigital portion  192 . The widths of the protrusion portions  112  and  122  are 0.2 mm, and the intervals between the protrusion portion  112 , the wiring portion  113 , and the protrusion portion  122  in the Y-axis direction are set as 0.62 mm. 
     The cover portion  180  is made of fire resistant resin. A relative permittivity of the fire resistant resin is 3.2. A dielectric tangent tan δ is 0.02. A length in the X-axis direction is approximately 39 mm. A width in the Y-axis direction is approximately 29 mm. A thickness in the Z-axis direction is approximately 2 mm. 
       FIG. 10  is a Smith chart illustrating an impedance characteristic in a case where the wireless communication device  100  functions as the RFID tag. The impedance illustrated in  FIG. 10  is the impedance of the wireless communication device  100  as the loop antenna  190  side is viewed from the terminals  113 A and  123 A from to which the IC chip  130  is connected. A black circle in  FIG. 10  indicates the impedance of the IC chip  130 . 
     When the communication frequency is changed from 900 MHz to 1000 MHz, a trajectory drawing a circle is obtained, and the impedance having the complex conjugate relationship with the impedance of the IC chip  130  indicated by the black circle is obtained as the impedance 920 MHz indicated by a triangular marker. 
     That is, for example, matching between the impedance of the wireless communication device  100  and the impedance of the IC chip  130  as the loop antenna  190  side is viewed from the terminals  113 A and  123 A may be confirmed. 
     In this manner, when the impedance of the loop antenna  190  is adjusted to have the impedance having the complex conjugate relationship with the impedance of the IC chip  130 , the loop antenna  190  and the IC chip  130  resonate at 920 MHz, and the power received by the loop antenna  190  is supplied to the IC chip  130 . 
       FIG. 11  is a Smith chart illustrating the impedance characteristic in a case where the wireless communication device  100  functions as the BLE communication device. The impedance illustrated in  FIG. 10  is the impedance of the wireless communication device  100  as the loop antenna  190  side is viewed from the protrusion portions  114  and  124  to which the matching circuit  150  is connected. 
     When the communication frequency is changed from 2000 MHz to 3000 MHz, the impedance at 2450 MHz is obtained at a position indicated by a triangular marker. The above-mentioned impedance may be set as 50Ω by setting the electrostatic capacitance of the capacitance  150 C of the matching circuit  150  and the inductor of the coil  150 L as follows. 
     First, the impedance indicated by the triangular marker is moved to a position indicated by an arrow ( 1 ) by appropriately selecting the electrostatic capacitance of the capacitance  150 C connected to the communication portion  160  in parallel. 
     The impedance is moved from the position indicated by the arrow ( 1 ) to a position indicated by an arrow ( 2 ) by appropriately selecting the inductor of the coil  150 L connected to the communication portion  160  in series. 
     Since the position indicated by the arrow ( 2 ) is 50Ω, when the electrostatic capacitance of the capacitance  150 C of the matching circuit  150  and the inductance of the coil  150 L are appropriately selected, the impedance of the wireless communication device  100  as the loop antenna  190  side is viewed from the two terminals of the matching circuit  150  to which the terminals  160 A and  160 B of the communication portion  160  are connected may be set as 50Ω. 
     More specifically, for example, the two terminals of the matching circuit  150  to which the terminals  160 A and  160 B of the communication portion  160  are connected are the terminal on the Y-axis negative direction side of the coil  150 L and the terminal on the X-axis negative direction side of the capacitance  150 C (terminals connected to the protrusion portions  114 ). The terminal  160 A of the communication portion  160  is connected to the terminal on the X-axis negative direction side of the capacitance  150 C via the protrusion portion  114 . 
     In this manner, since the impedance when the loop antenna  190  side is viewed from the two terminals of the matching circuit  150  to which the terminals  160 A and  160 B of the communication portion  160  are connected becomes 50Ω, the communication portion  160  may perform the communication based on BLE via the loop antenna  190 . 
     As described above, according to the embodiment, the equivalent state is established in which the coil  140 L having the inductance sufficiently higher than the loop antenna  190  is connected between the protrusion portions  114  and  124  of the loop antenna  190 , and the portion between the protrusion portion  114  and the protrusion portion  124  is open. 
     For this reason, the loop antenna  190  resonates with the IC chip  130  at 920 MHz, and the wireless communication device  100  may function as the RFID tag. 
     The capacitance  140 C having the electrostatic capacitance having the complex conjugate relationship with the inductance of the coil is connected to the coil  140 L in parallel. The matching circuit  150  is also connected between the protrusion portion  114  and the protrusion portion  124  to connect the communication portion  160  via the matching circuit  150 . The impedance when the matching circuit  150  side is viewed from the communication portion  160  is 50Ω. 
     For this reason, the beacon output by the communication portion  160  is radiated from the loop antenna  190 . 
     Therefore, according to the embodiment, the wireless communication device and the antenna device may be provided which the plurality of communications having the largely varying impedances may be performed. 
     The wireless communication device  100  may be used as follows, for example. A body temperature and/or sweat rate of a personnel working in open air or the like may be transmitted as Internet of Things (IoT) sensor information to manage a physical condition of the working personnel at an access point in the communication area of the BLE system. At this time, the personnel may be identified by reading the ID included in the beacon in the communication area of the BLE system. When the personnel passes through a gate (entry and exit gate) outside the communication area of the BLE system, the wireless communication device  100  may function as the RFID tag to read the ID of the personnel and grasp entry and exit times at the gate and the position. 
     A battery cell or a battery is mounted in a short-range wireless system based on BLE, Wifi, or LPWA in many cases, the RFID tag does not use the battery cell. For example, in a case where the reader of the RFID tag is arranged in a communication area of the short-range wireless system, the ID of the personnel may be grasped even when the battery cell or the battery of the short-range wireless system runs out. That is, for example, the function as the RFID tag may be used as a backup function. 
     The mode in which the loop antenna  190  is realized by the two antenna elements  110  and  120  has been described above, but the loop antenna  190  may be a loop-like antenna. That is, for example, the end portion  111 B of the antenna element  110  may be connected to the end portion  121 B of the antenna element  120 . 
     The mode in which the coil  150 L of the matching circuit  150  is connected between the protrusion portion  124  and the terminal  160 B of the communication portion  160  has been described above, but the coil  150 L may be connected between the protrusion portion  114  and the terminal  160 A. In this case, the terminals connected to the terminals  160 A and  160 B of the communication portion  160  of the matching circuit  150  are a terminal connected to the terminal  160 A of the communication portion  160  of the coil  150 L and a terminal connected to the terminal on the X-axis positive direction side of the capacitance  150 C via the protrusion portion  124 . 
     The mode in which the matching circuit  150  includes the coil  150 L connected to the communication portion  160  in series and the capacitance  150 C connected to the communication portion  160  in parallel has been described above. However, the matching circuit  150  may include a configuration including the coil  150 L connected to the communication portion  160  in parallel and the capacitance  150 C connected to the communication portion  160  in series. 
     In this case, the impedance at 920 MHz indicated by the triangular marker illustrated in  FIG. 11  is moved in the anticlockwise direction opposite to the clockwise direction arrows ( 1 ) and ( 2 ) by the coil  150 L connected to the communication portion  160  in parallel and the capacitance  150 C connected to the communication portion  160  in series to be moved to the positive at 50Ω indicated by the arrow ( 2 ). The beacon output by the communication portion  160  may be radiated from the loop antenna  190  in this manner too. 
     The mode in which the protrusion portion  114  is connected to the element  111  of the antenna element  110 , and the protrusion portion  124  is connected to the tip of the protrusion portion  122  of the antenna element  120  has been described above. However, the protrusion portion  114  may be connected to the tip of the protrusion portion  112 , and the protrusion portion  124  may be connected to the element  121 . In this case, a configuration may be adopted in which the coil  140 L, the capacitance  140 C, and the capacitance  150 C are connected between the protrusion portion  114  connected to the tip of the protrusion portion  112  and the protrusion portion  124  connected to the element  121 , and the coil  150 L is connected to the protrusion portion  114 . 
     The mode in which the wireless communication device  100  includes the matching circuit  150  has been described above. In a case where a distance for radiating the beacon output by the communication portion  160  from the loop antenna  190  may be short, it is also sufficient when the wireless communication device  100  does not include the matching circuit  150 . 
     The wireless communication device  100  according to the embodiment may be modified as illustrated in  FIG. 12  and  FIG. 13 .  FIG. 12  illustrates a wireless communication device  100 M 1  according to a first modified example of the embodiment. In  FIG. 12 , components similar to the components illustrated in  FIG. 1  to  FIG. 6  are assigned with the same reference signs, and descriptions thereof will be omitted. 
     The wireless communication device  100 M 1  includes the base portion  101 , the sheet portion  105 , antenna elements  110 M 1  and  120 M 1 , the IC chip  130 , the coil  140 L, the capacitance  140 C, the matching circuit  150  (the coil  150 L and the capacitance  150 C), the communication portion  160 , and the battery  170 . The cover portion  180  is omitted in  FIG. 12 . 
     The antenna element  110 M 1  includes an element  111 M 1 , the wiring portion  113 , and a protrusion portion  114 M. The antenna element  110 M 1  constitutes a loop antenna  190 M 1  together with the antenna element  120 M 1 . The antenna element  110 M 1  does not include the protrusion portion  112  (see  FIG. 1  to  FIG. 6 ). 
     The element  111 M 1  is a stripe-like pattern extending in the Y-axis direction, the wiring portion  113  extends in the X-axis positive direction from an end on the Y-axis negative direction side of the element  111 M 1 , and the protrusion portion  114 M extends in the Y-axis negative direction. One end of the coil  140 L, one end of the capacitance  140 C, and one end of the capacitance  150 C are connected to the protrusion portion  114 M. 
     The antenna element  120 M 1  includes an element  121 M 1 , a protrusion portion  122 M 1 , a wiring portion  123 M, and a protrusion portion  124 M. The antenna element  120 M 1  constitutes the loop antenna  190 M 1  together with the antenna element  110 M 1 . Two protrusion portions  122 M 1  are arranged, and the protrusion portion  124 M is connected to a tip of the protrusion portion  122 M 1  located on the Y-axis negative direction side. A capacitance having predetermined electrostatic capacitance is constituted between the two protrusion portions  122 M 1  and the wiring portion  123 M. This capacitance is used as a substitute of the interdigital portion  192 . The other end of the coil  140 L, the other end of the capacitance  140 C, the other end of the capacitance  150 C, and one end of the coil  150 L are connected to the protrusion portion  124 M. 
     As illustrated in  FIG. 12 , also in the wireless communication device  100 M 1  having the configuration in which the interdigital portion  192  (see  FIG. 1  to  FIG. 6 ) is not included, the loop antenna  190 M 1  resonates with the IC chip  130  at 920 MHz, and the wireless communication device  100  may function as the RFID tag. The beacon output by the communication portion  160  is radiated from the loop antenna  190 M 1 . 
     Therefore, according to the first modified example of the embodiment, the wireless communication device  100 M 1  and the antenna device which the plurality of communications having the largely varying impedances may be performed may be provided. 
       FIG. 13  illustrates a wireless communication device  100 M 2  according to a second modified example of the embodiment. In  FIG. 13 , components similar to the components illustrated in  FIG. 1  to  FIG. 6  and  FIG. 12  are assigned with the same reference signs, and descriptions thereof will be omitted. 
     The wireless communication device  100 M 2  includes the base portion  101 , the sheet portion  105 , antenna elements  110 M 2  and  120 M 2 , the IC chip  130 , the coil  140 L, the capacitance  140 C, the matching circuit  150  (the coil  150 L and the capacitance  150 C), the communication portion  160 , and the battery  170 . In  FIG. 13 , the cover portion  180  is omitted. 
     The antenna element  110 M 2  includes an element  111 M 2 , the wiring portion  113 , and a protrusion portion  114 M. The antenna element  110 M 2  constitutes a loop antenna  190 M 2  together with an antenna element  120 M 2 . The antenna element  110 M 2  does not include the protrusion portion  112  (see  FIG. 1  to  FIG. 6 ). 
     The element  111 M 2  is a rectangular pattern, and the wiring portion  113  extends in the X-axis positive direction from an end on the X-axis positive direction side of the element  111 M 2 . The protrusion portion  114 M extends in the Y-axis negative direction from an end on the Y-axis negative direction side of the element  111 M 2 . One end of the coil  140 L, one end of the capacitance  140 C, and one end of the capacitance  150 C are connected to the protrusion portion  114 M. 
     The antenna element  120 M 2  includes an element  121 M 2 , a protrusion portion  122 M 2 , the wiring portion  123 M, and the protrusion portion  124 M. The antenna element  120 M 2  constitutes the loop antenna  190 M 2  together with the antenna element  110 M 2 . One protrusion portion  122 M 2  is arranged, and the protrusion portion  124 M is connected to a tip of the protrusion portion  122 M 2 . A capacitance having the predetermined electrostatic capacitance is constituted between the protrusion portion  122 M 2  and the wiring portion  123 M. This capacitance is used as a substitute of the interdigital portion  192 . The other end of the coil  140 L, the other end of the capacitance  140 C, the other end of the capacitance  150 C, and one end of the coil  150 L are connected to the protrusion portion  124 M. 
     As illustrated in  FIG. 13 , also in the wireless communication device  100 M 2  including the configuration in which the interdigital portion  192  (see  FIG. 1  to  FIG. 6 ) is not included, the loop antenna  190 M 2  resonates with the IC chip  130  at 920 MHz, and the wireless communication device  100  may function as the RFID tag. The beacon output by the communication portion  160  is radiated from the loop antenna  190 M 2 . 
     Therefore, according to the second modified example of the embodiment, the wireless communication device  100 M 2  and the antenna device which the plurality of communications having the largely varying impedances may be performed may be provided. 
     The wireless communication device and the antenna device according to the illustrative embodiment have been described above, but the embodiment is not limited to the disclosed embodiment, and various modifications and alterations may be made without departing from the scope of the claims. 
     All examples and conditional language provided herein are intended for the pedagogical purposes of aiding the reader in understanding the invention and the concepts contributed by the inventor to further the art, and are not to be construed as limitations to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although one or more embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.