JP2007104325A - Non-contact communication device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-contact communication device which makes the most suitable impedance switching at the time of transmitting operation and receiving operation by a simple circuit in a high speed and by low consumption power. <P>SOLUTION: An impedance converting element 16a is established beforehand in an optimum impedance component (Z1) for receiving optimum data in a receiving operation. The impedance converting element 16b is established beforehand in an optimum impedance component (Z2) for optimum data transmission in a transmission operation. In a receiver in which the receiving operation is carried out, a switching unit 15a is switched so that the impedance converting element 16a is connected to an antenna 11. In an transmitter in which the transmission operation is carried out, the switching unit 15a is switched so that the impedance converting element 16b is connected to the antenna 11. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a non-contact communication apparatus that has a non-contact communication function, and performs antenna impedance matching in order to widen a communication distance.

  In general, a contactless communication apparatus uses a loop antenna for data transmission / reception, and its operating power is supplied from a reader / writer apparatus via a carrier wave used for communication. For data transmission, a method of changing the impedance of the loop antenna, that is, a so-called load modulation method is generally used. However, since the impedance change of the loop antenna at the time of transmission leads to a decrease in the power supply of the carrier wave supplied from the antenna, the supplied power is less than the power consumption of the circuits (control unit, clock generation unit, etc.) inside the non-contact communication device Impedance change that becomes Therefore, at the time of transmission, optimization of the initial value of the impedance is important, but it is very difficult.

  On the other hand, in recent years, non-contact communication devices are not limited to non-powered media such as IC cards, but are spreading to portable information terminals such as mobile phones, and non-contact communication without requiring power supply from reader / writer devices. Possible media have also been devised. In such a non-contact communication device that does not require power supply from the reader / writer device, the communication distance is rate-determined by the transmission load modulation degree, and the impedance setting or impedance more matched to the load modulation at the time of transmission. Control is desired.

Therefore, for example, Patent Document 1 proposes a conventional non-contact communication device having a function of switching the impedance of an antenna at transmission timing. This Patent Document 1 includes a variable impedance matching circuit connected in series and in parallel with an antenna, a detection circuit for detecting power transmission efficiency, and a power transmission state judgment circuit for judging the result, and standby power other than during communication. A technique related to a non-contact IC card for controlling a variable impedance matching circuit for the purpose of reducing the above is disclosed.
JP 2002-64403 A

  By the way, in the conventional technique described in the above-mentioned Patent Document 1, it is determined whether or not the non-contact communication apparatus is executing communication processing and the switching of antenna impedance is controlled. It is not determined whether is a transmission operation or a reception operation. For this reason, in this conventional technique, the supply power during the transmission operation and the supply power during the reception operation are set to the same value, that is, the antenna impedance during the transmission operation and the antenna impedance during the reception operation are controlled to the same value.

  However, when considering the improvement of the transmission load modulation degree in the non-contact communication device that does not require the power supply from the reader / writer device described above, the initial value of the antenna impedance of the non-contact communication device is set at the time of the reception operation and the transmission operation. It is preferable to set an optimum value independently at each time. In order to realize this, it is conceivable to incorporate an adjustment circuit that detects the communication state and dynamically optimizes the impedance according to the detection result into the non-contact communication device. Time, power consumption, and the like become new problems.

  Therefore, an object of the present invention is to provide a non-contact communication device capable of performing high-speed and low power consumption switching with a simple circuit by obtaining in advance optimum impedances during transmission operation and reception operation. It is to be.

  The present invention is directed to a non-contact communication device that performs non-contact communication with a reader / writer device and a portable device incorporating the non-contact communication device. And in order to achieve the said objective, the non-contact communication apparatus of this invention is provided with an antenna, a control part, and an impedance switching part.

  The antenna transmits and receives non-contact signals. The control unit determines a reception section in which data reception from the reader / writer apparatus is executed and a transmission section in which data transmission to the reader / writer apparatus is executed based on a signal given from the reader / writer apparatus. The impedance switching unit switches the impedance component loaded on the antenna between the reception period and the transmission period according to the determination of the control unit.

  Here, when a section in which data transmission by the own device can be performed is assigned in advance in the transmission section, the impedance switching unit performs the data transmission by the own device in the transmission section and the data transmission by the own device. The impedance component loaded on the antenna may be further switched between the section where transmission is impossible.

  The impedance switching unit loads an antenna with a data reception impedance component in the reception section and a data transmission impedance component in the transmission section. In addition, when a section in which data transmission by the own device can be performed in advance in the transmission section, an impedance component for data transmission is transmitted in a section in the transmission section in which data transmission by the own device can be performed. An impedance component for reducing signal interference to other devices is loaded on the antenna in a section in which data transmission by the own device is impossible.

  Moreover, it is preferable that the impedance switching unit loads the impedance component for data reception on the antenna until the reception section and the transmission section can be determined. Furthermore, the control unit may include a switching unit that can switch the function of the impedance switching unit between operation and non-operation.

  This non-contact communication apparatus may be composed of a non-contact medium and an external antenna. In this case, the non-contact medium and the external antenna are connected to each other via an external terminal, the non-contact medium includes a control unit, and the external antenna includes an antenna and an impedance switching unit. In addition, the external antenna can be configured by a primary antenna that transmits and receives a non-contact signal and a secondary antenna that is provided close to the primary antenna. In this case, the impedance switching unit is a secondary antenna. What is necessary is just to switch the impedance component loaded in.

According to the present invention, the impedance component loaded on the antenna is switched independently during the non-contact communication transmission operation and the reception operation. As a result, it is possible to select independent antenna impedances in the reception section and the transmission section, and data can always be transmitted with the optimum impedance, so that the non-contact communication distance can be extended.
Further, in addition to the non-contact communication transmission operation and the reception operation, the impedance component to be loaded on the antenna is switched independently during non-transmission operation in which another device performs data transmission. As a result, it is possible to select independent antenna impedances for the reception section and the transmission section, and data can be transmitted with the optimum impedance at all times, so that the non-contact communication distance can be extended and other devices It is possible to improve the communication quality by minimizing the signal interference.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[First Embodiment]
FIG. 1 is a diagram illustrating a configuration example of a contactless communication apparatus 1 according to the first embodiment of the present invention. In FIG. 1, the non-contact communication apparatus 1 according to the first embodiment includes an antenna 11, a reception unit 12, a clock generation unit 13, a modulation unit 14, an impedance switching unit 15, and a control unit 17. . The impedance switching unit 15 includes a switching unit 15a and impedance conversion elements 16a and 16b. The control unit 17 includes a timing control unit 171, a data recognition unit 172, and a data generation unit 173.

First, the outline | summary of each structure of the non-contact communication apparatus 1 which concerns on 1st Embodiment is demonstrated.
The antenna 11 transmits and receives signals exchanged in a non-contact manner with a reader / writer device (not shown). The receiving unit 12 extracts a data component from the received signal received via the antenna 11 and demodulates the extracted data. The clock generation unit 13 extracts a clock component from the reception signal received via the antenna 11 and generates a clock used by the control unit 17. The data recognition unit 172 recognizes the demodulated received data. The data generation unit 173 generates predetermined transmission data based on the reception data recognized by the data recognition unit 172. The timing control unit 171 controls the timing of each data according to the clock generated by the clock generation unit 13. The modulation unit 14 performs predetermined modulation on the transmission data generated by the data generation unit 173 and outputs the transmission data to the antenna 11 as a transmission signal. For this predetermined modulation, load modulation is typically used. The simplest load modulation circuit is a switch that grounds the connection line of the antenna 11 to GND in accordance with transmission data generated by the data generation unit 173. The switching unit 15 a switches the impedance component loaded on the antenna 11 in accordance with an instruction from the timing control unit 171. The switching unit 15a is typically a 1-input / 2-output selector switch, and an antenna 11 is connected to one input terminal, and impedance conversion elements 16a and 16b having different impedance components are connected to two output terminals, respectively. Has been.

Next, the operation of the non-contact communication apparatus 1 according to the first embodiment having the above configuration will be described.
In the present embodiment, it is assumed that the timing of transmission / reception performed between the non-contact communication device 1 and the reader / writer device is set in advance as in the communication timing shown in FIG. The example of FIG. 2 assumes a case where the reader / writer device communicates with a plurality of non-contact communication devices 1, and the transmission timing of each non-contact communication device 1 is assigned by dividing the transmission section in a time division manner. Yes. The communication timing is instructed by the timing controller 171 in synchronization with the clock generated by the clock generator 13.

  In this embodiment, the impedance conversion element 16a is set to the data reception impedance component (Z1) that is optimal for the reception operation, and the impedance conversion element 16b is the data transmission impedance component (Z2) that is optimal for the transmission operation. ). The impedance conversion elements 16a and 16b may be any elements that can achieve impedance matching between the antenna and the transmission / reception circuit, such as a capacitive element such as a capacitor, an inductive element such as an inductance, a pure resistance element, or a combination of these elements. It can be formed in various forms in the form of a circuit.

  In a state of waiting for a signal from the reader / writer device (reception section in FIG. 2), the timing control unit 171 outputs an impedance switching signal 18 indicating that a reception operation is being performed to the switching unit 15a. The switching unit 15a connects the impedance conversion element 16a to the antenna 11 in accordance with the impedance switching signal 18 indicating that this reception operation is being performed.

  When a signal is received from the reader / writer device (reception section in FIG. 2), the reception signal is separated into reception data and clock by the reception unit 12 and the clock generation unit 13, and the data recognition unit 172 and timing control unit 171 are separated. And given respectively. The timing control unit 171 instructs the timing of various processes performed in the non-contact communication device 1 in synchronization with the clock generated by the clock generation unit 13. The data recognition unit 172 recognizes the received data according to the timing instructed from the timing control unit 171. The data generation unit 173 generates transmission data corresponding to the reception data recognized by the data recognition unit 172.

  During the processing so far, the timing control unit 171 continues to output the impedance switching signal 18 indicating that the reception operation is being performed to the switching unit 15a. With this impedance switching process, the data receiving impedance component (Z1) optimum for the receiving operation is loaded on the antenna 11 during the receiving operation shown in the receiving section of FIG.

  Thereafter, when the communication state ends in the reception period and shifts to the transmission period, the timing control unit 171 outputs an impedance switching signal 18 indicating that the transmission operation is being performed to the switching unit 15a. The switching unit 15a connects the impedance conversion element 16b to the antenna 11 in accordance with the impedance switching signal 18 indicating that this transmission operation is being performed. Subsequently, when the timing (section) in which the data transmission of the own apparatus can be performed in the transmission section is reached, the timing control unit 171 instructs the data generation unit 173 to transmit the transmission data. The data generation unit 173 that has received an instruction to enable transmission transmits the generated transmission data to the modulation unit 14. The modulation unit 14 performs predetermined modulation on the transmission data transmitted from the data generation unit 173 and outputs the result to the antenna 11. On the other hand, by this impedance switching process, the data transmission impedance component (Z2) optimum for the transmission operation is loaded on the antenna 11 during the transmission operation shown in the transmission section of FIG.

  As described above, according to the non-contact communication device 1 according to the first embodiment of the present invention, the impedance component loaded on the antenna 11 is switched independently during the non-contact communication transmission operation and the reception operation. As a result, it is possible to select independent antenna impedances in the reception section and the transmission section, and data can always be transmitted with the optimum impedance, so that the non-contact communication distance can be extended.

[Second Embodiment]
FIG. 3 is a diagram illustrating a configuration example of the non-contact communication device 2 according to the second embodiment of the present invention. In FIG. 3, the non-contact communication device 2 according to the second embodiment includes an antenna 11, a receiving unit 12, a clock generating unit 13, a modulating unit 14, an impedance switching unit 25, and a control unit 27. . The impedance switching unit 25 includes a switching unit 25a and impedance conversion elements 26a, 26b, and 26c. The control unit 27 includes a timing control unit 271, a data recognition unit 172, and a data generation unit 173.

  As illustrated in FIG. 3, the non-contact communication device 2 according to the second embodiment is different from the non-contact communication device 1 according to the first embodiment in that the switching unit 25 a, the impedance conversion elements 26 a to 26 c, and The configuration of the timing control unit 271 is different. Hereinafter, the non-contact communication apparatus 2 according to the second embodiment will be described focusing on this different configuration. The transmission / reception timing performed between the non-contact communication device 2 and the reader / writer device is as shown in FIG.

  The switching unit 25 a switches the impedance component loaded on the antenna 11 in accordance with an instruction from the timing control unit 271. The switching unit 25a is typically a 1-input 3-output changeover switch, and an antenna 11 is connected to one input terminal, and impedance conversion elements 26a to 26c having different impedance components are connected to three output terminals, respectively. Has been. In the present embodiment, the impedance conversion element 26a is set to the data reception impedance component (Z1) that is optimal for the reception operation, and the impedance conversion element 26b is connected to another device that is optimal for the transmission non-operation in the transmission section. It is assumed that the impedance component (Z2) for reducing signal interference is set, and the impedance conversion element 26c is set to the impedance component (Z3) for data transmission optimal for the transmission operation in the transmission section.

  In a state of waiting for a signal from the reader / writer device (reception section in FIG. 4), the timing control unit 271 outputs an impedance switching signal 18 indicating that a reception operation is being performed to the switching unit 25a. The switching unit 25a connects the impedance conversion element 26a to the antenna 11 according to the impedance switching signal 18 indicating that this reception operation is being performed. After the signal is received from the reader / writer device, until the transition to the transmission section (reception section in FIG. 4), the timing control section 271 changes the impedance switching signal 18 indicating that the reception operation is being performed to the switching section 25a. Continue to output to. With this impedance switching process, the data receiving impedance component (Z1) optimum for the receiving operation is loaded on the antenna 11 during the receiving operation shown in the receiving section of FIG.

  Thereafter, when the communication state ends in the reception period and shifts to the transmission period, the timing control unit 271 outputs an impedance switching signal 18 indicating that the transmission is not in operation to the switching unit 25a. The switching unit 25a connects the impedance conversion element 26b to the antenna 11 in accordance with the impedance switching signal 18 indicating that the transmission is not in operation.

  Subsequently, when the timing at which the data transmission of the own device can be performed in the transmission interval (self-transmission timing) is reached, the timing control unit 271 instructs the data generation unit 173 to transmit the transmission data and performs the transmission operation. An impedance switching signal 18 indicating that it is in the middle is output to the switching unit 25a. The switching unit 25a connects the impedance conversion element 26c to the antenna 11 in accordance with the impedance switching signal 18 indicating that this transmission operation is being performed. The data generation unit 173 that has received an instruction to enable transmission transmits the generated transmission data to the modulation unit 14. The modulation unit 14 performs predetermined modulation on the transmission data transmitted from the data generation unit 173 and outputs the result to the antenna 11.

  Then, when the section in which the data transmission of the own apparatus is possible in the transmission section ends, the timing control unit 271 outputs the impedance switching signal 18 indicating that the transmission is not in operation to the switching unit 25a. The switching unit 25a connects the impedance conversion element 26b to the antenna 11 in accordance with the impedance switching signal 18 indicating that the transmission is not in operation.

  With this impedance switching process, the impedance component (Z2) that minimizes signal interference with other devices that perform data transmission is loaded in the antenna 11 during the transmission non-operation in the transmission section shown in FIG. During this, the antenna 11 is loaded with the impedance component (Z3) for data transmission that is optimal for the transmission operation of the device itself.

  As described above, according to the non-contact communication device 2 according to the second embodiment of the present invention, in the non-transmission operation in which another device performs data transmission in addition to the non-contact communication transmission operation and the reception operation. The impedance component loaded on the antenna 11 is switched independently. As a result, it is possible to select independent antenna impedances for the reception section and the transmission section, and data can be transmitted with the optimum impedance at all times, so that the non-contact communication distance can be extended and other devices It is possible to improve the communication quality by minimizing the signal interference.

[Third Embodiment]
FIG. 5 is a diagram illustrating a configuration example of the non-contact communication device 3 according to the third embodiment of the present invention. In FIG. 5, the non-contact communication device 3 according to the third embodiment includes an antenna 11, a reception unit 12, a clock generation unit 13, a modulation unit 14, an impedance switching unit 15, and a control unit 37. . The impedance switching unit 15 includes a switching unit 15a and impedance conversion elements 16a and 16b. The control unit 37 includes a timing control unit 171, a data recognition unit 172, a data generation unit 173, a switching unit 374, and a state detection unit 375.

  As illustrated in FIG. 5, the non-contact communication device 3 according to the third embodiment is different from the non-contact communication device 1 according to the first embodiment in the switching unit 374 and the state detection unit in the control unit 37. The configuration of 375 is different. Hereinafter, the non-contact communication apparatus 3 according to the third embodiment will be described focusing on this different configuration. The transmission / reception timing performed between the non-contact communication device 3 and the reader / writer device is as shown in FIG.

  The state detection unit 375 detects the communication state of the non-contact communication device 3 (whether it is a transmission operation or a reception operation) and controls switching of the switching unit 374 according to the detection result. This detection may be performed when power is supplied from the reader / writer device, or may be performed when a reception signal is detected. The switching unit 374 switches the impedance switching signal 18 output to the switching unit 15a according to the control of the state detection unit 375. The switching unit 374 is typically a 2-input 1-output selector switch, and the output from the timing control unit 171 and a fixed power source are connected to two input terminals, respectively, and the switching unit 15a is connected to one output terminal. Is connected.

  With this configuration, the non-contact communication device 3 can fix the impedance component loaded on the antenna 11 without switching the impedance between the transmission operation and the reception operation when necessary. If this function is used, for example, when the non-contact communication apparatus 3 receives power supply from the outside, the efficiency of power supply decreases due to frequent switching of impedance components in accordance with transmission / reception operations. The problem can be avoided.

  As described above, according to the non-contact communication device 3 according to the third embodiment of the present invention, it is possible to arbitrarily select whether or not to switch the impedance component loaded on the antenna 11.

  In the third embodiment, the control that does not switch the impedance component is automatically performed using the state detection unit 375. However, the control may be performed manually by providing an external switch. Further, the configuration of the switching unit 374 and the state detection unit 375 need not be built in the control unit 37, and may be provided in a block other than the control unit 37 or in an external configuration.

[Fourth Embodiment]
In the first to third embodiments, the configuration example in which the antenna 11 is incorporated in one housing of the non-contact communication devices 1 to 3 has been described. However, the antenna 11 may be provided separately from the main body that controls the non-contact communication. Therefore, in the fourth embodiment, an example of a non-contact communication system in which the antenna is formed separately from the non-contact communication device will be described.

-Non-contact communication system example (1)
FIG. 6 is a diagram illustrating an example of a non-contact communication system including the external antenna 41 and the non-contact medium 42. The non-contact medium 42 is, for example, an IC card or a multimedia card. In this non-contact communication system example, the external antenna 41 and the non-contact medium 42 are connected via a connection terminal.

-Non-contact communication system example (2)
FIG. 7 is a diagram illustrating an example of a non-contact communication system including the external antenna 43 and the non-contact medium 42. The non-contact medium 42 is, for example, an IC card or a multimedia card. In this non-contact communication system example, the external antenna 43 and the non-contact medium 42 are connected via a connection terminal. In the external antenna 43, the impedance component is not directly loaded on the antenna (primary antenna) 11, but the impedance component is loaded on the secondary antenna 411, and the antenna impedance is influenced by the interaction between the antenna 11 and the secondary antenna 411. Is changing.

  As described above, according to the contactless communication system according to the fourth embodiment of the present invention, even when the antenna 11 cannot be built in the contactless communication apparatus, data can always be transmitted with an optimum impedance. The contactless communication distance can be extended.

  In the first to fourth embodiments, the impedance switching signal 18 is described as one signal. However, the number of signals is not particularly limited, and any number of signals from one analog signal to a plurality of digital signals can be freely selected. Can be designed to

  Moreover, in the said 1st-4th embodiment, the structural example which provides switching part 15a, 25a and impedance conversion element 16a, 16b, 26a-26c in the position parallel to the antenna 11 or the secondary antenna 411 was shown. However, the switching units 15a and 25a and the impedance conversion elements 16a, 16b, and 26a to 26c may be provided in a position in series with the antenna 11 (see, for example, the configuration of FIG. 8), or a position in parallel with the antenna 11. And in series with each other (see, for example, the configuration of FIG. 9). In any configuration, the above-described useful effects can be exhibited.

  When the output level of the impedance switching signal 18 is the Lo level or the GND level, the switching units 15a and 25a set the output of the impedance switching signal 18 to the Lo level until the transmission interval and the reception interval (timing thereof) can be determined. Or you may fix to a GND level. In this way, it is possible to ensure the same performance as before by always selecting the optimum impedance when the timing of the transmission / reception section is indefinite when waiting for the received signal.

  The present invention can be used for a non-contact communication device such as a portable device that switches antenna impedance components, and is particularly suitable for switching an optimum antenna impedance between a transmission operation and a reception operation.

The figure which shows the structural example of the non-contact communication apparatus 1 which concerns on the 1st Embodiment of this invention. State transition diagram of impedance switching signal 18 in non-contact communication device 1 The figure which shows the structural example of the non-contact communication apparatus 2 which concerns on the 2nd Embodiment of this invention. State transition diagram of impedance switching signal 18 in non-contact communication device 2 The figure which shows the structural example of the non-contact communication apparatus 3 which concerns on the 3rd Embodiment of this invention. The figure which shows the structural example of the non-contact communication system which concerns on the 4th Embodiment of this invention. The figure which shows the other structural example of the non-contact communication system which concerns on the 4th Embodiment of this invention. The figure which shows the modification structural example of the non-contact communication apparatus 1. The figure which shows the other modified structural example of the non-contact communication apparatus 1.

Explanation of symbols

1-3 Non-contact communication apparatus 11, 411 Antenna 12 Receiving unit 13 Clock generating unit 14 Modulating unit 15, 25 Impedance switching unit 15a, 25a, 374 Switching unit 16a, 16b, 26a-26c Impedance conversion element 17, 27, 37 Control Unit 18 Impedance switching signals 41 and 43 External antenna system 42 Non-contact medium 171 and 271 Timing control unit 172 Data recognition unit 173 Data generation unit 375 State detection unit

Claims (9)

A non-contact communication device that performs non-contact communication with a reader / writer device,
An antenna for transmitting and receiving non-contact signals;
A control unit that determines, based on a signal given from the reader / writer device, a reception section in which data reception from the reader / writer device is executed and a transmission section in which data transmission to the reader / writer device is executed. When,
A non-contact communication apparatus comprising: an impedance switching unit that switches an impedance component loaded on the antenna between the reception section and the transmission section according to the determination of the control unit. A section in which data can be transmitted by the own device is assigned in advance within the transmission section,
The impedance switching unit further switches an impedance component loaded on the antenna between a section in which data can be transmitted by the own apparatus in the transmission section and a section in which data transmission by the own apparatus is impossible. The contactless communication apparatus according to claim 1.   The non-transistor according to claim 1, wherein the impedance switching unit loads the antenna with a data reception impedance component in the reception section and a data transmission impedance component in the transmission section. Contact communication device.   The impedance switching unit includes an impedance component for data reception in the reception section, an impedance component for data transmission in a section in which data can be transmitted by the own apparatus in the transmission section, and an own apparatus in the transmission section. 3. The non-contact communication apparatus according to claim 2, wherein an impedance component for reducing signal interference to another apparatus is loaded on the antenna in a section in which data transmission by cannot be performed.   The contactless communication apparatus according to claim 3, wherein the impedance switching unit loads an impedance component for data reception onto the antenna until the reception section and the transmission section can be determined.   The non-contact communication apparatus according to claim 1, wherein the control unit further includes a switching unit capable of switching a function of the impedance switching unit between operation and non-operation. A contactless communication system that performs contactless communication with a reader / writer device,
Non-contact medium and external antenna are connected to each other via external terminals,
The non-contact medium is a transmission section in which data reception from the reader / writer device is executed and transmission in which data transmission is executed to the reader / writer device based on a signal given from the reader / writer device. It has a control unit that judges the section,
The external antenna is
An antenna for transmitting and receiving non-contact signals;
A non-contact communication system comprising an impedance switching unit that switches an impedance component loaded on the antenna between the reception section and the transmission section in accordance with the determination of the control unit of the non-contact medium. A contactless communication system that performs contactless communication with a reader / writer device,
Non-contact medium and external antenna are connected to each other via external terminals,
The non-contact medium is a transmission section in which data reception from the reader / writer device is executed and transmission in which data transmission is executed to the reader / writer device based on a signal given from the reader / writer device. It has a control unit that judges the section,
The external antenna is
A primary antenna for transmitting and receiving non-contact signals;
A secondary antenna provided close to the primary antenna;
A non-contact communication system including an impedance switching unit that switches an impedance component loaded on the secondary antenna between the reception section and the transmission section in accordance with the determination of the control unit of the non-contact medium. The portable apparatus which incorporated the non-contact communication apparatus in any one of Claims 1-6.

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