JPH09135189A - Wireless communication system and wireless card - Google Patents

Abstract

(57) Abstract: A wireless communication system in which unnecessary radiation is less than that using a conventional multiplication circuit or the like, and a member for preventing unnecessary radiation is not required. A wireless card reader / writer uses, as a data wave f2, a second frequency obtained by dividing a first frequency of a power wave f1 by 1/4. In the wireless card 20, the power wave f1 from the wireless card reader / writer 10 received by the power wave antenna 21 is converted by the rectifier circuit 22 to be the operating power supply + B. In addition, a part of the received power wave f1 is divided by the frequency dividing circuit 23.
Then, the signal is frequency-divided by 1/4 and sent to the modulation circuit 27, modulated by the response signal from the CPU 28, and transmitted as a response wave f3 from the data wave antenna 24 via the transmission / reception changeover switch 25 controlled by the CPU 28. The data wave f2 from the wireless card reader / writer 10 received by the data wave antenna 24 is transmitted via the transmission / reception changeover switch 25 to the demodulation circuit 26.
The data signal is demodulated and sent to the CPU 28.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to wireless communication by wirelessly transmitting and receiving between a batteryless wireless card having a portable wireless communication function and a wireless card reader / writer (communication device). The present invention relates to a wireless communication system in which power is transmitted and data is transmitted and received from a card reader / writer to a wireless card, and data is transmitted and received from the wireless card to a wireless card reader / writer. The present invention also relates to a battery-less wireless card used in the above wireless communication system.

[0002]

2. Description of the Related Art Recently, a wireless card composed of a rectangular card-like IC card having a size of a business card has been developed. By holding this wireless card in front of a wireless card reader / writer, a wireless card reader can be contactlessly contacted. -There is a wireless communication system that transmits and receives data and the like by transmitting and receiving with a writer. This wireless card is equipped with a control unit (CPU) including a storage element such as a semiconductor memory. By storing appropriate data in the storage element, an ID card (personal identification card), a commuter pass, etc. Can be used as.

Some conventional wireless cards are equipped with a battery which serves as an operating power source for the circuit elements to be mounted, but the life of the battery and the cost for replacing the battery are problems. It was

Therefore, there is a technique in which a radio wave transmitted from a radio card reader / writer is received by the radio card and a received electric wave is rectified to obtain direct-current power for an operating power supply without mounting a battery on the radio card. Proposed. Part 1
One method is to modulate a power wave for power transmission with a data signal from a wireless card reader / writer and transmit power and data to a wireless card with one frequency signal. Another method is to supply power and data to a wireless card from a wireless card reader / writer using two frequency signals, a power wave for power transmission and a data wave for data transmission at a different frequency. It is something to send.

[0005]

In the method of using one frequency signal obtained by modulating the power wave with the data signal, demodulation of the data signal on the wireless card side is relatively easy. However, when a plurality of wireless communication systems using the same frequency are provided close to each other, for example, when a wireless card is used as a commuter pass and a plurality of ticket gates are installed in parallel, There is a problem in that it is easily affected by electric waves from other nearby ticket gates, and countermeasures such as shielding are required.

Further, in the method of transmitting the power wave and the data wave at different frequencies, the power wave is much larger than the data wave (for example, the power of 10 7 times), and the wireless card side. In the antenna that receives the data wave with
A signal in which a data wave of weak power is superimposed on a power wave of large power is received.

However, there is no established practical technique for extracting the data wave from the power wave. A coil element can be easily used to extract the data wave, but the coil element has a large shape and dimension and is not suitable as an element to be mounted on a wireless card.

Further, the coil element is not suitable for forming a circuit mounted on the wireless card into a one-chip IC (integrated circuit). Furthermore, conventionally, as a response wave from the wireless card to the wireless card reader / writer, a high frequency obtained by multiplying the first frequency of the power wave is generally used, and a countermeasure against unwanted radiation by a multiplication circuit is required. I was trying.

Further, in the method of transmitting the power wave and the data wave from the wireless card reader / writer at different frequencies, it is sufficient to dispose antennas for receiving the power wave and the data wave on the wireless card. There was a problem that a large space could not be obtained.

The power wave is transmitted from the wireless card reader / writer with an extremely large power as compared with the data wave, but the power wave is received efficiently in order to secure a sufficient operating power supply capacity in the wireless card. However, the outer diameter of the power wave antenna required for the wireless card becomes large and the arrangement is difficult.

Therefore, an object of the present invention is to provide a radio communication system which has less unnecessary radiation than a conventional one using a multiplication circuit or the like and which does not require a member for preventing unnecessary radiation.

Another object of the present invention is to provide a wireless communication system capable of transmitting and receiving a data wave and a response wave with a single antenna in a wireless card. Further, according to the present invention, when the card is held over the communication device, the power wave antenna and the data wave antenna are less likely to be covered by fingers of a hand holding the card, and each antenna is almost It is an object of the present invention to provide a wireless card in which a similar reception situation occurs and reliable transmission / reception is possible.

[0013]

A wireless communication system of the present invention is a wireless communication system for wirelessly transmitting and receiving between an external communication device and a wireless card, wherein the communication device communicates with the wireless card. Power wave unmodulated with high power at a first frequency, and a data wave obtained by modulating weak power with a data signal at a second frequency lower than the first frequency obtained by dividing the first frequency. And a response wave transmitted from the wireless card, the wireless card receives a power wave transmitted from the communication device with a power wave antenna, and the received power wave is rectified by a rectifier circuit. Is converted into direct current power to be used as an operating power source, and a part of the received power wave is divided by a frequency dividing circuit to be given to the modulation circuit as the second frequency, and the communication device is also provided. The data wave transmitted from the antenna is received by the data wave antenna, and the received data wave is applied to the demodulation circuit via the transmission / reception changeover switch controlled by the control means to demodulate into a data signal. A signal is given to the control means, and the control means gives a response signal to the modulation circuit to modulate the second frequency given from the frequency dividing circuit to generate a response wave, and the generated response wave. Is transmitted from the data wave antenna to the communication device via the transmission / reception changeover switch.

The wireless card of the present invention receives a power wave of a first frequency transmitted from an external communication device and a data wave of a second frequency different from the first frequency. The first coil forming the power wave antenna for receiving the power wave is arranged in the center of one surface of a rectangular card-shaped substrate formed of a member that transmits radio waves, and A second coil forming a data wave antenna for receiving a data wave is arranged so as to form a double loop with the first coil in a central portion of one surface of the substrate. ing.

According to the wireless communication system of the present invention, the conventional multiplying circuit is used by using the low second frequency obtained by dividing the first frequency of the power wave as the response wave from the wireless card. Compared with the above, less unnecessary radiation is required, and a member for preventing unnecessary radiation is not required. In addition, both the data wave and the response wave use the second frequency obtained by dividing the first frequency of the power wave, so that the data wave and the response wave can be transmitted / received by one antenna in the wireless card, which is particularly small. Suitable for required wireless cards.

Further, according to the wireless communication system of the present invention, the data wave superimposed on the power wave is extracted by using the amplifier circuit whose gain decreases as the frequency increases,
The high frequency power wave is suppressed, the low frequency data wave is amplified with a high gain, and by appropriately providing the number of stages of the amplifier circuit, the relative ratio of the data wave to the power wave can be improved to an appropriate size. It is easy to demodulate the data signal from the data wave by the shaping circuit.

According to the wireless card of the present invention, the first coil forming the power wave antenna for receiving the power wave and the data wave antenna for receiving the data wave are formed in the central portion of the card. By arranging the second coil so as to form a double loop, there is a possibility that the first coil and the second coil may be covered with a finger or the like holding the card when holding the card over the communication device. In addition, the first coil and the second coil have substantially the same reception status, and the reception status of both coils does not significantly differ.

According to the wireless card of the present invention, the first
By arranging the first coil and the second coil as a flat rectangle in the central section divided into three by the short side of the card, the first coil and the second coil can be held by a finger or the like holding the card. There is no risk of the coil being covered.

Further, according to the wireless card of the present invention, by disposing the second coil on the same plane of the substrate surrounded by the first coil, the power wave can be received more efficiently. Therefore, the capacity of the operating power supply can be increased correspondingly, and the operation can be surely achieved.

[0020]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows the configuration of a wireless communication system according to this embodiment. This wireless communication system includes a wireless card reader / writer 10 and a wireless card 20 as a communication device that performs contactless communication. From the wireless card reader / writer 10, a continuous non-modulated large power with a power wave f1 of the first frequency,
And a data wave f2 having a second frequency lower than the first frequency with weak power ASK-modulated by the data signal.
Are transmitted to the wireless card 20 via the power wave antenna 11 and the data wave antenna 12, respectively.

Here, the first frequency of the power wave f1 is, for example, 13.56 MHz, and the second frequency of the data wave f2.
The frequency of is, for example, 3.39 MHz obtained by dividing the first frequency by 1/4. Further, the power wave f1 is transmitted at a power of 10 7 times the power of the data wave f2, for example.

The wireless card 20 includes a power wave antenna 21, which is a parallel circuit of a first coil L1 and a first capacitor C1, a rectifier circuit 22 for generating power, a frequency divider circuit 23,
A data wave antenna 24 including a parallel circuit of a second coil L2 and a second capacitor C2, a transmission / reception changeover switch 25, a demodulation circuit 26, a modulation circuit 27, and a CPU (central processing unit) as a control means. 28.

That is, in the wireless card 20, the power wave f1 received by the power wave antenna 21 is rectified by the rectifier circuit 22 into a DC voltage, which is the operating power supply + B.
Used as Further, a part of the power wave f1 received by the power wave antenna 21 is sent to the frequency dividing circuit 23, where, for example, a second frequency is generated as a frequency-divided signal that is 1/4 frequency-divided. And sent to the modulation circuit 27.

A response signal to the wireless card reader / writer 10 is inputted from the CPU 28 to the modulation circuit 27,
The second frequency ASK-modulated by this response signal is sent to the transmission / reception changeover switch 25 as a response wave f3 as shown in FIG. Further, an input signal including the data wave received by the data wave antenna 24 is sent to the demodulation circuit 26 via the transmission / reception changeover switch 25, the data wave is appropriately extracted, and the waveform is shaped and demodulated as a data signal. And sent to the CPU 28.

The data wave antenna 24 is an LC resonance circuit, and its resonance frequency is set to the second frequency of the data wave f2 so that the reception of the power wave f1 is greater than the reception of the data wave f2. Although suppressed, it is difficult to say that it is sufficient to extract only the data wave f2 because the Q characteristic of the antenna is not steep.

The transmission / reception changeover switch 25 has a C
By receiving the transmission / reception switching signal from the PU 28,
The input from the data wave antenna 24 is transmitted to the demodulation circuit 26, or the modulated response wave f3 from the modulation circuit 27 is transmitted from the data wave antenna 24 to the wireless card reader / writer 10. Therefore, switching control is appropriately performed.

The demodulation circuit 26 is composed of, for example, an extraction circuit 26a for extracting the received data wave, and a shaping circuit 26b for shaping the waveform of the extracted data wave signal and demodulating and outputting the data signal.

The circuit member of the wireless card 20 includes a first coil L1 forming the power wave antenna 21 and a second coil L forming the data wave antenna 24.
Except for 2, the IC is a one-chip IC 29.

FIG. 2 shows the extraction circuit 2 in the demodulation circuit 26.
6a shows in detail the configuration of 6a. That is, the data wave signal from the data wave antenna 24 is input to the input end 31. The input terminal 31 is connected to the base of the NPN transistor T1 of the first amplifier circuit 32 via the DC blocking capacitor C3. The collector of the transistor T1 is
It is connected to the operating power supply + B through a parallel circuit of a collector resistor R1 and a collector capacitor C4. Transistor T
The emitter of 1 is grounded via a parallel circuit of an emitter resistor R2 and an emitter capacitor C5. Transistor T
The collector and base of 1 are connected via a bias resistor R3, and the collector of the transistor T1 is connected to the base of an NPN transistor T2 of the second amplifier circuit 33 via a DC blocking capacitor C6.

The collector of the transistor T2 is connected to the operating power source + B via a parallel circuit of a collector resistor R4 and a collector capacitor C7, and the transistor T2 is connected.
The second emitter is grounded. The collector and base of the transistor T2 are connected via a bias resistor R5, and the base of the transistor T2 is bias resistor R6.
Grounded. The collector of the transistor T2 is
The third amplifier circuit 3 is connected via the DC blocking capacitor C8.
4 is connected to the base of NPN transistor T3.

The collector of the transistor T3 is connected to the operating power source + B through a parallel circuit of a collector resistor R7 and a collector capacitor C9, and at the same time, the transistor T3.
The emitter of 3 is grounded. The base of the transistor T3 is connected to the operating power supply + B via the bias resistor R8, and is grounded via the bias resistor R9. The collector of the transistor T3 is a DC blocking capacitor C
It is connected via 10 to the base of the NPN transistor T4 of the fourth amplifier circuit 35.

The collector of the transistor T4 is connected to the operating power source + B through a parallel circuit of a collector resistor R10 and a collector capacitor C11, and the emitter of the transistor T4 is grounded. The collector and the base of the transistor T4 are connected via a bias resistor R11, and the collector of the transistor T4 has a resistor R
It is connected to the output terminal 36 via 12.

In the extraction circuit 29 having such a configuration,
The bias settings of the first to fourth amplifier circuits 32, 33, 34, and 35 are set to operate as class B or class C. Therefore, the input signal applied to the input terminal 31 is
As shown in FIG. 3A, in which the data wave f2 of the weak power d1 is superimposed on the power wave f1 of the large power b1, the class B or C class amplification operation of the first amplifier circuit 32 causes , The data wave f2 is amplified with a high gain, and the power wave f1
Is amplified with a smaller gain than this.

As a result, as the amplified output of the first amplifier circuit 32, as shown in FIG. 3B, the power of the data wave f2 is amplified to D1 and the relative ratio of the power to the power wave f1 is improved. To be done. Therefore, the second, third, and fourth amplifier circuits 3
By similarly amplifying at 3, 34 and 35, the power of the data wave f2 can be further amplified and the relative ratio with the power wave f1 can be greatly improved.

In the first and fourth amplifier circuits 32 and 35, the bases of the transistors T1 and T4 may be grounded via a bias resistor. Also, the second, third and fourth
In the amplifier circuits 33, 34 and 35 of
The emitters of T2, T3, and T4 may be grounded via an emitter resistor, and the bias voltage may be set so as to perform more class C operation.

Further, the first to the first which constitute the extraction circuit 26a
In the fourth amplifier circuits 32, 33, 34, and 35, any circuit may be omitted, or any circuit may be duplicated. In short, the number of stages of the amplifier circuit may be appropriately set according to the relative ratio between the power of the input power wave f1 and the power of the data wave f2 superimposed on it. Therefore,
The extraction circuit 26a may be composed of a single-stage amplifier circuit.

Further, the first to fourth amplifier circuits 32, 33,
The collectors of the transistors T1, T2, T3 and T4 of 34 and 35 have collector capacitors C4, C7, C9,
C11 is provided, and the gain of these amplifier circuit characteristics decreases as the frequency becomes higher for a frequency signal of a predetermined frequency or higher, as shown in FIG. Therefore, by setting the second frequency of the data wave f2 near the frequency where the gain decreases, the gain of the high frequency power wave f1 is decreased to suppress the amplification, and the low frequency data wave f2 is reduced.
Can be amplified with high gain. The data wave f2 can be extracted from the power wave f1 also from such an amplifier circuit characteristic.

By the way, the first amplifier circuit 32 is provided with the emitter resistor R2, and when the transistor T1 becomes conductive, the emitter potential rises and the voltage negative feedback acts. Further, the bias resistor R3 is the transistor T1.
Since the base and the collector are connected, the collector potential drops when the transistor T1 becomes conductive, and the base potential also drops accordingly. Therefore, negative current feedback works. Therefore, in the first amplifier circuit 32, both the voltage and the current negative feedback act, and the saturation of the transistor T1 is avoided. Further, in the second and fourth amplifier circuits 33 and 35, bias negative resistance acts on the bias resistors R5 and R11, and saturation of the transistors T2 and T4 is avoided. This prevents the data wave f2 from being distorted or becoming undetectable due to saturation.

As described above, the first to fourth amplifier circuits 3
The extraction circuit 2 is formed by the amplification operations of 2, 33, 34, and 35.
6a outputs a signal as shown in FIG. 5 (b) to the output terminal 36 in response to the input signal as shown in FIG. 5 (a).
That is, for the power b1 of the power wave f1, the data wave f2
Of the electric power d1 becomes the electric power D4 of the data wave f2 with respect to the electric power B4 of the electric power wave f1, and the relative ratio of the electric power of the data wave f2 becomes large. Therefore, FIG. 5 (b)
By appropriately shaping the waveform of the output of the extraction circuit 26a as shown in FIG. 5 by the shaping circuit 26b, a data signal as shown in FIG. 5C can be easily demodulated.

In the above description, the NPN transistors T1, T2, T3 and T4 are used as the amplifying elements of the first to fourth amplifying circuits 32, 33, 34 and 35, respectively.
A field effect transistor may be used as the amplification element.
By using the field effect transistor, the power consumption by the amplifier circuit itself can be suppressed, a sufficient margin can be given to the capacity of the operating power supply, and the 1-chip I
It is also suitable for conversion to C.

Next, the structure of the wireless card 20 will be described in detail with reference to FIG. The wireless card 20 is shown in FIG.
As shown in FIG. 5, the electromagnetic wave transmitting member, for example, is assembled on a business card-sized rectangular substrate 41 made of a dielectric material. That is, the first coil L1 and the second coil L2 are arranged in the central section P2 in which the surface of the substrate 41 is divided into three strips on the short side. Both the first and second coils L1 and L2 are formed into a flat rectangular shape,
The second coil L2 is arranged substantially concentrically inside the coil L1 so as to form a double loop on the same plane.

On the surface of the substrate 41, a ground foil 42 is provided in the section P3 on one long side, and the one-chip IC 29 is installed on the ground foil 42. The 1-chip IC 29 and the first and second coils L1 and L2 are
The connection lines 43, 43, ... Provided on the front surface and the back surface of the substrate 41, and through holes (not shown) for electrically connecting the front surface and the back surface of the substrate 41 are appropriately connected.

The first and second coils L1 and L2, the ground foil 42, and the connecting wires 43, 43, ... Are formed by, for example, etching a conductive foil or vapor deposition of a conductive metal.

Further, on the front surface and the back surface of the substrate 41,
As shown in FIG. 8B, the insulating layers 44 and 45 are respectively laminated and formed, and all the circuit members including the first and second coils L1 and L2 are sealed. Also, the ground foil 42
Section P1 on the other long side different from the long side provided with
The magnetic recording layer 46 faces one of the insulating layers 44 or 4
5 is disposed on the surface. In this way, the wireless card 2
0 is formed in the shape of a rectangular card whose outer shape is the size of a business card as a whole.

In such a structure, the substrate 41 and the insulating layers 44 and 45 allow electromagnetic waves to pass therethrough. Therefore, as shown in FIG. 9, the wireless card 20 is held in the hand 30, and the front or back surface of the wireless card 20 is held. By holding it over the wireless card reader / writer 10, the power wave f1 from the wireless card reader / writer 10 is received by the power wave antenna 21 including the first coil L1 in the central portion, and the data wave f2 is received by the second.
Received by the data wave antenna 24 including the coil L2 of
It functions as the wireless card 20.

Here, when holding the wireless card 20 over the wireless card reader / writer 10, as shown in FIG. 9, hold the long side by the hand 30 from the rectangular shape of the business card of the wireless card 20. Often retained. As a result, the first and second sections arranged in the central section P2 divided into three on the short side.
The coils L1 and L2 are less likely to be covered by the fingers of the hand 30 and the power wave f1 and the data wave f2 can be received reliably.

Further, since the first coil L1 has a large shape, the power wave f1 can be received efficiently, and the capacity of the operating power source of the wireless card 20 can be increased, so that the operation of the wireless card 20 can be improved. Surely done.

The first coil L1 and the second coil L2 are arranged next to each other by arranging the other coil inside the one coil so as to form a double ring on the same plane. In the case where the coils are arranged side by side, one coil is covered with a finger or the like, and only the other coil is not able to receive the power wave f1 or the data wave f2, and each of the first and second coils L1 and L21 is received. The situation is almost the same.

Furthermore, since the insulating layers 44 and 45 are laminated so that the circuit members of the wireless card 20 are sealed, electrical accidents such as coil disconnection and circuit short circuit are unlikely to occur, and durability is improved. Rich. Moreover, if the first and second coils L1, L2, etc. are constructed by etching or vapor deposition, they are suitable for mass production at low cost.

If the wireless card 20 is used as, for example, a commuter pass, a valid period and a valid section are appropriately printed on the surface of one of the insulating layers 44 or 45, and the magnetic recording layer 46 has the valid period. Data such as the period and valid sections are recorded as appropriate, and the CP
The data of the above-mentioned general period and general section are appropriately stored in the storage element of U28.

Then, if the wireless card reader / writer 10 is installed in the automatic ticket gate device of the station, etc., the ticket inspection is performed without contact, and the wireless card reader / writer 10 is not installed and the magnetic reading is performed. If a device or the like is installed, the data recorded on the magnetic recording layer 46 is used to execute the ticket inspection. If such an automatic ticket inspection device is not installed, the character inspection printed by the character data printed on the surface is used. Can be done.

In the above description, the first coil L1 and the second coil L2 are arranged in the central section as a flat rectangular shape, but if the magnetic recording layer 46 is not provided,
The first and second coils L1, so as to surround the central portion on the entire surface of the substrate 41 other than the place where the one-chip IC 29 is mounted.
L2 may be provided.

Further, the first coil L1 and the second coil L2 do not necessarily have to be provided in the central section which is equally divided into three on the short side of the substrate 41, and are arranged in the central portion. Good. Further, the first coil L1 and the second coil L2 may be provided on the front surface and the back surface of the substrate 41, respectively.

As described above, according to the wireless communication system of the above-described embodiment, the low second frequency obtained by dividing the first frequency of the power wave is used for the response wave from the wireless card. Compared with the conventional one using a multiplier circuit, unnecessary radiation is less and no member for preventing unnecessary radiation is required. Moreover, since the data wave and the response wave both use the second frequency obtained by dividing the first frequency of the power wave, the data wave and the response wave can be transmitted and received by one antenna. Therefore, it is particularly suitable for a wireless card that is required to be downsized.

Further, according to the wireless communication system of the above-described embodiment, the data wave superimposed on the power wave is extracted by using the amplifier circuit whose gain decreases as the frequency increases, so that the power wave of the high frequency is suppressed. The low-frequency data wave is amplified with a high gain, and by appropriately providing the number of stages of the amplification circuit, the relative ratio of the data wave to the power wave can be improved to an appropriate magnitude, and the data wave from the shaping circuit The signal can be easily demodulated.

Further, according to the wireless communication system of the above embodiment, the data wave superimposed on the power wave is classified into class B or C.
Since it is extracted by using the amplifier circuit that operates in the class, the power wave with large power is suppressed, the weak data wave superimposed on the envelope of the power wave is amplified with high gain, and the number of stages of the amplifier circuit is appropriately set. As a result, the relative ratio of the data wave to the power wave can be improved to an appropriate level, and the shaping circuit can easily demodulate the data signal from the data wave.

Further, according to the wireless communication system of the above-described embodiment, both the data wave and the response wave transmitted / received between the wireless card reader / writer and the wireless card use ASK modulation, so that the signal is demodulated. The circuit for doing this becomes extremely simple. Furthermore, since the amplifier circuit as the extraction circuit is formed without including the coil element, the circuit can be downsized only by the need for a coil element having a large size.
Moreover, it is easy to make an IC.

Further, according to the wireless card of the above embodiment, the first coil forming the power wave antenna for receiving the power wave and the data wave antenna for receiving the data wave are provided in the central portion of the card. Since the second coil to be formed is arranged so as to form a double loop, the first coil and the second coil are covered with a finger or the like holding this card when holding the card over the wireless card reader / writer. There is little fear, and moreover, the first coil and the second coil have substantially the same reception status, and the reception status of both coils is not significantly different. Furthermore, since the first coil and the second coil are provided on the substrate that transmits electromagnetic waves, communication can be performed regardless of which surface is held over the wireless card reader / writer.

Further, according to the wireless card of the above-mentioned embodiment, the first coil and the second coil are formed into a flat rectangular shape, and the central section is divided into three on the short side of the rectangular substrate of a business card size. Since the first coil and the second coil are arranged in the above, there is no possibility that the first coil and the second coil are covered with a finger or the like holding this card.

Further, according to the wireless card of the above embodiment, the second coil is arranged on the same plane of the substrate and surrounded by the first coil, so that the power wave can be received more efficiently. As a result, the capacity of the operating power supply can be increased and the operation can be performed reliably.

Further, according to the wireless card of the above-described embodiment, the circuit member including the first coil and the second coil is sealed by the insulating layer, so that an electrical accident such as disconnection of the coil or short circuit of the circuit may occur. It does not easily occur and is highly durable. Then, by recording the same content as the data stored in the storage element of the CPU on the magnetic recording layer provided on the surface of the insulating layer, it can be used not only as a wireless card of a wireless communication system but also as a magnetic reader. It can also be used as a magnetic card for reading data in between.

According to the extraction circuit of the demodulation circuit in the wireless card of the above embodiment, the amplification circuit is of class B or C.
Since it operates as a class, the data wave superimposed on the power wave is amplified with a higher gain than the power wave, the relative ratio of the power of the data wave to the power wave is improved, and the data wave is easily extracted. Moreover, since the coil element is not included as a circuit component, the circuit can be made smaller by that amount, and it is suitable for making the circuit into an IC. Therefore, it is most suitable as an extraction circuit that constitutes a circuit that has dimensional restrictions and is desired to be integrated into a single chip, such as a circuit mounted on a wireless card.

According to the extraction circuit of the above embodiment,
Since the gain of the amplifier circuit decreases as the frequency increases, the power wave of the high frequency has a low gain, and the data wave of a frequency lower than that has a high gain. As a result,
In the amplified output, the relative ratio of the power of the data wave to the power wave is improved, and the data wave is easily extracted.

Further, according to the extraction circuit of the above-mentioned embodiment, since the amplifier circuits for increasing the relative ratio of the power of the data wave to the power wave are connected in a plurality of stages, the power of the first input power wave and the power of the data wave are connected. By appropriately setting the number of stages in accordance with the relative ratio of, the relative ratio can be easily extracted from the data wave.

[0065]

As described above in detail, according to the present invention, there is provided a radio communication system in which unnecessary radiation is smaller than that using a conventional multiplier circuit and a member for preventing unnecessary radiation is not required. it can.

Further, according to the present invention, it is possible to provide a wireless communication system capable of transmitting and receiving a data wave and a response wave in one wireless antenna in a wireless card. Further, according to the present invention, when the card is held over the communication device, the power wave antenna and the data wave antenna are less likely to be covered by fingers of the hand holding the card, and each antenna Can provide a wireless card that enables reliable transmission and reception under almost the same reception conditions.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a circuit diagram showing a specific configuration example of an extraction circuit in a demodulation circuit.

FIG. 3 is a waveform diagram showing an example of an amplification operation by the extraction circuit.

FIG. 4 is a frequency vs. gain characteristic diagram of the amplifier circuit of the extraction circuit.

FIG. 5 is a waveform diagram for explaining the operation of the extraction circuit.

FIG. 6 is a waveform diagram showing an example of a response wave transmitted from the wireless card.

FIG. 7 is a diagram for explaining the structure of a wireless card,
(A) is a front view and (b) is a back view.

8A and 8B are diagrams illustrating stacking of insulating layers on both surfaces of a substrate forming a wireless card, FIG. 8A is a vertical cross-sectional side view after stacking, and FIG. 8B is an exploded perspective view.

FIG. 9 is a perspective view showing an example of a usage state of a wireless card.

[Explanation of symbols]

10 ... Wireless card reader / writer (communication device), 11
...... Power wave antenna, 12 …… Data wave antenna,
20 ... Wireless card, 21 ... Power wave antenna, 22
...... Rectifier circuit, 23 ...... Frequency divider circuit, 24 ...... Data wave antenna, 25 ...... Transmit / receive switch, 26 ...... Demodulator circuit, 26a ...... Extractor circuit, 26b ...... Shaping circuit, 27
...... Modulation circuit, 28 ... CPU (control means), 29 ...
1-chip IC, 32-35 ... Amplifier circuit, L1 ... 1st
Coil, L2 ... second coil, T1-T4 ... transistor, C1-C11 ... capacitor, R1-R12
...... Resistance, 41 ...... Board, 43 ...... Connection line, 44, 45
...... Insulating layer, 46 ...... Magnetic recording layer, f1 ...... Power wave, f
2 …… Data wave, f3 …… Response wave.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Ryo Horie 7-5-11 Takinogawa, Kita-ku, Tokyo Inside Stock Company (72) Inventor Yano Ko, 7-5-11 Takinogawa, Kita-ku, Tokyo Stock Association Inside the company

Claims (10)

[Claims] 1. A wireless communication system for wirelessly transmitting and receiving between an external communication device and a wireless card, wherein the communication device is unmodulated with high power at a first frequency with respect to the wireless card. A power wave and a data wave in which weak power is modulated with a data signal at a second frequency lower than the first frequency obtained by dividing the first frequency are transmitted, and transmitted from the wireless card. The wireless card receives a power wave transmitted from the communication device with a power wave antenna, converts the received power wave into DC power with a rectifier circuit, and uses it as an operating power supply. ,
A part of the received power wave is divided by a frequency divider circuit to give the second frequency to the modulation circuit, and a data wave transmitted from the communication device is received by a data wave antenna. The received data wave is given to a demodulation circuit through a transmission / reception changeover switch controlled by the control means to demodulate into a data signal, and the demodulated data signal is given to the control means, and the control means sends the response signal A response wave is generated by applying it to the modulation circuit to modulate the second frequency given from the frequency dividing circuit, and the generated response wave is transmitted from the data wave antenna to the communication via the transmission / reception changeover switch. A wireless communication system configured to transmit to a device. 2. The wireless communication system according to claim 1, wherein the communication device is a wireless card reader / writer. 3. The demodulation circuit has an extraction circuit for extracting a data wave of weak power superimposed on a power wave of high power received by the antenna for data waves, and the extraction circuit has a high frequency. The wireless communication system according to claim 1, wherein the wireless communication system is configured by using an amplifier circuit whose gain is reduced more. 4. The demodulation circuit has an extraction circuit for extracting a data wave of weak power superimposed on a power wave of high power received by the data wave antenna. The wireless communication system according to claim 1, wherein the wireless communication system is configured by using an amplifier circuit that operates in class C. 5. The communication device transmits, to the wireless card, a data wave obtained by ASK-modulating the second frequency with a data signal, and the wireless card receives a second wave obtained from the frequency dividing circuit. The wireless communication system according to claim 1, wherein a response wave in which a frequency is ASK-modulated by a response signal is transmitted to the communication device. 6. The wireless communication system according to claim 3, wherein the amplifier circuit is composed of a transistor, a resistor, and a capacitor. 7. A power wave of a first frequency transmitted from an external communication device, and a second wave different from the first frequency.
A radio card for receiving data waves of the respective frequencies, the first card forming a power wave antenna for receiving the power waves.
Is disposed in the center of one surface of a rectangular card-shaped substrate formed of a member that transmits radio waves, and a second coil that forms a data wave antenna for receiving the data wave is provided on the substrate. A wireless card, characterized in that it is arranged so as to form a double loop with the first coil at the center of one surface. 8. The first coil and the second coil are each formed into a flat rectangular shape, and the first coil and the second coil are provided in a central section when the substrate is divided into three by short sides. The wireless card according to claim 7, wherein each of the second coils is provided. 9. The wireless card according to claim 7, wherein the second coil is arranged inside the substrate surrounded by the first coil on the same plane. 10. A circuit member excluding the first coil and the second coil is arranged in one of the three long side sections of the substrate, and the first coil and the second coil are arranged. Insulating layers are laminated on both surfaces of the substrate on which the coil and the circuit member are arranged, and magnetic recording is performed on the surface of the insulating layer on one side facing the other long side section divided into three sections of the substrate. 9. The wireless card according to claim 8, wherein layers are provided.