JP2008306522A - Radio communication system and radio communication medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce flush of a radio IC tag by supply of an excessive electromagnetic wave and to reduce an electromagnetic exposure quantity to a patient in a scene for utilizing a radio communication medium 20 stuck to a skin of the patient and the radio communication medium 20 embedded in a body of the patient. <P>SOLUTION: In the radio communication medium 20, quantity of a current running to a load circuit 240 constituting a sensor and the quantity of the current running to a voltage clamp circuit 230 are detected, control information for reducing intensity of an electromagnetic wave is transmitted to a radio communication apparatus 50 in the case that the quantity of the current running to the voltage clamp circuit 230 is bigger than the quantity of the current running to the load circuit 240, and the intensity of the electromagnetic wave generated toward the radio communication medium 20 is reduced in the radio communication apparatus 50 based on the control information transmitted from the radio communication medium 20. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wireless communication system and a wireless communication medium.

  RFID (Radio Frequency IDentification) is a short-range wireless communication mechanism in which a wireless communication device (reader) reads and writes information stored in a wireless IC tag (RFID tag) using electromagnetic waves. Some wireless IC tags are also referred to as sesame grain chips. There is also a power receiving type wireless IC tag that uses an electromagnetic wave supplied from a wireless communication device to generate an electromotive force by electromagnetic induction and use it as an operating power source.

  An RFID system using a power receiving type wireless IC tag is widely spread as infrastructure such as electronic money or a prepaid card for public transportation, but is expected to be applied in the medical field. For example, there is a technique in which an ultra-compact power receiving type wireless IC tag is embedded in a patient's body (for example, subcutaneously) in advance, and in-vivo information such as electrocardiogram information is acquired without contact at the time of diagnosis.

  On the other hand, the power receiving type wireless IC tag has a problem that when an excessive electromagnetic wave is supplied from the wireless communication device, the power consumption of the wireless IC tag itself increases and generates heat. That is, the heat generation of the wireless IC tag is not preferable as it may cause a failure or malfunction. Further, for example, a wireless IC tag with a built-in temperature sensor has a problem of reading its own heat.

  Furthermore, in the case of a power receiving type wireless IC tag to be attached to the patient's skin or a power receiving type wireless IC tag embedded in the patient's body, if excessive electromagnetic waves are supplied from the wireless communication device, the electromagnetic Exposure may increase and the body may be adversely affected. In addition, as described above, there is a problem that the body temperature of the patient is raised by the heat generated by the wireless IC tag itself.

In addition, a system that wirelessly transmits body temperature information of a hospitalized patient to a wireless communication device from a wireless IC tag with a built-in temperature sensor attached to the body of the hospitalized patient has been proposed (see, for example, Patent Document 1). Further, Patent Document 2 discloses a technique in which the intensity of an induced magnetic field (electromagnetic wave) generated from an antenna is adjusted by controlling power supply based on temperature information detected by a wireless tag. Patent Documents 3 and 4 disclose that temperature is converted from current or voltage. Patent Document 4 also discloses that the amount of power consumption is adjusted by changing the voltage applied to the current load circuit that actually causes heat generation.
JP 2001-314378 A JP 2006-340085 A JP 2005-164527 A JP 2000-131379 A

  The present invention has been made to solve the above-described problems, suppresses the intensity of electromagnetic waves supplied from a wireless communication device to a wireless IC tag, and generates heat of the wireless IC tag due to excessive supply of electromagnetic waves. It aims at enabling it to control. Furthermore, the purpose of the present invention is to reduce the amount of electromagnetic exposure to a patient in a situation where a power receiving type wireless IC tag to be attached to a patient's skin or a power receiving type wireless IC tag embedded in a patient's body is used. To do.

  In order to solve the above-described problems, in the present invention, in a power receiving type wireless communication medium, the amount of current flowing in the load circuit constituting the sensor and the voltage are supplied to the load circuit by fixing the voltage below a predetermined level. If the amount of current flowing through the voltage clamp circuit is greater than the amount of current flowing through the load circuit, the intensity of the electromagnetic wave transmitted to the wireless communication medium is determined. The control information to be lowered is transmitted to the wireless communication device. In the wireless communication device, the intensity of electromagnetic waves generated toward the wireless communication medium is reduced based on control information transmitted from the wireless communication medium.

  In the power receiving type wireless communication medium, current information indicating the amount of current flowing through the load circuit and the amount of current flowing through the voltage clamp circuit may be transmitted to the wireless communication device. In the wireless communication device, the intensity of the electromagnetic wave generated toward the wireless communication medium may be reduced based on current information transmitted from the wireless communication medium.

  When an excessive electromagnetic wave is supplied from the wireless communication device to the wireless communication medium, the amount of current flowing through the voltage clamp circuit increases, and the amount of current flowing through the voltage clamp circuit is larger than the amount of current flowing through the load circuit. growing. According to the present invention configured as described above, when the amount of current flowing through the voltage clamp circuit is larger than the amount of current flowing through the load circuit, the intensity of electromagnetic waves generated toward the wireless communication medium is increased in the wireless communication device. Will be lowered.

  Thereby, heat_generation | fever of the radio | wireless communication medium by supply of an excessive electromagnetic wave can be suppressed. Furthermore, the amount of electromagnetic exposure to a patient can be reduced in a scene where a power receiving type wireless IC tag to be attached to a patient's skin or a power receiving type wireless IC tag embedded in a patient's body can be used. Can minimize adverse effects on the body.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating an example of an overview of a wireless communication system. The wireless communication system 10 includes a wireless communication device 50 and a power receiving type wireless communication medium 20. For example, as shown in FIG. 1, the wireless communication system 10 is used when a doctor 500 uses a wireless communication device 50 to examine a hospitalized patient 502 in which the wireless communication medium 20 is implanted subcutaneously. In addition, when using the radio | wireless communication medium 20 inside a living body as mentioned above, although the power consumption which should be permitted is about 100-200 mW, it is preferable to suppress to 50 mW or less in the site | part without a blood flow.

  The wireless communication medium 20 includes an antenna (not shown in FIG. 1) for transmitting and receiving electromagnetic waves and a sensor (not shown in FIG. 1). The wireless communication medium 20 receives power by receiving electromagnetic waves from the wireless communication device 50 via an antenna, and transmits and receives signals to and from the wireless communication device 50. For example, the wireless communication medium 20 receives a signal including control information indicating that a signal including in-vivo information of the inpatient 502 should be transmitted from the wireless communication device 50, and receives a signal including in-vivo information of the inpatient 502. Transmit to the wireless communication device 50. In addition, the wireless communication medium 20 sends a signal including control information (hereinafter referred to as “electromagnetic wave intensity suppression information”) that causes the wireless communication device 50 to control to reduce the intensity of the electromagnetic wave transmitted to the wireless communication medium 20. Send. Note that the illustrated wireless communication medium 20 has been enlarged for the sake of explanation, but may have a size of several millimeters or less.

  The wireless communication device 50 includes a main body 51, an antenna 53 that transmits and receives electromagnetic waves, and a cable 52 that connects the main body 51 and the antenna 53. The wireless communication device 50 supplies power by transmitting electromagnetic waves to the wireless communication medium 20 via the antenna 53 and transmits and receives signals to and from the wireless communication medium 20. For example, the wireless communication device 50 transmits a signal including control information indicating that a signal including in-vivo information of the inpatient 502 should be transmitted to the wireless communication medium 20, and a signal including in-vivo information of the inpatient 502. Receive from the wireless communication medium 20. Further, the wireless communication device 50 receives a signal including the electromagnetic wave intensity suppression information from the wireless communication medium 20.

  In addition, the wireless communication device 50 includes an electromagnetic wave intensity adjustment unit (not shown) that suppresses the strength of the electromagnetic wave supplied to the wireless communication medium 20 in the internal configuration of the main body 51. Specifically, when the electromagnetic wave intensity adjustment unit receives a signal including the electromagnetic wave intensity suppression information from the wireless communication medium 20 via the antenna 53, the electromagnetic wave intensity adjustment unit reduces the intensity of the electromagnetic wave transmitted from the antenna 53 to the wireless communication medium 20. It has a function to perform.

  FIG. 2 is a block diagram illustrating an example of the configuration of the wireless communication medium 20. The wireless communication medium 20 includes an antenna unit 200, a modem circuit 210, a rectifier circuit 220, a voltage clamp circuit 230, a load circuit 240, a current detection circuit 250, a current comparison circuit 260, and a signal processing circuit 270 in its internal configuration.

  The antenna unit 200 transmits and receives electromagnetic waves (modulated waves) to and from the wireless communication device 50. The antenna unit 200 generates electromotive force by electromagnetic induction using the received electromagnetic wave (modulated wave).

  The modem circuit 210 demodulates the electromagnetic wave (modulated wave) received by the antenna unit 200 and supplies the extracted signal to the signal processing circuit 270. Further, the modem circuit 210 modulates the signal supplied from the signal processing circuit 270 and supplies the modulated signal to the antenna unit 200.

  The signal processing circuit 270 generates control information (information for controlling the load circuit 240) from the signal (for example, a signal including information for controlling the load circuit 240) supplied from the modulation / demodulation circuit 210, and supplies the control information to the load circuit 240. . The signal processing circuit 270 generates a signal (a signal including in-vivo information) based on user information (for example, in-vivo information detected by a sensor of the load circuit 240) supplied from the load circuit 240, and modulates / demodulates the signal. Supply to circuit 210.

  In addition, the signal processing circuit 270 displays information (hereinafter referred to as “current comparison determination information”) indicating the determination result obtained by comparing the amount of current flowing through the voltage clamp circuit 230 and the amount of current flowing through the load circuit 240. Receive from 260. When the signal processing circuit 270 receives current comparison determination information indicating that the amount of current flowing through the voltage clamp circuit 230 is larger than the amount of current flowing through the load circuit 240, the signal processing circuit 270 generates a signal including electromagnetic wave intensity suppression information. To the modulation / demodulation circuit 210.

  The rectifier circuit 220 generates a DC voltage from the voltage due to the induced electromotive force generated in the antenna unit 200. The voltage clamp circuit 230 generates a voltage to be supplied to the load circuit 240 by fixing the DC voltage generated by the rectifier circuit 220 to a predetermined level or less.

  The load circuit 240 constitutes a sensor that detects in-vivo information. The load circuit 240 detects in-vivo information with the voltage fixed to a predetermined level or less by the voltage clamp circuit 230. The load circuit 240 supplies the detected in-vivo information to the signal processing circuit 270.

  The current detection circuit 250 detects the amount of current flowing through the voltage clamp circuit 230 and the load circuit 240, respectively. The current detection circuit 250 supplies current information indicating the amount of each detected current to the current comparison circuit 260. The current flowing through the voltage clamp circuit 230 is a current that flows toward the ground through the voltage clamp circuit 230, that is, a current that is discarded because it is a surplus current.

  The current comparison circuit 260 compares the amount of current flowing through the voltage clamp circuit 230 detected by the current detection circuit 250 with the amount of current flowing through the load circuit 240 to generate current comparison determination information. For example, the current comparison circuit 260 compares the amount of current flowing through the voltage clamp circuit 230 detected by the current detection circuit 250 with the amount of current flowing through the load circuit 240 to determine the amount of current flowing through the voltage clamp circuit 230. When it is determined that the amount of current flowing through the load circuit 240 is greater than the amount of current flowing through the load circuit 240, current comparison determination information indicating that the amount of current flowing through the voltage clamp circuit 230 is greater than the amount of current flowing through the load circuit 240 is generated. The current comparison circuit 260 supplies the generated current comparison determination information to the signal processing circuit 270.

  Hereinafter, the antenna unit 200, the rectifier circuit 220, the voltage clamp circuit 230, the load circuit 240, the current detection circuit 250, the current comparison circuit 260, and the signal processing circuit 270 will be described with reference to circuit diagrams. FIG. 3 is a circuit diagram illustrating an example of an electronic circuit of a wireless communication medium. FIG. 4 is a diagram illustrating an example of a current detection circuit 250 configured by connecting transistors in parallel. 3 and 4, the same reference numerals are given to the blocks described in FIG.

  The antenna unit 200 is a resonance circuit (tuning circuit) configured by a coil L1 and a capacitor C1. The rectifier circuit 220 is configured by a bridge circuit using diodes D1, D2, D3, and D4. The rectifier circuit 220 generates a DC voltage from an AC voltage generated by the induced electromotive force generated in the antenna 200 unit. The generated DC voltage is smoothed by the smoothing capacitor C <b> 2 and supplied to the voltage clamp circuit 230.

  The voltage clamp circuit 230 includes a resistor R1 and clamp diodes Dc1, Dc2, and Dc3. The voltage clamp circuit 230 generates a voltage to be supplied to the load circuit 240 by fixing the DC voltage generated by the rectifier circuit 220 to a predetermined level or less. The generated direct current voltage below a predetermined level is supplied to the stabilization circuit 241 of the load circuit 240.

  The load circuit 240 includes a stabilization circuit 241 and a sensor circuit 242. The stabilization circuit 241 includes a reference voltage Vz, resistors R2 and R3, an operational amplifier OP1, and a transistor MC5. The stabilization circuit 241 is a stable direct current having no ripple of a certain level to be supplied to the sensor circuit 242, which is defined by the reference voltage Vz and the resistors R 2 and R 3 from the direct current voltage generated by the voltage clamp circuit 230. A voltage VDD is generated.

More specifically, if the DC voltage VDD supplied to the sensor circuit 242 drops from a stable state, the current I ₁ flowing through the transistor MC5 decreases, and the voltage V ₂ on the transistor MC5 side of the resistor R2 and the resistor voltage _{V 3} of the resistance R2 side of R3 also decreases, the reference voltage Vz> voltage _{V 3.} Therefore, the output voltage of the operational amplifier OP1 becomes LOW output, decreases the gate voltage of the transistor MC5 is, current _{I 1} flowing through the transistor MC5 increases. Thereafter, the current I ₁ increases until the reference voltage Vz = the voltage V _3, and the DC voltage VDD supplied to the sensor circuit 242 is stabilized. The reference voltage Vz is implemented by a Zener diode, for example.

  The current detection circuit 250 includes a current detection circuit 250 a that detects the amount of current flowing through the voltage clamp circuit 230 and a current detection circuit 250 b that detects the amount of current flowing through the load circuit 240.

  The current detection circuit 250a includes a transistor MC1 inserted at a location where a current flowing toward the ground through the voltage clamp circuit 230 can be detected, and a current detection transistor MC2 connected to the transistor MC1 as a current mirror. . The current detection circuit 250a detects the amount of current flowing toward the ground through the voltage clamp circuit 230 by the transistors MC1 and MC2. The current detection circuit 250 a supplies the detected current amount flowing in the voltage clamp circuit 230 to the current comparison circuit 260.

In FIG. 3, the amount of current flowing toward the ground through the voltage clamp circuit 230 is the same as the amount of current supplied to the current comparison circuit 260, but the amount of current flowing toward the ground through the voltage clamp circuit 230. : It is preferable to design so that the amount of current supplied to the current comparison circuit 260 = n (value exceeding 1): 1. For example, as shown in FIG. 4, the amount of current I _MC1 that flows toward the ground through the voltage clamp circuit 230: current I _MC2 that is supplied to the current comparison circuit 260 = 10: 1 may be designed. In FIG. 4, the amount of current I _MC1 is the sum of the currents flowing through 10 transistors MC1-1, MC1-2,... MC1-10 connected in parallel, and the amount of current I _MC2 is It is the same as the amount of current flowing through MC1-1. Further, for example, by simply adjusting the gate areas of the transistors MC1 and MC2, the amount of current I _MC1 that flows toward the ground through the voltage clamp circuit 230: current I _MC2 supplied to the current comparison circuit 260 = 10: 1 You may design.

The current detection circuit 250b includes a transistor MC5 of the stabilization circuit 241, and a current detection transistor MC6 connected so that the source potential and the gate potential are common to the transistor MC5. Current detecting circuit 250b can be detected as the amount of current Ix flowing in the amount of current _{I 1} flowing through the transistor MC5 transistor MC6. However, in order to compare the amount and the amount of current _{I 1} flowing through the transistor MC5 of the current flowing toward the ground through the voltage clamp circuit 230 by the current comparator circuit 260, current detecting circuit 250b, a current flows through the transistor MC5 _{I 1} Of the current Ix = the amount of current flowing toward the ground through the voltage clamp circuit 230: it is necessary to detect the amount of the current Ix that is the amount of current detected by the current detection circuit 250a.

That is, the current detection circuit 250b, when and the amount of current detected the same by an amount the current detection circuit 250a of the current flowing toward the ground through the voltage clamping circuit 230, the current I ₁ flowing through the current Ix in transistor MC5 To detect. On the other hand, as shown in FIG. 4, the current detection circuit 250b is designed such that the amount of current flowing toward the ground through the voltage clamp circuit 230: the amount of current detected by the current detection circuit 250a = n: 1. the, for example, by adjusting the area of the gate of the transistor MC5, MC6, the amount of current _{I 1} flowing through the transistor MC5: the amount of current Ix detected by the current detecting circuit 250b = n: 1 and comprising such a current The amount of Ix is detected. The current detection circuit 250 b supplies the detected amount of current Ix to the current comparison circuit 260.

Further, the current flowing from the rectifier circuit 220 side to the load circuit 240 side (current _{I 1} flowing through the transistor MC5) is split into a current _{I L} flowing through the current sensor circuit 242 through the resistor R2, R3. Therefore, the current detection circuit 250b, instead of the current Ix, the amount of current _{I L} flowing through the sensor circuit 242: flows toward the ground via the amount = the voltage clamp circuit 230 of the current Ix 'detected by the current detecting circuit 250b Amount of current: A current Ix ′ that is the amount of current detected by the current detection circuit 250 a may be supplied to the current comparison circuit 260. For example, the current detection circuit 250b calculates the current Ix ′ by multiplying the detected current Ix by the ratio of the current I _L flowing in the sensor circuit 242 to the current I ₁ flowing in the transistor MC5 (current I _L / current I ₁ ). The calculated current Ix ′ may be supplied to the current comparison circuit 260.

  The current comparison circuit 260 is configured by a comparator. The current comparison circuit 260 compares the amount of current flowing through the voltage clamp circuit 230 detected by the current detection circuit 250a with the amount of current flowing through the load circuit 240 detected by the current detection circuit 250b. The current comparison circuit 260 supplies current comparison determination information indicating the result of comparing the amounts of both currents to the signal processing circuit 270.

  The signal processing circuit 270 generates a signal (a signal including in-vivo information) based on user information (in-vivo information detected by the sensor circuit 242) supplied from the sensor circuit 242. When the current comparison determination information indicating that the amount of current flowing through the voltage clamp circuit 230 is larger than the amount of current flowing through the load circuit 240 is supplied from the current comparison circuit 260, the signal processing circuit 270 A signal including intensity suppression information is generated. Note that the generated signal is transmitted to the wireless communication device 50 via the modulation / demodulation circuit 210 and the antenna unit 200.

  FIG. 5 is a block diagram illustrating another configuration of the wireless communication medium 30. In FIG. 5, the blocks described in FIG. The wireless communication medium 30 includes an antenna unit 200, a modem circuit 210, a voltage clamp circuit 232, a rectifier circuit 222, a load circuit 240, a current detection circuit 250, a current comparison circuit 260, and a signal processing circuit 270 in its internal configuration.

  The voltage clamp circuit 232 fixes the AC voltage generated by the induced electromotive force generated in the antenna unit 200 to a voltage equal to or lower than a predetermined level. The rectifier circuit 222 generates a DC voltage from the AC voltage below a predetermined level generated by the voltage clamp circuit 232.

  According to the above embodiment, when the amount of current flowing through the voltage clamp circuit 230 (or voltage clamp circuit 232) is larger than the amount of current flowing through the load circuit 240 in the wireless communication medium 20 (or wireless communication medium 30). The electromagnetic wave intensity suppression information generated by the signal processing circuit 270 is transmitted to the wireless communication device 50 via the modulation / demodulation circuit 210 and the antenna unit 200. Therefore, the electromagnetic wave intensity adjusting unit of the wireless communication device 50 uses the wireless communication medium. Control is performed to reduce the intensity of the electromagnetic wave generated toward 20. Thereby, the heat_generation | fever of the radio | wireless communication medium 20 (or radio | wireless communication medium 30) by supply of an excessive electromagnetic wave can be suppressed. Furthermore, the amount of electromagnetic exposure to a patient can be reduced in a scene where a power receiving type wireless IC tag to be attached to a patient's skin or a power receiving type wireless IC tag embedded in a patient's body can be used. Can minimize adverse effects on the body.

  In the above embodiment, when the amount of current flowing through the voltage clamp circuit 230 (or voltage clamp circuit 232) is greater than the amount of current flowing through the load circuit 240, the wireless communication medium 20 (or wireless communication medium 30) The signal including the electromagnetic wave intensity suppression information is transmitted to the wireless communication device 50. Instead, the wireless communication medium 20 (or the wireless communication medium 30) causes the current flowing through the voltage clamp circuit 230 (or the voltage clamp circuit 232). And a signal including current information indicating the amount of current flowing through the load circuit 240 may be transmitted to the wireless communication device 50.

  Note that the electromagnetic wave intensity adjustment unit (not shown) of the wireless communication device 50 receives the voltage clamp circuit 230 (or voltage clamp circuit) indicated by the current information when the signal including the current information is received by the antenna 53. 232) is compared with the amount of current flowing through the load circuit 240, and the amount of current flowing through the voltage clamp circuit 230 (or voltage clamp circuit 232) is greater than the amount of current flowing through the load circuit 240. When the determination is made, control is performed to reduce the intensity of the electromagnetic wave generated toward the wireless communication medium 20.

  As shown in FIG. 1, the wireless communication system 10 is used when a doctor 500 examines an inpatient 502 in which the wireless communication medium 20 (or the wireless communication medium 30) is subcutaneously embedded using the wireless communication device 50. It is used, but the usage scene is not limited to this. When the wireless communication system 10 is used in other scenes, the wireless communication medium 20 (or the wireless communication medium 30) is replaced with the sensor circuit 242 that detects in-vivo information, according to the other scene. A sensor circuit for detecting information is provided.

  The wireless communication medium 20 (or the wireless communication medium 30) includes a storage unit that temporarily stores information detected by the sensor circuit 242, a detection unit that detects information by the sensor circuit 242, and a storage unit that stores information detected by the sensor circuit 242. And a power source for storing data. Thus, the wireless communication medium 20 (or the wireless communication medium 30) can detect information even when there is no power reception from the wireless communication device 50, and can transmit the information to the other wireless communication device 50 at the time of power reception.

  In addition, each of the above-described embodiments is merely an example of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed in a limited manner. In other words, the present invention can be implemented in various forms without departing from the spirit or main features thereof.

It is a schematic diagram which shows the example of the external appearance of a radio | wireless communications system. It is a block diagram which shows the example of a structure of a radio | wireless communication medium. It is a circuit diagram which shows the example of the electronic circuit of a radio | wireless communication medium. It is a figure which shows the example of the electric current detection circuit comprised by connecting a transistor in parallel. It is a block diagram which shows the other structure of a radio | wireless communication medium.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Wireless communication system 20 Wireless communication medium 30 Wireless communication medium 50 Wireless communication apparatus 51 Main body 53 Antenna 200 Antenna part 220 Rectifier circuit 222 Rectifier circuit 230 Voltage clamp circuit 232 Voltage clamp circuit 240 Load circuit 241 Stabilization circuit 242 Sensor circuit 250 Current detection Circuit 260 Current comparison circuit 270 Signal processing circuit

Claims (6)

A power receiving type wireless communication medium having an antenna for transmitting and receiving electromagnetic waves, receiving power through the antenna and transmitting and receiving signals, and an antenna for transmitting and receiving electromagnetic waves to the wireless communication medium through the antenna A wireless communication system configured to include a wireless communication device that feeds power and transmits and receives the signal to and from the wireless communication medium,
The wireless communication medium is
A load circuit constituting the sensor;
A rectifier circuit that generates a DC voltage using the induced electromotive force generated in the antenna;
A voltage clamp circuit connected to the input side or the output side of the rectifier circuit and fixing a voltage supplied to the load circuit to a predetermined level or less;
A current detection circuit for detecting the amount of current flowing in each of the voltage clamp circuit and the load circuit;
A current comparison circuit that compares the amount of current flowing through the voltage clamp circuit detected by the current detection circuit with the amount of current flowing through the load circuit;
A signal processing circuit that generates the signal including the information detected by the sensor or the electromagnetic wave intensity suppression information that causes the wireless communication device to control to reduce the intensity of the electromagnetic wave transmitted to the wireless communication medium;
The signal processing circuit generates the signal including the electromagnetic wave intensity suppression information when the current comparison circuit determines that the amount of current flowing through the voltage clamp circuit is larger than the amount of current flowing through the load circuit. And
The wireless communication device is
When the signal including the electromagnetic wave intensity suppression information is received from the wireless communication medium via the antenna of the wireless communication apparatus, the intensity of the electromagnetic wave transmitted from the antenna of the wireless communication apparatus to the wireless communication medium is determined. A radio communication system comprising an electromagnetic wave intensity adjusting unit for lowering. A power receiving type wireless communication medium having an antenna for transmitting and receiving electromagnetic waves, receiving power through the antenna and transmitting and receiving signals, and an antenna for transmitting and receiving electromagnetic waves to the wireless communication medium through the antenna A wireless communication system configured to include a wireless communication device that feeds power and transmits and receives the signal to and from the wireless communication medium,
The wireless communication medium is
A load circuit constituting the sensor;
A rectifier circuit that generates a DC voltage using the induced electromotive force generated in the antenna;
A voltage clamp circuit connected to the input side or the output side of the rectifier circuit and fixing a voltage supplied to the load circuit to a predetermined level or less;
A current detection circuit for detecting the amount of current flowing in each of the voltage clamp circuit and the load circuit;
Signal processing for generating the signal including information detected by the sensor or current information indicating the amount of current flowing through the voltage clamp circuit and the amount of current flowing through the load circuit detected by the current detection circuit With circuit,
The wireless communication device is
When the signal including the current information is received from the wireless communication medium via the antenna of the wireless communication device, the amount of current flowing in the voltage clamp circuit indicated in the current information and the load circuit When the amount of current flowing through the voltage clamp circuit is determined to be greater than the amount of current flowing through the load circuit from the antenna of the wireless communication device to the wireless communication medium. A wireless communication system comprising an electromagnetic wave intensity adjustment unit for reducing the intensity of electromagnetic waves to be transmitted. The wireless communication system according to claim 1, wherein the sensor detects in-vivo information. An antenna for transmitting and receiving electromagnetic waves; receiving the electromagnetic waves transmitted from the wireless communication device via the antenna; and receiving and transmitting electromagnetic waves between the wireless communication devices and the wireless communication device A power receiving type wireless communication medium for transmitting and receiving signals between
A load circuit constituting the sensor;
A rectifier circuit that generates a DC voltage using the induced electromotive force generated in the antenna;
A voltage clamp circuit connected to the input side or the output side of the rectifier circuit and fixing a voltage supplied to the load circuit to a predetermined level or less;
A current detection circuit for detecting the amount of current flowing in each of the voltage clamp circuit and the load circuit;
A current comparison circuit that compares the amount of current flowing through the voltage clamp circuit detected by the current detection circuit with the amount of current flowing through the load circuit;
A signal processing circuit that generates the signal including the information detected by the sensor or the electromagnetic wave intensity suppression information that causes the wireless communication device to control to reduce the intensity of the electromagnetic wave transmitted to the wireless communication medium;
The signal processing circuit generates the signal including the electromagnetic wave intensity suppression information when the current comparison circuit determines that the amount of current flowing through the voltage clamp circuit is larger than the amount of current flowing through the load circuit. A wireless communication medium. An antenna for transmitting and receiving electromagnetic waves; receiving the electromagnetic waves transmitted from the wireless communication device via the antenna; and receiving and transmitting electromagnetic waves between the wireless communication devices and the wireless communication device A power receiving type wireless communication medium for transmitting and receiving signals between
A load circuit constituting the sensor;
A rectifier circuit that generates a DC voltage using the induced electromotive force generated in the antenna;
A voltage clamp circuit connected to the input side or the output side of the rectifier circuit and fixing a voltage supplied to the load circuit to a predetermined level or less;
A current detection circuit for detecting the amount of current flowing in each of the voltage clamp circuit and the load circuit;
Information detected by the sensor, or current information indicating the amount of current flowing through the voltage clamp circuit and the amount of current flowing through the load circuit detected by the current detection circuit, respectively, and the voltage clamp circuit When the amount of current flowing is compared with the amount of current flowing through the load circuit, and it is determined that the amount of current flowing through the voltage clamp circuit is greater than the amount of current flowing through the load circuit, the wireless communication medium A radio communication medium comprising: a signal processing circuit that generates the signal including current information for transmission to a radio communication apparatus that performs control to reduce the intensity of an electromagnetic wave to be transmitted.   The wireless communication medium according to claim 4, wherein the sensor detects in-vivo information.