JP2005115919A - Radio temperature sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radio temperature sensor capable of making even a person who needs care moving in a facility into a measuring object by attaching it to a body surface of the person who needs care and measuring body temperature. <P>SOLUTION: There is provided a radio temperature sensor which is sealed in a container of the radio temperature sensor 100 main body and includes a radio function form transmitting measured data via a chip antenna 1, the chip antenna 1 is formed with an antenna length of a reduction ratio that can be contained in the container and held in the container. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a wireless temperature sensor that measures the temperature of a close object and transmits the measurement result by wireless communication.

In hospitals and nursing care facilities, etc., it is necessary to observe the temperature of the cared person for 24 hours, so the caregiver measures the temperature of the cared person directly with a thermometer.
However, in the measurement method described above, it is necessary to regularly measure the temperature of many care recipients who are in charge of the caregiver, and the caregiver's time is considerably increased. Therefore, there is a problem that the burden given to the caregiver is large.

  For this reason, in order to simplify the measurement of the body temperature of a care recipient, a temperature sensor that can directly read measurement data with a terminal, for example, a temperature sensor that is embedded in the body and measures the temperature using a resonance frequency has been developed ( For example, see Patent Document 1).

However, the temperature sensor shown in Patent Document 1 described above must be used by being embedded in the body of the care recipient, and the specification application is limited.
For normal care recipients, it is not necessary to embed a temperature sensor in the body. Therefore, in the measurement of body temperature for many care recipients, the caregiver goes to the target care recipient and the body temperature. The problem of having to make measurements is not solved.

There is also a method of measuring / monitoring the body temperature of the cared person by connecting a thermometer to the computer terminal, but this cannot be used when the cared person moves within the facility.
Japanese Patent Laid-Open No. 62-192137

  The present invention has been made in view of such circumstances, and its purpose is to measure the body temperature by applying it to the surface of the cared person and to move the cared person. Another object of the present invention is to provide a wireless temperature sensor that can also be used as a measurement object.

  The wireless temperature sensor according to claim 1 is a wireless temperature sensor sealed in a container of a sensor body and provided with a wireless function for transmitting measured measurement data via an antenna, wherein the antenna is placed in the container. It is formed with an antenna length of a shortening rate that can be accommodated, and is housed in the container.

  According to a second aspect of the present invention, the wireless temperature sensor further includes a matching circuit that adjusts impedance between the antenna and a signal line that supplies a transmission signal.

  The wireless temperature sensor according to claim 3, wherein the antenna and the electric circuit including the matching circuit are formed on the same substrate, and the antenna is mounted in a region where the ground line of the substrate is not provided. It is characterized by.

  According to a fourth aspect of the present invention, there is provided the wireless temperature sensor, wherein the substrate is installed at a predetermined distance from a contact surface to be attached to the measurement target in the container.

  The wireless temperature sensor according to claim 5, wherein the grounding point of the high-frequency circuit is connected to the grounding point of the logic circuit through a filter that blocks a signal in a carrier frequency band used for communication. To do.

  The wireless temperature sensor according to claim 6 is characterized in that the container is formed in a size of approximately 500 yen coin.

  The wireless temperature sensor according to claim 7 is characterized in that the container is formed in a coin shape having a diameter of 9 to 27 mm and a thickness of 5 to 10 mm.

  The wireless temperature sensor according to claim 8 is characterized in that the antenna length of the antenna is 1/8 or less of the wavelength of the radio wave at the frequency to be used.

  The wireless temperature sensor according to claim 9 is characterized in that the frequency used is 300 MHz to 960 MHz.

  The wireless temperature sensor according to claim 10, wherein the antenna includes an antenna substrate, a conductor film provided on a part of the antenna substrate, a feeding point provided on the antenna substrate, and the antenna substrate. A loading portion formed by a linear conductor pattern formed in a longitudinal direction of an element body made of a dielectric material, an inductor portion connecting one end of the conductor pattern and the conductor film, and the conductor pattern And a feeding point for feeding power to a connection point between the inductor part and the inductor part, and the longitudinal direction of the loading part is arranged so as to be parallel to the end side of the conductor film.

  According to the wireless temperature sensor of the present invention, the antenna (chip antenna) can be designed to be small because the antenna length is designed so that the antenna can be accommodated in the container even when a carrier frequency having a long wavelength is used. The function of the wireless temperature sensor can be sealed in a small container that can be freely moved by a caregiver.

  In addition, according to the wireless temperature sensor of the present invention, it is possible to adjust the impedance matching between the antenna and the transmission signal line in a state where the container is attached to the measurement object. Therefore, it becomes possible to always transmit a transmission signal in the vicinity of the maximum value of the transmission power, and it is possible to prevent deterioration of radiation characteristics.

  Further, according to the wireless temperature sensor of the present invention, the substrate is placed inside the container by separating the antenna by a predetermined distance from the contact surface of the container to which the container is attached to the measurement object. Therefore, capacitive coupling with the measurement object can be prevented, and coupling loss can be reduced. In addition, it is possible to suppress an impedance shift between the antenna and a signal line that transmits a transmission signal to the antenna, and perform efficient transmission.

  Further, according to the wireless temperature sensor of the present invention, the shape of the wireless temperature sensor is a coin type having a size of about 500 yen coin, that is, a diameter of 9 to 27 mm and a thickness of 5 mm to 10 mm. Therefore, since a daily care recipient can be easily carried by being attached to the body surface without a sense of incongruity, a wider range for measuring body temperature can be taken.

  Further, according to the wireless temperature sensor of the present invention, an antenna length that is 1/8 or less of the carrier frequency to be used can be realized, and the shortening rate of the antenna can be greatly improved.

Hereinafter, a wireless temperature sensor 100 according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a conceptual diagram showing a configuration of a mounting surface on the surface of a substrate 10 on which circuit components of the wireless temperature sensor 100 of the embodiment are mounted. FIG. 2 is a conceptual diagram showing a component mounting configuration on the mounting surface on the back surface of the substrate 10.
Hereinafter, as an embodiment of the present invention, a wireless temperature sensor 100 that is attached (or closely adhered) to the surface of a person being cared for and measures the body temperature of the person being cared for will be described as an example.
As can be seen from FIGS. 1 and 2, the mounting surface of the substrate 10 is a region where the chip antenna 1 is separated from the peripheral portion of the substrate 10 by a predetermined distance, and no ground wiring (GND wiring) is formed. Implemented in the area. In addition, an electrical component such as an IC that forms a circuit of the wireless temperature sensor 100 is mounted in a circuit region where the ground wiring is formed.

Thereby, the ratio of capacitive coupling between the chip antenna 10 and the ground wiring can be greatly reduced. Therefore, it is possible to reduce the coupling loss and limit the consumption of useless energy, thereby improving the energy efficiency in communication.
The measurement unit 2 is a resistance element (such as an NTC thermistor) that directly measures the temperature of the sensor, and is connected to the sensor unit 4 by a connection line 2a. The battery 3 is mounted on the back surface of the wireless temperature sensor 100 (see FIG. 2), and supplies driving power to each circuit of the wireless temperature sensor 100.

FIG. 3A shows the size and shape of the wireless temperature sensor 100 (container). The shape is the same as that of a 500-yen coin, and the coin has a diameter of 9 mm to 27 mm and a thickness of about 5 mm to 10 mm. A chip antenna 1, a substrate 10, and the like (see FIG. 1) are accommodated in a mold container.
FIG. 3B is a cross-sectional view of the wireless temperature sensor 100 taken along line A in FIG.
As can be seen from FIG. 3B, the circuit 10 of the wireless temperature sensor 100 and the substrate 10 on which the chip antenna 1 is mounted are attached (or adhered) to the measurement surface of the measurement object (for example, a care recipient). The contact surface 100b is spaced a predetermined distance d, that is, the chip antenna 1 and the measurement object are separated from each other.

By providing this predetermined distance d, capacitive coupling between the chip antenna 1 and the measurement object can be reduced, and transmission energy can be reduced.
Further, the measurement unit 2 is fixed and arranged outside the opening 100a formed on the contact surface 100b so as to protrude by a predetermined distance.
Thereby, the measurement part 2 will adhere | attach directly on the human body surface of a cared person, and does not need to wait until the temperature of the whole container changes to the same temperature as body temperature, and can measure body temperature correctly. . Therefore, it is possible to cope with a sudden change in body temperature, and a temperature change can be detected accurately.

Next, a circuit formed on the substrate 10 will be described with reference to FIG. FIG. 4 is a block diagram illustrating a configuration example of the circuit of the wireless temperature sensor 100.
The sensor unit 4 includes an oscillator based on a Wien bridge circuit that is stable against voltage fluctuations and temperature fluctuations.
In the oscillator, the oscillation frequency is determined according to the resistance value of the measurement unit 2 constituted by a thermistor or the like. As the resistance value of the measurement unit 2 changes due to the temperature change, the oscillation frequency changes corresponding to the temperature. Thereby, even with respect to the voltage fluctuation of the battery 3, the fluctuation of the resistance value of the measuring unit 2 accompanying the temperature change can be detected by the oscillation frequency, and the stable temperature measurement can be performed.

On the receiving side, when the measurement data is received, the identification number and the oscillation frequency are extracted, and the temperature corresponding to the oscillation frequency is read out from the table indicating the relationship between the transmission frequency and the temperature. Then, the read temperature is stored as body temperature data in the database in order of time for each identification number.
In the wireless temperature sensor 100, predetermined threshold values for the upper limit and the lower limit of the oscillation frequency may be set in the control unit 6. For example, if it is determined that the measured oscillation frequency value is not within the threshold range between the upper limit and the lower limit, that is, if it is detected that the body temperature of the cared person is not within the normal range, the buzzer is turned on. You may add the function to sound and notify a care receiver or a nearby caregiver.

The counter 5 counts the pulses oscillated by the oscillator in the sensor unit 4 and transmits the count value to the transmission unit 7 every predetermined period (for example, 30 minutes). After “0”, a new count value is counted in a predetermined period.
That is, the sensor unit 4 outputs the body temperature (temperature) to be measured to the counter 5 as an oscillation frequency based on the resistance value (physical quantity) of the measurement unit 2 (for example, NTC (Negative Temperature Coefficient)).
The counter 5 measures a pulse of a predetermined period output from the sensor unit 4 as a count value (indicating an oscillation frequency), and outputs the count value to the control unit 6 as a measurement result.

The control unit 6 adds the identification number of the wireless temperature sensor 100 to the measured count value and outputs it to the transmission unit 7 as measurement data.
The transmission unit 7 modulates the carrier wave with the measurement data and outputs it to the matching circuit 8 as an RF signal of the transmission signal.
Note that the size of the chip antenna 1 is limited to about 27 mm when the chip antenna 1 or the like is accommodated in a container having a diameter of 27 mm of 500 yen coin. Therefore, assuming that the carrier frequency used is the 300, 400, 900 MHz band of weak radio or specific low power radio, the length shown below is required when the chip antenna 1 having a quarter wavelength is used. Become.
Frequency 1/4 wavelength 300MHz 250mm
400MHz 188mm
900MHz 83mm
960MHz 78mm

Therefore, in this embodiment, 89% or more, 85% or more, and 67% for each of the 300, 400, 900, and 960 MHz bands so that the chip antenna 1 can be built in the diameter 27 mm of the container of the wireless temperature sensor 100. As described above, the design / production is made with a reduction rate of 65%.
The above-described chip antenna 1 is configured with a resonant circuit including an inductance component and a capacitance component in order to realize an antenna with a high shortening rate and a small and high gain antenna as a circuit.

The chip antenna 1 according to the present embodiment is configured by incorporating a plurality of resonance circuits in order to obtain a high gain. In addition, two or more resonance circuits configured by electrically connecting an inductance component and a capacitance component in parallel are electrically connected in series.
In addition, the inductance portion includes a coil portion that is formed of a helical conductor with an axis as a center or a rectangular conductor that can approximate a helix. The axis of this coil part is aligned in substantially the same straight line at least in the adjacent resonance part, and at least one of the portions that circles the axis of the conductor is substantially included in a plane inclined with respect to this axis. ing.

According to the wireless temperature sensor 100 of the present embodiment, the communication distance is extended by using a carrier frequency in the 300 MHz band to the 960 MHz band of a specific low power radio or weak radio that does not require strict use examination in performing wireless communication. In addition, the case where the wireless temperature sensor 100 of the present embodiment uses a carrier wave frequency having a long wavelength has been described. In this case, in order to fit the chip antenna 1 in the container of the wireless temperature sensor 100 having a size and shape of a 500 yen coin, that is, a length that allows the chip antenna 1 to be incorporated in the container of the wireless temperature sensor 100 × In order to make the width, the antenna design was performed by calculating the shortening rate.

  However, since the chip antenna 1 is composed of an inductance component and a capacitance component, it is very easily affected by the surrounding environment. That is, when the wireless temperature sensor 100 is shipped, the impedance of the chip antenna that matches the impedance of the transmission signal line changes due to the influence of the metal casing of the container of the wireless temperature sensor 100, and the radiation characteristics are changed. May deteriorate. In order to eliminate the influence of the metal casing, the chip antenna 1 may be installed at a location away from the metal casing of the wireless temperature sensor 100. 100 will deviate from the original purpose of mounting in the 100.

For this reason, the wireless temperature sensor 100 according to the present embodiment is provided with a matching circuit 8 that performs impedance adjustment shown in FIG.
In the matching circuit 8, a DC blocking capacitor 16 is connected to one of the parallel connection of the variable capacitance diode 13 and the capacitor 15, and the coil 14 is connected to the other. The connection point R between the variable capacitance diode 13 and the capacitor 15 and the chip antenna 1 are connected.

  When a transmission signal (an RF signal that is a traveling wave) input from the transmission unit 7 is reflected at a contact (connection point R) having a different impedance, the traveling wave is affected by the reflected wave, and the traveling wave and the reflected wave are reflected on the line. A synthesized wave is generated. This is a standing wave. If the ratio of the maximum value | Vmax | and the minimum value | Vmin | of the voltage of the standing wave is the voltage standing wave ratio (VSWR), the VSWR is 1 in the case of no reflection, and this value is The smaller, the less reflection. In the case of a small antenna such as the chip antenna 1, the VSWR at the connection point is about 3 or less.

The control unit 6 measures the VSWR at the connection point R, and gives the control voltage so that this ratio is about 3 or less, for example. The variable capacitance diode 13 has a characteristic that the capacitance changes according to the applied control voltage (reverse voltage), and thereby adjusts the impedance of the line. The relationship between the reflected power and the control voltage is shown in FIG. The horizontal axis is the control voltage (V), and the vertical axis is the reflected power (VA).
Thereby, in the wireless temperature sensor 100 according to the present embodiment, the matching circuit 8 adjusts the impedance between the chip antenna 1 and the transmission signal line in a state where the wireless temperature sensor 100 is mounted on the wireless temperature sensor 100 or the like. Therefore, it becomes possible to always transmit a signal in the vicinity of the maximum transmission power, to prevent the deterioration of the radiation characteristics, and to improve the reception sensitivity.

Further, when the wireless temperature sensor 100 incorporating the chip antenna 1 is driven, a high-frequency current based on a digital signal of the digital circuit is input to the high-frequency circuit via a GND (ground) wiring.
As a result, noise due to the high-frequency current is superimposed on the transmission signal, and a transmission wave including a noise component (radiation noise) may be radiated from the chip antenna 1 in some cases.
In particular, if the frequency of the noise is present in and near the carrier frequency band, it is radiated as strong radiated noise, which adversely affects the reception characteristics of other wireless devices using the same carrier frequency band. Become.
However, since the frequency of the radiation noise differs depending on the device, it is difficult to remove this radiation noise on the receiving side.

  Therefore, in the wireless temperature sensor 100 of the present embodiment, as shown in FIG. 7, the transmission signal is generated by modulating the carrier wave with the modulated wave. Further, the GND wiring of the high-frequency circuit 17 radiating from the chip antenna 1 and the digital circuit 18 for processing measurement data is provided only in a predetermined frequency band (the carrier frequency band used by the wireless sensor for data transmission and reception and its It is connected via a band reject filter 19 (or a band elimination filter) that blocks passage through a frequency range including the vicinity.

That is, the GND wiring of the high-frequency circuit 17 is connected to the GND wiring of the wireless temperature sensor 100 through the band reject filter 19, and the high-frequency circuit of the high-frequency current in the carrier frequency band generated in the digital circuit 18 and the vicinity thereof. It is not input as noise to the 17 GND wirings, and generation of radiation noise is prevented.
Furthermore, the spatial coupling (capacitive coupling) between the GND wiring of the digital circuit 18 and the GND wiring of the high-frequency circuit 17 is reduced on the substrate 10 in the wireless temperature sensor 100. Therefore, the capacitive coupling can be reduced by forming these GND wirings on the same substrate surface with a predetermined distance through the band reject filter 19 without forming them above and below the substrate 10, respectively. Radiation noise can be further reduced.

As described above, according to the wireless temperature sensor 100 according to the present embodiment, the caregiver visits the cared person and does not measure the body temperature as in the past, and the caregiver's Body temperature data can be collected. Therefore, caregiver's labor can be significantly reduced, and time for performing other work can be obtained.
In addition, according to the wireless temperature sensor 100 according to the present embodiment, the communication distance is extended by using a carrier frequency in the 300 MHz band to the 960 MHz band of a specific low power radio or weak radio that does not have a strict usage examination when performing wireless communication. (For example, a communication distance of 100 meters). Therefore, the entire area in the facility can be covered as a communicable area, a change in the temperature of the cared person can be detected at any place in the facility, and a relatively long distance due to low energy. Communication can be performed and power consumption can be reduced.

  In the wireless temperature sensor 100 of the present embodiment, the GND wiring of the high-frequency circuit 17 that drives the antenna is connected to the GND wiring of the logic circuit of the wireless temperature sensor 100 through the band reject filter 19. Therefore, the carrier frequency band generated in the logic circuit (digital circuit) of the wireless temperature sensor 100 and the high-frequency current in the vicinity thereof are not input as noise to the GND wiring of the high-frequency circuit 17 to prevent the generation of radiation noise. Can do.

Next, a configuration example (chip antenna 1a) of the chip antenna 1 according to the embodiment of the present invention will be described with reference to FIGS.
The chip antenna 1a is an antenna used for mobile communication wireless devices such as mobile phones and wireless devices such as specific low power wireless and weak wireless.
As shown in FIGS. 8 and 9, the chip antenna 1 a includes an antenna substrate 20 made of an insulating material such as resin, and a ground portion 21 that is a rectangular conductor film provided on the surface of the antenna substrate 20. A feeding point P connected to a loading unit 22, an inductor unit 23, a capacitor unit 24, and a high-frequency circuit (not shown) provided outside the chip antenna 1a disposed on one surface of the antenna substrate 20. And has. The antenna operating frequency is adjusted by the loading unit 22 and the inductor unit 23, and radio waves are radiated at a center frequency of 430 MHz.

The loading portion 22 is configured by a conductor pattern 34 formed in a spiral shape with respect to the longitudinal direction of the surface of a rectangular parallelepiped element body 25 made of a dielectric material such as alumina.
Both ends of the conductor pattern 34 are connected to connection electrodes 27A and 27B provided on the back surface of the element body 25 so as to be electrically connected to rectangular installation conductors 26A and 26B provided on the surface of the antenna substrate 20, respectively. Has been. Further, one end of the conductor pattern 34 is electrically connected to the inductor portion 23 and the capacitor portion 24 via the installation conductor 26B, and the other end is an open end.
Here, the loading portion 22 is disposed so that the distance L1 from the end 21A of the ground portion 21 is 10 mm, for example, and the longitudinal length L2 of the loading portion 22 is 16 mm, for example. It has become.

  Since the loading unit 22 has a physical length shorter than ¼ of the antenna operating wavelength, the self-resonant frequency of the loading unit 22 is higher than the antenna operating frequency of 430 MHz. For this reason, when the antenna operating frequency of the chip antenna 1a is considered as a reference, it cannot be said that the chip antenna 1a is self-resonating, and therefore has a different property from the helical antenna that self-resonates at the antenna operating frequency.

The inductor portion 23 has a chip inductor 28, and is connected to the installation conductor 26B via an L-shaped pattern 29 that is a linear conductive pattern provided on the surface of the antenna substrate 20, and similarly, the antenna substrate. 20 is configured to be connected to the ground portion 21 via a ground portion connection pattern 30 which is a linear conductive pattern provided on the surface of the wire 20.
The inductance of the chip inductor 28 is adjusted so that the resonance frequency of the loading unit 22 and the inductor unit 23 is 430 MHz, which is the antenna operating frequency of the chip antenna 1a.
The L-shaped pattern 29 is formed such that the end side 29A is parallel to the ground portion 21, and the length L3 is 2.5 mm. As a result, the physical length L4 of the antenna element parallel to the end side 21A of the ground portion 21 is 18.5 mm.

The capacitor unit 24 includes a chip capacitor 31 and is connected to the installation conductor 26B via the installation conductor connection pattern 32 which is a linear conductive pattern provided on the surface of the antenna substrate 20, and similarly to the antenna. The power supply point P is connected via a power supply point connection pattern 33 which is a linear conductive pattern provided on the surface of the substrate 20.
The capacitance of the chip capacitor 31 is adjusted so as to match the impedance at the feeding point P.

FIG. 10 and FIG. 11 show the frequency characteristics of VSWR (Voltage Standing Wave Ratio) at a frequency of 400 to 450 MHz and the radiation pattern of horizontal polarization and vertical polarization in the chip antenna 1a configured as described above. Show.
As shown in FIG. 10, this chip antenna 1a has a frequency of 430 MHz, a VSWR of 1.05, and a bandwidth at VSWR = 2.5 of 14.90 MHz.

  By using the chip antenna 1a according to the present embodiment, an antenna length of 1/8 wavelength or less of the frequency to be used can be realized, and the shortening rate can be greatly improved.

  The embodiments of the present invention have been described above with reference to the drawings. However, the specific configuration is not limited to these embodiments, and design changes and the like can be made without departing from the scope of the present invention. It is.

It is a conceptual diagram of the surface mounting surface of the board | substrate 10 in the wireless temperature sensor 100 by embodiment of this invention. It is a conceptual diagram of the back surface mounting surface of the board | substrate 10 in the wireless temperature sensor 100 of this embodiment. It is a line sectional view of radio temperature sensor 100 of this embodiment. It is a conceptual diagram which shows an example of the circuit of the wireless temperature sensor 100 by this embodiment. FIG. 3 is a block diagram illustrating a configuration example of a matching circuit 8. It is a graph which shows the relationship between reflected electric power and control voltage. 2 is a conceptual diagram showing a configuration in which a tangent line between a high-frequency circuit 17 and a digital circuit 18 is connected via a band reject filter 19. FIG. It is a top view which shows the chip antenna 1a by other embodiment of this invention. It is a perspective view which shows the chip antenna 1a by this embodiment. It is a graph which shows the frequency characteristic of VSWR of the chip antenna 1a by this embodiment. It is a graph which shows the radiation pattern of the chip antenna 1a by this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1a ... Chip antenna 2 ... Measurement part 3 ... Battery 4 ... Sensor part 5 ... Counter 6 ... Control part 7 ... Transmission part 8 ... Matching circuit 10 ... Board 13 ... Variable capacitance diode 14 ... Coil 15 ... Capacitor 16 ... DC blocking capacitor 17 ... High frequency circuit 18 ... Digital circuit 19 ... Band reject filter 20 ... · Antenna substrate 21 ··· Earth portion 22 · · · Loading portion 23 · · · Inductor portion 24 · · · Capacitor portion 25 · Element body 100 · · · Wireless temperature sensor 100a · · · Opening portion 100b ··· Adhering surface P ... Power feeding point

Claims (10)

A wireless temperature sensor sealed in a container of a sensor body and provided with a wireless function for transmitting measured data via an antenna,
A wireless temperature sensor, wherein the antenna is formed with an antenna length of a shortening rate that fits in the container, and is housed in the container.   The wireless temperature sensor according to claim 1, further comprising a matching circuit that adjusts impedance between the antenna and a signal line that supplies a transmission signal. The antenna and the electric circuit including the matching circuit are formed on the same substrate,
The wireless temperature sensor according to claim 2, wherein the antenna is mounted on a region of the substrate where a ground line is not provided.   4. The wireless temperature sensor according to claim 3, wherein the substrate is installed at a predetermined distance from a close contact surface to be attached to a measurement target in the container.   5. The wireless temperature according to claim 3, wherein the grounding point of the high-frequency circuit is connected to the grounding point of the logic circuit through a filter that blocks a signal in a carrier frequency band used for communication. Sensor.   The wireless temperature sensor according to any one of claims 1 to 5, wherein the container is formed in a size of approximately 500 yen coins.   The wireless temperature sensor according to any one of claims 1 to 5, wherein the container is formed in a coin shape having a diameter of 9 to 27 mm and a thickness of 5 mm to 10 mm.   The wireless temperature sensor according to any one of claims 1 to 7, wherein an antenna length of the antenna is 1/8 or less of a wavelength of a radio wave at a frequency to be used.   The wireless temperature sensor according to claim 8, wherein the frequency used is 300 MHz to 960 MHz. The antenna is
An antenna substrate;
A conductor film provided on a part of the antenna substrate;
A feeding point provided on the antenna substrate;
A loading portion provided on the antenna substrate and configured by a linear conductor pattern formed in a longitudinal direction of an element body made of a dielectric material;
An inductor portion for connecting one end of the conductor pattern and the conductor film;
A feeding point for feeding power to a connection point between the one end of the conductor pattern and the inductor part;
10. The wireless temperature sensor according to claim 1, wherein a longitudinal direction of the loading portion is arranged so as to be parallel to an end side of the conductor film. 11.

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