JP4636234B2 - Wireless sensor transmission device and wireless sensor device - Google Patents

Description

  The present invention relates to a wireless sensor transmission device and a wireless sensor device.

  Conventionally, a wireless sensor transmission device is known in which a sensor for measuring temperature, humidity, and the like, a wireless transmission unit, and a second antenna unit are integrated (see Patent Document 1). This type of wireless sensor transmitter can be spatially separated from devices that use measured values of temperature, humidity, or illuminance, so the measured values obtained by placing the wireless sensor transmitters in multiple locations, respectively Can be used in various forms, such as centralized management, and wireless sensor transmitters can be moved and carried.

  As is well known, in the wireless device, as the radio frequency decreases, the shape of the antenna increases, which becomes an obstacle to the reduction in size and thickness of the wireless sensor device. Usually, in order to transmit the output from the wireless transmission unit to the antenna without loss, the output impedance of the wireless transmission unit is matched with the input impedance of the antenna unit. Usually 50Ω, but originally the antenna has a very high impedance, such as 1KΩ.

  On the other hand, the output of the wireless transmission unit is often taken from the output of a semiconductor such as a transistor, and the output impedance of the wireless transmission unit must be a low impedance such as 50Ω.

  Therefore, the pattern length constituting the antenna is set to 1/4 or 1/2 of the effective wavelength λe of the radio frequency, and the resonance point of the impedance is adjusted to the frequency of radio transmission. For example, if the radio frequency is f, the quarter wavelength is 250 mm when the radio frequency f is 300 MHz, 75 mm when 1000 MHz, and 37.5 mm when 2000 MHz. Determine the antenna pattern length.

  Here, as the radio frequency f decreases, the quarter wavelength becomes longer, and as a result, the antenna shape also increases. There is also a method of adjusting the impedance by forming the antenna in a coil shape by helical winding or spiral winding, etc., but the area of the antenna pattern becomes larger as the radio frequency f is lower. It must be large.

  In this type of wireless sensor device, if there is no geometric limitation, an antenna structure with low loss and good radiation efficiency can be easily realized by matching the antenna pattern length to ¼ wavelength. However, in reality, this type of wireless sensor device has a strong demand for size reduction, and an ideal antenna structure having a quarter wavelength cannot be adopted.

  Under such circumstances, how to reduce the loss of the antenna and improve the radiation efficiency of the electromagnetic field becomes a serious issue, but there are still known technologies that are effective in solving such a problem. Not.

  In addition, in the conventional wireless sensor transmitter, since it is common to have a configuration that requires a commercial power supply (AC power supply), the installation environment is limited in terms of securing the power supply, and the power supply range is limited. It could only be installed in the environment.

  It seems that the installation problem described above can be solved once if the power source is required for the battery.

  However, when the wireless sensor transmission device is driven by a battery, it is technically difficult to realize both a request for size reduction of the wireless sensor device itself and a request for reduction of current consumption.

  This is because when the antenna shape is reduced due to demands for size reduction, thickness reduction, and weight reduction, the current consumption required for the wireless sensor transmission device increases, and the wireless sensor transmission device is battery-driven. In this case, the battery life is disadvantageously terminated in a short period of half a year to one year.

When a large battery is used, the above-mentioned inconveniences can be solved, but the original demands for reduction in size, thickness and weight cannot be sufficiently met.
JP 2002-14072 A

  An object of the present invention is to provide a wireless sensor transmission device and a wireless sensor device that achieve a reduction in loss of the second antenna unit and an improvement in electromagnetic radiation efficiency while achieving downsizing.

  Another object of the present invention is to provide a wireless sensor transmission device and a wireless sensor device that can ensure a longer battery life and continuous operation time.

  In order to solve the above-described problems, a wireless sensor transmission device according to the present invention includes a circuit board, a sensor unit, a signal processing unit, a transmission circuit unit, a first antenna unit, and a second antenna unit. Including. The circuit board has the sensor unit, the signal processing unit, and the transmission circuit unit on one surface.

  The sensor unit detects a physical quantity, and the signal processing unit processes a detection signal output from the sensor. The transmission circuit unit transmits a signal supplied from the signal processing unit.

  The first antenna unit is electrically connected between the second antenna unit and the transmission circuit to match the impedance between the two. The second antenna unit radiates radio waves.

  As described above, the wireless sensor transmission device according to the present invention includes a circuit board, a sensor unit, a signal processing unit, a transmission circuit unit, and a second antenna unit, and detects a physical quantity by the sensor. Since the detection signal output from the sensor is processed by the signal processing unit and the signal supplied from the signal processing unit is supplied to the antenna unit by the transmission circuit unit and can be radiated into the air, the physical quantity detected by the sensor is Wireless transmission can be performed toward the receiving device. Physical quantities to be measured include various quantities such as temperature, humidity, illuminance, acceleration, and impact.

  The present invention has a first antenna unit as a characteristic component, and the first antenna unit is electrically connected between the second antenna unit and the transmission circuit unit, The impedance between the two is matched. According to the above configuration, impedance matching is performed by the first antenna unit between the input of the second antenna unit having a high input impedance and the output of the wireless transmission unit having a low output impedance. Data can be efficiently input from the circuit unit to the second antenna unit, and a radiated electric field can be efficiently radiated from the second antenna unit.

  In addition, impedance matching can be achieved without matching the pattern length of the second antenna portion to ¼ wavelength of the effective frequency of the radio frequency, so that an ideal antenna structure of ¼ wavelength cannot be adopted. Even in a small wireless sensor transmission device, data can be efficiently input from the transmission circuit unit to the second antenna unit, and a radiated electric field can be efficiently radiated from the second antenna unit.

  As a further important effect of providing the first antenna unit separately from the second antenna unit, the manufacturing variation of the second antenna unit and the variation of the antenna efficiency due to changes in temperature and humidity are reduced. The point which can be suppressed can be mentioned.

  That is, when the second antenna unit is configured with a helical winding pattern so that it matches the output impedance of the transmission circuit unit, the substrate thickness, the width of the antenna conductor pattern formed on the substrate, and the thickness are manufactured. Due to variations and changes in the dielectric constant of the substrate due to temperature and humidity, impedance mismatching is likely to occur between the transmission circuit section and the second antenna section, and the antenna efficiency will be degraded accordingly. .

  On the other hand, when the first antenna portion is provided separately from the second antenna portion, the thickness of the substrate that supports the second antenna portion, the width and thickness of the antenna conductor pattern formed on the substrate. The antenna efficiency can be maintained by minimizing the variation in the dielectric constant of the substrate due to manufacturing variations and temperature and humidity.

  The second antenna unit includes a support substrate and an antenna conductor as one specific aspect. The support substrate is made of an electrically insulating material. The antenna conductor is helical and winds in a direction parallel to a plane in the thickness direction of the support substrate, with the thickness of the support substrate being two sides of the opening.

  Since the antenna conductor is helically wound, the overall length of the second antenna portion can be remarkably shortened by its shape effect. Therefore, it is possible to provide a wireless sensor transmission device whose shape is significantly reduced.

  In addition, since the antenna conductor advances in one direction parallel to the surface in the thickness direction of the support substrate, the second antenna portion is assembled to the circuit substrate so that the surface of the support substrate is parallel to the surface of the circuit substrate. By combining them, the component penetrating the ground electrode in the high-frequency current magnetic field flowing through the second antenna portion can be significantly reduced, and the generation of eddy current due to the high-frequency current magnetic field can be suppressed. Further, it is possible to avoid the electromagnetic noise from getting on the second antenna portion despite the fact that the whole is downsized.

  Furthermore, since the second antenna portion is helical and the thickness of the support substrate is two sides of the opening, the gain of the second antenna portion can be improved by controlling the area of the opening. Can do.

  As a result, it is possible to realize both a request for miniaturization of the wireless sensor transmitter itself and a request for reduction of current consumption, and to achieve a reduction in the loss of the second antenna unit and an improvement in the radiation efficiency of the electromagnetic field. Can do. That is, with a lower input power to the second antenna unit, the communication distance is increased, and the power consumption of the circuit unit in front of the second antenna unit is reduced reflectively. Reduction of the battery life and, in turn, increase of battery life and continuous operation time can be achieved.

  As one aspect, a plurality of second antenna portions can be provided, and each of the second antenna portions can be provided on the periphery of the circuit board. According to this configuration, the directivity of transmission can be adjusted.

  The wireless sensor transmission device according to the present invention preferably includes a battery, and the battery supplies power to the sensor unit, the signal processing unit, and the transmission circuit unit. Therefore, when installing a new wireless sensor transmitter, or when moving to any location after installation, the installation environment is not restricted by the installation environment, and can be installed freely in an environment without AC power. Can be used. That is, there is no restriction on the installation environment.

  The battery is preferably assembled on the other surface of the circuit board. That is, the sensor unit, the signal processing unit, and the transmission circuit unit are arranged on one side of the circuit board, and the battery is arranged on the other side. Therefore, a small, thin, and lightweight wireless sensor transmission device can be realized.

  The battery preferably has a circular outer periphery and is in the plane of the circuit board. According to such a configuration, the overall planar outer dimension can be reduced to a shape that is exclusively determined by the plane area of the circuit board without being affected by the outer diameter of the battery.

  By the way, when the wireless sensor transmission device is driven by a battery, it is technically difficult to satisfy both the request for miniaturization of the wireless sensor transmission device itself and the request for reduction of current consumption. For example, if the size of the second antenna portion is reduced due to demands for size reduction, thickness reduction, and weight reduction, the current consumption required for the wireless sensor transmission device increases, so the battery life is reduced. This may cause inconvenience that the process is completed in a short period of six months to one year.

  Of course, the battery life can be maintained for a long period of time by increasing the capacity and size of the battery, such as creating a 3.0V power supply using two AA batteries, but it is downsized. Therefore, it becomes impossible to sufficiently meet the demands for thickness reduction and weight reduction.

  Furthermore, in order to realize both the request for miniaturization of the wireless sensor transmission device itself and the request for reduction of current consumption, the communication distance must be increased with a lower input power to the second antenna unit. I must. For this purpose, it is necessary to reduce the loss of the second antenna unit and increase the radiation efficiency of the electromagnetic field.

  In the present invention, the second antenna portion is formed in a helical shape, the thickness of the support substrate is set to the two sides of the opening portion, and the area of the opening portion is controlled so that the second antenna portion gain can be improved. In addition, the first antenna unit is combined with this to improve the antenna efficiency.

  As a result, it is possible to realize both a request for miniaturization of the wireless sensor transmitter itself and a request for reduction of current consumption, and to achieve a reduction in the loss of the second antenna unit and an improvement in the radiation efficiency of the electromagnetic field. Can do. That is, with a lower input power to the second antenna unit, the communication distance is increased, the power consumption of the circuit unit in front of the second antenna unit is reduced, and the current consumption of the entire wireless sensor device is reduced. As a result, the battery life and the continuous operation time can be prolonged.

  Preferably, the second antenna portion is provided outside the battery mounting area. According to this configuration, it is possible to suppress the generation of eddy current due to the high-frequency current magnetic field in the battery and improve the antenna efficiency.

  The wireless sensor transmission device according to the present invention is combined with a reception device to constitute a wireless sensor device. The receiving device receives and processes the wireless signal transmitted from the wireless sensor transmitting device through the second antenna unit. Thereby, the physical quantity measured at the remote place can be received by the receiving device, decoded, and displayed.

  Other features of the present invention and the operational effects thereof will be described in more detail by way of examples with reference to the accompanying drawings.

  FIG. 1 is an electric circuit diagram of a wireless sensor transmission device according to the present invention. Referring to the figure, a wireless sensor transmission device according to the present invention includes sensors 21 to 2n, sensor circuits 31 to 3n, a signal processing unit 4, a transmission circuit unit 5, an antenna unit 6, and a battery 91. .

  Sensors 21 to 2n (n is the number) detect physical quantities. Physical quantities to be measured include various quantities such as temperature, humidity, illuminance, acceleration, and impact. Various sensors may be used in combination, or may be configured as a kind of sensor. The sensor circuits 31 to 3n convert the signals detected by the sensors 21 to 2n into signals suitable for transmission and processing to the signal processing unit 4 at the subsequent stage, and output the signals.

  The signal processing unit 4 processes detection signals output from the sensor circuits 31 and 32. The transmission circuit unit 5 is a circuit that supplies a signal supplied from the signal processing unit 4 to the antenna unit 6.

  The antenna unit 6 includes a first antenna unit 601 and a second antenna unit 602. The first antenna unit 601 is electrically connected between the second antenna unit 602 and the transmission circuit unit 5, and matches the impedance between them. In this embodiment, the first antenna unit 601 is an LC circuit including capacitors C11 and C12 and an inductor L11. However, the circuit configuration of the first antenna unit 601 is not limited to the illustration, and various circuit configurations suitable for impedance matching can be employed. In the simplest case, as shown in FIG. 2, the first antenna unit 601 can be configured by one inductor L12. The second antenna unit 602 radiates radio waves into the air.

  As described above, the wireless sensor transmission device according to the present invention detects physical quantities by the sensors 21 to 2n and outputs detection signals output from the sensors 21 to 2n via the sensor circuits 31 to 3n to the signal processing unit 4. Since the signal supplied from the signal processing unit 4 is supplied to the antenna unit 6 by the transmission circuit unit 5, the physical quantity detected by the sensors 21 to 2n is wirelessly transmitted to the receiving device. Can do.

  The present invention has a first antenna unit 601 as a characteristic component, and the first antenna unit 601 is electrically connected between the second antenna unit 602 and the transmission circuit unit 5. Match the impedance between them.

  According to the above configuration, impedance matching by the first antenna unit 601 is performed between the input of the second antenna unit 602 having a high impedance and the output of the transmission circuit unit 5 having a low output impedance. The data can be efficiently input from the transmission circuit unit 5 to the second antenna unit 602, and the radiated electric field can be efficiently radiated from the second antenna unit 602.

  In addition, impedance matching can be achieved without matching the second antenna portion pattern length to a quarter wavelength of the effective frequency of the radio frequency, so that the ideal antenna structure having a quarter wavelength cannot be adopted. Also in the wireless sensor transmission device, data can be efficiently input from the transmission circuit unit 5 to the second antenna unit 602, and a radiated electric field can be efficiently radiated from the second antenna unit 602.

  3 is a plan view of the wireless sensor transmission device shown in FIG. 1 or FIG. 2, FIG. 4 is a front view of the wireless sensor transmission device shown in FIG. 3, and FIG. 5 is a wireless sensor transmission device shown in FIGS. FIG. The illustrated wireless sensor transmission device is modularized, and includes a circuit board 1, sensors 21 to 2n, sensor circuit units 31 to 3n, a signal processing unit 4, a transmission circuit unit 5, and a second antenna unit. 602, a first antenna portion 601 and a battery 91 are included.

  The circuit board 1 only needs to be made of an insulating material, and any of an organic insulating material, an inorganic insulating material, and a composite insulating material may be used. Moreover, the whole may be comprised with the dielectric material, and the combination of a dielectric material layer and a magnetic material layer may be sufficient.

  In the illustrated embodiment, the sensors 21 to 2n, the sensor circuits 31 and 32, the signal processing unit 4 and the transmission circuit unit 5 are mounted on one surface of the circuit board 1.

  The first antenna unit 601 is a surface-mount type electronic component and is assembled on one surface of the circuit board 1. The second antenna unit 602 is assembled to the circuit board 1. In the illustrated embodiment, the second antenna portion 602 is provided on the periphery of the circuit board 1 on one surface.

  The ground electrode 7 is so-called “solid coating”, but is not formed in a portion where the second antenna portion 602 is located. This is to avoid the adverse effect of the ground electrode 7 on the second antenna portion 602.

  The battery 91 supplies power to the sensors 21 to 2n, the signal processing unit 4, and the transmission circuit unit 5, and is assembled on the other surface of the circuit board 1, that is, on the side where the ground electrode 7 is provided. In the illustrated embodiment, the battery 91 is a so-called “coin type” having a circular outer periphery, and the outer peripheral surface is provided on the other surface of the circuit board 1 so as not to go outside. More specifically, it is arranged inside a holder 92 made of an insulating synthetic resin or the like. One surface of the holder 92 is attached to the surface of the ground electrode 7 provided on the other surface of the circuit board 1 by means such as adhesion. Inside the holder 92, terminals 93 and 94 that are in contact with the anode and electrode of the battery 91 are provided.

  The wireless sensor transmission device of the illustrated embodiment includes a battery 91, and the battery 91 supplies power to the sensors 21 to 2 n, the signal processing unit 4, and the transmission circuit unit 5. Therefore, when installing a new wireless sensor transmitter, or when moving to any location after installation, the installation environment is not restricted by the installation environment, and can be installed freely in an environment without AC power. Can be used. That is, there is no restriction on the installation environment.

  The battery 91 is assembled on the other surface (ground electrode side) of the circuit board 1. That is, the sensors 21 to 2n, the signal processing unit 4 and the transmission circuit unit 5 are arranged on one side of the circuit board 1, and the battery 91 is arranged on the other side. Therefore, a small, thin, and lightweight wireless sensor transmission device can be realized.

  The battery 91 preferably has a circular outer periphery and is in the plane of the circuit board 1. According to such a configuration, the overall planar outer dimension can be reduced to a shape determined solely by the plane area of the circuit board 1 without being affected by the outer diameter of the battery 91.

  By the way, when the wireless sensor transmission device is driven by a battery, it is technically difficult to satisfy both the request for miniaturization of the wireless sensor transmission device itself and the request for reduction of current consumption. For example, when the shape of the second antenna portion 602 is reduced due to demands for size reduction, thickness reduction, and weight reduction, the current consumption required for the wireless sensor transmission device increases, so that the battery life is increased. However, it may end in a short period of six months to one year.

  Of course, the battery life can be maintained for a long period of time by increasing the capacity and size of the battery, such as creating a 3.0V power supply using two AA batteries, but it is downsized. Therefore, it becomes impossible to sufficiently meet the demands for thickness reduction and weight reduction.

  Furthermore, in order to realize both the request for miniaturization of the wireless sensor transmission device itself and the request for reduction of current consumption, the communication distance can be increased with a lower input power to the second antenna unit 602. There must be. For this purpose, it is necessary to reduce the loss of the second antenna portion 602 and increase the radiation efficiency of the electromagnetic field.

  In order to meet the above-described demand, the illustrated second antenna unit 602 includes a support substrate formed of the circuit board 1 and antenna conductors 61 to 64. The circuit board 1 is made of an electrically insulating material. The antenna conductors 61 to 64 have a helical shape as a whole, and are wound in one direction parallel to the surface of the circuit board 1 with the thickness of the circuit board 1 being two sides of the opening.

  More specifically, as shown in FIG. 6, the first conductor pieces 61 are formed on one surface of the circuit board 1 at a predetermined interval in one direction, and on the other surface, the first conductor pieces 61 and The second conductor pieces 62 are formed in the same direction at the same pitch. Then, the end portions of the first conductor piece 61 and the second conductor piece 62 are made to be helically connected by the third conductor piece 63 and the fourth conductor piece 64 penetrating the circuit board 1 in the thickness direction. Connect sequentially. Thereby, an opening surrounded by the first conductor piece 61, the third conductor piece 63, the second conductor piece 62, and the fourth conductor piece 64 is generated. The area of this opening is approximately the product XY of the effective length X of the first conductor piece 61 and the second conductor piece 62 and the effective length Y of the third conductor piece 63 and the fourth conductor piece 64. Determined.

  In order to adjust the resonance point of the impedance to the frequency for wireless transmission, the opening area, the number of turns, and the dielectric constant of the substrate material may be adjusted. The lower the radio transmission frequency, the higher the open area, the number of turns, or the dielectric constant. In order to increase the open area, the thickness of the circuit board 1 or the area of the second antenna portion forming portion may be increased. However, the shape of the second antenna portion forming portion also increases and the device shape also increases. .

  On the other hand, if the number of turns and the dielectric constant of the substrate material are increased, the impedance can be lowered without increasing the device shape. Increasing the number of turns increases the pattern length and therefore increases the conductor loss due to the pattern. However, if the relative dielectric constant (εr) of the material constituting the circuit board 1 is increased, the number of turns can be reduced. Thereby, the conductor loss by a pattern can be reduced and a shape can be reduced in size, without increasing the loss as the 2nd antenna part 602. FIG.

As an example, the relationship between the relative dielectric constant of the substrate and the shape of the second antenna portion is shown below.
Relative permittivity configuration shape (length x width x thickness)
εr = 4 18 × 3 × 2mm
εr = 20 9 × 3 × 2mm
εr = 80 3 × 3 × 2mm
As described above, the shape of the second antenna portion can be reduced by the relative dielectric constant of the material to be configured.

  As described above, in the second antenna portion 602, since the antenna conductors 61 to 64 are formed in a helical winding, the overall length of the second antenna portion 602 can be remarkably shortened by its shape effect. Therefore, it is possible to provide a wireless sensor transmission device whose shape is significantly reduced.

  Moreover, since the antenna conductors 61 to 64 advance in one direction parallel to the surface of the circuit board 1, the component penetrating the ground electrode 7 in the high-frequency current magnetic field flowing through the second antenna portion 602 is significantly reduced. Generation of eddy current due to a high-frequency current magnetic field can be suppressed. Further, it is possible to avoid the electromagnetic noise from getting on the second antenna portion 602 despite the fact that the whole is downsized.

  Further, since the second antenna portion 602 has a helical shape and the thickness of the circuit board 1 is two sides of the opening, the second antenna portion gain is improved by controlling the area of the opening. be able to.

  In the present invention, since the first antenna unit 601 is combined with the second antenna unit 602 having the above advantages, impedance matching between the second antenna unit 602 and the transmission circuit unit 5 is achieved, and the antenna efficiency is improved. Can be further improved.

  For example, when the output impedance of the transmission circuit unit 5 is set to 50Ω and the input impedance of the second antenna unit 602 is 100Ω, the input impedance of the first antenna unit 601 is set to 50Ω and the output impedance is By setting to 100Ω, almost perfect impedance matching can be achieved between the transmission circuit unit 5 and the second antenna unit 602.

  That is, about the impedance matching between the transmission circuit unit 5 and the second antenna unit 602, half of the impedance mismatch that occurs between them is compensated by the first antenna unit 601. For this reason, the area required for the second antenna portion 602 formed of a helical pattern is half that required when the first antenna portion 601 is not provided.

  As a result, both the request for downsizing of the wireless sensor transmission device itself and the request for reduction of current consumption are realized, and the second antenna unit 602 is reduced in loss and electromagnetic radiation efficiency is improved. be able to. That is, with a low input power to the second antenna unit 602, the communication distance is increased, the power consumption of the circuit unit in front of the second antenna unit is reflected, and the current consumption of the entire wireless sensor device is reduced. Reduction of the battery life and, in turn, increase of battery life and continuous operation time can be achieved.

  As a further important effect of providing the first antenna unit 601 separately from the second antenna unit 602, the manufacturing efficiency of the second antenna unit 602 and the antenna efficiency due to temperature and humidity changes. The point which can suppress the fluctuation | variation of is mentioned. Manufacturing variations, changes in temperature and humidity cause impedance mismatch between the transmission circuit unit 5 and the second antenna unit 602, resulting in an increase in current consumption of the transmission circuit unit 5 and deterioration in battery life. As a sensor transmission device, the continuous operation time is reduced. In addition, the communication distance is deteriorated.

  That is, when the second antenna unit 602 is all configured with a helical winding pattern so as to match the output impedance of the transmission circuit unit 5, the substrate thickness, the width of the antenna conductor pattern formed on the substrate, Due to variations in thickness and changes in the dielectric constant of the substrate due to temperature and humidity, impedance mismatching is likely to occur between the transmission circuit unit 5 and the second antenna unit 602, and the antenna efficiency is accordingly increased. It will deteriorate.

  On the other hand, according to the present invention in which the first antenna unit 601 is provided separately from the second antenna unit 602, manufacturing variations in the substrate thickness, the width and thickness of the antenna conductor pattern formed on the substrate are provided. In addition, the change in the dielectric constant of the substrate due to temperature and humidity can be minimized, and the antenna efficiency can be maintained. Next, this point will be specifically described.

  An example of the change rate of the relative permittivity and the consumption current of the wireless sensor transmitter in the comparative example and the example is shown below for the case where FR-4 having a relative permittivity εr = 4.5 is used as the circuit board 1.

<Comparative example>
The first antenna unit 601 was not provided, and the second antenna unit 602 was all configured with a helical winding pattern so as to match the output impedance of the transmission circuit unit 5.
(1) When the circuit board 1 is held in an atmosphere of 85 ° C. for 1000 hours
εr change rate = about -10%
Initial current consumption = 1.1mA
Current consumption after 1000 hours = 1.3 mA
(2) When the circuit board 1 is held in an atmosphere of 85 ° C. and 85% RH for 1000 hours
εr change rate = about + 20%
Initial current consumption = 10mA
Current consumption after 1000 hours = 9 mA
From the above results, if the second antenna unit 602 is entirely configured with a helical winding pattern so as to be matched with the output impedance of the transmission circuit unit 5, wireless sensor transmission is performed due to changes in temperature and humidity. It can be seen that the antenna efficiency of the device changes greatly.

<Example>
(1) When the circuit board 1 is held in an atmosphere of 85 ° C. for 1000 hours
εr change rate = about -10% (same as comparative example)
Initial current consumption = 1.1mA
Current consumption after 1000 hours = 1.1 mA
(2) When the circuit board 1 is held in an atmosphere of 85 ° C. and 85% RH for 1000 hours
εr change rate = about + 20% (same as comparative example)
Initial current consumption = 1.1 mA
Current consumption after 1000 hours = 1.4 mA
As is clear from the above results, when the second antenna unit is divided into the second antenna unit 16 and the first antenna unit 601, consumption of the wireless sensor transmission device with respect to changes in temperature and humidity. The change in current is significantly smaller than in the comparative example. That is, stable antenna efficiency can be ensured regardless of changes in temperature and humidity.

  The battery life decreases in proportion to the increase in current consumption, and the decrease rate is 0% when left at high temperature and about 30% when left at high temperature and high humidity.

  In the embodiment of FIG. 1, the second antenna unit includes two blocks: a first antenna unit 601 configured by an L or LC circuit, and a second antenna unit 602 configured by a helical winding pattern on the circuit board 1. Consists of Specifically, the first antenna unit 601 is configured by a circuit including one inductor L11 and two capacitors C11 and C12. As such an LC circuit component, a surface mount component displayed as 1005 (1 mm × 0.5 mm) or 1608 (1.6 mm × 0.8 mm) can be used. For this reason, it is hardly affected by installation environment conditions, manufacturing tolerances of the substrate, and the like.

  In the case of FIG. 2, as the first antenna portion 601, a surface mount type component in which a helical pattern similar to the second antenna portion 602 is formed on a ceramic block can be used. The size of the ceramic block can be about 2 mm, and is hardly affected by installation environment conditions and substrate manufacturing tolerances. For this reason, even when the width and thickness of the pattern formed on the substrate, the thickness of the substrate, and the like change due to manufacturing variations and the input impedance of the second antenna portion 602 changes, the first antenna portion The matching state between the input of the second antenna unit 602 and the output impedance of the transmission circuit unit 5 due to 601 is not substantially affected. The same is true for the effect of εr on the substrate over time.

  The second antenna unit 602 is provided outside the battery 91 mounting area. In addition, it is preferable that an electrical element other than the second antenna unit 602, for example, a conductor pattern or other components is not disposed in the occupied area of the second antenna unit 602. According to such a configuration, it is possible to avoid interference of electric signals and electromagnetic fields with respect to the second antenna unit 602, to suppress noise generation, to reduce eddy current leakage, and to improve the second antenna unit gain. To do.

  FIG. 7 is a plan view showing another embodiment of the wireless sensor transmission device according to the present invention, FIG. 8 is a partial cross-sectional view of the wireless sensor transmission device shown in FIG. 7, and FIG. 9 is the wireless communication shown in FIGS. It is a bottom fragmentary sectional view of a sensor transmitter. This embodiment is characterized in that the support substrate 60 that supports the antenna conductors 61 to 64 is independent from the circuit substrate 1 for the wireless sensor transmission device. The second antenna unit 602 is mounted on one surface of the circuit board 1 on which the sensors 21 to 2n, the signal processing unit 4 and the transmission circuit unit 5 are mounted.

  According to this embodiment, since the circuit board 1 does not affect the opening area of the second antenna portion 602, it is possible to reduce the thickness of the circuit board 1 and reduce the thickness of the entire apparatus. Since the sensors 21 to 2n, the signal processing unit 4, and the transmission circuit unit 5 are originally mounted on one surface of the circuit board 1 on which the second antenna unit 602 is mounted, the second antenna unit 602 is connected to the circuit. Even if it is mounted on one surface of the substrate 1, the thickness of the entire apparatus will not increase.

  In addition, since the support substrate 60 that supports the antenna conductors 61 to 64 is independent from the circuit board 1, the support substrate 60 is a dielectric material having a relative dielectric constant higher than that of the dielectric material constituting the circuit board 1. The second antenna portion gain can be improved while achieving downsizing. The second antenna portion gain can also be adjusted by adjusting the dielectric constant of the dielectric material constituting the support substrate 60.

  10 is a plan view showing another embodiment of the wireless sensor transmission device according to the present invention, and FIG. 11 is a partial sectional view of the wireless sensor transmission device shown in FIG. In this embodiment, the second antenna portion 602 is remarkably shortened. In the second antenna portion 602, the support substrate 60 that supports the antenna conductors 61 to 64 is independent of the circuit substrate 1 for the wireless sensor transmission device.

  12 is a plan view showing another embodiment of the wireless sensor transmission device according to the present invention, FIG. 13 is a partial cross-sectional view of the wireless sensor transmission device shown in FIG. 12, and FIG. 14 is the wireless communication shown in FIGS. It is a bottom view of a sensor transmitter. In this embodiment, the second antenna portion 602 is significantly shortened and assembled to the circuit board 1 for the wireless sensor transmission device.

  FIG. 15 is a plan view showing still another embodiment of the wireless sensor transmitter according to the present invention. The feature of this embodiment is that a plurality of second antenna portions 602 are provided on the periphery of the circuit board 1. According to such an arrangement configuration, the lengths of the respective antenna conductors 61 to 64 can be adjusted in the plurality of second antenna portions 602 so as to correspond to the frequencies to be used. The number of the second antenna portions 602 may be four or less, for example, a configuration (two in total) provided at two opposite edges, or four or more depending on the planar shape of the circuit board 1. Also good.

  FIG. 16 is a block diagram showing a configuration of a wireless sensor device according to the present invention. In the figure, parts corresponding to the constituent parts shown in the above-mentioned drawings are given the same reference numerals. As illustrated, the wireless sensor transmission devices 101 to 10m according to the present invention are combined with the reception device 8 to constitute a wireless sensor device. In the illustrated embodiment, m wireless sensor transmitters 101 to 10m are provided. These shall be arrange | positioned in a mutually different position. The number m (m = 1, 2, 3,...) Of the wireless sensor transmission devices 101 to 10 m may be arbitrary.

  The receiving device 8 includes an antenna 81, a receiving circuit 82, a signal processing circuit 83 configured by a CPU or the like, and a display unit 84 such as a display. In addition, a conversion unit for interfacing with a personal computer may be provided. The reception device 8 receives the wireless signal transmitted from the wireless sensor transmission devices 101 to 10 m by the antenna 81 and the reception circuit 82 and processes the signal by the signal processing device 83. Then, the processing result is displayed on the display unit 84. Thereby, the physical quantity measured at the remote place can be received by the receiving device 8, decoded, and displayed.

  FIG. 17 is a block diagram showing a configuration of a wireless sensor device according to the present invention. In the figure, parts corresponding to the constituent parts shown in the above-mentioned drawings are given the same reference numerals. As shown in the drawing, in the illustrated embodiment, m receiving devices 801 to 80m are provided for one wireless sensor transmitting device. These shall be arrange | positioned in a mutually different position. The number m (m = 1, 2, 3,...) Of the receiving devices 801 to 80m may be arbitrary.

  Each of the reception devices 801 to 80m receives the wireless signal transmitted from the wireless sensor transmission device 10 by the antenna 81 and the reception circuit 82 and processes the signal by the signal processing device 83. Then, the processing result is displayed on the display unit 84. Thereby, the physical quantity measured at the remote place can be individually received, decoded, and displayed by the receiving devices 801 to 80m installed at different places.

  Although the contents of the present invention have been specifically described above with reference to the preferred embodiments, it is obvious that those skilled in the art can take various modifications based on the basic technical idea and teachings of the present invention. It is.

It is an electric circuit diagram of the wireless sensor transmitter according to the present invention. It is an electrical circuit diagram which shows another example of the wireless sensor transmitter which concerns on this invention. It is a top view of the wireless sensor transmitter concerning the present invention. FIG. 4 is a front view of the wireless sensor transmission device shown in FIG. 3. FIG. 5 is a partially broken bottom view of the wireless sensor transmission device shown in FIGS. 3 and 4. It is an enlarged view of a 2nd antenna part. It is a top view which shows another Example of the wireless sensor transmitter which concerns on this invention. It is a fragmentary sectional view of the wireless sensor transmitter shown in FIG. FIG. 9 is a partially broken bottom view of the wireless sensor transmission device shown in FIGS. 7 and 8. It is a top view which shows another Example of the wireless sensor transmitter which concerns on this invention. It is a fragmentary sectional view of the wireless sensor transmitter shown in FIG. It is a top view which shows another Example of the wireless sensor transmitter which concerns on this invention. It is a fragmentary sectional view of the radio | wireless sensor transmission apparatus shown in FIG. 14 is a bottom surface of the wireless sensor transmission device illustrated in FIGS. 12 and 13. FIG. It is a top view which shows another Example of the wireless sensor transmitter which concerns on this invention. It is a block diagram which shows the structure of the wireless sensor apparatus which concerns on this invention. It is a block diagram which shows the structure of the wireless sensor apparatus which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Circuit board 21-2n Sensor 31-3n Sensor circuit 4 Signal processing part 5 Transmission circuit part 6 Antenna part 601 1st antenna part 602 2nd antenna part 60 Support substrate 61-64 Antenna conductor 91 Battery

Claims (13)

A wireless sensor transmission device including a circuit board, a sensor unit, a signal processing unit, a transmission circuit unit, and an antenna unit,
The circuit board has the sensor unit, the signal processing unit, and the transmission circuit unit on one surface,
The sensor unit detects a physical quantity,
The signal processing unit is a circuit that processes a detection signal output from the sensor,
The transmission circuit unit is a circuit that transmits a signal supplied from the signal processing unit,
The antenna unit includes a first antenna unit and a second antenna unit, and is assembled to the circuit board;
The first antenna unit is electrically connected between the second antenna unit and the transmission circuit unit, and matches the impedance between the two,
The second antenna portion has a helical antenna conductor,
The first antenna unit is provided adjacent to a side of the second antenna unit as viewed in a direction in which the antenna conductor of the second antenna unit winds.
Wireless sensor transmitter. The wireless sensor transmission device according to claim 1, comprising a battery,
The battery is assembled to the other surface of the circuit board, and supplies power to the sensor unit, the signal processing unit, and the transmission circuit unit.
The first antenna unit is provided outside the mounting area of the battery when the circuit board is viewed in plan.
Wireless sensor transmitter. 3. The wireless sensor transmission device according to claim 2 , wherein the first antenna unit is provided so as not to overlap the battery when the circuit board is viewed in plan . A wireless sensor transmitting apparatus according to claim 2 or 3, wherein the second antenna portion, the circuit board is provided outside the mounting region of the battery when viewed from the top, wireless sensor transmitting device . 5. The wireless sensor transmission device according to claim 4 , wherein the second antenna unit is provided so as not to overlap the battery when the circuit board is viewed in plan . 6. The wireless sensor transmission device according to claim 2 , wherein the battery has a circular outer periphery and is in a plane of the circuit board . 7. 7. The wireless sensor transmission device according to claim 1, wherein the second antenna unit includes a support substrate and an antenna conductor.
The support substrate is made of an electrically insulating material,
The antenna conductor has a helical shape, and the thickness of the support substrate is two sides of the opening, and the antenna conductor advances in a direction parallel to a surface in the thickness direction of the support substrate.
Wireless sensor transmitter. 7. The wireless sensor transmission device according to claim 1, wherein the antenna conductor of the second antenna portion has a thickness of the circuit board as two sides of the opening, and the surface of the circuit board. Wireless sensor transmitter that winds in a direction parallel to the sensor. A wireless sensor transmitting apparatus according to any one of claims 1 to 8, wherein the second antenna portion is a plurality, are provided on the peripheral edge of the circuit board, the wireless sensor transmitting device. A wireless sensor transmitting apparatus according to any one of claims 1 to 9, wherein the ground electrode, the ground electrode, in other surface of the circuit board, the full range excluding the second antenna portion A wireless sensor transmitter configured in a solid shape . 11. The wireless sensor transmission device according to claim 1, wherein the first antenna unit is configured by an electronic component including an inductor, and is mounted on the one surface of the circuit board. A wireless sensor transmitter. 11. The wireless sensor transmission device according to claim 1, wherein the first antenna unit is configured by an electronic component including an inductor and a capacitor, and is mounted on the one surface of the circuit board. A wireless sensor transmission device. A wireless sensor device including a wireless sensor transmission device and a reception device,
The wireless sensor transmission device is the one described in any one of claims 1 to 12 ,
The receiving device receives and processes a radio signal transmitted from the wireless sensor transmitting device ;
Wireless sensor device.

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