CN102750572B - RFID label tag, rfid system and the humidity detection method of a kind of band wet sensitive device - Google Patents
RFID label tag, rfid system and the humidity detection method of a kind of band wet sensitive device Download PDFInfo
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- CN102750572B CN102750572B CN201210180344.6A CN201210180344A CN102750572B CN 102750572 B CN102750572 B CN 102750572B CN 201210180344 A CN201210180344 A CN 201210180344A CN 102750572 B CN102750572 B CN 102750572B
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Abstract
The present invention provides RFID label tag, rfid system and the humidity detection method of a kind of band wet sensitive device, and the chip of RFID label tag has two pins;Wet sensitive device forms parallel-connection structure with the antenna of RFID label tag, the circuit that wet sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection is with the part that the logic circuit controlling break-make is chip: when logic circuit disconnects, wet sensitive device not with sky line parallel, after being now placed on certain humidity level's lower a period of time, the first resonant frequency of antenna and signal intensity keep constant;When logic circuit is connected, wet sensitive device and sky line parallel, after being now placed on certain humidity level's lower a period of time, now Antenna Operation is under the second resonant frequency;The instruction that RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna.The present invention can detect humidity change at lower cost.
Description
Technical field
The present invention relates to RFID(RadioFrequencyIdentification, RF identification) technical field, particularly relate to RFID label tag, rfid system and the humidity detection method of a kind of band wet sensitive device.
Background technology
In recent years, rfid system had become more prevalent.Rfid system is mainly used in the identification to people and thing.In general, this system includes at least a RFID reader, and this RFID reader can be launched in the range of a setting and accept the radiofrequency signal from one or more RFID label tag.This RFID label tag is usually encapsulated, and can paste on one object, and it includes that one can carry out the microchip of communication for information with antenna.This microchip is an integrated circuit in general, and it can be used to store and process information, modulation /demodulation radiofrequency signal, and can run other specific function.The antenna of RFID label tag is used to receive and send radiofrequency signal, and is commonly available to a kind of special frequency.
In some equipment, when the humidity having been used for monitoring product local environment with the rfid system of wet sensitive device has exceeded acceptable humidity.In general these equipment requirements induction installations to have a lasting energy source, is used for detecting the change of humidity, but this can increase the cost of equipment.It addition, some equipment requirements induction installations to be also connected with a comparator circuit, thus detecting the degree size of deviation reference voltage, this requirement considerably increases the cost of equipment.In a word, improving what rfid system was a need for, it requires to can be used to when not using lasting energy source or using the adjunct circuit of a kind of low cost detect humidity change.
Summary of the invention
The embodiment of the present invention provides RFID label tag, rfid system and the humidity detection method of a kind of band wet sensitive device, detects humidity change at lower cost.
On the one hand, embodiments provide the RFID label tag of a kind of band wet sensitive device, the chip of described RFID label tag has two pins;Described wet sensitive device is connected with the two pin, and form parallel-connection structure with the antenna of described RFID label tag, the change of ambient humidity can cause the change of the resistance of wet sensitive device own, the circuit that described wet sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines wet sensitive device with sky line parallel: when logic circuit disconnects, wet sensitive device not with sky line parallel, after being now placed on certain humidity level's lower a period of time, first resonant frequency of antenna and signal intensity keep constant;When logic circuit is connected, wet sensitive device and sky line parallel, after being now placed on certain humidity level's lower a period of time, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency;The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is monopole antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is double-doublet antenna: described wet sensitive device forms parallel-connection structure with a wherein antenna;Or described wet sensitive device and two antennas concurrently form parallel-connection structure.
Optionally, in an embodiment of the present invention, described wet sensitive device is resistor-type wet sensitive device, and described wet sensitive device includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device, inorganic some solution matter formula wet sensitive device, quartz resonance wet sensitive device.
On the other hand, embodiments provide the RFID label tag of a kind of band wet sensitive device, the chip of described RFID label tag has a pin;One end of described wet sensitive device is connected with this pin, the other end is connected on the antenna of described RFID label tag, and form parallel-connection structure with antenna, the change of ambient humidity can cause the change of the resistance of wet sensitive device own, the circuit that described wet sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines wet sensitive device with sky line parallel: when logic circuit disconnects, wet sensitive device not with sky line parallel, after being now placed on certain humidity level's lower a period of time, first resonant frequency of antenna and signal intensity keep constant;When logic circuit is connected, wet sensitive device and sky line parallel, after being now placed on certain humidity level's lower a period of time, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency;The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is monopole antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is double-doublet antenna: described wet sensitive device forms parallel-connection structure with a wherein antenna;Or described wet sensitive device and two antennas concurrently form parallel-connection structure.
Optionally, in an embodiment of the present invention, described wet sensitive device is resistor-type wet sensitive device, and described resistor-type wet sensitive device includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device, inorganic some solution matter formula wet sensitive device, quartz resonance wet sensitive device.
Another aspect, embodiments provide the RFID label tag of a kind of band wet sensitive device, described wet sensitive device is connected on the antenna of described RFID label tag, and form parallel-connection structure with antenna, the change of ambient humidity can cause the change of the resistance of wet sensitive device own, the circuit that described wet sensitive device is connected with antenna has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines wet sensitive device with sky line parallel: when logic circuit disconnects, wet sensitive device not with sky line parallel, after being now placed on certain humidity level's lower a period of time, first resonant frequency of antenna and signal intensity keep constant;When logic circuit is connected, wet sensitive device and sky line parallel, after being now placed on certain humidity level's lower a period of time, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency;The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is monopole antenna.
Optionally, in an embodiment of the present invention, the antenna of described RFID label tag is double-doublet antenna: described wet sensitive device forms parallel-connection structure with a wherein antenna;Or described wet sensitive device and two antennas concurrently form parallel-connection structure.
Optionally, in an embodiment of the present invention, described wet sensitive device is resistor-type wet sensitive device, and described resistor-type wet sensitive device includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device, inorganic some solution matter formula wet sensitive device, quartz resonance wet sensitive device.
Another further aspect, embodiments provides the rfid system of a kind of band wet sensitive device, and described rfid system includes that RFID label tag and RFID reader, described RFID label tag include the RFID label tag of above-mentioned band wet sensitive device;Described RFID reader sends the instruction break-make with the logic circuit of control RFID label tag, thus by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna.
Another further aspect, embodiments provide the humidity detection method of the rfid system of a kind of band wet sensitive device, described humidity detection method is applied to the rfid system of above-mentioned band wet sensitive device, including: send instruction to control the break-make of the logic circuit of RFID label tag by described RFID reader;The break-make with control logic circuit is instructed: when logic circuit disconnects by what RFID tag RFID reader sent, wet sensitive device not with sky line parallel, now being placed under certain humidity intensity, the first resonant frequency of antenna and signal intensity keep constant;When logic circuit is connected, wet sensitive device and sky line parallel, now it is placed under certain humidity intensity, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency;Described RFID reader is utilized to compare from the difference between the signal intensity of the different frequency of antenna to detect the change of humidity.
Technique scheme has the advantages that because using and having two pins on the chip of RFID label tag;Wet sensitive device forms parallel-connection structure with the antenna of RFID label tag, the circuit that wet sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection is with the part that the logic circuit controlling break-make is chip: when logic circuit disconnects, wet sensitive device not with sky line parallel, after being now placed on certain humidity level's lower a period of time, the first resonant frequency of antenna and signal intensity keep constant;When logic circuit is connected, wet sensitive device and sky line parallel, after being now placed on certain humidity level's lower a period of time, now Antenna Operation is under the second resonant frequency;The instruction that RFID tag RFID reader sends is with the break-make of control logic circuit, thus realize by the technological means comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna, so having reached to detect at lower cost the technique effect of humidity change, and utilize the energy that RFID obtains, solve the powerup issue of Humidity Detection.
Accompanying drawing explanation
In order to be illustrated more clearly that the embodiment of the present invention or technical scheme of the prior art, the accompanying drawing used required in embodiment or description of the prior art will be briefly described below, apparently, accompanying drawing in describing below is only some embodiments of the present invention, for those of ordinary skill in the art, on the premise of not paying creative work, it is also possible to obtain other accompanying drawing according to these accompanying drawings.
Fig. 1 is the schematic diagram that embodiment of the present invention wet sensitive device is connected with RFID label chip;
Fig. 2 is the equivalent circuit diagram of RFID label chip inside antenna;
Fig. 3 is the schematic diagram that embodiment of the present invention wet sensitive device, logic switch are connected with RFID label chip inside antenna equivalent circuit;
Fig. 4 is that embodiment of the present invention wet sensitive device is joined directly together, with RFID label antenna, the schematic diagram connect;
Fig. 5 .1-Fig. 5 .2 is the structure explanatory diagram of embodiment of the present invention wet sensitive device;
Fig. 6 is the flow chart of embodiment of the present invention humidity level based on signal intensity detection method.
Detailed description of the invention
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, it is clear that described embodiment is only a part of embodiment of the present invention rather than whole embodiments.Based on the embodiment in the present invention, the every other embodiment that those of ordinary skill in the art are obtained under not making creative work premise, broadly fall into the scope of protection of the invention.
The wet sensitive device of the embodiment of the present invention is connected with the chip of RFID label tag and at least there are three kinds of situations:
Two pins structure:
The embodiment of the present invention is a kind of device, system and technology for detecting humidity change.This system contains a RFID label tag, and the chip of this RFID label tag has two pins.Wet sensitive device is connected with the two pin, forms parallel-connection structure with antenna.The change of ambient humidity can cause the change of the resistance of wet sensitive device own.The circuit that pin is connected with chip has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip.
The break-make of logic circuit determine wet sensitive device whether with sky line parallel.When logic circuit disconnects, wet sensitive device not with sky line parallel, after being now placed on certain humidity level's lower a period of time, the first resonant frequency of antenna and signal intensity keep constant.When logic circuit is connected, wet sensitive device and sky line parallel, after being now placed on certain humidity level's lower a period of time, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency.RFID reader can send the break-make of instruction control logic circuit to label, when logic circuit is connected, and can be by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna.
For an example, this system contains a RFID label tag, an only antenna on this label.Two pins are had on the chip of this label.Wet sensitive device is connected with the two pin, forms parallel-connection structure with this root antenna.Having a logic circuit controlling break-make with chip on the circuit that pin is connected, the circuit of this connection and the logic circuit of control break-make are parts for chip.The change of ambient humidity can cause the change of the resistance of wet sensitive device own.
After being placed on certain humidity level's lower a period of time when logic circuit is connected, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency.RFID reader can send instruction to label, and can be detected the change of humidity by the difference between the signal intensity of different frequency during CL Compare Logic connecting and disconnecting of the circuit.More precisely, wet sensitive device should have relatively low resistance, its instantiation includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device (Se(selenium) evaporating film wet sensitive device, silicon MOS type Al2O3Wet sensitive device), inorganic solution matter formula wet sensitive device (stepping on Morse LiCl wet sensitive device, impregnated wet sensitive device, DWS-P type LiCl(lithium chloride) humistor device), quartz resonance wet sensitive device etc..
For another example, this system contains a RFID label tag, and this label has two antennas.Now there are two kinds of situations.The first situation is that wet sensitive device is connected with the two pin, forms parallel-connection structure with first antenna.Having a logic circuit controlling break-make with chip on the circuit that pin is connected, the circuit of this connection and the logic circuit of control break-make are parts for chip.The change of ambient humidity can cause the change of the resistance of wet sensitive device own.And second antenna is all the time with the first resonant frequency proper communication.
When logic circuit is connected, after being placed on certain humidity level's lower a period of time, at least meeting of the characteristic frequency of first antenna and signal intensity changes, and it is operated under the second resonant frequency.RFID reader can send instruction to label, and can detect the change of humidity by difference between the signal intensity of the different frequency of first and second antennas during CL Compare Logic circuit ON.The change of humidity can also be detected by the difference between the signal intensity of the different frequency during logic circuit break-make that compares second antenna self.
The second situation is, wet sensitive device is connected with the two pin, concurrently forms parallel-connection structure with two antennas.Having a logic circuit controlling break-make with chip on the circuit that pin is connected, the circuit of this connection and the logic circuit of control break-make are parts for chip.The change of ambient humidity can cause the change of the resistance of wet sensitive device own.This situation only containing an antenna with label is similar.
After being placed on certain humidity level's lower a period of time when logic circuit is connected, antenna features frequency and signal intensity at least have one and change, and it is operated under the second resonant frequency.RFID reader can send instruction to label, and can be detected the change of humidity by the difference between the signal intensity of different frequency during CL Compare Logic connecting and disconnecting of the circuit.The first situation circuit connects fairly simple, and during work, the resonant frequency of two antennas may be different, can affect the precision of measurement.The second situation circuit connects more complicated, but during work, the resonant frequency of two antennas is consistent, and certainty of measurement is higher.More precisely, wet sensitive device should have relatively low resistance, its instantiation includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device (Se(selenium) evaporating film wet sensitive device, silicon MOS type Al2O3Wet sensitive device), inorganic solution matter formula wet sensitive device (stepping on Morse LiCl wet sensitive device, impregnated wet sensitive device, DWS-P type LiCl(lithium chloride) humistor device), quartz resonance wet sensitive device etc..
One pin configuration:
The chip of this label can only have a pin, and this pin outwards one end with wet sensitive device is connected, and the other end of wet sensitive device is attached directly on antenna.Pin is similar at the junction point of chip internal and the situation of two pins, finally remains and to reach and the purpose of sky line parallel.On the circuit that pin is connected, there is a logic circuit controlling break-make with chip internal circuits simultaneously.When logic circuit disconnects, wet sensitive device not with sky line parallel, after being now placed on certain humidity level's lower a period of time, the first resonant frequency of antenna and signal intensity keep constant.
When logic circuit is connected, wet sensitive device and sky line parallel, after being now placed on certain humidity level's lower a period of time, antenna features frequency and signal intensity at least have one and change, and it is operated under the second resonant frequency.RFID reader can send the break-make of instruction control logic circuit to label, when logic circuit is connected, and can be by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna.
For an example, this system contains a RFID label tag, an only antenna on this label.A pin is had on the chip of this label.Wet sensitive device is connected with this pin, and the wet sensitive device other end is attached directly on antenna, forms parallel-connection structure with antenna.Having a logic circuit controlling break-make with chip on the circuit that pin is connected, the circuit of this connection and the logic circuit of control break-make are parts for chip.The change of ambient humidity can cause the change of the resistance of wet sensitive device own.
After being placed on certain humidity level's lower a period of time when logic circuit is connected, Antenna Operation is under the second resonant frequency, and its characteristic frequency and signal intensity at least have one and change.RFID reader can send instruction to label, and can be detected the change of humidity by the difference between the signal intensity of different frequency during CL Compare Logic connecting and disconnecting of the circuit.More precisely, wet sensitive device should have relatively low resistance, its instantiation includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device (Se(selenium) evaporating film wet sensitive device, silicon MOS type Al2O3Wet sensitive device), inorganic solution matter formula wet sensitive device (stepping on Morse LiCl wet sensitive device, impregnated wet sensitive device, DWS-P type LiCl(lithium chloride) humistor device), quartz resonance wet sensitive device etc..
For another example, this system contains a RFID label tag, and this label has two antennas.Now there are two kinds of situations.The first situation is to have a pin on the chip of this label.Wet sensitive device is connected with this pin, and the wet sensitive device other end is attached directly on antenna, forms parallel-connection structure with first antenna.Having a logic circuit controlling break-make with chip on the circuit that pin is connected, the circuit of this connection and the logic circuit of control break-make are parts for chip.The change of ambient humidity can cause the change of the resistance of wet sensitive device own.And second antenna is all the time with the first resonant frequency communication.
When logic circuit is connected, after being placed on certain humidity level's lower a period of time, first Antenna Operation is under the second resonant frequency, and at least meeting of its characteristic frequency and signal intensity changes.RFID reader can send instruction to label, and can detect the change of humidity by difference between the signal intensity of the different frequency of first and second antennas during CL Compare Logic circuit ON.The change of humidity can also be detected by the difference between the signal intensity of the different frequency during logic circuit break-make that compares second antenna self.
The second situation is, the chip of this label has a pin.Wet sensitive device is connected with this pin, and the wet sensitive device other end is attached directly on antenna, concurrently forms parallel-connection structure with two antennas.Having a logic circuit controlling break-make with chip on the circuit that pin is connected, the circuit of this connection and the logic circuit of control break-make are parts for chip.The change of ambient humidity can cause the change of the resistance of wet sensitive device own.This situation only containing an antenna with label is similar.
After being placed on certain humidity level's lower a period of time when logic circuit is connected, Antenna Operation is under the second resonant frequency, and its characteristic frequency and signal intensity at least have one and change.RFID reader can send instruction to label, and can be detected the change of humidity by the difference between the signal intensity of different frequency during CL Compare Logic connecting and disconnecting of the circuit.The first situation circuit connects fairly simple, and during work, the resonant frequency of two antennas may be different, can affect the precision of measurement.The second situation circuit connects more complicated, but during work, the resonant frequency of two antennas is consistent, and certainty of measurement is higher.More precisely, wet sensitive device should have relatively low resistance, its instantiation includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device (Se(selenium) evaporating film wet sensitive device, silicon MOS type Al2O3Wet sensitive device), inorganic solution matter formula wet sensitive device (stepping on Morse LiCl wet sensitive device, impregnated wet sensitive device, DWS-P type LiCl(lithium chloride) humistor device), quartz resonance wet sensitive device etc..
Without pin configuration:
When not having pin on the chip of RFID label tag, wet sensitive device can be attached directly on antenna.In this case, the antenna being connected with wet sensitive device can not depart from wet sensitive device and with normal frequency for communication.After being placed on certain humidity level's lower a period of time, the characteristic frequency of antenna and signal intensity at least have one and change.RFID reader can send instruction to label apparatus, by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna.
For an example, this system contains a RFID label tag, and this label has two antennas.Wet sensitive device is directly connected with first antenna, and second antenna is not connected with wet sensitive device all the time with the first resonant frequency proper communication.After being placed on certain humidity level's lower a period of time, first Antenna Operation is under the second resonant frequency, and at least meeting of its characteristic frequency and signal intensity changes, and the characteristic frequency of second antenna and signal intensity are constant.RFID reader can send instruction to label, and can detect the change of humidity by comparing the difference between the signal intensity of the different frequency of first and second antennas.More precisely, wet sensitive device should have relatively low resistance, its instantiation includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device (Se(selenium) evaporating film wet sensitive device, silicon MOS type Al2O3Wet sensitive device), inorganic solution matter formula wet sensitive device (stepping on Morse LiCl wet sensitive device, impregnated wet sensitive device, DWS-P type LiCl(lithium chloride) humistor device), quartz resonance wet sensitive device etc..
In the same way, the chip of antenna can also can carry one can also carry multiple pin without pin by band.The radical of antenna can be one, two the most.Can also connect one or more wet sensitive device accordingly, the model of wet sensitive device can be the same or different simultaneously.For a kind of instantiation of device, after being placed on certain humidity level's lower a period of time, at least meeting of the characteristic frequency of the antenna being connected with wet sensitive device and signal intensity changes.RFID reader can send instruction to label apparatus, by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna.
For the instantiation of a kind of wet sensitive device, simultaneous compares the method for numerical value and includes that these compare numerical value compares with most signal strength values.These signal strength values belong to different frequencies, and are associated with most humidity values, are simultaneously based on comparison mentioned above and can detect the level of humidity.
But, for another aspect, a rfid system includes a RFID label tag device and a RFID reader device.This RFID label tag device is used to send two kinds of signals, and signal when signal when the most above-mentioned logic circuit disconnects is connected with logic circuit, the request being subject to is responded by a kind of meeting of both signals.RFID reader device is used at least sending RFID label tag device one request.Install reading device be in order to accept from the logic circuit of label connect time signal strength values and logic circuit disconnect time signal strength values between fiducial value, and these fiducial values are converted into the varying level of humidity.
In an example, the antenna of RFID label tag is connected with wet sensitive device, has a logic circuit controlling break-make on this connection line.In the case of logic circuit break-make whether two kinds, have corresponding two kinds of different frequencies from antenna.After logic circuit is connected and this label apparatus is positioned over certain humidity level's lower a period of time, due to the change of resonant frequency, the intensity level of two kinds of unlike signals will be produced.
In an example, RFID label tag device includes first, second two antennas, and wherein the first signal launched by first antenna, and secondary signal launched by second antenna.Preferably, first antenna is connected with wet sensitive device, after this label apparatus is placed on certain humidity level's lower a period of time, due to the change of resonant frequency, will produce the different of secondary signal intensity level and the first signal strength values.
Another further aspect, embodiments provides the rfid system of a kind of band wet sensitive device, and described rfid system includes that RFID label tag and RFID reader, described RFID label tag include the RFID label tag of above-mentioned band wet sensitive device;Described RFID reader sends the instruction break-make with the logic circuit of control RFID label tag, thus by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna.
Another further aspect, embodiments provide the humidity detection method of the rfid system of a kind of band wet sensitive device, described humidity detection method is applied to the rfid system of above-mentioned band wet sensitive device, including: send instruction to control the break-make of the logic circuit of RFID label tag by described RFID reader;The break-make with control logic circuit is instructed: when logic circuit disconnects by what RFID tag RFID reader sent, wet sensitive device not with sky line parallel, now being placed under certain humidity intensity, the first resonant frequency of antenna and signal intensity keep constant;When logic circuit is connected, wet sensitive device and sky line parallel, now it is placed under certain humidity intensity, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency;Described RFID reader is utilized to compare from the difference between the signal intensity of the different frequency of antenna to detect the change of humidity.
As it is shown in figure 1, the schematic diagram feeling wet label 10 being connected with RFID label chip for embodiment of the present invention wet sensitive device.In Fig. 1, label apparatus 10, including a base 15, a surface-mounted integrated circuit 13,16,17 and one double-doublet antennas 11,12 of two pins.Having two pins 16,17 on surface-mounted integrated circuit 13, the two pin is outwards connected with wet sensitive device 14, and the two pin is in parallel with the equivalent circuit of antenna at chip internal, and has a logic circuit controlling break-make on the circuit connected.Can control whether wet sensitive module is access in chip circuit by the break-make of logic circuit, such that it is able to affect the frequency of the antenna being connected with radio-frequency module.When logic circuit disconnects, label antenna is with the first resonant frequency communication.When logic circuit is connected, after being placed on certain humidity level's lower a period of time, Antenna Operation is under the second resonant frequency, and its characteristic frequency and signal frequency and signal intensity at least have one and change.
In an example, transmitting terminal 11,12 are made up of one or more different low electrical resistant materials, these materials have higher electric conductivity, such as copper, silver, and aluminum, they and wet sensitive device mentioned above are connected by two pins 16,17 and antenna 11,12, when antenna 11, after 12 are placed on certain humidity level's lower a period of time, wet sensitive device can cause the change of one or more transmitting terminal generation resonant frequency, thus causes a different frequency.The change of this frequency is the most different with the frequency received and send.Such as, after wet sensitive device is positioned over certain humidity level's lower a period of time, may result in transmission frequency and accept in frequency that at least one changes.
In another example, the antenna frequencies value set at the beginning will be above the antenna frequencies under certain humidity environment, and then when reaching certain humidity, it will reduce.In another example, the antenna frequencies set at the beginning is less than the antenna frequencies under certain humidity level, and when reaching certain humidity level, it will rise.The such wet sensitive device that can be used for the present invention has: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device (Se(selenium) evaporating film wet sensitive device, silicon MOS type Al2O3Wet sensitive device), inorganic solution matter formula wet sensitive device (stepping on Morse LiCl wet sensitive device, impregnated wet sensitive device, DWS-P type LiCl(lithium chloride) humistor device), quartz resonance wet sensitive device etc..
Type based on wet sensitive device is different, causes the humidity level of change to be probably a specific humidity value and is also likely to be the scope of a selectively humidity value.The length of time necessarily causes the change of antenna resonance frequency, and antenna quality also results in different changes.Such as, on antenna with the type of wet sensitive device can affect and change the length of antenna resonance frequency required time.
As in figure 2 it is shown, be the equivalent circuit diagram of RFID label antenna.In tag coil antenna enters the alternating magnetic field that read write line produces, the interaction between label antenna and reading and writing device antenna is similar to transformator.Both coils are equivalent to primary coil and the secondary coil of transformator.The resonant tank formed by label antenna is as it can be seen, include the coil inductance (L) of label antenna, parasitic capacitance (Cp) and shunt capacitance (C2), its resonant frequency isIn formula, C is CpAnd C2Parallel equivalent electric capacity, R1, R2For circuit internal inductance coil and the equivalent resistance of other devices.The carrier frequency that label and read write line two-way communication use is exactly f.When requiring that tag antenna coil profile is the least, i.e. area is little, and need certain operating distance, the aerial coil mutual induction amount that RFID label tag and read write line are asked the most substantially can not meet actual demand, the Ferrite Material with high permeability can be inserted inside tag antenna coil, to increase mutual induction amount, thus the problem that bucking coil cross section is little.
As it is shown on figure 3, for embodiment of the present invention wet sensitive device, control the schematic diagram that the logic circuit of break-make is connected with RFID label antenna equivalent circuit.The resonant tank formed by label antenna is as it can be seen, include the coil inductance (L) of label antenna, parasitic capacitance (Cp) and shunt capacitance (C2), its resonant frequency isFormula C is CpAnd C2Parallel equivalent electric capacity, R1, R2For circuit internal inductance coil and the equivalent resistance of other devices.M is the variable resistance representing wet sensitive device, and S is the logic circuit controlling break-make.When logic circuit disconnects, wet sensitive device not with sky line parallel, after being now placed on certain humidity level's lower a period of time, the first resonant frequency of antenna and signal intensity keep constant.When logic circuit is connected, wet sensitive device and sky line parallel, after being now placed on certain humidity level's lower a period of time, Antenna Operation is under the second resonant frequency, and its characteristic frequency and signal intensity at least have one and change.
As shown in Figure 4, the sketch of the passive RFID tags device 40 of humidity change can be detected for the embodiment of the present invention.As shown in Figure 4, label apparatus 40 includes a base 45, an integrated circuit 43 and a double-doublet antenna 41,42.The wet sensitive device 44 being connected with antenna 42 will affect the resistance of antenna 42.The material that wet sensitive device 44 is suitable for can be according to antenna 41, and the current voltage of any in 42 controls any one frequency both pinpointed.For an example, antenna 41,42 is installed it can be made to produce resonance in identical frequency.For another example, antenna 41,42 is installed it can be made to produce resonance in different frequencies.
In an example, transmitting terminal double-doublet antenna 41,42 is made up of one or more different low electrical resistant materials, and these materials have higher electric conductivity, such as copper, silver, and aluminum, they are connected with wet sensitive device mentioned above, when antenna 41, after 42 are placed on certain humidity level's lower a period of time, wet sensitive device can cause the change of one or more transmitting terminal generation resonant frequency, thus causes a different frequency.The change of this frequency is the most different with the frequency received and send.Such as, after wet sensitive device is positioned over certain humidity level's lower a period of time, may result in transmission frequency and accept in frequency that at least one changes.
In another example, the antenna frequencies value set at the beginning will be above the antenna frequencies under certain humidity environment, and then when reaching certain humidity, it will reduce.In another example, the antenna frequencies set at the beginning is less than the antenna frequencies under certain humidity level, and when reaching certain humidity level, it will rise.Such wet sensitive device of the invention that can be used for this has: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device (Se(selenium) evaporating film wet sensitive device, silicon MOS type Al2O3Wet sensitive device), inorganic solution matter formula wet sensitive device (stepping on Morse LiCl wet sensitive device, impregnated wet sensitive device, DWS-P type LiCl(lithium chloride) humistor device), quartz resonance wet sensitive device etc..
Type based on wet sensitive device is different, causes the humidity level of change to be probably a specific humidity value and is also likely to be the scope of a selectively humidity value.The length of time necessarily causes the change of antenna resonance frequency, and antenna quality also results in different changes.Such as, on antenna with the type of wet sensitive device can affect and change the length of antenna resonance frequency required time.
As shown in Fig. 5 .1, Al2O3Wet sensitive device is outside conductor, to spray one layer of Al with plasma spraying method in the way of interior electrode 5132O3Humidity-sensitive film 512, makes porous metal electrode 511 on film and forms.Its sense moor reason is: the stainless steel tube 513 in figure, i.e. as the interior electrode 513 of sensor, is again Al simultaneously2O3The carrier of humidity-sensitive film 512.This structure is considered as a capacitor, when after the hydrone outer metal electrode 511 through porous, then by Al2O3Humidity-sensitive film 512 adsorbs, thus causes Al2O3Humidity-sensitive film 512 dielectric constant changes, and brings the change of sensor capacitance.Reduce along with the resistance increasing sensor of Vapor adsorption amount and make capacitance increase.And the logarithm value of resistance is linear with humidity, there is hygrometric scope and working range width.
As shown in Fig. 5 .2, for ZrO2The structure chart of type wet sensitive device.This structure includes dustproof filter film 521, the ZrO of printing2Humidity sensing layer 522, the Au comb electrode 523 printed by silk screen print method, a ceramic substrate 524, and two contact conductors 525,526.Humidity sensing layer 522 is a kind of porous ZrO2Being thick-film material, its available bases metal regulation tissue size also improves its long-time stability.Its sense moor reason is owing to the water of physical absorption dissociates on the surface of wet sensitive device humidity sensing layer, and result generates proton and participates in conduction.
As shown in Figure 6, for the embodiment of the present invention by using the label apparatus of multiple antennas to detect a kind of method flow diagram that humidity changes.Need it is contemplated that, device mentioned above uses a label integrated circuit to carry out and the exchanging of multiple antennas.
As shown in Figure 6,50, RFID reader sends energy and instruction to label apparatus.52, logic circuit is in the state of disconnection at initial time, and the label apparatus antenna not being connected with wet sensitive device receives energy and instruction.54, the electromagnetic wave carrying energy is converted into a DC(direct current by label apparatus) voltage, thus label just can be made to perform the requirement of instruction.And this conversion needs to use an electric charge pump, a rectification circuit, or be connected with each other, or to use other energy conversion device.56, label apparatus sends signal by the sky alignment reader not being connected with wet sensitive device.58, the energy intensity receiving signal is measured and recorded to reader.60, reader sends the instruction connecting logic circuit to label apparatus.62, the label apparatus antenna being connected with wet sensitive device sends data.64, reader measurement receives the energy intensity of signal.66, reader calculated goes out the fiducial value of a reaction signal intensity.68, fiducial value is changed into different humidity values by reader.For an example, reader can set a time period for receiving the signal of label, and without receiving signal, signal intensity will be recorded as 0 by reader.
In this system, reader will compare from the signal strength values of the antenna not being connected with wet sensitive device as a reference value, the signal strength values of the label antenna that it is connected with wet sensitive device.By the signal from the transmitting terminal being connected with wet sensitive device and be not connected with wet sensitive device received, reader can collect the fiducial value representing unlike signal intensity.Then, RFID reader can be converted into the humidity level residing for label such a fiducial value.For a concrete example, configuring this RFID reader is in order to the difference from connection or the RF signal intensity of the antenna being not connected to wet sensitive device received is converted into humidity value by the reference data stored by use.
Best situation is, using be not connected to wet sensitive device antenna as a reference, the change caused due to the coupling between label and reader can be filtered out.Additionally, as previously mentioned, the time length that wet sensitive device is applied in design to make the change of its resistance value and label be placed under specified moisture forms relation one to one.Such as, wet sensitive device is only positioned on an antenna, the signal from RFID label tag device so can be allowed to change within the specific limits as a kind of function, and the function that this function antenna just just has after being placed on the time under certain humidity.Ibid, the application of the invention, under conditions of RFID label tag is passive, RFID reader be able to detect that label apparatus be placed under certain humidity and this humidity the most within the acceptable range.
The various RFID label tag not using two antennas also can perceive the change of humidity with wet sensitive device, and the change of perception humidity is also to be able to recognize antenna based on the change of resonant frequency on antenna to receive the change of signal.
Such as by the design to the antenna being connected with wet sensitive device, the frequency of antenna can be made at ISM(IndustrialScientificMedical, industry, science, medical science) the interior change of frequency range, the label of standard can connect this antenna being connected with wet sensitive device and logic circuit.
Such as in a concrete example, label antenna can so set, before being exposed in certain humidity environment, the resonant frequency of antenna is 902-928MHZ, but label is once exposed in certain humidity environment, impact due to humidity, the resonant frequency of antenna just reduces to 899.5-927.5MHZ, frequency bins (902-928MHZ) at U.S. RFID is divided into 52 channels, the channel that can not receive of skipping that reader can be random in these 52 channels goes, the benefit of this jump of reader is exactly can effectively to prevent multiple reader from attempting the conflict using same frequency to be caused in same physical space.
The most in one example, RFID frequency range (902-928MHZ) is not divided into 52 channels but has been divided equally into the antenna settings of n channel tag and has been operated under this frequency range (902-928MHZ).Owing to label antenna is connected with wet sensitive device, as long as so humidity has exceeded the scope of value set in advance, the operating frequency of antenna tag antenna drops down among (899.5-927.5MHZ) this frequency range.Therefore just being got rid of from band limits by channel n compared with original frequency range and go, therefore the frequency range (899.5-927.5MHZ) after change just no longer allows label to carry out exchanging of information with channel n.
In concrete example, if the environment at label place has exceeded intended humidity range, reader can only send instruction by channel 1 to n-1 to label, label also can be made a response, because the antenna in label just can only be at this frequency ranges of operation, when reader sends instruction with the frequency of n channel to label, because the change of label humidity already leads to the resonant frequency of label antenna and has descended to 899.5-927.5MHZ and no longer reach 928MHZ so label is the most no longer made a response, transmit information back to reader.
Favourable aspect is that the change of the operating frequency of antenna caused beyond value set in advance due to humidity is just reflected by the disappearance of this communication for information.
In a model, reader can send an instruction between channel n-1 and channel n to label and further confirm that the operating frequency range of label antenna has occurred that drift, because label can receive the instruction sent by channel n-1, and can pass through channel n-1 can be to reader feedback information, because label can not receive the instruction sent by channel n, and can not pass through channel n can be to reader feedback information, and the operating frequency range thus determining label antenna has occurred that drift.
The change of humidity causes the operating frequency of label antenna to occur drift up and down and current invention to be not limited in and frequency range is averagely divided into n channel.
The embodiment of the present invention can detect humidity change at lower cost, and utilizes the energy that RFID obtains, and solves the powerup issue of Humidity Detection.
The enforcement of each feature of this system may relate to software, hardware is likely to relate to the combination of software and hardware and can be only achieved, and the enforcement of many advantages of such as system is to realize by the way of programming a kind of high-caliber process and OO programming language and computer and other equipment machines mutual exchanges.Each such function program may be stored in a storage intermediary to be read by a computer and processor in such as read only memory and realize above-mentioned function.
Those skilled in the art are it will also be appreciated that the various illustrative components, blocks (illustrativelogicalblock) listed of the embodiment of the present invention, unit, and step can pass through electronic hardware, computer software, or both combinations realize.For clearly showing that the replaceability (interchangeability) of hardware and software, above-mentioned various illustrative components (illustrativecomponents), unit and step the most universally describe their function.Such function is to realize depending on specifically applying the design requirement with whole system by hardware or software.Those skilled in the art can be for every kind of specific application, it is possible to use the function described in the realization of various methods, but this realization is understood not to the scope beyond embodiment of the present invention protection.
Various illustrative logical block described in the embodiment of the present invention, or unit can pass through general processor, digital signal processor, special IC (ASIC), field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or the design of any of the above described combination realize or operate described function.General processor can be microprocessor, and alternatively, this general processor can also be any traditional processor, controller, microcontroller or state machine.Processor can also realize by calculating the combination of device, such as digital signal processor and microprocessor, multi-microprocessor, one or more microprocessors one Digital Signal Processor Core of associating, or any other like configuration realizes.
Method or the step of algorithm described in the embodiment of the present invention can be directly embedded into hardware, the software module of processor execution or the combination of both.Software module can be stored in RAM memory, flash memory, ROM memory, eprom memory, eeprom memory, depositor, hard disk, moveable magnetic disc, CD-ROM or this area in other any form of storage medium.Exemplarily, storage medium can be connected with processor, so that processor can read information from storage medium, it is possible to deposit write information to storage medium.Alternatively, storage medium can also be integrated in processor.Processor and storage medium can be arranged in ASIC, and ASIC can be arranged in user terminal.Alternatively, processor and storage medium can also be arranged in the different parts in user terminal.
In one or more exemplary designs, the above-mentioned functions described by the embodiment of the present invention can realize in the combination in any of hardware, software, firmware or this three.If realized in software, these functions can store with on the medium of computer-readable, or is transmitted on the medium of computer-readable with one or more instructions or code form.Computer readable medium includes computer storage medium and is easy to so that allowing computer program transfer to the telecommunication media in other place from a place.Storage medium can be that any general or special computer can be with the useable medium of access.Such as, such computer readable media can include but not limited to RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage device, or other any may be used for carrying or storage with instruction or data structure and other can be read the medium of program code of form by general or special computer or general or special processor.In addition, any connection can be properly termed computer readable medium, such as, if software is by coaxial cable, optical fiber computer, twisted-pair feeder, Digital Subscriber Line (DSL) or being also contained in defined computer readable medium with wireless way for transmittings such as the most infrared, wireless and microwaves from a web-site, server or other remote resource.Described video disc (disk) and disk (disc) include Zip disk, radium-shine dish, CD, DVD, floppy disk and Blu-ray Disc, and disk is generally with magnetic duplication data, and video disc generally carries out optical reproduction data with laser.Combinations of the above can also be included in computer readable medium.
Above-described detailed description of the invention; the purpose of the present invention, technical scheme and beneficial effect are further described; it is it should be understood that; the foregoing is only the detailed description of the invention of the present invention; the protection domain being not intended to limit the present invention; all within the spirit and principles in the present invention, any modification, equivalent substitution and improvement etc. done, should be included within the scope of the present invention.
Claims (8)
1. the RFID label tag of a band wet sensitive device, it is characterised in that have two pins on the chip of described RFID label tag;Described wet sensitive device is connected with the two pin, and form parallel-connection structure with the antenna of described RFID label tag, the change of ambient humidity can cause the change of the resistance of wet sensitive device own, the circuit that described wet sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines wet sensitive device with sky line parallel: when logic circuit disconnects, wet sensitive device not with sky line parallel, after being now placed on certain humidity level's lower a period of time, first resonant frequency of antenna and signal intensity keep constant;When logic circuit is connected, wet sensitive device and sky line parallel, after being now placed on certain humidity level's lower a period of time, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency;The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna;
Wherein, described antenna is double-doublet antenna, and described wet sensitive device and two antennas concurrently form parallel-connection structure;
When the antenna of described RFID label tag enters in the alternating magnetic field that RFID reader produces, transformator is formed between antenna and the antenna of RFID reader of described RFID label tag, with thinking that wet sensitive device provides energy source, the antenna of RFID label tag and the antenna of RFID reader are respectively primary coil and the secondary coil of transformator, the electromagnetic wave that the antenna of RFID label tag receives is converted to DC voltage by the most interconnective electric charge pump and rectification circuit by described wet sensitive device, with thinking that described RFID label tag performs the instruction offer energy source that described RFID reader sends.
2. the RFID label tag of band wet sensitive device as claimed in claim 1, it is characterised in that described wet sensitive device is resistor-type wet sensitive device, and described wet sensitive device includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device, inorganic some solution matter formula wet sensitive device, quartz resonance wet sensitive device.
3. the RFID label tag of a band wet sensitive device, it is characterised in that have a pin on the chip of described RFID label tag;One end of described wet sensitive device is connected with this pin, the other end is connected on the antenna of described RFID label tag, and form parallel-connection structure with antenna, the change of ambient humidity can cause the change of the resistance of wet sensitive device own, the circuit that described wet sensitive device is connected with the chip of RFID label tag has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines wet sensitive device with sky line parallel: when logic circuit disconnects, wet sensitive device not with sky line parallel, after being now placed on certain humidity level's lower a period of time, first resonant frequency of antenna and signal intensity keep constant;When logic circuit is connected, wet sensitive device and sky line parallel, after being now placed on certain humidity level's lower a period of time, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency;The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna;
Wherein, described antenna is double-doublet antenna, and described wet sensitive device and two antennas concurrently form parallel-connection structure;
When the antenna of described RFID label tag enters in the alternating magnetic field that RFID reader produces, transformator is formed between antenna and the antenna of RFID reader of described RFID label tag, with thinking that wet sensitive device provides energy source, the antenna of RFID label tag and the antenna of RFID reader are respectively primary coil and the secondary coil of transformator, the electromagnetic wave that the antenna of RFID label tag receives is converted to DC voltage by the most interconnective electric charge pump and rectification circuit by described wet sensitive device, with thinking that described RFID label tag performs the instruction offer energy source that described RFID reader sends.
4. the RFID label tag of band wet sensitive device as claimed in claim 3, it is characterised in that described wet sensitive device is resistor-type wet sensitive device, and described resistor-type wet sensitive device includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device, inorganic some solution matter formula wet sensitive device, quartz resonance wet sensitive device.
5. the RFID label tag of a band wet sensitive device, it is characterized in that, described wet sensitive device is connected on the antenna of described RFID label tag, and form parallel-connection structure with antenna, the change of ambient humidity can cause the change of the resistance of wet sensitive device own, the circuit that described wet sensitive device is connected with antenna has a logic circuit controlling break-make, the circuit of this connection and the part that the logic circuit controlling break-make is chip, whether the break-make of logic circuit determines wet sensitive device with sky line parallel: when logic circuit disconnects, wet sensitive device not with sky line parallel, after being now placed on certain humidity level's lower a period of time, first resonant frequency of antenna and signal intensity keep constant;When logic circuit is connected, wet sensitive device and sky line parallel, after being now placed on certain humidity level's lower a period of time, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency;The instruction that described RFID tag RFID reader sends is with the break-make of control logic circuit, thus realizes by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna;
Wherein, described antenna is double-doublet antenna, and described wet sensitive device and two antennas concurrently form parallel-connection structure;
When the antenna of described RFID label tag enters in the alternating magnetic field that RFID reader produces, transformator is formed between antenna and the antenna of RFID reader of described RFID label tag, with thinking that wet sensitive device provides energy source, the antenna of RFID label tag and the antenna of RFID reader are respectively primary coil and the secondary coil of transformator, the electromagnetic wave that the antenna of RFID label tag receives is converted to DC voltage by the most interconnective electric charge pump and rectification circuit by described wet sensitive device, with thinking that described RFID label tag performs the instruction offer energy source that described RFID reader sends.
6. the RFID label tag of band wet sensitive device as claimed in claim 5, it is characterised in that described wet sensitive device is resistor-type wet sensitive device, and described resistor-type wet sensitive device includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device, inorganic some solution matter formula wet sensitive device, quartz resonance wet sensitive device.
7. a rfid system for band wet sensitive device, described rfid system includes RFID label tag and RFID reader, it is characterised in that
Described RFID label tag includes the RFID label tag of band wet sensitive device according to any one of claim 1-2, or the RFID label tag of band wet sensitive device according to any one of claim 3-4, or the RFID label tag of band wet sensitive device according to any one of claim 5-6;
Described RFID reader sends the instruction break-make with the logic circuit of control RFID label tag, thus by comparing the change detecting humidity from the difference between the signal intensity of the different frequency of antenna.
8. the humidity detection method of the rfid system of a band wet sensitive device, it is characterised in that described humidity detection method is applied to the rfid system of band wet sensitive device described in claim 7, including:
Instruction is sent to control the break-make of the logic circuit of RFID label tag by described RFID reader;
The break-make with control logic circuit is instructed: when logic circuit disconnects by what RFID tag RFID reader sent, wet sensitive device not with sky line parallel, now being placed under certain humidity intensity, the first resonant frequency of antenna and signal intensity keep constant;When logic circuit is connected, wet sensitive device and sky line parallel, now it is placed under certain humidity intensity, the characteristic frequency of antenna and signal intensity at least have one and change, and now Antenna Operation is under the second resonant frequency;
Described RFID reader is utilized to compare from the difference between the signal intensity of the different frequency of antenna to detect the change of humidity.
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CN101383020A (en) * | 2008-10-14 | 2009-03-11 | 厦门大学 | Environment sensitive type passive electronic label |
CN202563540U (en) * | 2012-06-01 | 2012-11-28 | 北京物资学院 | RFID label with moisture sensing device and RFID system |
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CN1965324A (en) * | 2004-04-08 | 2007-05-16 | 3M创新有限公司 | Variable frequency radio frequency identification (RFID) tags |
CN101383020A (en) * | 2008-10-14 | 2009-03-11 | 厦门大学 | Environment sensitive type passive electronic label |
CN202563540U (en) * | 2012-06-01 | 2012-11-28 | 北京物资学院 | RFID label with moisture sensing device and RFID system |
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