CN102737268B - The rfid system of a kind of measuring moisture and the method for measuring moisture thereof - Google Patents
The rfid system of a kind of measuring moisture and the method for measuring moisture thereof Download PDFInfo
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- CN102737268B CN102737268B CN201210180318.3A CN201210180318A CN102737268B CN 102737268 B CN102737268 B CN 102737268B CN 201210180318 A CN201210180318 A CN 201210180318A CN 102737268 B CN102737268 B CN 102737268B
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Abstract
The present invention provides the rfid system of a kind of measuring moisture and the method for measuring moisture thereof, the rfid system of described measuring moisture includes: RFID reader, the first RFID label tag and the second RFID label tag, and described first RFID label tag and described second RFID label tag have identical chip and antenna；After described first RFID label tag is placed on certain humidity level's lower a period of time, described first RFID label tag is operated under the first resonant frequency；Described second RFID label tag is the RFID label tag of band wet sensitive device, described wet sensitive device forms parallel-connection structure with the antenna of described second RFID label tag, after being now placed on certain humidity level's lower a period of time, described second RFID label tag is operated under the second resonant frequency；Described first RFID label tag and described second RFID label tag receive instruction the feedback signal that described RFID reader sends respectively, and described RFID reader detects the change of humidity by comparing from the difference between the signal intensity of described first RFID label tag and described second RFID label tag different frequency.The present invention can detect humidity change at lower cost.
Description
Technical field
The present invention relates to RFID(Radio Frequency Identification, RF identification) technical field, particularly relate to one
Plant rfid system and the method for measuring moisture thereof of measuring moisture.
Background technology
In recent years, rfid system had become more prevalent.Rfid system is mainly used in the identification to people and thing.General next
Saying, this system includes at least a RFID reader, and this RFID reader can be sent out in the range of a setting
Penetrate and accept the radiofrequency signal from one or more RFID label tag.This RFID label tag is usually encapsulated, can
With patch on one object, it includes that one can carry out the chip of communication for information with antenna, and this chip is microchip, one
Being an integrated circuit from the point of view of as, 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
Different frequency.
In some equipment, the rfid system of a kind of measuring moisture has been used for monitoring when the humidity of product local environment surpasses
Cross acceptable humidity.In general these equipment requirements induction installations to have a lasting energy source, is used for examining
The change of measuring moisture, but this can increase the cost of equipment.It addition, some equipment requirements induction installations also to compare with one
Device circuit is connected, thus detects the degree size of deviation reference voltage, and this requirement considerably increases the cost of equipment.
In a word, improving what rfid system was a need for, it requires do not using lasting energy source or using a kind of low cost
Adjunct circuit time can be used to detect humidity change.
Summary of the invention
The embodiment of the present invention provides a kind of rfid system and the method for measuring moisture thereof of measuring moisture, detects wet at lower cost
Degree change.
On the one hand, embodiments provide the rfid system of a kind of measuring moisture, the rfid system bag of described measuring moisture
Include: RFID reader, the first RFID label tag and the second RFID label tag, described first RFID label tag and described 2nd RFID
Label has identical chip and antenna；After described first RFID label tag is placed on certain humidity level's lower a period of time,
First resonant frequency of the antenna of described first RFID label tag and signal intensity keep constant, the most described RFID mark
Label are operated under the first resonant frequency；Described second RFID label tag is the RFID label tag of band wet sensitive device, described 2nd RFID
Two pins are had on the chip of label；Described wet sensitive device is connected with the two pin, and with described second RFID label tag
Antenna forms parallel-connection structure, and the change of ambient humidity can cause the change of the resistance of wet sensitive device own, now be placed on certain
After humidity level's lower a period of time, characteristic frequency and the signal intensity of the antenna of described second RFID label tag at least have one
Changing, the most described second RFID label tag is operated under the second resonant frequency；Described first RFID label tag and described
Second RFID label tag receives instruction the feedback signal that described RFID reader sends respectively, and described RFID reader is passed through
Relatively examine from the difference between the signal intensity of described first RFID label tag and described second RFID label tag different frequency
The change of measuring moisture.
Optionally, in an embodiment of the present invention, the antenna of described first RFID label tag and described second RFID label tag is equal
For monopole antenna: described wet sensitive device forms parallel-connection structure with the antenna of described second RFID label tag.
Optionally, in an embodiment of the present invention, the antenna of described first RFID label tag and described second RFID label tag is equal
For double-doublet antenna: an antenna of described wet sensitive device and described second RFID label tag forms parallel-connection structure, or with
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, Fe3O4
Wet 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, the rfid system of a kind of measuring moisture, the rfid system of described measuring moisture are embodiments provided
Including: RFID reader, the first RFID label tag and the second RFID label tag, described first RFID label tag and described second
RFID label tag has identical chip and antenna；When described first RFID label tag is placed on certain humidity level next section
After between, the first resonant frequency of the antenna of described first RFID label tag and signal intensity keep constant, the most described RFID
Labeling task is under the first resonant frequency；Described second RFID label tag is the RFID label tag of band wet sensitive device, described second
A pin is had on the chip of RFID label tag；One end of described wet sensitive device is connected with this pin, and the other end is connected to institute
Stating on the antenna of RFID label tag, and form parallel-connection structure with antenna, the change of ambient humidity can cause wet sensitive device electricity itself
The change of resistance, after being now placed on certain humidity level's lower a period of time, the feature of the antenna of described second RFID label tag
Frequency and signal intensity at least have one and change, and the most described second RFID label tag is operated under the second resonant frequency；
Described first RFID label tag and described second RFID label tag receive instruction the feedback letter that described RFID reader sends respectively
Number, described RFID reader is by comparing from described first RFID label tag and described second RFID label tag different frequency
Difference between signal intensity detects the change of humidity.
Optionally, in an embodiment of the present invention, the antenna of described first RFID label tag and described second RFID label tag is equal
For monopole antenna: described wet sensitive device forms parallel-connection structure with the antenna of described second RFID label tag.
Optionally, in an embodiment of the present invention, the antenna of described first RFID label tag and described second RFID label tag is equal
For double-doublet antenna: an antenna of described wet sensitive device and described second RFID label tag forms parallel-connection structure, or with
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 fills
Put and include: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive fills
Put, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device,
Inorganic solution matter formula wet sensitive device, quartz resonance wet sensitive device.
Another aspect, embodiments provides the rfid system of a kind of measuring moisture, the rfid system of described measuring moisture
Including: RFID reader, the first RFID label tag and the second RFID label tag, described first RFID label tag and described second
RFID label tag has identical chip and antenna；When described first RFID label tag is placed on certain humidity level next section
After between, the first resonant frequency of the antenna of described first RFID label tag and signal intensity keep constant, the most described RFID
Labeling task is under the first resonant frequency；Described second RFID label tag is the RFID label tag of band wet sensitive device, described wet sensitive
Device is connected on the antenna of described RFID label tag, and forms parallel-connection structure with antenna, and the change of ambient humidity can cause wet
The change of the resistance of quick device own, after being now placed on certain humidity level's lower a period of time, described second RFID label tag
The characteristic frequency of antenna and signal intensity at least have one and change, the most described second RFID label tag is operated in
Under two resonant frequencies；Described first RFID label tag and described second RFID label tag receive described RFID reader respectively and send
Instruction and feedback signal, described RFID reader is by comparing from described first RFID label tag and described 2nd RFID
Difference between the signal intensity of label different frequency detects the change of humidity.
Optionally, in an embodiment of the present invention, the antenna of described first RFID label tag and described second RFID label tag is equal
For monopole antenna: described wet sensitive device forms parallel-connection structure with the antenna of described second RFID label tag.
Optionally, in an embodiment of the present invention, the antenna of described first RFID label tag and described second RFID label tag is equal
For double-doublet antenna: an antenna of described wet sensitive device and described second RFID label tag forms parallel-connection structure, or with
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 fills
Put and include: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive fills
Put, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, high molecular resistance type wet sensitive device, semiconductor-type wet sensitive device,
Inorganic solution matter formula wet sensitive device, quartz resonance wet sensitive device.
Another further aspect, the method embodiments providing the rfid system measuring moisture of a kind of measuring moisture, described method should
For the rfid system of above-mentioned measuring moisture, including: described first RFID label tag is placed on certain humidity level next
After the section time, the first resonant frequency of the antenna of described first RFID label tag and signal intensity keep constant, and the most described the
One RFID label tag is operated under the first resonant frequency: described second RFID label tag is placed on certain humidity level next
After the section time, the characteristic frequency of the antenna of described second RFID label tag and signal intensity at least have one and change, this
Shi Suoshu the second RFID label tag is operated under the second resonant frequency；Described is sent instructions to by described RFID reader
One RFID label tag and described second RFID label tag also receive feedback signal；Utilize described RFID reader more described first
When RFID label tag and described second RFID label tag work, the difference between the signal intensity of different frequency detects changing of humidity
Become.
Technique scheme has the advantages that because using the rfid system of described measuring moisture to include: RFID reads
Device, the first RFID label tag and the second RFID label tag, described first RFID label tag and described second RFID label tag have phase
Same chip and antenna；After described first RFID label tag is placed on certain humidity level's lower a period of time, described first
RFID label tag is operated under the first resonant frequency；Described second RFID label tag is the RFID label tag of band wet sensitive device, described
Wet sensitive device forms parallel-connection structure with the antenna of described second RFID label tag, is now placed on next section of certain humidity level
After time, described second RFID label tag is operated under the second resonant frequency；Described first RFID label tag and described 2nd RFID
Label receive respectively described RFID reader send instruction and feedback signal, described RFID reader by compare from
Difference between the signal intensity of described first RFID label tag and described second RFID label tag different frequency detects humidity
The technological means changed, so having reached to detect at lower cost the technique effect of humidity change, and utilizes RFID to obtain
Energy, 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, below will be to embodiment or existing skill
In art description, the required accompanying drawing used is briefly described, it should be apparent that, the accompanying drawing in describing below is only the present invention
Some embodiments, for those of ordinary skill in the art, on the premise of not paying creative work, it is also possible to root
Other accompanying drawing is obtained according to these accompanying drawings.
Fig. 1 is the rfid system structural representation of a kind of measuring moisture of the embodiment of the present invention；
The schematic diagram that Fig. 2 is embodiment of the present invention wet sensitive device and the second RFID label chip is connected；
Fig. 3 is the equivalent circuit diagram of the embodiment of the present invention the second RFID label chip inside antenna；
Fig. 4 is the signal that embodiment of the present invention wet sensitive device, the second RFID label chip inside antenna equivalent circuit are connected
Figure；
Fig. 5 is that embodiment of the present invention wet sensitive device is joined directly together, with RFID label antenna, the schematic diagram connect；
Fig. 6 .1-Fig. 6 .2 is the structure explanatory diagram of embodiment of the present invention wet sensitive device；
Fig. 7 is the method flow diagram of embodiment of the present invention measuring moisture based on signal intensity.
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 carried out clearly and completely
Describe, it is clear that described embodiment is only a part of embodiment of the present invention rather than whole embodiments.Based on this
Embodiment in invention, the every other reality that those of ordinary skill in the art are obtained under not making creative work premise
Execute example, broadly fall into the scope of protection of the invention.
As it is shown in figure 1, be the rfid system structural representation of a kind of measuring moisture of the embodiment of the present invention, the RFID of described measuring moisture
System includes: RFID reader the 1, first RFID label tag 2 and the second RFID label tag 3, described first RFID label tag 2
With described second RFID label tag 3, there is identical chip and antenna；Described first RFID label tag 2 is placed on certain
After humidity level's lower a period of time, the first resonant frequency of the antenna of described first RFID label tag 2 and signal intensity keep not
Becoming, the most described first RFID label tag 2 is operated under the first resonant frequency；Described second RFID label tag 3 is band wet sensitive
The RFID label tag of device, described wet sensitive device forms parallel-connection structure with the antenna of described second RFID label tag 3, extraneous wet
The change of degree can cause the change of the resistance of wet sensitive device own, after being now placed on certain humidity level's lower a period of time, institute
Characteristic frequency and the signal intensity of stating the antenna of the second RFID label tag 3 at least have one and change, and the most described second
RFID label tag 3 is operated under the second resonant frequency；Described first RFID label tag 2 and described second RFID label tag 3 are respectively
Receiving instruction feedback signal that described RFID reader 1 sends, described RFID reader 1 is by comparing from described
Difference between the signal intensity of the first RFID label tag 2 and described second RFID label tag 3 different frequency detects humidity
Change.The wet sensitive device of the embodiment of the present invention and the chip of the second RFID label tag are connected and at least there are three kinds of situations:
Two pins structure:
The embodiment of the present invention is a kind of rfid system for detecting humidity change.This system contains two RFID marks
Sign: the first RFID label tag and the second RFID label tag.Have two pins on the chip of the second RFID label tag, wet sensitive device with
The two pin is connected, and forms parallel-connection structure with antenna, and the change of ambient humidity can cause the change of the resistance of wet sensitive device own.
After being now placed on certain humidity level's lower a period of time, the first resonant frequency of the antenna of the first RFID label tag and letter
Number intensity keeps constant.The characteristic frequency of the antenna of the second RFID label tag and signal intensity at least have one and change,
Now Antenna Operation is under the second resonant frequency.RFID reader can send instruction to label, it is achieved communication, Ke Yitong
Cross compare the first RFID label tag and the second RFID label tag work time different frequency signal intensity between difference wet to detect
The change of degree.
For an example, this system contains a kind of RFID label tag, described label comprise the first RFID label tag and
Second RFID label tag, the first RFID label tag and the second RFID label tag all only have an antenna.The core of the second RFID label tag
Having two pins on sheet, wet sensitive device is connected with the two pin, forms parallel-connection structure, the change meeting of ambient humidity with antenna
Cause the change of the resistance of wet sensitive device own.After being now placed on certain humidity level's lower a period of time, a RFID
First resonant frequency of the antenna of label and signal intensity keep constant.The characteristic frequency of the antenna of the second RFID label tag and letter
Number intensity at least has one and changes, and now Antenna Operation is under the second resonant frequency.RFID reader can give mark
Sign and issue and send instruction, it is achieved communication, can by compare the first RFID label tag and the second RFID label tag work time different frequency
Signal intensity between difference detect the change of humidity.
More precisely, wet sensitive device should have relatively low resistance, its instantiation includes: MgCr2O4-TiO2Wet sensitive fills
Put, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5
Wet 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 (step on Morse LiCl wet sensitive device, impregnated wet sensitive dress
Put, DWS-P type LiCl(lithium chloride) humistor device), quartz resonance wet sensitive device etc..
For another example, this system contains two RFID label tag: the first RFID label tag and the 2nd RFID
Label；First RFID label tag and the second RFID label tag have two antennas.Two are had to draw on the chip of the second RFID label tag
Foot, wet sensitive device is connected with the two pin, concurrently forms parallel-connection structure with two antennas.The change of ambient humidity can cause
The change of the resistance of wet sensitive device own.This situation only containing an antenna with the second RFID label tag is similar.Now it is placed on
After certain humidity level's lower a period of time, the first resonant frequency of the antenna of the first RFID label tag and signal intensity keep not
Become.The characteristic frequency of the antenna of the second RFID label tag and signal intensity at least have one and change, now Antenna Operation
Under the second resonant frequency.RFID reader can send instruction to label, it is achieved communication, can be by comparing a RFID
When label and the work of the second RFID label tag, the difference between the signal intensity of different frequency detects the change of humidity.More precisely
Ground is said, wet sensitive device should have relatively low resistance, and its instantiation includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3
Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, height
Molecular resistors formula wet sensitive device, semiconductor-type wet sensitive device (Se(selenium) evaporating film wet sensitive device, silicon MOS type Al2O3
Wet sensitive device), inorganic solution matter formula wet sensitive device (step 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:
This system contains two RFID label tag: the first RFID label tag and the second RFID label tag, the second RFID label tag
Chip on have a pin, this pin outwards one end with wet sensitive device is connected, and the other end of wet sensitive device is attached directly to
On antenna.Pin is similar at the junction point of chip internal and the situation of two pins, finally remains and to reach and sky line parallel
Purpose.The change of ambient humidity can cause the change of the resistance of wet sensitive device own.Now it is placed on certain humidity level
After lower a period of time, the first resonant frequency of the antenna of the first RFID label tag and signal intensity keep constant.2nd RFID
The characteristic frequency of the antenna of label and signal intensity at least have one and change, and now Antenna Operation is at the second resonant frequency
Under.RFID reader can send instruction to label, it is achieved communication, can be by comparing the first RFID label tag and second
During RFID label tag work, the difference between the signal intensity of different frequency detects the change of humidity.
For an example, this system contains two RFID label tag: the first RFID label tag and the second RFID label tag；
First RFID label tag and the second RFID label tag all only have an antenna.A pin is had on the chip of the second RFID label tag,
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.Outward
The change of boundary's humidity can cause the change of the resistance of wet sensitive device own.Now it is placed on certain humidity level's lower a period of time
After, the first resonant frequency of the antenna of the first RFID label tag and signal intensity keep constant.The antenna of the second RFID label tag
Characteristic frequency and signal intensity at least have one and change, now Antenna Operation is under the second resonant frequency.RFID
Reader can send instruction to label, it is achieved communication, can be by comparing the first RFID label tag and the second RFID label tag
During work, difference between the signal intensity of different frequency detects the change of humidity.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 fill
Put, semiconductor-type wet sensitive device (Se(selenium) evaporating film wet sensitive device, silicon MOS type Al2O3Wet sensitive device), inorganic point
Solve matter formula wet sensitive device (stepping on Morse LiCl wet sensitive device, impregnated wet sensitive device, DWS-P type LiCl(lithium chloride) wet
Quick resistance device), quartz resonance wet sensitive device etc..
Without pin configuration:
This system contains two RFID label tag: the first RFID label tag and the second RFID label tag, the 2nd RFID marks
Pin, wet sensitive device is not had to be attached directly on antenna on the chip signed.In this case, the antenna being connected with wet sensitive device is not
Wet sensitive device can be departed from and with normal frequency for communication.After being placed on certain humidity level's lower a period of time, antenna
Characteristic frequency and signal intensity at least have one and change.RFID reader can send instruction to label apparatus, real
Now communicate, by comparing from the difference between the signal intensity of the first RFID label tag and the different frequency of the second RFID label tag
The different change detecting humidity.
For an example, this system contains two RFID label tag: the first RFID label tag and the second RFID label tag；
First RFID label tag and the second RFID label tag all only have an antenna.Pin is not had on the chip of the second RFID label tag, wet
Quick device is attached directly on antenna.The change of ambient humidity can cause the change of the resistance of wet sensitive device own.Now it is placed on
After certain humidity level's lower a period of time, the first resonant frequency of the antenna of the first RFID label tag and signal intensity keep not
Become.The characteristic frequency of the antenna of the second RFID label tag and signal intensity at least have one and change, now Antenna Operation
Under the second resonant frequency.RFID reader can send instruction to label, and by comparing the first RFID label tag and second
Difference between the signal intensity of different frequency during root labeling task can detect the change of humidity.More precisely, wet sensitive
Device should have relatively low resistance, and its instantiation includes: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive fills
Put, ZrO2Type wet sensitive device, Al2O3Wet sensitive device, Fe3O4Wet sensitive device, TiO2-V2O5Wet sensitive device, macromolecule electricity
Resistive 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 (steps on Morse LiCl wet sensitive device, impregnated wet sensitive device, DWS-P type LiCl(chlorination
Lithium) 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.My god
The radical of line can be one, two the most.One or more wet sensitive device can also be connected accordingly, simultaneously
The model of wet sensitive device can be the same or different.For a kind of instantiation of device, certain wet when being placed on
After degree level 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
Become.RFID reader can to label apparatus send instruction, by compare the different frequency from antenna signal intensity it
Between difference detect the change of humidity.
For the instantiation of a kind of wet sensitive device, simultaneous compares the method for numerical value and includes these compare numerical value and majority
Signal strength values compares.These signal strength values belong to different frequencies, and are associated, simultaneously with most humidity values
The level of humidity can be detected based on comparison mentioned above.
But, for another aspect, a rfid system includes that two RFID label tag devices and a RFID read
Device device.The two RFID label tag device is used to send two kinds of signals, i.e. the signal of the first RFID label tag and second
The signal of RFID label tag, reader receives signal and the signal of the second RFID label tag of the first RFID label tag respectively, passes through
Fiducial value between first RFID label tag and the signal strength values of the second RFID label tag of background process, and these are compared
Value is converted into the varying level of humidity.
As in figure 2 it is shown, the wet label 10 of sense being connected for embodiment of the present invention wet sensitive device and the second RFID label chip
Schematic diagram.In Fig. 2, label apparatus 10, including a base 15, a surface-mounted integrated circuit 13, two pins 16,17
With a double-doublet antenna 11,12.Having two pins 16,17 on surface-mounted integrated circuit 13, the two pin is outwards and wet sensitive
Device 14 is connected, and the two pin is in parallel with the equivalent circuit of antenna at chip internal.This label can be carried out with reader
Communication.
In an example, transmitting terminal 11,12 are 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 and wet sensitive device mentioned above are by two pins 16,17 and antenna
11,12 are connected, and when antenna 11, after 12 are placed on certain humidity level's lower a period of time, wet sensitive device can cause one
Individual or the change of multiple transmitting terminal generation resonant frequency, thus cause a different frequency.The change of this frequency and reception
The most different with the frequency sent.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, then
When reaching certain humidity, it will reduce.In another example, the antenna frequencies set at the beginning is less than the wettest
Antenna frequencies under degree level, when reaching certain humidity level, it will rise.Can be used for such wet sensitive of the present invention
Device has: MgCr2O4-TiO2Wet sensitive device, ZnO-Cr2O3Wet sensitive device, ZrO2Type wet sensitive device, Al2O3Wet sensitive fills
Put, 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 (step 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 one
The scope of individual selectively humidity value.The length of time necessarily causes the change of antenna resonance frequency, and antenna quality also can be led
Cause different changes.Such as, on antenna with the type of wet sensitive device can affect change antenna resonance frequency required time
Length.
As it is shown on figure 3, be the equivalent circuit diagram of the first RFID label antenna.Produce when tag coil antenna enters read write line
Alternating magnetic field in, the interaction between label antenna and reading and writing device antenna is similar to transformator.Both coils are suitable
Primary coil and secondary coil in transformator.The resonant tank formed by label antenna is as it can be seen, include label antenna
Coil inductance (L), parasitic capacitance (Cp) and shunt capacitance (C2), its resonant frequency is
In formula, C is
CpAnd C2Parallel equivalent electric capacity, R1, R2For circuit internal inductance coil and the equivalent resistance of other devices.Label and read-write
The carrier frequency that device two-way communication uses is exactly f.When requiring that tag antenna coil profile is the least, i.e. area is little, and needs 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, Ke Yi
Tag antenna coil is internal inserts the Ferrite Material with high permeability, to increase mutual induction amount, thus bucking coil cross section
Little problem.
As shown in Figure 4, for showing that embodiment of the present invention wet sensitive device and the second RFID label antenna equivalent circuit are connected
It is intended to.The resonant tank formed by label antenna is as it can be seen, include the coil inductance (L) of label antenna, parasitic capacitance (Cp)
With shunt capacitance (C2), its resonant frequency is
Formula 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.This label is put
Put under certain humidity level after a period of time, Antenna Operation under the second resonant frequency, its characteristic frequency and signal intensity
At least have one to change.
As it is shown in figure 5, the sketch of the passive RFID tags device 40 of humidity change can be detected for the embodiment of the present invention.Such as figure
Shown in 4, label apparatus 40 includes a base 45, an integrated circuit 43 and a double-doublet antenna 41,42.With sky
The wet sensitive device 44 that line 42 is connected will affect the resistance of antenna 42.The material that wet sensitive device 44 is suitable for can be according to sky
Line 41, the current voltage of any in 42 controls any one frequency both pinpointed.For an example, peace
Dress antenna 41,42 can make it produce resonance in identical frequency.For another example, installing antenna 41,42 can
So that it produces 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, this
A little materials have higher electric conductivity, such as copper, silver, and aluminum, and 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 one or more transmitting terminal that resonance frequency occurs
The change of rate, thus cause a different frequency.The change of this frequency is the most different with the frequency received and send.Example
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 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, then
When reaching certain humidity, it will reduce.In another example, the antenna frequencies set at the beginning is less than the wettest
Antenna frequencies under degree level, when reaching certain humidity level, it will rise.Can be used for the such wet of invention originally
Quick device 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 (step on not
Formula LiCl wet sensitive device, impregnated wet sensitive device, DWS-P type LiCl(lithium chloride) humistor device), quartz resonance
Formula 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 one
The scope of individual selectively humidity value.The length of time necessarily causes the change of antenna resonance frequency, and antenna quality also can be led
Cause different changes.Such as, on antenna with the type of wet sensitive device can affect change antenna resonance frequency required time
Length.
As shown in Fig. 6 .1, Al2O3Wet sensitive device is outside conductor, to spray one with plasma spraying method in the way of interior electrode 513
Layer Al2O3Humidity-sensitive film 512, makes porous metal electrode 511 on film and forms.Its sense moor reason is: the rustless steel in figure
Pipe 513, i.e. as the interior electrode 513 of sensor, is again Al simultaneously2O3The carrier of humidity-sensitive film 512.This structure can be seen
Make a capacitor, when after the hydrone outer metal electrode 511 through porous, then by Al2O3Humidity-sensitive film 512 adsorbs, from
And cause Al2O3Humidity-sensitive film 512 dielectric constant changes, and brings the change of sensor capacitance.Along with Vapor adsorption amount
Increase sensor resistance reduce and make capacitance increase.And the logarithm value of resistance is linear with humidity, has survey
Wet scope and working range width.
As shown in Fig. 6 .2, for ZrO2The structure chart of type wet sensitive device.This structure includes dustproof filter film 521, the ZrO of printing2
Humidity sensing layer 522, the Au comb electrode 523 printed by silk screen print method, a ceramic substrate 524, and two electrodes draw
Line 525,526.Humidity sensing layer 522 is a kind of porous ZrO2Being thick-film material, its available bases metal regulation tissue size also carries
Its long-time stability high.Its sense moor reason is owing to the water of physical absorption solves on the surface of wet sensitive device humidity sensing layer
From, result generates proton and participates in conduction.
As it is shown in fig. 7, be the method flow diagram of embodiment of the present invention measuring moisture based on signal intensity, described method is applied to
The rfid system of above-mentioned measuring moisture, including:
701, after described first RFID label tag being placed on certain humidity level's lower a period of time, a described RFID mark
First resonant frequency of the antenna signed and signal intensity keep constant, and the most described first RFID label tag is operated in the first resonance
Under frequency:
702, after described second RFID label tag being placed on certain humidity level's lower a period of time, described 2nd RFID mark
Characteristic frequency and the signal intensity of the antenna signed at least have one and change, and the most described second RFID label tag is operated in
Under second resonant frequency；
703, described first RFID label tag and described second RFID label tag are sent instructions to also by described RFID reader
Receive feedback signal；
When 704, utilizing more described first RFID label tag of described RFID reader and described second RFID label tag to work not
Difference between the signal intensity of same frequency detects the change of humidity.
RFID reader can measure the energy intensity receiving signal, calculates the fiducial value of a reaction signal intensity, then
Fiducial value is changed into different humidity values.For an example, reader can set a time period for receiving label
Signal, without receiving signal, signal intensity will be recorded as 0 by reader.
In this system, RFID reader is by the signal strength values from the first RFID label tag not being connected with wet sensitive device
As a reference value, the signal strength values of the second RFID label tag that it is connected with wet sensitive device compares.Logical
Cross receive from the first RFID label tag being connected with wet sensitive device and be not connected with wet sensitive device and the second RFID label tag
Signal, RFID reader can collect the fiducial value representing unlike signal intensity.Then, RFID reader can be so
One fiducial value is converted into the humidity level residing for label.For a concrete example, configure this RFID reader
Be in order to the reference data stored by use by receive from connecting or be not connected to the RFID label tag of wet sensitive device
The difference of RF signal intensity is converted into humidity value.
Best situation is, using be not connected to wet sensitive device the first RFID label tag as a reference, can be by due to label
With the change that the coupling between reader is caused filters out.Additionally, as previously mentioned, wet sensitive device is employed
The time length formation one that the change of its resistance value is placed under specified moisture can be made with the second RFID label tag in design
One-to-one correspondence.Ibid, the application of the invention, under conditions of RFID label tag is passive, RFID reader can be examined
Measure 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, perception humidity
Change 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, it is possible to make the frequency of antenna at ISM(Industrial
Scientific Medical, industry, science, medical science) the interior change of frequency range, the label of standard can connect this and wet
The antenna that quick device and logic circuit are connected.
Such as in a concrete example, label antenna can so set, before being exposed in certain humidity environment, and sky
The resonant frequency of line is 902-928MHZ, but label is once exposed in certain humidity environment, due to the impact of humidity, sky
The resonant frequency of line just reduces to 899.5-927.5MHZ, divided at the frequency bins (902-928MHZ) of U.S. RFID
Being 52 channels, the channel that can not receive of skipping that reader can be random in these 52 channels goes, and reader is this
The benefit jumped can effectively prevent multiple reader from attempting to use same frequency institute in same physical space exactly
The conflict caused.
The most in one example, RFID frequency range (902-928MHZ) is not divided into 52 channels but averagely divides
The antenna settings having become n channel tag is operated under this frequency range (902-928MHZ).Owing to label antenna is with wet
Quick device is connected, as long as so humidity has exceeded the scope of value set in advance, the operating frequency of antenna tag antenna just declines
Among (899.5-927.5MHZ) this frequency range.Therefore compared with original frequency range just by channel n from frequency range model
Enclosing middle eliminating to go, therefore the frequency range (899.5-927.5MHZ) after change just no longer allows label and channel n to carry out information
Exchange.
In concrete example, if the environment at label place has exceeded intended humidity range, reader can only pass through channel
1 to n-1 sends instruction to label, and label also can be made a response, because the antenna in label just can only be in this frequency range
Interior work, when reader sends instruction with the frequency of n channel to label, because the change of label humidity already leads to label
The resonant frequency of antenna has descended to 899.5-927.5MHZ and no longer reaches 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 by this letter
Cease the disappearance of exchange and reflect.
In a model, reader can further confirm that to label one instruction between channel n-1 and channel n of transmission
Once the operating frequency range of label antenna has occurred that drift, is sent by channel n-1 because label can receive
Instruction, and can by channel n-1 can be to reader feedback information because label can not receive by channel n
The instruction sent, and can not thus determine the work of label antenna to reader feedback information by channel n
Working frequency scope has occurred that drift.
The change of humidity causes the operating frequency of label antenna to occur drift up and down and current invention not to limit
Frequency range is averagely being divided into n channel by system.
The embodiment of the present invention can detect humidity change at lower cost, and utilizes the energy that RFID obtains, and solves humidity
The powerup issue of detection.
The enforcement of each feature of this system may relate to software, and hardware is likely to relate to the combination ability of software and hardware
Reaching, the enforcement of many advantages of such as system is by programming a kind of high-caliber process and OO programming language
Realize with the mode mutually exchanged of computer and other equipment machines.Each such function program may be stored in one
Individual storage intermediary is read by a computer and processor in such as read only memory and realizes above-mentioned function.
Those skilled in the art are it will also be appreciated that the various illustrative components, blocks (illustrative that list of the embodiment of the present invention
Logical block), unit, and step can pass through electronic hardware, computer software, or both combinations realize.For
Clearly show that the replaceability (interchangeability) of hardware and software, above-mentioned various illustrative components (illustrative
Components), unit and step the most universally describe their function.Such function is by hardware or soft
Part realizes depending on specifically applying the design requirement with whole system.Those skilled in the art can be specific for every kind
Application, it is possible to use the function described in the realization of various methods, but this realization is understood not to protect beyond the embodiment of the present invention
The scope protected.
Various illustrative logical block described in the embodiment of the present invention, or unit can pass through general processor, numeral
Signal processor, special IC (ASIC), field programmable gate array (FPGA) or other FPGA dress
Put, discrete gate or transistor logic, discrete hardware components, or the design of any of the above described combination realizes or operates described
Function.General processor can be microprocessor, alternatively, this general processor can also be any traditional processor,
Controller, microcontroller or state machine.Processor can also realize, such as at digital signal by calculating the combination of device
Reason device and microprocessor, multi-microprocessor, one or more microprocessors one Digital Signal Processor Core of associating, or appoint
What its similar configuration realizes.
Method or the step of algorithm described in the embodiment of the present invention can be directly embedded into hardware, the software mould of processor execution
Block or the combination of both.Software module can be stored in RAM memory, flash memory, ROM memory, EPROM
In memorizer, eeprom memory, depositor, hard disk, moveable magnetic disc, CD-ROM or this area, other is any
In the storage medium of form.Exemplarily, storage medium can be connected with processor, so that processor can be from storage matchmaker
Jie reads information, 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 hardware, software,
The combination in any of firmware or this three realizes.If realized in software, these functions can store the matchmaker with computer-readable
On Jie, or it is transmitted on the medium of computer-readable with one or more instructions or code form.Computer readable medium includes computer
Store medium and be easy to so that allowing computer program transfer to the telecommunication media in other place from a place.Storage medium can be
Any general or special computer can be with the useable medium of access.Such as, such computer readable media can include but not
It is limited to RAM, ROM, EEPROM, CD-ROM or other optical disc storage, disk storage or other magnetic storage device,
Other any may be used for carrying or storage with instruction or data structure and other can by general or special computer or general or
Special processor reads the medium of the program code of form.Additionally, any connection can be properly termed computer-readable
Medium, such as, if software is by coaxial cable, a light from a web-site, server or other remote resource
Fine computer, twisted-pair feeder, Digital Subscriber Line (DSL) or with the wireless way for transmittings such as the most infrared, wireless and microwave also by
It is included in defined computer readable medium.Described video disc (disk) and disk (disc) include Zip disk, radium-shine
Dish, CD, DVD, floppy disk and Blu-ray Disc, disk is generally with magnetic duplication data, and video disc generally carries out light with laser
Learn and replicate data.Combinations of the above can also be included in computer readable medium.
Above-described detailed description of the invention, has been carried out the purpose of the present invention, technical scheme and beneficial effect the most in detail
Illustrate, be it should be understood that the detailed description of the invention that the foregoing is only the present invention, be not intended to limit the present invention
Protection domain, all within the spirit and principles in the present invention, any modification, equivalent substitution and improvement etc. done, all should wrap
Within being contained in protection scope of the present invention.
Claims (4)
1. the rfid system of a measuring moisture, it is characterised in that the rfid system of described measuring moisture includes: RFID reads
Read device, the first RFID label tag and the second RFID label tag, described first RFID label tag and described second RFID label tag to have
Identical chip and antenna；After described first RFID label tag is placed on certain humidity level's lower a period of time, described
First resonant frequency of the antenna of one RFID label tag and signal intensity keep constant, the most described first RFID label tag work
Under the first resonant frequency；Described second RFID label tag is the RFID label tag of band wet sensitive device, described second RFID label tag
Chip on have two pins；Described wet sensitive device is connected with the two pin, and with the antenna of described second RFID label tag
Forming parallel-connection structure, the change of ambient humidity can cause the change of the resistance of wet sensitive device own, now be placed on certain humidity
After level lower a period of time, the characteristic frequency of the antenna of described second RFID label tag and signal intensity at least have a generation
Change, the most described second RFID label tag is operated under the second resonant frequency；Described first RFID label tag and described second
RFID label tag receives instruction the feedback signal that described RFID reader sends respectively, and described RFID reader is by comparing
Detect wet from the difference between the signal intensity of described first RFID label tag and described second RFID label tag different frequency
The change of degree；
Wherein, described wet sensitive device is outside conductor, to spray one layer of Al2O3 sense wet with plasma spraying method in the way of interior electrode
Film, and on film, make the Al2O3 wet sensitive device of porous metal electrode；
Wherein, when the antenna of described RFID label tag enters in the alternating magnetic field that RFID reader produces, described RFID marks
Transformator is formed, with thinking that humidity sensitive device provides energy source, RFID between antenna and the antenna of RFID reader signed
The antenna of label and the antenna of RFID reader are respectively primary coil and the secondary coil of transformator, mark at described RFID
The inner antenna signed inserts the Ferrite Material of high permeability.
2. the rfid system of as claimed in claim 1 measuring moisture, it is characterised in that described first RFID label tag and described
The antenna of the second RFID label tag is monopole antenna: the dwi hastasana of described wet sensitive device and described second RFID label tag
Become parallel-connection structure.
3. the rfid system of as claimed in claim 1 measuring moisture, it is characterised in that described first RFID label tag and described
The antenna of the second RFID label tag is double-doublet antenna: a sky of described wet sensitive device and described second RFID label tag
Line forms parallel-connection structure, or concurrently forms parallel-connection structure with two antennas.
4. the method for the rfid system measuring moisture of a measuring moisture, it is characterised in that described method is applied to claim
The rfid system of measuring moisture according to any one of 1-3, including:
After described first RFID label tag is placed on certain humidity level's lower a period of time, described first RFID label tag
First resonant frequency of antenna and signal intensity keep constant, and the most described first RFID label tag is operated in the first resonant frequency
Under:
After described second RFID label tag is placed on certain humidity level's lower a period of time, described second RFID label tag
The characteristic frequency of antenna and signal intensity at least have one and change, and the most described second RFID label tag is operated in second
Under resonant frequency；
Send instructions to described first RFID label tag and described second RFID label tag by described RFID reader and receive
Feedback signal；
Utilize more described first RFID label tag of described RFID reader and different frequencies during described second RFID label tag work
Difference between the signal intensity of rate detects the change of humidity.
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| CN111461269A (en) * | 2020-04-07 | 2020-07-28 | 南京大学 | Diaper humidity detection system based on radio frequency identification technology and working method thereof |
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| CN101842689A (en) * | 2007-08-02 | 2010-09-22 | Nxp股份有限公司 | Humidity sensor based on progressive corrosion of exposed material |
| CN202584153U (en) * | 2012-06-01 | 2012-12-05 | 北京物资学院 | RFID system for measuring humidity |
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| US8228172B2 (en) * | 2008-09-30 | 2012-07-24 | Motorola Solutions, Inc. | RFID tag device with temperature sensitive antenna |
| KR101138836B1 (en) * | 2010-08-09 | 2012-05-10 | 에스케이하이닉스 주식회사 | Rfid tag |
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| CN101842689A (en) * | 2007-08-02 | 2010-09-22 | Nxp股份有限公司 | Humidity sensor based on progressive corrosion of exposed material |
| CN202584153U (en) * | 2012-06-01 | 2012-12-05 | 北京物资学院 | RFID system for measuring humidity |
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