CN109447223A - A method of enhancing ultra-high frequency RFID label reflection power - Google Patents
A method of enhancing ultra-high frequency RFID label reflection power Download PDFInfo
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- CN109447223A CN109447223A CN201811283580.4A CN201811283580A CN109447223A CN 109447223 A CN109447223 A CN 109447223A CN 201811283580 A CN201811283580 A CN 201811283580A CN 109447223 A CN109447223 A CN 109447223A
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K19/00—Record carriers for use with machines and with at least a part designed to carry digital markings
- G06K19/06—Record carriers for use with machines and with at least a part designed to carry digital markings characterised by the kind of the digital marking, e.g. shape, nature, code
- G06K19/067—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components
- G06K19/07—Record carriers with conductive marks, printed circuits or semiconductor circuit elements, e.g. credit or identity cards also with resonating or responding marks without active components with integrated circuit chips
- G06K19/077—Constructional details, e.g. mounting of circuits in the carrier
- G06K19/07749—Constructional details, e.g. mounting of circuits in the carrier the record carrier being capable of non-contact communication, e.g. constructional details of the antenna of a non-contact smart card
- G06K19/07773—Antenna details
- G06K19/07786—Antenna details the antenna being of the HF type, such as a dipole
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Abstract
The invention discloses a kind of methods for enhancing tag reflection power, the absorbing state impedance value Z including determining label chipabsorb；Set antenna impedance Zant=Zabsorb*, wherein ZabsorbIt * is the absorbing state impedance value Z of label chipabsorbConjugate impedance, change the impedance of chip modulation circuit so that reflection power PreReach the first value；So that it is determined that the reflective condition impedance value Z of label chipreflect；By antenna impedance ZantIt is set as maximum value Zant_max, so that reflection power PreReach maximum reflection power；In antenna impedance Zant=Zabsorb* in the case where, meter sensitivity loss and reflection coefficient difference absolute value；In antenna impedance Zant=Zant_maxIn the case where, meter sensitivity loss and reflection coefficient difference absolute value；And compromise between maximum reflection power and minimum sensitivity penalty values, so that it is determined that the reflection power of label chip.
Description
Technical field
The present invention relates to ultra-high frequency RFID label fields more particularly to one kind can enhance ultra-high frequency RFID label reflection function
The method of rate.
Background technique
RFID radio frequency identification is a kind of contactless automatic identification technology, it passes through radiofrequency signal automatic identification target pair
As and obtain related data, identify that work without manual intervention, is operable with various adverse circumstances.RFID technique can recognize high speed
Moving object simultaneously can identify multiple electronic tags simultaneously, swift and convenient to operate.Ultra-high frequency RFID technology logistics, manufacture, medical treatment,
Transport, retail, national defence etc. etc. are widely applied.Ultrahigh frequency RFID is divided into label and reader.Label is by label day
Line and label chip are constituted.
The reflection power of ultrahigh-frequency tag is codetermined by label antenna and label chip.Therefore how to obtain higher
Tag reflection power, while other performances for optimizing label are the pursuing a goal for a long time in ultrahigh-frequency tag field.
Summary of the invention
The invention proposes a kind of methods for enhancing ultra-high frequency RFID label reflection power, comprising:
Determine the absorbing state impedance value Z of label chipabsorb；
Set antenna impedance Zant=Zabsorb*, wherein ZabsorbIt * is the absorbing state impedance value Z of label chipabsorbBe total to
Yoke impedance changes the impedance of chip modulation circuit, so that reflection power PreReach the first value；So that it is determined that the reflection shape of label chip
State impedance value Zreflect；
By antenna impedance ZantIt is set as maximum value Zant_max, so that reflection power PreReach maximum reflection power；
In antenna impedance Zant=Zabsorb* in the case where, meter sensitivity loss and reflection coefficient difference absolute value；
In antenna impedance Zant=Zant_maxIn the case where, meter sensitivity loss and reflection coefficient difference absolute value；And
Compromise between maximum reflection power and minimum sensitivity penalty values, so that it is determined that the reflection function of label chip
Rate.
In one embodiment of the invention, as reflection power PreWhen reaching the first value, reflection coefficient difference absolute value is greater than
0.5 and less than 1.
In one embodiment of the invention, as reflection power PreWhen reaching the first value, reflection coefficient difference absolute value is
0.8。
In one embodiment of the invention, compromise packet is carried out between maximum reflection power and minimum sensitivity penalty values
It includes: on the contour that loss of sensitivity is first threshold, finding the point of reflection coefficient maximum value, and set antenna impedance to
Impedance value corresponding with reflection coefficient maximum value.
In one embodiment of the invention, the change chip modulation circuit impedance includes changing label modulation circuit
Equivalent and column capacitance and equivalent resistance value arranged side by side, thus label chip reflective condition impedance value ZreflectIt changes.
In one embodiment of the invention, in antenna impedance Zant=Zant_maxWhen,
Enable Zabsorb=z1_re+jz1_im, wherein z1_re is real part, and z1_im is imaginary part；
Zreflect=z2_re+jz2_im, wherein z2_re is real part, and z2_im is imaginary part；
Then ZAnt_max=Zant_re+jZant_im is determined by following formula:
Zant_re=z1_re*z2_re* ((z1_re+z2_re) ^2+ (z1_im-z2_im) ^2)) ^ (1/2)/(z1_re+
z2_re)；
Zant_im=- (z1_re*z2_im+z2_re*z1_im)/(z1_re+z2_re)；
Wherein symbol ^ indicates power exponent, for example, z2_im^2 represents 2 powers of z2_im.
In one embodiment of the invention, in antenna impedance Zant=Zant_maxIn the case where,
Loss of sensitivity MlossAre as follows:
Reflection coefficient difference absolute value | Δ Γ | are as follows:
In one embodiment of the invention, in antenna impedance Zant=Zabsorb* in the case where,
Loss of sensitivity MlossAre as follows:
Mloss=0；
Reflection coefficient difference absolute value | Δ Γ | are as follows:
In one embodiment of the invention, the absorbing state impedance value Z of label chip is determinedabsorbIncluding disconnecting label
Chip modulation circuit switch, obtained overall impedance is chip absorbing state impedance Zabsorb。
The method of enhancing ultra-high frequency RFID label reflection power disclosed by the invention can meet spirit according to actual needs
Under conditions of sensitivity requires, the reflection power of ultra-high frequency RFID label is made to obtain maximum enhancing.
Detailed description of the invention
For the above and other advantages and features for each embodiment that the present invention is furture elucidated, will be presented with reference to attached drawing
The more specific description of various embodiments of the present invention.It is appreciated that these attached drawings only describe exemplary embodiments of the invention, therefore
It is not to be regarded as being restriction on its scope.In the accompanying drawings, in order to cheer and bright, identical or corresponding component will use identical or class
As mark indicate.
Fig. 1 shows the process of the method for enhancing ultra-high frequency RFID label reflection power according to an embodiment of the invention
Figure.
Fig. 2 shows label chip absorbing state schematic diagrames.
Fig. 3 shows label chip reflective condition schematic diagram.
Fig. 4 is the contour map of tag reflection coefficient difference absolute value.
Fig. 5 is the contour map of tag sensitivity loss.
Fig. 6 is the contour map of tag reflection coefficient difference absolute value and tag sensitivity loss.
Specific embodiment
In the following description, with reference to each embodiment, present invention is described.However, those skilled in the art will recognize
Know can in the case where none or multiple specific details or with other replacements and/or addition method, material or component
Implement each embodiment together.In other situations, well known structure, material or operation are not shown or are not described in detail in order to avoid making this
The aspects of each embodiment of invention is obscure.Similarly, for purposes of explanation, specific quantity, material and configuration are elaborated, with
Comprehensive understanding to the embodiment of the present invention is just provided.However, the present invention can be implemented in the case where no specific detail.This
Outside, it should be understood that each embodiment shown in the accompanying drawings is illustrative expression and is not drawn necessarily to scale.
In the present specification, the reference of " one embodiment " or " embodiment " is meaned to combine embodiment description
A particular feature, structure, or characteristic is included at least one embodiment of the invention.Occur in everywhere in this specification short
Language " in one embodiment " is not necessarily all referring to the same embodiment.
In the course of work of label, the reflection power of tag sensitivity and label is to measure the important ginseng of tag performance
Number.The present invention proposes a kind of method for enhancing ultra-high frequency RFID label reflection power, can be by tag sensitivity by this method
It is adjusted to optimal value with the reflection power of label, so that the performance of label significantly improves.
The working principle of the method for enhancing tag reflection power disclosed by the invention is introduced first.
Frequency range all has an impact to chip impedance, antenna impedance, sensitivity gradient figure, sensitivity contour etc..For RFID
For chip and antenna, essentially all of electrical parameter is all the function of frequency.However, RFID chip and antenna are usually operated at one
In a frequency range, calculates assume that label is in working frequency range below, therefore ignore this parameter of working frequency.
During labeling task, label chip impedance value is in reflective condition impedance value ZreflectWith absorbing state impedance
Value ZabsorbBetween switch.
Tag reflection power PreAre as follows:
Here PtIt is the radio-frequency power value that label antenna receives, | Δ Γ | it is reflection coefficient difference absolute value, ZantIt is antenna
Impedance, ZreflectIt is label chip reflective condition impedance value, ZabsorbIt is label chip absorbing state impedance value, wherein antenna hinders
Anti- Zant, label chip reflective condition impedance value ZreflectWith label chip absorbing state impedance value ZabsorbIt is plural number, symbol*Table
Show the conjugate impedance of the complex impedance.
In reflective condition impedance value ZreflectWith absorbing state impedance value ZabsorbIn the case where determination, PreReach maximum anti-
Penetrating power condition is antenna impedance Zant=Zant_max。
Tag sensitivity loss are as follows:
It is antenna impedance Z that minimum sensitivity, which loses condition,ant=Zabsorb *。
So maximum reflection power condition is different with minimum sensitivity loss condition for ultra-high frequency RFID label, need
To compromise according to actual needs.It is well known that minimum sensitivity loss condition is label maximum sensitivity condition.
According to above realization principle, the embodiment of the present invention proposes a kind of enhancing ultra-high frequency RFID label reflection power
Method.Fig. 1 shows the flow chart of the method for enhancing ultra-high frequency RFID label reflection power according to an embodiment of the invention.
This method includes three steps.
In step 101, in absorbing state impedance value ZabsorbIn the case where determination, antenna impedance Z is setant=Zabsorb*,
Change the impedance of chip modulation circuit, so that reflection power PreReach the larger value.In one embodiment of the invention, representative value is about
For | Δ Γ |=0.8.In other embodiments of the invention, | Δ Γ | value should be greater than 0.5, less than 1.
Step 102, in reflective condition impedance value ZreflectWith absorbing state impedance value ZabsorbIn the case where determination, pass through
Set antenna impedance Zant=Zant_maxValue, obtains maximum reflection power Pre_max。
Step 103, it calculates separately to obtain the sensitivity damage under the conditions of maximum reflection power condition and minimum sensitivity loss
Lose MlossWith reflection coefficient difference absolute value | Δ Γ |.Antenna impedance value is adjusted according to actual needs, in maximum reflection power and most
Compromise between sluggishness penalty values.
Here is the detailed description of three steps.
In a step 101, label chip absorbing state impedance value ZabsorbIt is integrally determined by chip.Close label chip tune
Circuit processed, obtained overall impedance are chip absorbing state impedance Zabsorb.Label chip reflective condition impedance value ZreflectBy
Chip integrally determines.Label chip modulation circuit switch is connected, obtained overall impedance is chip reflective condition impedance
Zreflect。
In a step 101, antenna impedance Zant=Zabsorb* conjugate impedance match, so that the power maximum for reaching label antenna passes
It is input into label chip, i.e. label has farthest reading distance, and step 101 makes label with farthest distance is read, has
There is stronger reflection power.
At this time, reflection coefficient is 0 under absorbing state, and label has sensitivity peak.
Zant=Zabsorb *Conjugate impedance match, then reflection power PreIt can be with abbreviation are as follows:
The modulation circuit of label is adjusted, then the equivalent and column capacitance of label modulation circuit and equivalent resistance value arranged side by side change
Become.To label chip reflective condition impedance value ZreflectIt changes.
During adjusting the modulation circuit of label, because of absorbing state impedance value, obtained when modulation circuit is switched and disconnected
It arrives, so label chip absorbing state impedance value ZabsorbSubstantially it does not change.
Therefore, during the modulation circuit for adjusting label, Zant=Zabsorb *It does not change, and reflection power PreOccur
Change.To keep adjustment process simple and effective.
In a step 102, in label chip reflective condition impedance value ZreflectWith label chip absorbing state impedance value
ZabsorbIn the case where determination, Zant=Zant_maxWhen, PreReach maximum reflection power.
Label chip reflective condition impedance value ZreflectWith label chip absorbing state impedance value ZabsorbFor plural number, enable:
Zabsorb=z1_re+jz1_im, wherein z1_re is real part, and z1_im is imaginary part,
Zreflect=z2_re+jz2_im, wherein z2_re is real part, and z2_im is imaginary part,
Then ZAnt_max=Zant_re+jZant_im is determined by following formula:
Zant_re=z1_re*z2_re* ((z1_re+z2_re) ^2+ (z1_im-z2_im) ^2)) ^ (1/2)/(z1_re+
z2_re)；
Zant_im=- (z1_re*z2_im+z2_re*z1_im)/(z1_re+z2_re)；
Wherein symbol ^ indicates power exponent, for example, z2_im^2 represents 2 powers of z2_im.
Step 102 makes label antenna and the non-conjugated matching of chip, so that tag reflection power is most strong.
Note that the reflection coefficient that step 102 will lead to chip absorbing state is not 0.
Loss of sensitivity are as follows:
Mloss=-10log (1- | Γabsorb_max|2)
Step 103, it calculates separately to obtain the sensitivity damage under the conditions of maximum reflection power condition and minimum sensitivity loss
Lose MlossWith reflection coefficient difference absolute value | Δ Γ |.Antenna impedance value is adjusted according to actual needs, it can be in maximum reflection power
Compromise between value and minimum sensitivity penalty values.For example, tag sensitivity loss needs to be less than threshold value Loss1.In step
103, on the contour that tag sensitivity loss is threshold value Loss1, reflection coefficient maximum value is found, and antenna impedance is arranged
For impedance value corresponding with reflection coefficient maximum value.
Wherein maximum reflection power condition is Zant=Zant_max, it is Z that minimum sensitivity, which loses condition,ant=Zabsorb*。
Under maximum reflection power condition, loss of sensitivity are as follows:
Reflection coefficient difference absolute value
Under the conditions of minimum sensitivity loss
Loss of sensitivity are as follows:
Mloss=0
Reflection coefficient difference absolute value
Wherein typical actual demand is that tag sensitivity loss needs to be less than threshold value Loss1.Then compromise algorithm is to mark
It signs on the contour that loss of sensitivity is threshold value Loss1, finds reflection coefficient maximum value, and set the value for antenna impedance.
Implementation result is to be lost on equal contour in tag sensitivity, and reflection power obtains maximum value.
In an embodiment of the present invention, step 101 makes labeling task in conjugate impedance match, can have sizable
Reflection power.Step 102 is by adjusting label antenna impedance, so that the non-conjugated matching of label, so that reflection power reaches most strong.
Step 103, compromise adjustment is carried out according to actual needs.In short, the embodiment of the present invention realize it is anti-to ultra-high frequency RFID label
The enhancing of power is penetrated, there is advance.
Enhancing ultra-high frequency RFID label reflection power according to the present invention is discussed in detail below with reference to specific label antenna
Method process.
Fig. 2 shows label chip absorbing state schematic diagrames.As shown in Fig. 2, a1 is other circuit equivalent impedances of label chip
Value, a2 are the equivalent resistance value arranged side by side of modulation circuit, and a3 is that modulation circuit is equivalent and column capacitance value, and a4 is opening of being in an off state
It closes, a5 is the port RF.Here, after a4 switch disconnects, the impedance value entered in terms of the port a5 is Zabsorb=4000ohm | |
0.61pF.In frequency point 920MHz, there is Zabsorb=20-j282ohm.
Step 101 is carried out below, in ZabsorbIn the case where determination, Z is setant=Zabsorb *, change chip modulation circuit
Impedance.So setting Z in frequency point 920MHz hereant=Zabsorb *=20+j282ohm.Set the position of five-pointed star c1 in Fig. 4
It sets.Fig. 3 is label chip reflective condition schematic diagram, as shown in figure 3, b1 is other circuit equivalent impedance values of label chip, b2 is
The equivalent resistance value arranged side by side of modulation circuit, b3 are that modulation circuit is equivalent and column capacitance value, b4 are the switch in connected state, and b5 is
The port RF.After b4 switch connection, the equivalent resistance value arranged side by side of adjustment modulation circuit and modulation circuit is equivalent and column capacitance value, so that instead
It penetrates sufficiently strong.
Make herein, the equivalent resistance value arranged side by side of modulation circuit is equal to 4000ohm, and modulation circuit is equivalent and column capacitance value etc.
In 0.23pF.Adjust modulation circuit equivalent impedance, i.e. the position of rectangular c2 in adjustment Fig. 4, five-pointed star in Fig. 4 during this
C1, ZabsorbIt is worth constant, enables Zreflect=0.84pF | | 2000ohm.In frequency point 920MHz, Zreflect=21-j203.8ohm.
In this case, according toCan obtain, reflection coefficient difference absolute value | Δ Γ |=
0.89, reflection power Pre=0.7921*Pt.At this time, reflection coefficient is 0 under absorbing state, and label has sensitivity peak.
Complete step 101.
Next, carrying out step 102.
According to the following formula:
Zant_re=(z1_re*z2_re* ((z1_re+z2_re) ^2+ (z1_im-z2_im) ^2)) ^ (1/2)/(z1_re
+z2_re)；
Zant_im=- (z1_re*z2_im+z2_re*z1_im)/(z1_re+z2_re)；
Available Zant_max=44.2+j243.9, reflection coefficient difference absolute value is maximum value under the conditions of this | Δ Γ |
=1.21, maximum reflection power Pre_max=1.4641*Pt
Fig. 4 is the contour map of tag reflection coefficient difference absolute value.X-axis is antenna impedance real part, and y-axis is that antenna impedance is empty
Portion traverses antenna impedance in setting range.Wherein, five-pointed star c1 is that the impedance of chip absorbing state is conjugated Zabsorb *, side
Shape c2 is that chip reflective condition impedance value is conjugated Zreflect *, triangle c3 is to calculate gained maximum reflection impedance value Zant_max.Deng
High line c4 be reflection coefficient difference absolute value | Δ Γ | contour.Reflection coefficient difference absolute value is chip impedance and chip impedance
Function.After determining chip impedance, antenna impedance just has an optimum position, i.e. conjugate impedance match point is reflected at this point
Zero.Contour c4 makes the circle around conjugate impedance match point, is the equal point of reflection coefficient difference absolute value, by setting reflection coefficient
Poor absolute value will parse contour c4.Circle is bigger, reflects stronger.The impedance that a5 is seen into Fig. 2, as five-pointed star c1's
It is conjugated, the impedance that b5 is seen into Fig. 3, the conjugation of as rectangular c2.
It can be seen that comparing matching status ZAnt=Zabsorb *If antenna impedance is set as maximum reflection impedance value ZAnt=
Zant_max, i.e. antenna is set as the position triangle c3, then reflection power is in contour center on entire figure, that is,
In maximum value.
After completing step 102, step 103 is carried out.
Fig. 5 is the contour map of tag sensitivity loss.Wherein, five-pointed star d1 is chip absorbing state impedance conjugation
Zabsorb *, rectangular d2 is that chip reflective condition impedance value is conjugated Zreflect *, triangle d3 is to calculate gained maximum reflection impedance value
Zant_max.Contour d4 is that tag sensitivity loses MlossContour.Signing loss of sensitivity is chip impedance and chip impedance
Function.After determining chip impedance, antenna impedance just has an optimum position, at this point, loss of sensitivity zero.Contour
D4 is the circle for the point for being zero around loss of sensitivity, be loss of sensitivity is equal point, passes through setting loss of sensitivity
Value can parse contour d4.From fig. 5, it is seen that maximum reflection power condition Zant=Zant_max, that is, it is located at triangle
The position d3, Mloss=1.98dB, | Δ Γ |=1.21；Minimum sensitivity loses condition, Zant=Zabsorb *, that is, it is located at five-pointed star d1
Position, Mloss=0dB, | Δ Γ |=0.89.So accordingly can between reflection power maximum value and sensitivity peak into
Row compromise.
Such as in the present embodiment, loss of sensitivity threshold value is set as Loss1=0.5dB, then antenna resistance can be adjusted
It is anti-, so that the reflection power value on loss of sensitivity 0.5dB contour is most strong.
Fig. 6 is the contour map of tag reflection coefficient difference absolute value and tag sensitivity loss.Wherein, five-pointed star e1 is
Chip absorbing state impedance is conjugated Zabsorb *, rectangular e2 is that chip reflective condition impedance value is conjugated Zreflect *, triangle e3 is meter
Calculate gained maximum reflection impedance value Zant_max.Solid line contour e4 is that tag sensitivity loses MlossContour.Dashed contour
E5 be tag reflection coefficient difference absolute value | Δ Γ | contour.Diamond shape e6 is that the loss of Loss1=0.5dB tag sensitivity is contour
Maximum reflection power points on line.The value of diamond shape e6 is Zant=34.36+j278.8ohm.
It will be seen from figure 6 that Loss1=0.5dB tag sensitivity loss contour in point can meet it is sensitive
Degree demand, but the point reflection coefficient difference absolute value in Loss1=0.5dB tag sensitivity loss contour is different, reflection
Coefficient difference absolute value is from 0.6122 to 1.112.According to step 103, the value that antenna impedance value should be diamond shape e6 is Zant=
34.36+j278.8ohm。
If antenna impedance design value will fall in Loss1=0.5dB label spirit at random without method disclosed by the invention
Sensitivity is lost in contour.Coefficient difference absolute value minimum point is penetrated and highest point is compared if negated, and the embodiment of the present invention makes
The reflection power for obtaining ultra-high frequency RFID label improves 20*log10 (1.112/0.6122)=5.18dB.
In some embodiments of the invention, method disclosed by the invention can pass through hardware device, software or its any group
It closes and realizes.The example of hardware device may include processor, microprocessor, circuit, circuit element (for example, transistor, resistance
Device, capacitor, inductor, etc.), integrated circuit, specific integrated circuit (ASIC), programmable logic device (PLD), number letter
Number processor (DSP), field programmable gate array (FPGA), logic gate, register, semiconductor devices, chip, microchip,
Chipset, etc..
The example of software may include component software, program, application, computer program, application program, system program, machine
Device program, operating system software, middleware, firmware, software module, routine, subroutine, function, method, process, software interface,
Application programming interfaces (API), instruction set, calculation code, computer code, code segment, computer code segments, word, numerical value, symbol
Number, or any combination thereof.
Some embodiments can be realized for example using machine readable storage medium or product.Storage medium can store instruction
Or instruction set, the instruction or instruction set can lead to machine when being executable by a machine and execute method according to the embodiment and/or operation.
Such machine may include, for example, any suitable processing platform, computing platform, calculate equipment, processing equipment, computing system,
Processing system, computer, processor or the like, and realized using any suitable hardware and/or combination of software.
Embodiment may include storage medium or machine readable product.Such as, it may include the memory list of any suitable type
Member, memory devices, memory product, storage medium, storage equipment, storage product, storage medium and/or storage unit,
For example, memory, removable or irremovable medium, erasable or non-erasable medium, writeable or rewritable media, number or
Simulation medium, floppy disk, compact disk read-only memory (CD-ROM), can record compact disk (CD-R), solid state drive (CD- at hard disk
RW), CD, magnetic medium, magnet-optical medium, mobile memory card or disk, various types of digital versatile discs (DVD), band, tape drum
Deng.Instruction may include being realized using any suitable advanced, rudimentary, object-oriented, visual, compilation and/or interpreted programming language
Source code, assembly code, interpretive code, executable code, static code, dynamic code, encrypted code etc. it is any suitable
Close the code of type.
Although described above is various embodiments of the present invention, however, it is to be understood that they are intended only as example to present
, and without limitation.For those skilled in the relevant art it is readily apparent that various combinations, modification can be made to it
Without departing from the spirit and scope of the invention with change.Therefore, the width of the invention disclosed herein and range should not be upper
It states disclosed exemplary embodiment to be limited, and should be defined according only to the appended claims and its equivalent replacement.
Claims (10)
1. a kind of method for enhancing tag reflection power, comprising:
Determine the absorbing state impedance value Z of label chipabsorb；
Set antenna impedance Zant=Zabsorb*, wherein ZabsorbIt * is the absorbing state impedance value Z of label chipabsorbConjugation resistance
It is anti-, change the impedance of chip modulation circuit, so that reflection power PreReach the first value；So that it is determined that the reflective condition of label chip hinders
Anti- value Zreflect；
By antenna impedance ZantIt is set as maximum value Zant_max, so that reflection power PreReach maximum reflection power；
In antenna impedance Zant=Zabsorb* in the case where, meter sensitivity loss and reflection coefficient difference absolute value；
In antenna impedance Zant=Zant_maxIn the case where, meter sensitivity loss and reflection coefficient difference absolute value；And
Compromise between maximum reflection power and minimum sensitivity penalty values, so that it is determined that the reflection power of label chip.
2. the method for enhancing tag reflection power as described in claim 1, which is characterized in that as reflection power PreReach first
When value, reflection coefficient difference absolute value is greater than 0.5 and less than 1.
3. the method for enhancing tag reflection power as described in claim 1, which is characterized in that as reflection power PreReach first
When value, reflection coefficient difference absolute value is 0.8.
4. the method for enhancing tag reflection power as described in claim 1, which is characterized in that in maximum reflection power and minimum
It includes: to find reflection coefficient most on the contour that loss of sensitivity is first threshold that compromise is carried out between loss of sensitivity value
The point being worth greatly, and impedance value corresponding with reflection coefficient maximum value is set by antenna impedance.
5. the method for enhancing tag reflection power as described in claim 1, which is characterized in that the change chip modulation circuit
Impedance includes the equivalent and column capacitance for changing label modulation circuit and equivalent resistance value arranged side by side, so that label chip reflective condition hinders
Anti- value ZreflectIt changes.
6. the method for enhancing tag reflection power as described in claim 1, which is characterized in that in antenna impedance Zant=Zant_max
When,
Enable Zabsorb=z1_re+jz1_im, wherein z1_re is real part, and z1_im is imaginary part；
Zreflect=z2_re+jz2_im, wherein z2_re is real part, and z2_im is imaginary part；
Then ZAnt_max=Zant_re+jZant_im is determined by following formula:
Zant_re=z1_re*z2_re* ((z1_re+z2_re) ^2+ (z1_im-z2_im) ^2)) ^ (1/2)/(z1_re+z2_
re)；
Zant_im=- (z1_re*z2_im+z2_re*z1_im)/(z1_re+z2_re)；
Wherein symbol ^ indicates power exponent, for example, z2_im^2 represents 2 powers of z2_im.
7. the method for enhancing tag reflection power as described in claim 1, which is characterized in that in antenna impedance Zant=Zant_max
In the case where,
Loss of sensitivity MlossAre as follows:
Reflection coefficient difference absolute value | Δ Γ | are as follows:
8. the method for enhancing tag reflection power as described in claim 1, which is characterized in that in antenna impedance Zant=
Zabsorb* in the case where,
Loss of sensitivity MlossAre as follows:
Mloss=0；
Reflection coefficient difference absolute value | Δ Γ | are as follows:
9. the method for enhancing tag reflection power as described in claim 1, which is characterized in that determine the absorption shape of label chip
State impedance value ZabsorbIncluding disconnecting label chip modulation circuit switch, obtained overall impedance is chip absorbing state impedance
Zabsorb。
10. a kind of system for enhancing tag reflection power, comprising:
Memory, the memory store machine-executable instruction；And
Processor, the processor require any one of 1 to 9 the method for perform claim.
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