CN110018351B - Non-contact antenna impedance measuring method and system - Google Patents

Non-contact antenna impedance measuring method and system Download PDF

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CN110018351B
CN110018351B CN201910386502.5A CN201910386502A CN110018351B CN 110018351 B CN110018351 B CN 110018351B CN 201910386502 A CN201910386502 A CN 201910386502A CN 110018351 B CN110018351 B CN 110018351B
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impedance
antenna
chip
adjustable device
tag
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CN110018351A (en
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张俊
章国豪
黄国宏
唐浩
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Synergy Innovation Institute Of Gdut Heyuan
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R27/00—Arrangements for measuring resistance, reactance, impedance, or electric characteristics derived therefrom
    • G01R27/02—Measuring real or complex resistance, reactance, impedance, or other two-pole characteristics derived therefrom, e.g. time constant

Abstract

A non-contact antenna impedance measuring method and a measuring system thereof are disclosed, wherein the measuring method comprises the following steps: (1) electrically connecting the antenna, the adjustable device and the chip to form a measuring system; (2) placing the measuring system in the reading distance range of the ultrahigh frequency RFID system; (3) changing the impedance of the adjustable device for 3 times, and respectively recording the starting power and the corresponding frequency of the reader label by the ultrahigh frequency RFID system software; (4) and (3) performing data processing calculation by using the reader tag starting power obtained by 3 times of measurement, the adjustable device impedance and the impedance formed by the chip to obtain the impedance of the antenna under the specific frequency. The non-contact antenna impedance measuring method provided by the invention is simple, convenient and quick in measuring operation, and has the advantages of high measuring efficiency and high measuring accuracy.

Description

Non-contact antenna impedance measuring method and system
Technical Field
The invention relates to the technical field of radio frequency identification and antennas, in particular to a non-contact antenna impedance measuring method and a non-contact antenna impedance measuring system.
Background
The RFID technology completes communication through wireless radio frequency signals, can acquire and identify relevant information of an object without physical contact with the object, has the advantages of long sensing distance, high identification accuracy, high reading speed, large information storage capacity and the like, and is widely applied to the fields of industrial production, traffic, logistics and the like. With the development and the improvement of the RFID technology, the RFID technology has great application potential, and application scenes are more diversified.
Impedance matching is very important in antenna performance studies, and in practical tests, detecting whether an antenna achieves impedance matching depends on measuring its impedance. The conventional antenna impedance measuring method is that an antenna is connected to a measuring instrument through a feeder, the measuring instrument measures the impedance of the antenna, but the defect that the measurement result has larger deviation from the actual result due to insufficient signal passing through the feeder and calibration exists frequently, and particularly for an electrically small antenna, the error caused by a measuring clamp becomes more serious. Therefore, it is a problem to be solved by those skilled in the art to develop a non-contact antenna impedance measurement method and system with simple measurement method, high efficiency and high accuracy.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a non-contact antenna impedance measuring method which effectively utilizes the RFID technology to measure the antenna impedance in a non-contact manner, is simple, convenient and quick, and has simple measuring method, high measuring efficiency and high measuring accuracy.
Another object of the present invention is to provide a system for measuring impedance of a contactless antenna.
In order to achieve the purpose, the invention adopts the following technical scheme:
a non-contact antenna impedance measuring method is characterized in that: the method comprises the following steps:
(1) electrically connecting the antenna, the adjustable device and the chip to form a measuring system;
(2) placing the measuring system in the reading distance range of the ultrahigh frequency RFID system;
(3) changing the impedance of the adjustable device for 3 times, and respectively recording the starting power and the corresponding frequency of the reader label by the ultrahigh frequency RFID system software;
(4) and (3) performing data processing calculation by using the reader tag starting power obtained by 3 times of measurement, the impedance formed by the adjustable device and the chip to obtain the impedance of the antenna under the corresponding frequency.
Further, the electrically connecting the antenna, the adjustable device and the chip specifically includes: the antenna, the adjustable device and the chip are sequentially connected in series or the adjustable device and the chip are firstly connected in parallel and then connected in series with the antenna.
Further, the reader-tag activation power is:
Figure GDA0002232380230000021
where d is the distance between the reader and the antenna, λ0Is a free space wavelength, PthIs the activation power of the tag chip, GR(Θ, Φ) is the reader tag gain,
Figure GDA0002232380230000022
is the tag antenna gain, τ is the power transmission coefficient, ηρIs the polarization mismatch coefficient.
Further, the power transmission coefficient between the tag antenna and the tag chip is:
Figure GDA0002232380230000023
wherein S is11The impedance formed by the connection of the adjustable device and the chip is Zc＝Rc+jXcThe antenna impedance is Za＝Ra+jXa，Represents ZaThe conjugate impedance of (1), RcIs the real part of the chip impedance, XcIs the imaginary part of the chip impedance, RaIs the real part of the antenna impedance, XaIs the imaginary part of the antenna impedance and j is the complex representation of the imaginary part.
Further, in step (3), the impedance of the adjustable device changes 3 times, and the corresponding reader tag start powers are respectively set as follows: pR1、PR2、PR3(ii) a The impedance formed by the connection of the adjustable device and the chip is as follows: zc1＝Rc1+jXc1、Zc2＝Rc2+jXc2、Zc3＝Rc3+jXc3According to the relational expression of the starting power of the reader tag and the power transmission coefficient between the tag antenna and the tag chip, the following equation set is obtained:
Figure GDA0002232380230000031
Figure GDA0002232380230000032
further, the data processing calculation specifically includes: starting work of reader label obtained by 3 times of measurementSubstituting the impedance composed of the frequency, the adjustable device and the chip into the equation set, and solving the equation to obtain the real impedance part R of the antenna under the corresponding frequencyaImaginary part XaObtaining the antenna impedance as Za。
A non-contact antenna impedance measuring system comprises an antenna, an adjustable device and a chip, wherein the antenna, the adjustable device and the chip are sequentially connected in series or the adjustable device is firstly connected with the chip in parallel and then connected with the antenna in series.
Further, the tunable device is a tunable capacitor.
The invention has the beneficial effects that: the invention sets a measuring system composed of an antenna, an adjustable device and a chip, places the measuring system in the reading distance range of the ultrahigh frequency RFID system, and uses the way of changing the impedance of the adjustable device for 3 times, thereby utilizing the reader label starting power obtained by 3 times of measurement, the impedance composed of the adjustable device and the chip, and obtaining the impedance of the antenna under the corresponding frequency rapidly and accurately through data processing calculation.
Drawings
FIG. 1 is a schematic diagram of a system for measuring impedance of a contactless antenna according to one embodiment of the present invention;
FIG. 2 is a schematic diagram of a system for measuring impedance of a contactless antenna according to one embodiment of the present invention;
FIG. 3 is a graph of real part of chip impedance as a function of tunable capacitance according to an embodiment of the present invention;
FIG. 4 is a graph of the imaginary part of the chip impedance as a function of the tunable capacitance for one embodiment of the present invention;
FIG. 5 is a graph comparing real and extracted impedance values of an antenna according to an embodiment of the present invention;
FIG. 6 is a graph comparing the real and extracted imaginary values of the impedance for an antenna according to one embodiment of the present invention;
wherein: the antenna comprises an antenna 1, an adjustable device 2, a chip 3 and an adjustable capacitor 4.
Detailed Description
The technical scheme of the invention is further explained by the specific implementation mode in combination with the attached drawings. Wherein the showings are for the purpose of illustration only and are shown by way of illustration only and not in actual form, and are not to be construed as limiting the present patent; to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted.
The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there is an orientation or positional relationship indicated by the terms "upper", "lower", "left", "right", etc. based on the orientation or positional relationship shown in the drawings, it is only for convenience of describing the present invention and simplifying the description, but it is not intended to indicate or imply that the referred device or element must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and are not to be construed as limiting the present patent, and the specific meaning of the terms may be understood by those skilled in the art according to specific circumstances.
A non-contact antenna impedance measuring method comprises the following steps:
(1) electrically connecting the antenna 1, the adjustable device 2 and the chip 3 to form a measuring system;
(2) placing the measuring system in the reading distance range of the ultrahigh frequency RFID system;
(3) changing the impedance of the adjustable device for 3 times, and respectively recording the starting power and the corresponding frequency of the reader label by the ultrahigh frequency RFID system software;
(4) and (3) performing data processing calculation by using the reader tag starting power obtained by 3 times of measurement, the impedance formed by the adjustable device and the chip to obtain the impedance of the antenna under the corresponding frequency.
Further, the electrical connection among the antenna 1, the adjustable device 2, and the chip 3 is specifically as follows: the antenna 1, the adjustable device 2 and the chip 3 are sequentially connected in series or the adjustable device 2 and the chip 3 are firstly connected in parallel and then connected in series with the antenna 1.
Further, the reader-tag activation power is:
Figure GDA0002232380230000051
where d is the distance between the reader and the antenna, λ0Is a free space wavelength, PthIs the activation power of the tag chip, GR(Θ, Φ) is the reader tag gain,
Figure GDA0002232380230000052
is the tag antenna gain, τ is the power transmission coefficient, ηρIs the polarization mismatch coefficient.
Further, the power transmission coefficient between the tag antenna and the tag chip is:
Figure GDA0002232380230000053
wherein S is11The impedance formed by the connection of the adjustable device and the chip is Zc＝Rc+jXcThe antenna impedance is Za＝Ra+jXa，
Figure GDA0002232380230000054
Represents ZaThe conjugate impedance of (1), RcIs the real part of the chip impedance, XcIs the imaginary part of the chip impedance, RaIs the real part of the antenna impedance, XaIs the imaginary part of the antenna impedance and j is the complex representation of the imaginary part.
Further, in step (3), the impedance of the adjustable device changes 3 times, and the corresponding reader tag start powers are respectively set as follows: pR1、PR2、PR3(ii) a The impedance formed by the connection of the adjustable device and the chip is as follows: zc1＝Rc1+jXc1、Zc2＝Rc2+jXc2、Zc3＝Rc3+jXc3According to the starting power of the reader label and the power transmission coefficient between the label antenna and the label chipThe following equation set is obtained:
Figure GDA0002232380230000055
Figure GDA0002232380230000056
further, the data processing calculation specifically includes: substituting the reader tag starting power obtained by 3 times of measurement, the impedance formed by the adjustable device and the chip into an equation set, solving the equation to obtain the real impedance part R of the antenna under the corresponding frequencyaImaginary part XaObtaining the antenna impedance as Za。
A non-contact antenna impedance measuring system comprises an antenna 1, an adjustable device 2 and a chip 3, wherein the antenna 1, the adjustable device 2 and the chip 3 are sequentially connected in series or the adjustable device 2 is firstly connected with the chip 3 in parallel and then connected with the antenna 1 in series, as shown in figures 1 and 2.
Further, the tunable device 2 is a tunable capacitor 4.
Examples
As shown in fig. 2-6, a non-contact antenna impedance measuring method and a measuring system thereof, the measuring system includes an antenna 1, an adjustable capacitor 4 and a chip 3; the adjustable capacitor 4 is connected in parallel with the chip 3 and then connected in series with the antenna 1 to form a measuring system, as shown in fig. 2. The measuring method of the system comprises the following steps:
the impedance of the chip is 1.9k omega; placing the measuring system in the reading distance range of the ultrahigh frequency RFID system; the impedance of the adjustable capacitor 4 is changed for 3 times, the capacitance values are 0.76PF, 0.86PF and 0.96PF respectively, and the ultrahigh frequency RFID system software records the starting power and the corresponding frequency of the reader label respectively; by using the reader tag starting power obtained by 3 times of measurement, the impedance formed by the adjustable device and the chip, the following data processing calculation is carried out to obtain the impedance of the antenna under the corresponding frequency:
the starting power of the reader tag is as follows:
Figure GDA0002232380230000061
where d is the distance between the reader and the antenna, λ0Is a free space wavelength, PthIs the activation power of the tag chip, GR(Θ, Φ) is the reader tag gain,
Figure GDA0002232380230000062
is the tag antenna gain, τ is the power transmission coefficient, ηρIs the polarization mismatch coefficient;
in addition, the power transfer coefficient is:
wherein S is11The impedance formed by the connection of the adjustable device and the chip is Zc＝Rc+jXcThe antenna impedance is Za＝Ra+jXa，Represents ZaThe conjugate impedance of (1), RcIs the real part of the chip impedance, XcIs the imaginary part of the chip impedance, RaIs the real part of the antenna impedance, XaIs the imaginary part of the antenna impedance and j is the complex representation of the imaginary part.
Changing the impedance of the adjustable device for 3 times, and setting the starting power of the corresponding reader tag as follows: pR1、PR2、PR3(ii) a The impedance formed by the connection of the adjustable device and the chip is as follows: zc1＝Rc1+jXc1、Zc2＝Rc2+jXc2、Zc3＝Rc3+jXc3From the relational expressions of (1) and (2) above, the following equation set is obtained:
Figure GDA0002232380230000073
substituting the reader tag starting power obtained by 3 times of measurement, the impedance formed by the adjustable device and the chip into an equation set, solving the equation to obtain the real impedance part R of the antenna under the corresponding frequencyaImaginary part XaObtaining the antenna impedance as Za. The curve situation of the real part of the chip impedance along with the change of the adjustable capacitance is shown in fig. 3, the curve situation of the imaginary part of the chip impedance along with the change of the adjustable capacitance is shown in fig. 4, the comparison graph of the real part of the impedance of the antenna and the value of the extracted real part of the impedance of the antenna is shown in fig. 5, and the comparison graph of the real part of the impedance of the antenna and the value of the extracted imaginary part of the impedance of the antenna is shown in fig. 6. Therefore, the non-contact antenna impedance measuring method provided by the invention has higher accuracy.
The technical principle of the present invention is described above in connection with specific embodiments. The description is made for the purpose of illustrating the principles of the invention and should not be construed in any way as limiting the scope of the invention. Based on the explanations herein, those skilled in the art will be able to conceive of other embodiments of the present invention without inventive effort, which would fall within the scope of the present invention.

Claims (3)

1. A non-contact antenna impedance measuring method is characterized in that: the method comprises the following steps:
(1) electrically connecting the antenna, the adjustable device and the chip to form a measuring system;
(2) placing the measuring system in the reading distance range of the ultrahigh frequency RFID system;
(3) changing the impedance of the adjustable device for 3 times, and respectively recording the starting power and the corresponding frequency of the reader label by the ultrahigh frequency RFID system software;
(4) performing data processing calculation by using the reader tag starting power obtained by 3 times of measurement, the impedance formed by the adjustable device and the chip to obtain the impedance of the antenna under the corresponding frequency;
the specific steps of electrically connecting the antenna, the adjustable device and the chip are as follows: sequentially connecting the antenna, the adjustable device and the chip in series or firstly connecting the adjustable device and the chip in parallel and then connecting the adjustable device and the chip in series with the antenna;
the starting power of the reader tag is as follows:
Figure DEST_PATH_IMAGE001
wherein the content of the first and second substances,
Figure DEST_PATH_IMAGE002
is the distance between the reader and the antenna,
Figure DEST_PATH_IMAGE003
is the wavelength of the free space light,
Figure DEST_PATH_IMAGE004
is the activation power of the tag chip,
Figure DEST_PATH_IMAGE005
is the gain of the reader tag or tags,is the gain of the tag antenna and,
Figure DEST_PATH_IMAGE007
is the power transfer coefficient (co) of the power,is the polarization mismatch coefficient;
the power transmission coefficient between the tag antenna and the tag chip is as follows:
Figure DEST_PATH_IMAGE009
wherein the content of the first and second substances,S 11is composed of reflection coefficient, adjustable device and chip
Figure DEST_PATH_IMAGE010
The antenna impedance is，
Figure DEST_PATH_IMAGE012
To represent
Figure DEST_PATH_IMAGE013
The impedance of the first and second electrodes of the first,R c is the real part of the chip impedance,X c is the imaginary part of the impedance of the chip,R a is the real part of the antenna impedance,X a is the imaginary part of the impedance of the antenna,jis a complex representation of the imaginary part;
in the step (3), the impedance of the adjustable device changes for 3 times, and the corresponding reader tag starting powers are respectively set as follows:P R1 、P R2 、P R3(ii) a The impedance formed by the connection of the adjustable device and the chip is as follows:
Figure DEST_PATH_IMAGE014
、
Figure DEST_PATH_IMAGE015
、
Figure DEST_PATH_IMAGE016
according to the relational expression of the starting power of the reader tag and the power transmission coefficient between the tag antenna and the tag chip, the following equation set is obtained:
Figure DEST_PATH_IMAGE017
Figure DEST_PATH_IMAGE018
；
the numberThe specific processing calculation is as follows: substituting the reader tag starting power obtained by 3 times of measurement, the impedance formed by the adjustable device and the chip into an equation set, solving the equation to obtain the real impedance part of the antenna under the corresponding frequencyR a Imaginary partX a Obtaining an antenna impedance ofZ a 。
2. A measuring system adapted to the method for measuring impedance of a contactless antenna according to claim 1, characterized in that: the antenna, the adjustable device and the chip are sequentially connected in series or the adjustable device is connected with the chip in parallel and then connected with the antenna in series.
3. The system of claim 2, wherein the system is further configured to: the adjustable device is an adjustable capacitor.
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Publication number Priority date Publication date Assignee Title
CN110018351B (en) * 2019-05-09 2020-01-07 河源广工大协同创新研究院 Non-contact antenna impedance measuring method and system
CN114047385B (en) * 2022-01-13 2022-07-08 北京智芯微电子科技有限公司 Method and device for testing impedance and sensitivity of RFID chip and electronic equipment

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1784882A (en) * 2003-05-12 2006-06-07 艾利森电话股份有限公司 Method and arrangement for loop test of a disturbed line
CN101149407A (en) * 2007-11-02 2008-03-26 武汉大学 Method and device for power frequency inference source live line measurement for mutual inductance line zero-sequence impedance parameter
WO2008076130A1 (en) * 2006-12-15 2008-06-26 Halliburton Energy Services, Inc. Antenna coupling component measurement tool having rotating antenna configuration
CN101609169A (en) * 2009-04-08 2009-12-23 中国石油集团钻井工程技术研究院 A kind of method that improves electromagnetic wave resistivity measurement precision and its measurement range of expansion
CN203376472U (en) * 2013-07-15 2014-01-01 中国民用航空飞行学院 Radio automatic direction finder antenna signal simulator

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH07333269A (en) * 1994-06-07 1995-12-22 Nippon Hoso Kyokai <Nhk> Impedance measurement device
CN102162824B (en) * 2010-12-24 2014-11-26 中科院杭州射频识别技术研发中心 Online testing method for mass production of ultrahigh frequency (UHF) identification electronic tag antenna
CN103592517B (en) * 2013-11-26 2016-05-11 中国船舶重工集团公司第七二二研究所 A kind of antenna impedance test macro and method
CN110018351B (en) * 2019-05-09 2020-01-07 河源广工大协同创新研究院 Non-contact antenna impedance measuring method and system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1784882A (en) * 2003-05-12 2006-06-07 艾利森电话股份有限公司 Method and arrangement for loop test of a disturbed line
WO2008076130A1 (en) * 2006-12-15 2008-06-26 Halliburton Energy Services, Inc. Antenna coupling component measurement tool having rotating antenna configuration
CN101149407A (en) * 2007-11-02 2008-03-26 武汉大学 Method and device for power frequency inference source live line measurement for mutual inductance line zero-sequence impedance parameter
CN101609169A (en) * 2009-04-08 2009-12-23 中国石油集团钻井工程技术研究院 A kind of method that improves electromagnetic wave resistivity measurement precision and its measurement range of expansion
CN203376472U (en) * 2013-07-15 2014-01-01 中国民用航空飞行学院 Radio automatic direction finder antenna signal simulator

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
天线测量理论中的基本方程组;沈国连 等;《航空电子技术》;20020630;第41-48页 *

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