A portable RFID field tester

Abstract

The present application discloses a portable RFID field tester, comprising a control terminal, a reader and an antenna; the control terminal is a computer or an embedded mainboard containing application software, which controls the work between the various components of the tester; the reader is a device for reading tag information, comprising a control unit and a radio frequency module; the radio frequency module comprises a transmitter and a receiver, the transmitter is used to send radio signals to the tag, and the receiver is used to receive the radio signals of the tag; the antenna is a transmitting and receiving device for transmitting data between the tag and the reader; the control terminal controls the reader to send electromagnetic waves through the antenna, and after the tag enters the magnetic field of the electromagnetic wave, the coil inside the tag will generate an induced current, the tag will start to work and receive the radio frequency signal sent by the reader; if it is an active tag, it will actively send a radio frequency signal of a certain frequency, the reader obtains the signal through the antenna, and after decoding, sends it to the control unit of the reader for relevant data processing.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic measurement and relates to a portable RFID field tester. Background Art

[0002] In radio communication technology, RFID technology, or radio frequency identification technology, is a non-visual, two-way communication automatic recognition technology without mechanical or optical contact. It has the advantages of high sensitivity, high speed, strong anti-interference ability, rich and encrypted information, and long life. It is widely used in tag identification, readers, testing and performance evaluation of RFID products.

[0003] The research of RFID technology is of great significance. It is similar to the working mechanism of radar. Radar determines the location, shape, state and other characteristics of an object by processing radio waves or microwaves reflected by an object. The same is true for RFID. As early as the Second World War, the military began to use it. Since the 1990s, it has developed rapidly. So far, various RFID products have emerged. With the rapid development of the RFID industry today, the quality requirements for RFID products are more stringent. Therefore, RFID detectors for detecting the performance of RFID products have come into being. However, RFID detection faces many difficulties, such as many standards, high performance requirements, and bulky large-scale detection system equipment is too inconvenient. Therefore, the design and implementation of portable RFID detectors have become very necessary, and the design of related RFID electronic tags and readers has also become diversified. Summary of the invention

[0004] In order to solve the deficiencies in the prior art, the present application provides a portable RFID field tester that can transmit, collect and record UHF and microwave band RFID standard radio frequency signals, and analyze the radio frequency parameters, protocol parameters and signaling data of the tested signals according to relevant independent standards. It has the characteristics of ingenious design, convenient operation and high measurement accuracy, and has good application prospects.

[0005] In order to achieve the above objectives, this application adopts the following technical solutions:

[0006] A portable RFID field tester, the tester is used in conjunction with an RFID tag, the tag is an identification object of the RFID field tester, is composed of a coupling element and a radio frequency chip, stores user information, and is installed on the surface of the object to be identified. The tester includes a control terminal, a reader, and an antenna;

[0007] The control terminal is a computer or embedded motherboard containing application software, which controls the work between the various components of the tester;

[0008] The reader is a device for reading tag information, comprising a control unit and a radio frequency module; the radio frequency module comprises a transmitter and a receiver, the transmitter is used to send a radio signal to the tag, and the receiver is used to receive the radio signal of the tag;

[0009] The antenna is a transmitting and receiving device for transmitting data between the tag and the reader;

[0010] The control terminal controls the reader to send electromagnetic waves through the antenna. After the tag enters the magnetic field of the electromagnetic wave, the coil inside it will generate an induced current, and the tag will start working and receive the radio frequency signal sent by the reader; if it is a passive tag, it will send out the product information stored in the chip; if it is an active tag, it will actively send a radio frequency signal of a certain frequency. The reader obtains the signal through the antenna, decodes it, and sends it to the control unit of the reader for relevant data processing, and finally feeds back to the control terminal to realize data interaction.

[0011] The present invention further includes the following preferred embodiments:

[0012] Preferably, the control terminal of the tester and the control unit of the reader are assembled on a mainboard with a programmable embedded dual-core processor as the core chip, and the programmable embedded dual-core processor is peripherally connected with a power management module, a key function module, a capacitive touch module, an asynchronous transceiver module and a radio frequency unit of the reader; the radio frequency unit is an RF agile transceiver;

[0013] The key function module and the capacitive touch module are used to implement data interaction with the user;

[0014] The asynchronous receiver / transmitter is used to realize the communication interface function of the detector;

[0015] The power management module is used to realize the conversion between external and internal power supply modes.

[0016] Preferably, the tester is used for signal monitoring and performance evaluation of readers and tags during RFID deployment;

[0017] The signal monitoring during the RFID deployment process includes detection of the RFID deployment environment, analysis of RFID radio frequency communication signaling, and performance evaluation based on reference tags;

[0018] The performance evaluation of the reader and the tag is divided into tag compliance detection and reader compliance detection.

[0019] Preferably, the RFID deployment environment detection operation process is: during the RFID deployment process, a portable RFID field tester and its antenna are placed in the RFID deployment environment, and the tester is used to record the signal strength of each channel; the latest spectrum scanning data is displayed in real time within the real-time spectrum analysis bandwidth according to the set frequency to realize the evaluation of the field environment.

[0020] Preferably, the RFID radio frequency communication signaling analysis operation process is: when the RFID under test is in a working state, a portable RFID field tester and its antenna are placed within the working range of the RFID under test, the tester is used to analyze the communication status of the reader and the tag, and the signaling and timing parameters during the working process are recorded. The RFID radio frequency communication signaling analysis function is realized by analyzing the signaling and timing parameters.

[0021] Preferably, the reference tag-based performance evaluation operation process is: when the RFID under test is not in a working state, placing a portable RFID field tester and supporting equipment within the working range of the RFID under test, the supporting equipment including a detection antenna and a reference tag kit;

[0022] The reference tag communicates with the reader under test, and the tester is used to collect the radio frequency signal of the product under test for time domain and frequency domain analysis to obtain the main parameters of the radio frequency performance, which include operating frequency, in-band power, reading distance, and writing distance;

[0023] When the RFID under test shows abnormal working status, reference tags can be used to replace failed products with degraded RF performance parameters for verification, to assist in locating and diagnosing system faults.

[0024] Preferably,

[0025] The label compliance detection process is as follows:

[0026] By sending command signals to the tested tag, the returned response signals are collected and analyzed;

[0027] Perform modulation depth, pulse width, under-modulation or over-modulation, and frequency domain analysis on the returned response signal;

[0028] The modulation depth refers to the ratio of the amplitude of the modulated wave to the amplitude of the carrier wave;

[0029] The pulse width is the period during which the pulse can reach the amplitude;

[0030] The under-modulation refers to the ratio of the time when the peak value of the modulation signal wave peak is lower than the normal modulation amplitude to the pulse width time;

[0031] The overmodulation refers to the ratio of the time when some peak values ​​of the modulation signal exceed the normal modulation amplitude to the pulse width;

[0032] The frequency domain analysis includes analyzing the center frequency, frequency drift, adjacent channel leakage ratio and phase of the measured signal;

[0033] The center frequency is the theoretical center frequency of the measured signal, expressed as f o express;

[0034] Frequency drift refers to the situation where the output frequency value of a radio frequency device changes in one direction over time when it works continuously for a long time. Δ The actual detected value f of the center frequency of the measured signal mea With the theoretical center frequency f o The difference is expressed as:

[0035] f Δ =f mea -f o

[0036] The adjacent channel leakage ratio is used to measure the impact of the radio frequency equipment on the channels outside the main working frequency when it is working. It is expressed as the ratio of the power P(R) of the tested tag in the transmission channel R to the power P(S) of other channels S:

[0037]

[0038] The reader compliance detection includes performing time domain signal analysis and reader detection frequency analysis on the signal emitted by the reader;

[0039] The time domain signal analysis displays the time domain waveform of the measured signal after frequency conversion and various parameters analyzed based on the time domain waveform;

[0040] The reader detection frequency analysis includes the center frequency, frequency drift, adjacent channel leakage ratio and phase analysis of the measured signal.

[0041] Beneficial effects achieved by this application:

[0042] This application realizes an integrated, small-volume, and portable RFID field tester through targeted design of the RFID field tester, which can perform performance tests on tags and readers at the tag installation point, and realizes instant and reliable detection of RFID-related equipment, so that RFID products can obtain better performance, more reliable product guarantees, and more user-friendly technical support. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A schematic diagram of the system architecture of a portable RFID field tester for this application;

[0044] Figure 2 A schematic diagram of the hardware architecture of a portable RFID field tester for this application;

[0045] Figure 3 A schematic diagram of the compliance test software architecture of a portable RFID field tester is provided for this application. DETAILED DESCRIPTION

[0046] The present application is further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present application.

[0047] like Figure 1 As shown, a portable RFID field tester of the present application is used in conjunction with an RFID tag. The tag is an identification object of the RFID field tester, is composed of a coupling element and a radio frequency chip, stores user information, and is installed on the surface of the object to be identified. The tester includes a control terminal, a reader, and an antenna;

[0048] The control terminal is a computer or embedded motherboard containing application software, which controls the work between the various components of the tester;

[0049] The reader is a device for reading tag information, comprising a control unit and a radio frequency module; the radio frequency module comprises a transmitter and a receiver, the transmitter is used to send a radio signal to the tag, and the receiver is used to receive the radio signal of the tag;

[0050] The antenna is a transmitting and receiving device for transmitting data between the tag and the reader. In practical applications, the system power, the shape and relative position of the antenna will affect the transmission and reception performance of the reader data.

[0051] The control terminal controls the reader to send electromagnetic waves through the antenna. After the tag enters the magnetic field of the electromagnetic wave, the coil inside it will generate an induced current, and the tag will start working and receive the radio frequency signal sent by the reader; if it is a passive tag, it will send out the product information stored in the chip; if it is an active tag, it will actively send a radio frequency signal of a certain frequency. The reader obtains the signal through the antenna, decodes it, and sends it to the control unit of the reader for relevant data processing, and finally feeds back to the control terminal to realize data interaction.

[0052] like Figure 2As shown, in a specific embodiment of the present application, the control terminal of the tester and the control unit of the reader are assembled on a mainboard with a programmable embedded dual-core processor as the core chip. When the programmable embedded dual-core processor is actually implemented, Xilinx ZYNQ SOC is selected. The programmable embedded dual-core processor is peripherally connected with a power management module, a key function module, a capacitive touch module, an asynchronous transceiver module and a radio frequency unit of the reader; the radio frequency unit is an RF agile transceiver, and when it is actually implemented, the RF agile transceiver uses AD9361;

[0053] The key function module and the capacitive touch module are used to implement data interaction with the user;

[0054] The asynchronous receiver / transmitter is used to realize the communication interface function of the detector;

[0055] The power management module is used to realize the conversion between external and internal power supply modes.

[0056] In a specific implementation, the tester is used for signal monitoring and performance evaluation of readers and tags during RFID deployment;

[0057] The signal monitoring during the RFID deployment process includes detection of the RFID deployment environment, analysis of RFID radio frequency communication signaling, and performance evaluation based on reference tags;

[0058] like Figure 3 As shown, the performance evaluation of the reader and the tag is divided into tag compliance detection and reader compliance detection.

[0059] In the specific embodiment of the present application, the RFID deployment environment detection operation process is as follows: during the RFID deployment process, a portable RFID field tester and its antenna are placed in the RFID deployment environment, and the tester is used to record the signal strength of each channel; the latest spectrum scanning data is displayed in real time within the real-time spectrum analysis bandwidth according to the set frequency to evaluate the field environment. In addition, for signal interference problems in complex RF environments, the RF communication process signal can be captured, and big data can be collected over a long period of time to obtain an interference event of unknown duration that occurs at an unknown time and place.

[0060] In a specific embodiment of the present application, the RFID radio frequency communication signaling analysis operation process is: when the RFID under test is in a working state, the portable RFID field tester and its antenna are placed within the working range of the RFID under test, the tester is used to analyze the communication between the reader and the tag, and the signaling and timing parameters during the working process are recorded. The RFID radio frequency communication signaling analysis function is realized by analyzing the signaling and timing parameters. The signaling analysis function is mainly aimed at the detection, verification and analysis of the communication signaling between the reader and the tag. It can analyze the signaling receiving and sending sequence, and track and detect, so as to intuitively observe the timing of the communication between the reader and the tag, and analyze the signaling point with problems. When the RFID under test is in an abnormal working state, the specific situation of the abnormal phenomenon can be further analyzed, and the cause of the abnormality can be traced. Under the RFID radio frequency communication signaling mode configuration, the detector works in different detection modes such as reader simulation, tag simulation, and signal monitoring. Among them, the reader mode can actively transmit command signals, and at the same time receive and analyze tag response signals, which is suitable for electronic tag detection; the tag mode can receive and analyze command signals, and at the same time transmit response signals, which is suitable for reader compliance and performance detection; the signal monitoring mode can collect, stream and play back RFID communication signals in real time, which is suitable for RFID overall performance detection and fault diagnosis.

[0061] In a specific embodiment of the present application, the reference tag-based performance evaluation operation process is as follows: when the RFID under test is not in a working state, a portable RFID field tester and supporting equipment are placed within the working range of the RFID under test, and the supporting equipment includes a detection antenna and a reference tag kit;

[0062] like Figure 3 As shown, the reference tag communicates with the reader under test, and the tester is used to collect the RF signal of the product under test for time domain and frequency domain analysis to obtain the main parameters of the RF performance, which include operating frequency, in-band power, reading distance, and writing distance;

[0063] When the RFID under test shows abnormal working status, reference tags can be used to replace failed products with degraded RF performance parameters for verification, to assist in locating and diagnosing system faults.

[0064] In a specific embodiment of the present application, the tag compliance detection process is: by sending a command signal to the tag under test, collecting and analyzing the returned response signal;

[0065] Includes modulation depth, pulse width, under-modulation or over-modulation, and frequency domain analysis of the returned response signal;

[0066] The modulation depth refers to the ratio of the amplitude of the modulated wave to the amplitude of the carrier wave, expressed as a percentage Rmd express;

[0067] If the modulation function p(t) of the signal is known:

[0068] p(t)=(A+m(t))×cos 2πft

[0069] Where: A is the carrier amplitude; m(t) is the modulated waveform function; f is the frequency; t is the time.

[0070] The modulation depth R md It can be expressed as:

[0071]

[0072] Where: peak(m) is the peak value of the modulated waveform function;

[0073] Modulation Depth R md It can also be expressed by the amplitude relationship between the modulated wave and the carrier:

[0074]

[0075] Where: m max is the maximum amplitude of the modulated wave; m min is the minimum amplitude of the modulated wave; p max is the maximum amplitude of the carrier; p min is the minimum amplitude of the carrier;

[0076] The pulse width represents the period during which the pulse can reach the amplitude, which is represented by T, that is:

[0077] T=t um +t om +t am

[0078] Where: t um is the under-modulation time; t om Overmodulation time; t am Time of normal modulation amplitude;

[0079] Undermodulation refers to the time t when the peak value of the modulation signal peak is lower than the normal modulation amplitude. um The ratio of the pulse width time T to the normal modulation amplitude time t um The ratio to the pulse width time T is expressed as:

[0080]

[0081] The overmodulation is the time t when some peak values ​​of the modulation signal exceed the normal modulation amplitude. om Ratio to pulse width T, time t of normal modulation amplitude omThe ratio to the pulse width T is expressed as:

[0082]

[0083] Frequency domain analysis includes the center frequency, frequency drift, adjacent channel leakage ratio and phase of the measured signal;

[0084] The center frequency is the theoretical center frequency, expressed as f o express;

[0085] Frequency drift refers to the situation where the output frequency value of a radio frequency device changes in one direction over time when it is working continuously for a long time. Δ The actual detected value f of the center frequency of the measured signal is used mea With the theoretical center frequency f o The difference is expressed as:

[0086] f Δ =f mea -f o

[0087] The adjacent channel leakage ratio is used to measure the impact of the radio frequency equipment on the channels outside the main working frequency when it is working. It is expressed as the ratio of the power P(R) of the tested tag in the transmission channel R to the power P(S) of other channels S:

[0088]

[0089] The software has designed a communication data module, including decoding data, to display the decoding and identification results of RF signals. It can analyze the relevant measurement values, encoding, preamble check, cyclic redundancy check, etc. of the reverse link frequency of the measured signal, and realize the compliance detection of various indicators of RFID tags.

[0090] In specific implementation, the reader compliance detection operation process is: collecting and analyzing the signal sent by the reader, setting the center frequency, collection time, sampling rate and bandwidth parameters to carry out the detection;

[0091] The reader compliance detection includes time domain signal analysis and reader detection frequency analysis of the signal sent by the reader;

[0092] The time domain signal analysis displays the time domain waveform of the signal after frequency conversion and various parameters analyzed based on the time domain waveform;

[0093] The reader detection frequency analysis is similar to the tag compliance test analysis, and also includes the center frequency, frequency drift, adjacent channel leakage ratio and phase analysis of the measured signal.

[0094] The communication data module of the reader compliance detection includes decoded data, preamble check and CRC check, and analyzes the measurement values ​​related to the encoding method and the measurement of the reference time T_c.

[0095] By monitoring signals during the deployment of UHF and microwave RFID, as well as evaluating the performance of readers and tags, we can effectively optimize the deployment of the system, solve problems such as how many antennas to deploy, how to determine the best location for each antenna, and the best labeling location for each item, and achieve optimization of the RFID deployment process.

[0096] Abbreviations:

[0097] RFID, Radio Frequency Identification, abbreviated as RFID;

[0098] MD, Modulation Depth, modulation depth, also called modulation degree, referred to as MD;

[0099] PW, Pulse Width, pulse width, referred to as PW;

[0100] UM, Under Modulation, also called undershoot, referred to as UM;

[0101] OM, Over Modulation, also called overshoot, referred to as OM;

[0102] ACLR, Adjacent Channel Leakage Ratio, adjacent channel leakage ratio, referred to as ACLR;

[0103] CRC, Cyclic Redundancy Check, cyclic redundancy check, abbreviated as CRC.

[0104] The applicant of the present invention has made a detailed explanation and description of the implementation examples of the present invention in conjunction with the drawings in the specification. However, those skilled in the art should understand that the above implementation examples are only preferred implementation schemes of the present invention, and the detailed description is only to help readers better understand the spirit of the present invention, but not to limit the scope of protection of the present invention. On the contrary, any improvements or modifications based on the inventive spirit of the present invention should fall within the scope of protection of the present invention.

Claims

1. A portable RFID field tester, which is used in conjunction with an RFID tag. The tag is the identification object of the RFID field tester, consists of a coupling element and a radio frequency chip, stores user information, and is installed on the surface of the object to be identified. It is characterized by: The tester includes a control terminal, a reader and an antenna; The control terminal controls the work between the various components of the tester; The reader is a device for reading tag information, comprising a control unit and a radio frequency module; the radio frequency module comprises a transmitter and a receiver, the transmitter is used to send a radio signal to the tag, and the receiver is used to receive the radio signal of the tag; The antenna is a transmitting and receiving device for transmitting data between the tag and the reader; The control terminal controls the reader to send electromagnetic waves through the antenna. After the tag enters the electromagnetic wave magnetic field, the coil inside it will generate an induced current, and the tag will start to work and receive the radio frequency signal sent by the reader; if it is a passive tag, it will send out the product information stored in the chip; if it is an active tag, it will actively send a radio frequency signal of a certain frequency. The reader obtains the signal through the antenna, decodes it, and sends it to the control unit of the reader for relevant data processing, and finally feeds it back to the control terminal to realize data interaction; The tester is used to detect the RFID deployment environment during the RFID deployment process. The operation process is as follows: during the RFID deployment process, the portable RFID field tester and its antenna are placed in the RFID deployment environment, and the signal strength of each channel is recorded using the tester; the latest spectrum scan data is displayed in real time within the real-time spectrum analysis bandwidth according to the set frequency to evaluate the on-site environment; The tester is also used for label compliance detection, and performs modulation depth, pulse width, under-modulation or over-modulation, and frequency domain analysis on the response signal returned during the label compliance detection process; The modulation depth refers to the ratio of the modulated wave amplitude peak (m) to the carrier amplitude A, or: Where: R md is the modulation depth; m max is the maximum amplitude of the modulated wave; m min is the minimum amplitude of the modulated wave; p max is the maximum amplitude of the carrier; p min is the minimum amplitude of the carrier; The pulse width is the period during which the pulse can reach the amplitude, expressed as T, that is: T=t um +t om +t am Where: t um is the under-modulation time; t om is the overmodulation time; t am Time of normal modulation amplitude; The under-modulation refers to the ratio of the time when the peak value of the modulation signal wave peak is lower than the normal modulation amplitude to the pulse width time; The overmodulation refers to the ratio of the time when some peak values ​​of the modulation signal exceed the normal modulation amplitude to the pulse width; The frequency domain analysis includes analyzing the center frequency, frequency drift, adjacent channel leakage ratio and phase of the measured signal; The center frequency is the theoretical center frequency of the measured signal, expressed as f o express; Frequency drift refers to the situation where the output frequency value of a radio frequency device changes in one direction over time when it works continuously for a long time. Δ The actual detected value f of the center frequency of the measured signal is used mea With the theoretical center frequency f o The difference is expressed as: f Δ =f mea -f o The adjacent channel leakage ratio is used to measure the impact of the radio frequency equipment on the channels outside the main working frequency when it is working. It is expressed as the ratio of the power P(R) of the tested tag in the transmission channel R to the power P(S) of other channels S: The tester is also used for reader compliance detection, including time domain signal analysis and reader detection frequency analysis of the signal emitted by the reader; the time domain signal analysis displays the time domain waveform of the measured signal after frequency conversion and various parameters analyzed based on the time domain waveform; the reader detection frequency analysis includes center frequency, frequency drift, adjacent channel leakage ratio and phase analysis of the measured signal.

2. A portable RFID field tester according to claim 1, characterized in that: The control terminal of the tester and the control unit of the reader are assembled on a mainboard with a programmable embedded dual-core processor as the core chip, and the programmable embedded dual-core processor is peripherally connected with a power management module, a key function module, a capacitive touch module, an asynchronous transceiver module and a radio frequency unit of the reader; the radio frequency unit is an RF agile transceiver; The key function module and the capacitive touch module are used to implement data interaction with the user; The asynchronous receiver / transmitter is used to realize the communication interface function of the detector; The power management module is used to realize the conversion between external and internal power supply modes.

3. A portable RFID field tester according to claim 1, characterized in that: The tester is used for signal monitoring during RFID deployment and performance evaluation of readers and tags; The signal monitoring during the RFID deployment process includes detection of the RFID deployment environment, analysis of RFID radio frequency communication signaling, and performance evaluation based on reference tags; The performance evaluation of the reader and the tag is divided into tag compliance detection and reader compliance detection.

4. A portable RFID field tester according to claim 3, characterized in that: The RFID radio frequency communication signaling analysis operation process is as follows: When the RFID under test is in working condition, place the portable RFID field tester and its antenna within the working range of the RFID under test, use the tester to analyze the communication between the reader and the tag, record the signaling and timing parameters during the working process, and realize the RFID radio frequency communication signaling analysis function through the analysis of the signaling and timing parameters.

5. The portable RFID field tester according to claim 3, characterized in that: The performance evaluation operation process based on the reference tag is as follows: When the RFID to be tested is not in working state, the portable RFID field tester and supporting equipment are placed within the working range of the RFID to be tested, wherein the supporting equipment includes a detection antenna and a reference tag kit; The reference tag communicates with the reader under test, and the tester is used to collect the radio frequency signal of the product under test for time domain and frequency domain analysis to obtain the main parameters of the radio frequency performance, which include operating frequency, in-band power, reading distance, and writing distance; When the RFID under test shows abnormal working status, reference tags are used to replace failed products with degraded RF performance parameters for verification, to assist in locating and diagnosing system faults.

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