An analog system and method for a passive radio frequency identification tag

Abstract

The present invention belongs to the technical field of test and measurement, and particularly relates to an analog system and method for passive radio frequency identification tags. The present invention is composed of a reader under test, an attenuator, a radio frequency coupler, a short radio frequency connection line, a radio frequency switch, and a reflector, which are sequentially connected by lines. The other end of the radio frequency switch is connected to a fixed reflector by a line. The other ends of the radio frequency coupler and the radio frequency switch are both connected to an acquisition response module by lines. The other end of the acquisition response module is connected to a computer by a line. The other ends of the computer and the reflector are both connected to a reflector controller by lines. By means of radio frequency coupling, radio frequency acquisition, protocol stack simulation, and real-time programmed reflectivity and high and low reflection states, the response of the tag to the radio command of the reader is completely simulated, and the reflection amplitude can be adjusted, achieving the effect of truly simulating the radio interface and protocol behavior of the passive tag, which has great value for traceable and stable measurement of the performance and protocol consistency of RFID readers.

Description

Technical Field

[0001] The present invention belongs to the radio frequency identification reader test technology in the field of test and measurement technology, and particularly relates to a passive radio frequency identification tag simulation system and method. Background Art

[0002] In radio frequency identification (RFID) communication protocols, many mainstream protocols actively transmit radio carriers and instructions from a reader or a card issuer to a tag. The tag reflects the carrier wave and modulates the reflected wave by quickly changing the reflectivity, so that the reader can receive the tag information. This passive tag communication method is relatively common in the RFID field. When testing a reader, it is necessary to simulate the reflected echo of the tag, including the echo debugging amplitude and the communication protocol stack state transition behavior, so as to test the performance and function of the reader.

[0003] The traditional reader test method uses the method of active radio frequency emission to actively emit a radio frequency signal close to the carrier frequency to the reader to simulate the tag reflection. Since the carrier waves of the reader under test and the signal source cannot achieve absolute phase fixation, the echo phase uncertainty of this traditional method reduces the test accuracy and reliability. Summary of the Invention

[0004] Aiming at the deficiencies existing in the above-mentioned prior art, the present invention provides a passive radio frequency identification tag simulation system and method, the purpose of which is to provide a simulation of a passive tag receiving an RFID reader signal, demodulating and decoding the signal, and making a response to the reader in the form of a change in reflectivity according to a set state machine, the response information and encoding of which conform to the corresponding RFID protocol, and the reflectivity and response time of which can be adjusted within a certain range; the above adjustment can also be set through computer software; the reflected signal power of the simulator can be traced and measured.

[0005] The technical solution adopted by the present invention to achieve the above purpose is as follows:

[0006] A passive radio frequency identification tag simulation system is connected in sequence by a reader under test, an attenuator, a radio frequency coupler, a short radio frequency connection line, a radio frequency switch, and a reflector through lines. The other end of the radio frequency switch is connected to a fixed reflector through a line. The other ends of the radio frequency coupler and the radio frequency switch are both connected to a collection and response module through lines. The other end of the collection and response module is connected to a computer through a line. The other ends of the computer and the reflector are both connected to a reflector controller through lines.

[0007] Further, the reader under test, radio frequency coupler, short radio frequency connection line, radio frequency switch, and reflector are sequentially connected by lines. The other end of the radio frequency switch is connected to the fixed reflector by a line. The other ends of the radio frequency coupler and the radio frequency switch are both connected to the acquisition and response module by lines. The other end of the acquisition and response module is connected to the computer by a line.

[0008] Further, the radio frequency coupler is provided with three ports. Among them, IN is port ①, OUT is port ②, and CPL is port ③. Port ① is connected to the attenuator, port ② is connected to the short radio frequency connection line, and port ③ is connected to the acquisition and response module. Among them, ports ① and ② communicate bidirectionally.

[0009] A method for simulating a passive radio frequency identification tag includes the following steps:

[0010] Step 1: Connect an analog system for a passive radio frequency identification tag;

[0011] Step 2: Operate the reader under test to enter the inventory state;

[0012] Step 3: Run the test software on the computer.

[0013] Further, the test software includes the instrument ISO 18000-63 ultra-high frequency RFID reader test software and the instrument national standard 800-900 MHz RFID reader test software.

[0014] Further, running the test software on the computer includes the following steps:

[0015] Step (1) Radio frequency link and control;

[0016] Step (2) Calibration.

[0017] Further, the radio frequency link and control include:

[0018] The reader under test is connected to the attenuator. Let the output power of the reader under test be P_out (unit: dBm), the attenuation of the attenuator be A (unit: dB), and the output power of the attenuator be P1 (dBm):

[0019] P1 = P_out – A Formula 1

[0020] The attenuator is an optional component. When the output power of the reader is not high or the simulated reflected signal is large, the attenuator can be skipped and the reader under test can be directly connected to port ① of the radio frequency coupler. When the reader under test is connected to the attenuator, the other port of the attenuator is connected to the radio frequency coupler. The radio frequency coupler can be a directional coupler or a non-directional power divider;

[0021] The RF coupler is provided with three ports. Among them, port ① is connected to the attenuator, port ② is connected to the RF connection short line, and port ③ is connected to the acquisition response module. Among them, ports ① and ② pass bidirectionally, and port ③ performs coupled sampling. Let the transmission S parameter from port ① to port ② of the RF signal be S21, the transmission S parameter from port ② to port ① be S12, the signal sent by the reader-writer passes through attenuation, and the S parameter output from port ① to port ③ of the RF coupler is S31, and the coupled S parameter of the back-end reflected signal from port ② to port ③ is S32. According to the naming convention of RF S parameters, the port number in the S parameter suffix is in the order of output first and input second.

[0022] The power P3_in (dBm) of the reader-writer signal output from coupler port ③:

[0023] P3_in = P1 + S31 Formula 2

[0024] Port ② of the RF coupler is connected to a connectable and disconnecable RF connection short line, simply referred to as "short line". The power P2 of the reader-writer signal input to the short line:

[0025] P2 = P1 + S21 Formula 3

[0026] The other end of the RF connection short line is connected to an electrically controlled two-way RF switch. The RF connection short line is connected to the common end of the RF switch. The RF switch selects to connect port ① to the RF input end of the electrically adjustable variable reflector, and the switch selects to connect port ② to the fixed load. Let the insertion loss of the short line be A_cable; the transmission loss from the common end of the two-way switch to each selected end is basically the same, which is A_switch; the complex reflection coefficient reflected by the electrically adjustable variable reflector The complex reflection coefficient of the fixed reflector Then, the change in the RF power ΔP2_r (dBm) reflected to coupler port ② caused by the switch switching:

[0027]

[0028] ΔP2_r = P2 – 2*A_cable – 2*A_switch + R Formula 5

[0029] Here, ΔP2_r is the simulated reflected signal power of the passive tag. A_cable is the insertion loss of the short line, A_switch is the transmission loss from the common end of the two-way switch to each selected end, and R is the amplitude of the reflection difference vector between the electric regulator and the fixed reflector.

[0030] The power ΔP3_r (dBm) of the reflected signal output through coupler port ③:

[0031] ΔP3_r = ΔP2_r + S32 Formula 6

[0032] In the above formula, S32 is the transmission coefficient between ports ③ and ②;

[0033] On the other hand, the power ΔP1_r of the reflected signal returned to the reader through the coupler and attenuator:

[0034] ΔP1_r = ΔP2_r + S21 – A Formula 7

[0035] In the above formula, S21 is the transmission coefficient from port ① to port ②, and A is the attenuation of the attenuator;

[0036] The radio frequency output of port ③ of the radio frequency coupler is input to the radio frequency input of the acquisition and response module. The acquisition and response module has three ports, namely a radio frequency input port, a digital control output port, and a computer control port; the acquisition and response module acquires radio frequency signals from the radio frequency input port, including the instructions of the measured reader and the simulator reflection response, demodulates and decodes the instructions, and calculates the simulated tag response logic waveform through the built-in protocol state machine; the logic waveform is sent from the digital control output port to the radio frequency switch to realize the control of the simulated reflection waveform; the computer control port of the acquisition and response module and the computer are connected through a computer bus or network cable or USB cable to form a computer communication connection line;

[0037] In addition to connecting the acquisition and response module, the computer also connects to the variable reflector controller. The computer software sets the reflection intensity, connects to the variable reflector through the variable reflector controller, and controls the reflection coefficient through analog signals or digital signals.

[0038] Furthermore, the electrically adjustable variable attenuation reflector can be replaced by a fixed reflector.

[0039] Furthermore, the calibration includes:

[0040] Disconnect the short wire, and measure the transmission loss PL1 from port ② of the radio frequency coupler to the input end of the attenuator and the transmission loss (or coupling degree) PL2 from port ② of the radio frequency coupler to port ③ of the radio frequency coupler by using the conventional radio frequency measurement method. The difference between the two:

[0041] ΔPL = PL1 – PL2 Formula 8

[0042] According to the fact that PL2 and S32 are the transmission loss and transmission coefficient between the same ports, according to the radio frequency principle:

[0043] PL2 = -S32 Formula 9

[0044] Also according to the topological structure, PL1 is the comprehensive effect of the attenuator and S21 of the radio frequency coupler:

[0045] PL1 = A – S21 Formula 10

[0046] ΔPL = S32 – S21 + A Formula 11

[0047] Combining Equation 6 and Equation 7:

[0048] ΔP1_r = ΔP3_r – S32 + S21 - A Equation 12

[0049] Substituting into Equation 11:

[0050] ΔP1_r = ΔP3_r – ΔPL Equation 13

[0051] By calibrating the input power measurement of the acquisition response module and the transmission loss difference ΔPL, and by measuring the reflected signal power at port ③ of the RF coupler, the reflected signal power received by the reader under test is calculated.

[0052] A computer storage medium stores a computer program thereon, and when the computer program is executed by a processor, the steps of the analog method for a passive radio frequency identification tag are implemented.

[0053] The present invention has the following beneficial effects and advantages:

[0054] By means of RF coupling, RF acquisition, protocol stack simulation, and real-time programmable reflectivity and high / low reflection states, the present invention completely simulates the response of a tag to a reader's radio instruction, and can adjust the reflection amplitude, achieving the effect of truly simulating the radio interface and protocol behavior of a passive tag. It has great value for traceable and stable measurement of RFID reader performance and protocol consistency.

[0055] This system truly reflects the signal of the reader under test, which is exactly the same as the tag reflection response mechanism, with a high degree of simulation; it has the ability of metrological traceability through scientific structural design; it realizes simulation through electrically tunable reflection, with a long service life and fast response; it adopts a software-defined radio architecture and is adaptable to multiple protocols and protocol upgrades. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] The above and / or additional aspects and advantages of the present invention will become apparent and be readily understood from the following description of the embodiments in conjunction with the accompanying drawings, where:

[0057] Figure 1 is a schematic diagram of the principle of the present invention;

[0058] Figure 2 is a schematic diagram of the principle of the present invention omitting the attenuator and adopting a fixed reflection load.

[0059] In the figure:

[0060] Reader under test 1, attenuator 2, RF coupler 3, RF connecting short line 4, RF switch 5, reflector 6, fixed reflector 7, acquisition response module 8, reflector controller 9, computer 10. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0061] In order to more clearly understand the above-mentioned objects, features, and advantages of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that, without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other.

[0062] In the following description, many specific details are set forth in order to fully understand the present invention. However, the present invention can also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited by the specific embodiments disclosed below.

[0063] The following refers to Figure 1 - Figure 2 Describe the technical solutions of some embodiments of the present invention.

[0064] Embodiment 1

[0065] The present invention provides an embodiment, an analog system of a passive radio frequency identification tag, as Figure 1 shown, Figure 1 is a schematic diagram of the principle of the present invention.

[0066] In the system, the attenuator 2 uses a Minicircuits BW-S10W5+ fixed attenuator. The radio frequency coupler 3 uses a Minicircuits ZFDC-10-2-S directional coupler. The radio frequency coupler 3 is provided with three ports, IN, OUT, and CPL, where IN is used as port ①, OUT is used as port ②, and CPL is used as port ③. The radio frequency connection short line 4 uses a Shanghai Junyou SMA(M)-SMA(M) semi-rigid connecting line. The radio frequency switch 5 uses a Minicircuits ZFSWA2-63DR+ solid-state single-pole double-throw radio frequency switch. The reflector 6 uses a Minicircuits ZX73-2500-S+ voltage-adjustable attenuator, with an open circuit at the terminal. Its reflectivity is approximately twice the attenuation. The fixed reflector 7 uses a Minicircuits BW-S30W2+ 30dB fixed attenuator. The acquisition response module 8 is composed of a Signal Core PXIe5305 downconverter and an instrument PXIe-7506 intelligent intermediate frequency processor. The computer 10 uses a Jianyi Technology PXIe-3975 embedded controller plus a PXIe-2315 chassis. The reflector controller 9 uses a USB-D1208M data acquisition module. The above devices are all commercially available products.

[0067] The test object is an ImpinJ Speedway ISO 18000-63 ultra-high frequency electronic tag reader.

[0068] According to the above Figure 1arranged in the manner shown, and those skilled in the art can implement it smoothly.

[0069] An analog method for a passive radio frequency identification tag, the specific steps are as follows:

[0070] Step 1: Connect the analog system of a passive radio frequency identification tag of the present invention as Figure 1 shown.

[0071] Among them, the measured reader-writer 1, the attenuator 2, the radio frequency coupler 3, the radio frequency connecting short line 4, the radio frequency switch 5, and the reflector 6 are connected in sequence through lines. The other end of the radio frequency switch 5 is connected to the fixed reflector 7 through a line. The other ends of the radio frequency coupler 3 and the radio frequency switch 5 are both connected to the acquisition response module 8 through lines. The other end of the acquisition response module 8 is connected to the computer 10 through a line. The other ends of the computer 10 and the reflector 6 are both connected to the reflector controller 9 through lines.

[0072] The specific connection relationship is as follows:

[0073] The measured reader-writer 1 is connected to a port of the attenuator 2. The other port of the attenuator is connected to the through port ① of the radio frequency coupler 3. The through port ② of the radio frequency coupler 3 is connected to the common end of the radio frequency connecting short line 4 and the radio frequency switch 5. The control end of the radio frequency switch 5 is connected to the control end of the acquisition response module 8. The coupling port ③ of the radio frequency coupler 3 and the acquisition end of the acquisition response module 8 are connected. The computer interface end of the acquisition response module 8 is connected to the computer 10. The other interface of the computer is connected to the computer interface of the reflector controller 9. The control end of the reflector controller 9 is connected to the control end of the reflector 6. The two branch ports of the radio frequency switch 5 are respectively connected to the radio frequency end of the reflector 6 and the radio frequency end of the fixed reflector 7.

[0074] Step 2: Operate the measured reader-writer to enter the inventory state.

[0075] Step 3: Run the instrument ISO 18000-63 ultra-high frequency RFID reader-writer test software on the computer.

[0076] The ISO 18000-63 ultra-high frequency RFID reader-writer test software is a commercially available product purchased through regular channels.

[0077] Embodiment 2

[0078] The present invention provides an embodiment, an analog system for a passive radio frequency identification tag, as Figure 2 shown, Figure 2 is a schematic diagram of the principle of the present invention omitting the attenuator and using a fixed reflection load.

[0079] In the system, the RF coupler 3 uses a Minicircuits ZFRSC-42-S+ power divider for coupling. This power divider has three ports. Among them, the first port serves as port ① of the RF coupler in the figure, port S serves as port ②, and the second port serves as port ③. The RF connection short line 4 uses a Shanghai Junyou SMA(M)-SMA(M) semi-rigid connection. The RF switch 5 uses a Minicircuits ZFSWA2-63DR+ solid-state single-pole double-throw RF switch. The reflector 6 is not connected and is terminated open. The fixed reflector 7 uses a Minicircuits BW-S30W2+ 30dB fixed attenuator. The acquisition and response module 8 is composed of a Signal Core PXIe 5305 downconverter and an instrument PXIe-7506 intelligent intermediate-frequency processor. The computer 10 uses a Jianyi Technology PXIe-3975 embedded controller plus a PXIe-2315 chassis. The above devices are all commercially available products.

[0080] The test object is a national standard 800-900 MHz electronic tag reader.

[0081] According to the connection method as Figure 2 described, those skilled in the art can implement it smoothly.

[0082] A method for simulating a passive radio frequency identification tag, the specific steps are as follows:

[0083] Step 1: Connect the simulation system of a passive radio frequency identification tag of the present invention according to the connection method as Figure 2 shown.

[0084] Among them, the measured reader-writer 1, the RF coupler 3, the RF connection short line 4, the RF switch 5, and the reflector 6 are connected in sequence through lines. The other end of the RF switch 5 is connected to the fixed reflector 7 through a line. The other ends of the RF coupler 3 and the RF switch 5 are both connected to the acquisition and response module 8 through lines. The other end of the acquisition and response module 8 is connected to the computer 10 through a line.

[0085] The specific connection relationship is as follows:

[0086] The measured reader-writer 1 is connected to the through port ① of the RF coupler 3. The through port ② of the RF coupler 3 is connected to the common end of the RF connection short line 4 and the RF switch 5. The control end of the RF switch 5 is connected to the control end of the acquisition and response module 8. The coupling port ③ of the RF coupler 3 is connected to the acquisition end of the acquisition and response module 8. The computer interface end of the acquisition and response module 8 is connected to the computer 10. The two branch ports of the RF switch 5 are respectively connected to the RF ends of the reflector 6 and the reflector 7.

[0087] Step 2: Operate the measured reader-writer to enter the inventory state.

[0088] Step 3: Run the national standard 800 - 900MHz RFID reader / writer test software on the computer.

[0089] Embodiment 3

[0090] The present invention provides an embodiment, a method for simulating a passive radio frequency identification tag, comprising the following steps:

[0091] Step (1). Radio frequency link and control.

[0092] The reader / writer under test 1 is connected to the attenuator 2. Let the output power of the reader / writer under test 1 be P_out (unit: dBm), the attenuation of the attenuator be A (unit: dB), and the output power of the attenuator be P1 (dBm).

[0093] P1 = P_out – A Formula 1

[0094] The attenuator 2 is an optional component. When the output power of the reader / writer is not high or the simulated reflected signal is large, the attenuator can be skipped, and the reader / writer under test 1 can be directly connected to port ① of the radio frequency coupler 3. When the reader / writer under test 1 is connected to the attenuator 2, the other port of the attenuator 2 is connected to the radio frequency coupler 3. The radio frequency coupler 3 can be a directional coupler or a non - directional power divider.

[0095] The radio frequency coupler 3 is provided with three ports. Among them, port ① is connected to the attenuator 2, port ② is connected to the radio frequency connecting short line 4, and port ③ is connected to the acquisition response module 8. Among them, ports ① and ② are bidirectional, and port ③ plays a role of coupling and sampling. Let the transmission S parameter from port ① to port ② of the radio frequency signal be S21, the transmission S parameter from port ② to port ① be S12, the S parameter of the signal emitted by the reader / writer after attenuation and output from port ① to port ③ of the radio frequency coupler be S31, and the coupling S parameter of the reflected signal at the back end from port ② to port ③ be S32. Here, according to the naming convention of radio frequency S parameters, the port number in the S parameter suffix is in the order of output first and input second.

[0096] The power of the reader / writer signal output from coupler port ③ is P3_in (dBm)

[0097] P3_in = P1 + S31 Formula 2

[0098] The radio frequency coupler port ② is connected to a radio frequency connecting short line 4 that can be connected and disconnected, hereinafter referred to as "short line" for short. The power of the reader / writer signal input to the short line is P2:

[0099] P2 = P1 + S21 Formula 3

[0100] The other end of the short RF connection line 4 is connected to the electronically controlled RF switch 5 with two choices. The short RF connection line 4 is connected to the common end of the RF switch 5. The selected port ① of the RF switch 5 is connected to the RF input end of the electrically adjustable variable reflector 6, and the selected port ② of the switch is connected to the fixed load. Let the insertion loss of the short line be A_cable; the transmission loss from the common end of the two-choice switch to each selected end is basically the same, which is A_switch; the complex reflection coefficient reflected by the electrically adjustable variable reflector The complex reflection coefficient of the fixed reflector 7 Then, the change in the RF power ΔP2_r (dBm) reflected to the coupler port ② caused by the switch switching

[0101]

[0102] ΔP2_r = P2 – 2*A_cable – 2*A_switch + R Formula 5

[0103] In the above formula, ΔP2_r is the power of the reflected signal of the passive tag simulated by the present invention, A_cable is the insertion loss of the short line, A_switch is the transmission loss from the common end of the two-choice switch to each selected end, and R is the amplitude of the reflection difference vector between the electric regulator and the fixed reflector.

[0104] The power ΔP3_r (dBm) of the reflected signal output through the coupler port ③

[0105] ΔP3_r = ΔP2_r + S32 Formula 6

[0106] In the above formula, S32 is the transmission coefficient between port ③ and port ②;

[0107] On the other hand, the power ΔP1_r of the reflected signal returned to the reader through the coupler and the attenuator:

[0108] ΔP1_r = ΔP2_r + S21 – A Formula 7

[0109] In the above formula, S21 is the transmission coefficient from port ① to port ②, and A is the attenuation amount of the attenuator;

[0110] The RF output from port ③ of the RF coupler 3 is input to the acquisition and response module 8. The acquisition and response module 8 has three ports, namely an RF input port, a digital control output port, and a computer control port. The acquisition and response module 8 collects RF signals from the RF input port, including the instructions of the measured reader and the reflected response of the simulator, demodulates and decodes the instructions, and calculates the simulated tag response logic waveform through the built-in protocol state machine. The logic waveform is sent from the digital control output port to the RF switch to realize the control of the simulated reflection waveform. The computer control port of the acquisition and response module 8 is connected to the computer 10, and this connection can be a computer bus, a network cable, a USB cable, or a connection line that can realize computer communication.

[0111] In addition to connecting to the acquisition response module 8, the computer 10 is also connected to the variable reflector controller 9. The computer software sets the reflection intensity, connects to the variable reflector through the variable reflection controller, and controls the reflection coefficient. This control can be either an analog signal or a digital signal.

[0112] The above-mentioned electrically adjustable variable attenuation reflector can be replaced with a fixed reflector, and the reflector controller can be omitted. The system still maintains the function of an analog passive tag, but the reflection size cannot be adjusted by software.

[0113] Step (2). Calibration.

[0114] Disconnect the short wire, and the transmission loss PL1 from the port ② of the RF coupler to the input end of the attenuator and the transmission loss (or coupling degree) PL2 from the port ② of the RF coupler to the port ③ of the RF coupler can be measured by sampling conventional RF measurement methods. The difference between the two is:

[0115] ΔPL = PL1 – PL2 Formula 8

[0116] According to the fact that PL2 and S32 are the transmission loss and transmission coefficient between the same ports, according to RF principles

[0117] PL2 = -S32 Formula 9

[0118] Also according to the topological structure, PL1 is the combined effect of the attenuator and the S21 of the RF coupler:

[0119] PL1 = A – S21 Formula 10

[0120] ΔPL = S32 – S21 + A Formula 11

[0121] Combining Formula 6 and Formula 7

[0122] ΔP1_r = ΔP3_r – S32 + S21 - A Formula 12

[0123] Substitute into Formula 11

[0124] ΔP1_r = ΔP3_r – ΔPL Formula 13

[0125] That is to say, by calibrating the input power measurement of the acquisition response module and the transmission loss difference ΔPL, we can calculate the reflected signal power received by the reader under test by measuring the reflected signal power at the port ③ of the RF coupler.

[0126] Example 4

[0127] Based on the same inventive concept, an embodiment of the present invention further provides a computer storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the simulation method of a passive radio frequency identification tag described in Embodiment 1 are implemented.

[0128] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0129] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or multiple flows and / or blocks

[0130] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the functions specified in Figure 1 one or more of the flows Figure 1 or multiple flows and / or blocks

[0131] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in Figure 1 one or more of the flows Figure 1 or multiple flows and / or blocks

[0132] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent substitutions can still be made to the specific implementation manners of the present invention, and any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the protection scope of the claims of the present invention.

Claims

1. An analog method for passive radio frequency identification tags, characterized in that: It is implemented by using an analog system of a passive radio frequency identification tag. The analog system consists of a reader under test (1), an attenuator (2), a radio frequency coupler (3), a short radio frequency connection line (4), a radio frequency switch (5), and a reflector (6) connected in sequence by lines. The other end of the radio frequency switch (5) is connected to a fixed reflector (7) by a line. The other ends of the radio frequency coupler (3) and the radio frequency switch (5) are both connected to an acquisition response module (8) by lines. The other end of the acquisition response module (8) is connected to a computer (10) by a line. The other ends of the computer (10) and the reflector (6) are both connected to a reflector controller (9) by lines; The radio frequency coupler (3) has three ports, where IN is port ①, OUT is port ②, and CPL is port ③; Port ① is connected to the attenuator (2), port ② is connected to the short radio frequency connection line (4), and port ③ is connected to the acquisition response module (8); Among them, ports ① and ② pass bidirectionally; The analog method of the passive radio frequency identification tag includes the following steps: Step 1: Connect an analog system of a passive radio frequency identification tag; Step 2: Operate the reader under test to enter the inventory state; Step 3: Run test software on the computer. The test software includes instrument ISO 18000-63 ultra-high frequency RFID reader test software and instrument national standard 800-900MHz RFID reader test software; Running the test software on the computer includes the following steps: Step (1) Radio frequency link and control; Step (2) Calibration; The radio frequency link and control include: The reader under test is connected to the attenuator. Let the output power of the reader under test be P_out (unit: dBm), the attenuation of the attenuator be A (unit: dB), and the output power of the attenuator be P1 (dBm): P1 = P_out – A Formula 1 The attenuator is an optional component. When the output power of the reader is not high or the simulated reflection signal is large, the attenuator can be skipped and the reader under test can be directly connected to port ① of the radio frequency coupler; When the reader under test is connected to the attenuator, the other port of the attenuator is connected to the radio frequency coupler. The radio frequency coupler can be a directional coupler or a non-directional power divider; The radio frequency coupler has three ports, where port ① is connected to the attenuator, port ② is connected to the short radio frequency connection line, and port ③ is connected to the acquisition response module; Among them, ports ① and ② pass bidirectionally, and port ③ performs coupling sampling; Let the transmission S parameter of the radio frequency signal from port ① to port ② be S21, the transmission S parameter from port ② to port ① be S12, the S parameter of the signal emitted by the reader after attenuation and output from port ① to port ③ of the radio frequency coupler be S31, and the coupling S parameter of the back-end reflection signal from port ② to port ③ be S32; According to the naming convention of radio frequency S parameters, the port number of the S parameter suffix is output first and input later; The power of the reader signal output from coupler port ③ is P3_in (dBm): P3_in = P1 + S31 Formula 2 The second port of the RF coupler is connected to a short RF connection line that can be connected and disconnected, abbreviated as "short line". The power P2 of the reader-writer signal input by the short line: P2 = P1 + S21 Formula 3. The other end of the RF connection short line is connected to an electronically controlled two-way RF switch. The RF connection short line is connected to the common end of the RF switch. The switch selects port ① to be connected to the RF input end of the electrically adjustable variable reflector, and the switch selects port ② to be connected to a fixed load; let the insertion loss of the short line be A_cable; the transmission loss from the common end of the two-way switch to each selected end is basically the same, which is A_switch; the complex reflection coefficient reflected by the electrically adjustable variable reflector Complex reflection coefficient of the fixed reflector Then, the change in RF power ΔP2_r (dBm) reflected to the second port of the coupler caused by the switch switching is: ΔP2_r = P2 – 2*A_cable – 2*A_switch + R Formula 5 Here, ΔP2_r is the power of the reflected signal of the simulated passive tag, A_cable is the insertion loss of the short cable, A_switch is the transmission loss from the common end of the two-way switch to each selected end, and R is the amplitude of the reflection difference vector between the electrical regulator and the fixed reflector; The power ΔP3_r (dBm) of the reflected signal output through coupler port ③: ΔP3_r = ΔP2_r + S32 Equation 6 In the above formula, S32 is the transmission coefficient between port ③ and port ②; On the other hand, the power ΔP1_r of the reflected signal returned to the reader-writer through the coupler and the attenuator: ΔP1_r = ΔP2_r + S21 – A Equation 7 In the above formula, S21 is the transmission coefficient from port ① to port ②, and A is the attenuation of the attenuator; The radio frequency output from port ③ of the radio frequency coupler is input to the radio frequency input of the acquisition and response module. The acquisition and response module has three ports: a radio frequency input port, a digital control output port, and a computer control port; the acquisition and response module acquires radio frequency signals from the radio frequency input port, including the commands of the reader-writer under test and the reflection responses of the simulator, demodulates and decodes the commands, and calculates the simulated tag response logic waveform through the built-in protocol state machine; the logic waveform is sent from the digital control output port to the radio frequency switch to control the simulated reflection waveform; the computer control port of the acquisition and response module and the computer are connected through a computer bus, a network cable, or a USB cable to form a computer communication connection line; In addition to connecting the acquisition and response module, the computer also connects to the variable reflector controller. The computer software sets the reflection intensity, connects to the variable reflector through the variable reflector controller, and controls the reflection coefficient through analog signals or digital signals.

2. The analog method for passive radio frequency identification tags according to claim 1, characterized in that: The electrically adjustable variable attenuation reflector can be replaced by a fixed reflector.

3. The analog method for passive radio frequency identification tags according to claim 1, characterized in that: The calibration includes: Disconnect the short cable, and measure the transmission loss PL1 from port ② of the radio frequency coupler to the input end of the attenuator and the transmission loss (or coupling degree) PL2 from port ② of the radio frequency coupler to port ③ of the radio frequency coupler using the conventional radio frequency measurement method. The difference between the two: ΔPL = PL1 – PL2 Equation 8 According to the fact that PL2 and S32 are the transmission loss and transmission coefficient between the same ports, according to the radio frequency principle: PL2 = -S32 Equation 9 Also according to the topological structure, PL1 is the combined effect of the attenuator and S21 of the radio frequency coupler: PL1 = A – S21 Equation 10 ΔPL = S32 – S21 + A Equation 11 Combining Equation 6 and Equation 7: ΔP1_r = ΔP3_r – S32 + S21 - A Equation 12 Substitute Equation 11: ΔP1_r = ΔP3_r – ΔPL Equation 13 By calibrating the input power measurement of the acquisition and response module and the transmission loss difference ΔPL, and measuring the power of the reflected signal at port ③ of the radio frequency coupler, the power of the reflected signal received by the reader-writer under test is calculated.

4. A computer storage medium, characterized in that: The computer storage medium stores a computer program, and when the computer program is executed by a processor, the steps of a method for simulating a passive radio frequency identification tag as claimed in claims 1-3 are implemented.

Images