An RFID sensor system device and method based on magnetron antenna coupling

Abstract

The application discloses a kind of RFID sensing system device and method based on magnetron antenna coupling.The product of required identification label has two separable parts, label and antenna coupler are installed in one part of product, magnet is installed in another part of product, coupling structure is formed between antenna coupler and label, read-write system is used to transmit radio frequency signal, receive and process the radio frequency signal returned by label, reed switch is connected between two coupling radiators to form antenna coupler, magnet is used to control the state of antenna coupler, the method comprises device installation, using read-write system to receive and process the radio frequency signal generated by label, and judging the state of antenna coupler through the data information of radio frequency signal to judge the use state of product.The application uses magnet to carry out wireless, passive sensing for various actions, and the inductive function does not need to design specific label, so the structure is simple and easy to deploy, and has good application potential in Internet of Things and smart home.

Description

Technical Field

[0001] This invention belongs to the field of RFID sensing technology, specifically to a sensing system device and method based on magnetically controlled antenna coupling. Background Technology

[0002] Ultra-high frequency radio frequency identification (UHF RFID) technology is a non-contact automatic identification technology that uses radio frequency to identify tags and acquire data. RFID technology is now widely used in various fields such as retail, freight management, healthcare, transportation, and security monitoring, and has great development potential and a wide range of applications. Compared to traditional tags such as barcodes, RFID technology has advantages that it lacks, including longer lifespan, longer reading distance, faster reading speed, and the ability to identify multiple tags in batches. It greatly facilitates people's daily lives and has wide applications in intelligent sensing systems.

[0003] A Radio Frequency Identification (RFID) system generally consists of three parts: a reader, electronic tags, and a data management system. The system works by having the reader emit radio frequency signals. When a tag enters the range of these signals, it is activated and transmits its data to the reader, enabling the reader to identify the tag. In addition to reading the data from the tag, the reader can also acquire information such as Received Signal Strength (RSS), frequency, phase, and Doppler shift. This information further facilitates the development of RFID tag functionality.

[0004] However, existing applications of radio frequency identification (RFID) sensing still have some shortcomings. Firstly, commercial tags have limited sensing capabilities, restricting their application scenarios and often requiring tag modification for sensing. This necessitates designing more functional chips or modifying tag antennas, which is more difficult and increases costs. Secondly, for sensing in compact areas, multiple RFID tags can interfere with each other and are difficult to install. These shortcomings limit the application of RFID sensing. Summary of the Invention

[0005] To address the shortcomings of the prior art, this invention proposes an RFID sensing system device and method based on magnet-controlled antenna coupling. This RFID sensing method eliminates the need for specific tag design; commercial tags can be used to achieve the sensing purpose, making it convenient, effective, and easy to apply. Furthermore, when only one tag is present, multiple magnet-controlled antenna couplers can be used to meet complex sensing requirements, avoiding interference between multiple tags and enabling the simple and effective application of RFID sensing in a wider range of scenarios.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] I. An RFID sensing system device based on magnetically controlled antenna coupling:

[0008] The product to be identified by the tag has two separable parts: the tag and the antenna coupler are both mounted on one part of the product, and the magnet is mounted on the other part of the product. The antenna coupler and the tag form a coupling structure. The reading and writing system is used to transmit radio frequency signals and to receive and process the radio frequency signals returned by the tag.

[0009] By using magnets to influence the operating state of the antenna coupler, the radio frequency signal output by the tag coupled to the antenna coupler can be altered.

[0010] The antenna coupler mainly consists of a reed switch and two coupling radiators, with the reed switch connected between the two coupling radiators;

[0011] By using a magnet to influence the opening and closing state of a reed switch, the operating state of the antenna coupler is changed, thereby altering the radio frequency signal output by the tag coupled to the antenna coupler.

[0012] The reading and writing system includes a reader antenna, a reader, and a host computer. One end of the reader is connected to the reader antenna, and the other end of the reader is connected to the host computer. The reader antenna is used to transmit radio frequency signals and receive radio frequency signals returned by the tag. The radio frequency signals received by the reader antenna are read by the reader and transmitted to the host computer, which then obtains the data information of the radio frequency signals.

[0013] The antenna coupler can be either a conducting coupler or a non-conducting coupler. The magnet is used to control the state of the antenna coupler: when the magnet is away from the reed switch in the antenna coupler, the antenna coupler is a conducting coupler; when the magnet is close to the reed switch, the antenna coupler is a non-conducting coupler. The conducting coupler and the non-conducting coupler form two different coupling structures when coupled to the tag, respectively.

[0014] II. A radio frequency identification sensing method applied to the device, comprising the following steps:

[0015] Step 1: Install the tag, antenna coupler, and magnet on the product to be tagged. Install the tag and antenna coupler on one part of the product according to the installation distance d between the tag and the antenna coupler, and install the magnet on the other part of the product. Place the reader antenna close to the tag and connect the reader antenna to the host computer through the reader. Turn on the host computer to make the reader antenna generate radio frequency (RF) signals. When the tag is in the RF signal area generated by the reader antenna, the tag is activated and also generates RF signals. The RF signals generated in the tag are received by the reader antenna, then read and written by the reader, and finally the data information of the RF signals in the tag is obtained in the host computer.

[0016] Step 2: Using the data information of the radio frequency signal in the tag received by the host computer, determine whether the magnet affects the antenna coupler, and then determine the usage status of the product whose tag needs to be identified.

[0017] Step two specifically involves determining the operating state of the antenna coupler by observing changes in the received signal strength (RSS) and phase in the data information, thereby determining whether the magnet affects the antenna coupler.

[0018] If the received signal strength (RSS) and phase are equal to the preset signal strength and preset phase respectively, the antenna coupler is identified as a conducting coupler. In this case, the reed switch in the antenna coupler remains closed without being affected by the magnet. The part of the product where the magnet is installed is far away from the antenna coupler.

[0019] If the received signal strength (RSS) is not equal to the preset signal strength or the phase is not equal to the preset phase, the antenna coupler is identified as a non-conductive coupler. In this case, the reed switch in the antenna coupler is affected by the magnet and changes to the open state. The part of the product where the magnet is installed is close to the antenna coupler.

[0020] In step 1, the installation distance l between tag 1 and antenna coupler 2 is calculated according to the following formula:

[0021]

[0022] Among them, Z in Let Z0 represent the input impedance of the tag 1 antenna, where j is the symbol for the imaginary part, and Z0 is the impedance of the tag 1 antenna, i.e., the input impedance Z0. in The real part, Input impedance Z in The imaginary part of Z mLet be the impedance of antenna coupler 2, l be the installation distance between tag 1 and antenna coupler 2, f be the frequency of the radio frequency signal transmitted by the antenna of tag 1 and the value of f is in the range of 902MHz-927MHz, μ be the permeability of the medium of tag 1, l0 be the length of tag 1, I be the minimum starting current of tag 1, S be the area of ​​the magnetic field generated by the antenna coupler 2 projected vertically onto tag 1, α be the loss coefficient of the device, π be pi, which is taken as 3.1415926, and d be the differential sign.

[0023] This invention designs a magnetically controlled antenna coupler consisting of a coupled radiator and a reed switch. The reed switch has two states, on and off, controlled by a magnet. Coupled with a radio frequency identification (RFID) tag, this antenna coupler can influence the tag's operating state. This replaces the relationship between the sensing source and the antenna's operating mode with a relationship between the sensing source and the reed switch's state. This RFID sensing method eliminates the need for specific tag design, and even with only one tag, complex sensing requirements can be met using multiple magnetically controlled antenna couplers, avoiding interference between multiple tags. This simple and effective approach allows RFID sensing to be applied in a wider range of scenarios.

[0024] The beneficial effects of this invention are:

[0025] 1. This invention differs from traditional RFID sensing methods. It utilizes a magnet to control an antenna coupler with a reed switch, thereby influencing the operating state of the RFID tag. Under the control of the magnet, the reed switch has two states: open and closed, corresponding to two different states of the antenna coupler, with different resonant frequencies and coupling performance. Coupled with an RFID commercial tag using this coupler, the tag's operating state changes. The changes in the tag's operating state are checked and judged by the received signal strength (RSS) and phase data reflected by the RFID tag read by the reader.

[0026] 2. This invention uses magnets to wirelessly and passively sense various movements. The sensing function can be achieved using commercial tags, eliminating the need for designing specific tags. Furthermore, when using only a single tag, complex sensing requirements can be met through multiple magnetically controlled antenna couplers, effectively avoiding interference between multiple tags.

[0027] 3. This invention has a simple structure and is easy to deploy, and has good application potential in healthcare, the Internet of Things, and smart homes. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the system device structure of the present invention.

[0029] Figure 2 This is a schematic diagram of a magnetically controlled antenna coupler.

[0030] Figure 3 This is a schematic diagram of the equivalent coupled radiator when the reed switch of the magnetically controlled antenna coupler is open and closed.

[0031] Figure 4 This is a schematic diagram of the equivalent coupled radiator when the reed switch of the magnetically controlled antenna coupler is open.

[0032] Figure 5 This is a schematic diagram of the structure of an application device for detecting the open / closed state of a cabinet door according to the present invention.

[0033] Figure 6 This is a schematic diagram of the structure of an application device for detecting the rotation state of a bottle cap according to the present invention.

[0034] Figure 7 This is a schematic diagram of an RFID sensing method based on multiple magnetically controlled antenna couplers.

[0035] In the diagram: 1. Tag; 2. Antenna coupler; 3. Magnet; 4. Reader antenna; 5. Reader; 6. Host computer; 7. Reed switch; 8. Coupler radiator; 9. Conductive coupler; 10. Non-conductive coupler. Detailed Implementation

[0036] The present invention will be further described and illustrated below with reference to the accompanying drawings and examples: This example is based on the technical solution of the present invention and provides specific implementation methods and operation procedures. The scope of protection of the present invention includes, but is not limited to, the following examples.

[0037] like Figure 1 As shown, the device includes a tag 1, an antenna coupler 2, a magnet 3, and a reading and writing system. The product to be identified by the tag has two separable parts. The tag 1 and the antenna coupler 2 are both mounted on one part of the product, and the magnet 3 is mounted on the other part of the product. The two parts can move away from each other and closer to each other. The antenna coupler 2 and the tag 1 form a coupling structure. The reading and writing system is used to transmit radio frequency signals and receive and process the radio frequency signals returned by the tag 1.

[0038] The magnet 3 is used to influence the working state of the antenna coupler 2, thereby changing the radio frequency signal output by the tag (1) coupled to the antenna coupler (2).

[0039] like Figure 2 As shown, the antenna coupler 2 mainly consists of a reed switch 7 and two coupling radiators 8. The reed switch 7 is connected between the two coupling radiators 8. The reed switch 7 is a normally closed reed switch. The tag 1 is a radio frequency identification tag.

[0040] The magnet 3 is used to affect the opening and closing state of the reed switch 7 in the antenna coupler 2, thereby changing the working state of the antenna coupler 2, and thus changing the radio frequency signal output by the tag 1 coupled to the antenna coupler 2. The reading and writing system obtains the data information of the radio frequency signal in the tag 1, and judges the working state of the antenna coupler 2 through the data information of the radio frequency signal, thereby judging the usage status of the product whose identification tag is required.

[0041] The coupling radiator 8 is made of copper foil with a thickness of 0.05 mm. One arm of the coupling radiator 8 has a length of a = 44 mm, and the other arm of the coupling radiator 8 has a length of b = 60 mm. The fold height of the coupling radiator 8 is c = 16 mm, and the fold width is d = 8 mm.

[0042] The reading and writing system includes a reader antenna 4, a reader 5, and a host computer 6. One end of the reader 5 is wired to the reader antenna 4, and the other end of the reader 5 is wired to the host computer 6. The reader antenna 4 is used to transmit radio frequency signals and receive radio frequency signals returned by the tag 1. The radio frequency signals received by the reader antenna 4 are read by the reader 5 and transmitted to the host computer 6, which then obtains the data information of the radio frequency signals.

[0043] like Figure 3 and Figure 4 As shown, antenna coupler 2 is either a conducting coupler 9 or a non-conducting coupler 10. Magnet 3 is used to control the state of antenna coupler 2: when magnet 3 is away from reed switch 7 in antenna coupler 2, reed switch 7 remains closed due to the influence of magnet 3, and the two coupled radiators 8 are connected, so antenna coupler 2 is equivalent to conducting coupler 9; when magnet 3 is close to reed switch 7, reed switch 7 is opened due to the influence of magnetic field, and the two coupled radiators 8 are not connected, so antenna coupler 2 is equivalent to non-conducting coupler 10.

[0044] When the conducting coupler 9 and the non-conducting coupler 10 are coupled to the tag 1 respectively, they form two different coupling structures. The different coupling structures have different resonant frequencies and coupling performance, which will cause the tag 1 in the coupling structure to emit different radio frequency signals.

[0045] The reader antenna 4 receives the radio frequency signal emitted by the tag 1, and then the reader 5 reads and writes the signal. The host computer 6 outputs the received signal strength (RSS) and phase value of the radio frequency signal. Therefore, the coupling structure between the tag 1 and the antenna coupler 2 can be detected based on the received signal strength (RSS) and phase value obtained after processing by the host computer 6, and the magnet 3 can be used to determine whether it affects the antenna coupler 2 based on the coupling structure.

[0046] A radio frequency identification sensing method for a device includes the following steps:

[0047] Step 1: Install the tag 1, antenna coupler 2, and magnet 3 on the product for which the tag needs to be identified. Install the tag 1 and antenna coupler 2 on one part of the product according to the installation distance d between the tag (1) and the antenna coupler (2), and install the magnet 3 on the other part of the product. Place the reader antenna 4 close to the tag 1, and connect the reader antenna 4 to the host computer 6 through the reader 5. Turn on the host computer 6 so that the reader antenna 4 generates a radio frequency signal in a certain area. When the tag 1 is located in the area of ​​the radio frequency signal generated by the reader antenna 4, the tag 1 is activated and generates a radio frequency signal. The radio frequency signal generated in the tag 1 is received by the reader antenna 4, and then read and written by the reader 5. Finally, the host computer 6 obtains the data information of the radio frequency signal in the tag 1. The data information includes the received signal strength (RSS), frequency, phase, Doppler shift, etc.

[0048] Step 2: Using the data information of the radio frequency signal in tag 1 received by host computer 6, determine whether magnet 3 affects antenna coupler 2, and then determine the usage status of the product to be identified by the tag.

[0049] Step two is as follows: If the position of magnet 3 is changed, the distance between magnet 3 and antenna coupler 2 will change simultaneously, causing the working state of antenna coupler 2 to change. Antenna coupler 2 is either a conducting coupler 9 or a non-conducting coupler 10. When the conducting coupler 9 and the non-conducting coupler 10 are coupled to tag 1 respectively, the data information of the radio frequency signal generated in tag 1 will change. The state of antenna coupler 2 is determined by whether the received signal strength (RSS) and phase in the data information change, thereby determining whether magnet 3 affects antenna coupler 2.

[0050] If the received signal strength (RSS) and phase are equal to the preset signal strength and preset phase respectively, the antenna coupler 2 is identified as the conducting coupler 9. Then the reed switch 7 remains closed without the influence of the magnet 3. The part of the product where the magnet 3 is installed is far away from the antenna coupler 2, that is, the two parts of the product are far apart.

[0051] If the received signal strength (RSS) is not equal to the preset signal strength or the phase is not equal to the preset phase, the antenna coupler 2 is identified as a non-conducting coupler 10. Then the reed switch 7 is affected by the magnet 3 and turns into an open state. The part of the product where the magnet 3 is installed is close to the antenna coupler 2, that is, the two parts of the product are close together.

[0052] The state of antenna coupler 2 is controlled by magnet 3. When magnet 3 is far away from reed switch 7, the magnetic flux Φ through reed switch 7 is less than or equal to the critical magnetic flux Φ0, and reed switch 7 is in a closed state unaffected by the magnetic field of magnet 3. When magnet 3 is close to reed switch 7, the magnetic flux Φ through reed switch 7 is greater than or equal to the critical magnetic flux Φ0, and reed switch 7 is in an open state affected by the magnetic field of magnet 3. In the two different states, antenna coupler 2 and tag 1 have different coupling performance, where Φ0 is the critical magnetic flux value for the switching state transition of reed switch 7.

[0053] The reader 5 emits radio frequency (RF) signals through the reader antenna 4. When tag 1 enters the effective range of the RF signal emitted by the reader antenna 4, tag 1 is activated and generates an RF signal. The reading system then reads the basic information of the RF signal generated by tag 1. The antenna of tag 1 and the antenna coupler 2 together form a coupling structure. The input impedance Z of the antenna of tag 1 is... in Represented as:

[0054] Z in =R in +jX in

[0055] R in =Z o

[0056]

[0057]

[0058] Among them, R in Input impedance Z in The real part, X in Input impedance Z in The imaginary part, j is the symbol representing the imaginary part, Z0 is the impedance of the antenna of tag 1, Z m Let M be the impedance of antenna coupler 2, M be the coupling coefficient between antenna coupler 2 and tag 1, f be the frequency of the radio frequency signal transmitted by the antenna of tag 1, Φ be the magnetic flux of antenna coupler 2, μ be the permeability of the medium of tag 1, l0 be the length of tag 1, I be the minimum starting current of tag 1, S be the area of ​​the magnetic field generated by the perpendicular projection of antenna coupler 2 onto tag 1, l be the installation distance between tag 1 and antenna coupler 2, α be the loss coefficient of the device, π be pi, taken as 3.1415926, and d be the differential sign.

[0059] When the frequency of the radio frequency signal transmitted by the tag 1 antenna is at the resonant frequency, the input impedance Z of the tag 1 antenna is... in The real part R in with and imaginary part X in They are represented as follows:

[0060]

[0061] X in =2πfL m

[0062] Among them, R m L represents the resistance value of antenna coupler 2. m Here is the inductance value of antenna coupler 2;

[0063] By changing the distance between tag 1 and antenna coupler 2, the coupling coefficient M between antenna coupler 2 and tag 1 can be changed, thereby changing the input impedance Z. in Due to the influence of magnet 3, when reed switch 7 changes from closed to open, the input impedance Z of tag 1 antenna... in As the frequency f of the radio frequency signal emitted by the antenna of tag 1 changes, the radio frequency signal received by the reader antenna 4 from the emitted radio frequency signal of tag 1 also changes. Thus, the change in the working state of tag 1 can be detected by the received signal strength (RSS) and phase value of the radio frequency signal obtained by the host computer 6, and then the dynamic changes related to magnet 3 can be obtained.

[0064] The method senses changes in the relative position between magnet 3 and tag 1 on the same product. The sensing function can be achieved by using commercial tags without the need to design specific tags.

[0065] The reader antenna 4, reader 5 and host computer 6 can receive the radio frequency signal returned by tag 1, digitize the returned radio frequency signal, and extract data information such as received signal strength (RSS), frequency, phase and Doppler shift from tag 1.

[0066] In the sensing application of tag 1, two commonly used parameters are the received signal strength (RSS) and the phase of the radio frequency signal obtained from the host computer 6. The received signal strength (RSS) is related to the backscattered signal strength of tag 1, and therefore is easily affected by changes in the environment in which tag 1 is located and changes in the state of tag 1 itself, such as the sensitivity of the chip, impedance matching, polarization matching, modulation depth, and tag characteristics between antennas in tag 1. In this embodiment of the invention, the influence of the coupling between tag 1 and the magnetically controlled antenna coupler 2 also needs to be considered. When the distance between the reader antenna 4 and tag 1 is D, the received signal strength (RSS) R... D Represented as:

[0067]

[0068] Where, σ MThe influence of the coupling between tag 1 and magnetically controlled antenna coupler 2, σ represents the influence of environmental and equipment factors, and G represents the influence of the coupling between tag 1 and magnetically controlled antenna coupler 2. t and G tag These represent the gain of reader antenna 4 and the gain of tag antenna 1, respectively, and the power P. t λ is the transmission power of the radio frequency signal emitted by the reader antenna 4, and λ is the transmission signal wavelength of the radio frequency signal emitted by the reader antenna 4.

[0069] The phase of the radio frequency signal received by the reader antenna 4 is affected by the reflection characteristics of the tag 1 itself and the transmitter and receiver in the reader 5. In this embodiment of the invention, the influence of the coupling between the tag 1 and the magnetically controlled antenna coupler 2 also needs to be considered. The phase of the radio frequency signal received by the reader antenna 4 at time T... Represented as:

[0070]

[0071]

[0072] in, The additional phase introduced by the coupling between tag 1 and magnetically controlled antenna coupler 2, the transmitter and receiver of reader 5, and the reflection characteristics of tag 1 is considered. An additional phase introduced for the transmitter in reader 5. The additional phase introduced for the receiver in reader 5. Additional phase introduced for the reflectivity of tag 1 This is the additional phase introduced by the coupling between tag 1 and the magnetically controlled antenna coupler 2. Generally, the additional phase caused by the transmitter and receiver of reader 5 is constant. Therefore, given a fixed distance D between reader antenna 4 and tag 1 and a fixed wavelength λ of the radio frequency signal, the phase change caused by tag 1 can be received by reader antenna 4 as the phase of the radio frequency signal. This should be reflected in the text.

[0073] As can be seen from the above theoretical analysis, the physical characteristics and status of tag 1 can be reflected in the received radio frequency signal parameters of reader antenna 4, especially the received signal strength (RSS) and phase. Subsequent applications will mainly use these two types of parameters to detect the working status of the tag, thereby judging the operational status of the product.

[0074] Example 1:

[0075] Figure 5 This is a schematic diagram of the structure of an application device for detecting the open / closed status of a cabinet door, as shown in this example. Figure 5As shown, magnet 3 is placed on the inner wall of the wooden cabinet door, while tag 1 and antenna coupler 2 are placed on the outer wall of the same side of the cabinet. When the cabinet door is closed, magnet 3 is near antenna coupler 2, and reader antenna 4 is placed in front of tag 1. When the cabinet door is wide open, magnet 3 moves away from antenna coupler 2, and the reed switch 7 remains closed due to the absence of magnet 3. When the cabinet door is closed, magnet 3 moves closer to antenna coupler 2, and reed switch 7 is opened due to the magnetic field. Antenna coupler 2 is coupled to tag 1, and the change in the opening and closing state of reed switch 7 in antenna coupler 2 affects the working state of tag 1. During this process, the received signal strength (RSS) and phase results obtained by the host computer 6 differ due to the change in the working state of tag 1, thus allowing the determination of the cabinet door's opening and closing state.

[0076] Example 2:

[0077] Figure 6 This is a schematic diagram of the structure of an application device for detecting the rotation state of a bottle cap, as shown in this example. Figure 6 As shown, magnet 3 is placed on the outside of the bottle cap, antenna coupler 2 is placed on the outer wall of the bottle near the cap, tag 1 is placed on the outer wall of the bottle below antenna coupler 2, and reader antenna 4 is placed in front of tag 1. When the bottle cap is rotated, if magnet 3 on the cap approaches antenna coupler 2, reed switch 7 is affected by the magnetic field and switches to the open state; otherwise, reed switch 7 remains closed, unaffected by magnet 3. Antenna coupler 2 couples with tag 1, and the switching state of reed switch 7 in antenna coupler 2 affects the working state of tag 1. During this process, the received signal strength (RSS) and phase results obtained by the host computer 6 differ due to the change in the tag's working state, thus allowing the determination of the bottle cap's rotation state.

[0078] Figure 7 As shown, multiple antenna couplers 2 are placed around tag 1, with tag 1 facing the reader antenna 4. When multiple antenna couplers 2 are present, magnet 3 influences different antenna couplers 2, causing multiple antenna couplers 2 to couple with tag 1, thereby changing the operating state of tag 1 and obtaining different received signal strength (RSS) and phase results. From this, the state of the antenna couplers 2 and the open / closed state of magnet 3 can be determined. In this way, even when using only one tag 1, complex sensing requirements can be met, effectively avoiding the problem of mutual interference between multiple tags 1.

Claims

1. A kind of RFID sensing system device based on magnetron antenna coupling, characterized by: Including label (1), antenna coupler (2), magnet (3) and read-write system, the product required to identify label has two separable parts, label (1) and antenna coupler (2) are installed on the part of product, magnet (3) is installed on the other part of product, antenna coupler (2) and label (1) form coupling structure between, read-write system is used to transmit radio frequency signal, and receive and process the radio frequency signal returned by label (1); Radio frequency signal output by label (1) coupled with antenna coupler (2) is changed by using magnet (3) to influence the working state of antenna coupler (2); Label (1) and antenna coupler (2) are installed on product at interval distance simultaneously; The antenna coupler (2) is mainly composed of reed switch (7) and two coupling radiators (8), reed switch (7) is connected between two coupling radiators (8); Radio frequency signal output by label (1) coupled with antenna coupler (2) is changed by using magnet (3) to influence the opening and closing state of reed switch (7), and then change the working state of antenna coupler (2); The antenna coupler (2) is through-coupler (9) or non-through-coupler (10), magnet (3) is used to control the state of antenna coupler (2): When magnet (3) is away from reed switch (7) in antenna coupler (2), antenna coupler (2) is through-coupler (9);When magnet (3) is close to reed switch (7), antenna coupler (2) is non-through-coupler (10), through-coupler (9) and non-through-coupler (10) are coupled with label (1) respectively to form two different coupling structures.

2. The RFID sensor system device based on magnetron antenna coupling according to claim 1, characterized in that: The read-write system includes reader antenna (4), reader (5) and host computer (6), one end of reader (5) is connected with reader antenna (4), the other end of reader (5) is connected with host computer (6), reader antenna (4) is used to transmit radio frequency signal, and receive the radio frequency signal returned by label (1), the radio frequency signal received by reader antenna (4) is transmitted to host computer (6) after being read by reader (5), and the data information of radio frequency signal is obtained by using host computer.

3. A radio frequency identification sensing method applied to the device of any one of claims 1-2, characterized in that, Including the following steps: Step one: install the tag (1), antenna coupler (2), and magnet (3) on the product to be identified, install the tag (1) and antenna coupler (2) on one part of the product according to the installation distance l between the tag (1) and antenna coupler (2), install the magnet (3) on another part of the product, place the reader antenna (4) near the tag (1), connect the reader antenna (4) to the host computer (6) through the reader (5), turn on the host computer (6) to make the reader antenna (4) generate a radio frequency signal: when the tag (1) is in the radio frequency signal area generated by the reader antenna (4), the tag (1) is activated and also generates a radio frequency signal, the radio frequency signal generated in the tag (1) is received by the reader antenna (4), then read and write through the reader (5), and finally obtain the data information of the radio frequency signal in the tag (1) in the host computer (6); Step two: use the data information of the radio frequency signal in the tag (1) received by the host computer (6) to determine whether the magnet (3) has an impact on the antenna coupler (2), and further determine the use state of the product to be identified.

4. The radio frequency identification sensing method of the device according to claim 3, wherein: Step two is specifically: determining the working state of the antenna coupler (2) by whether the received signal strength (RSS) and phase in the data information change, so as to determine whether the magnet (3) has an impact on the antenna coupler (2): If the received signal strength (RSS) and phase are equal to the preset signal strength and preset phase respectively, the antenna coupler (2) is identified as a through coupler (9), the reed switch (7) in the antenna coupler (2) is not affected by the magnet (3) and remains closed, and the part of the product where the magnet (3) is installed is far away from the antenna coupler (2); If the received signal strength (RSS) is not equal to the preset signal strength or the phase is not equal to the preset phase, the antenna coupler (2) is identified as a non-through coupler (10), the reed switch (7) in the antenna coupler (2) is affected by the magnet (3) and changes to an open state, and the part of the product where the magnet (3) is installed is close to the antenna coupler (2).

5. The radio frequency identification sensing method of the device according to claim 3, wherein: In step one, the installation distance l between the tag (1) and antenna coupler (2) is calculated according to the following formula: wherein Z in represents the input impedance of the tag (1) antenna, j is a symbol representing the imaginary part, Z0is the impedance of the tag (1) antenna, Z m is the impedance of the antenna coupler (2), f is the frequency of the radio frequency signal emitted by the tag (1) antenna, d is the differential symbol, μ is the magnetic permeability of the medium of the tag (1), lo is the length of the tag (1), I is the minimum activation current of the tag (1), S is the area of the antenna coupler (2) projected perpendicularly onto the magnetic field generated by the tag (1), π is the ratio of the circumference to the diameter, taken as 3.1415926.

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