Small animal group reading identification system and method based on high-frequency RFID technology

Abstract

The invention discloses a small animal group reading identification system and method based on the high-frequency RFID technology, and relates to the technical field of radio frequency identification, and the system comprises RFID tags, each small animal is provided with one RFID tag; the box body is used for bearing small animals; the reader-writer antenna at least comprises a coil pair sleeved outside the box body; and the RFID reader-writer is used for identifying, reading and writing the RFID tag through the reader-writer antenna. According to the invention, a three-dimensional uniform magnetic field is constructed through coil pairs with coincident axes and current in the same direction, and a 13.56 MHz + / -7kHz high-frequency RFID tag is matched, so that a signal blind area can be effectively eliminated, multi-tag conflict is avoided, and stable and efficient group reading of small animals is realized.

Description

Technical Field

[0001] This invention relates to the field of radio frequency identification (RFID) technology, and in particular to a small animal group reading and identification system and method based on high-frequency RFID technology. Background Technology

[0002] Radio Frequency Identification (RFID) technology, as a non-contact automatic identification method, has been widely used in the field of animal identification and management, especially in the identification and tracking of individual small laboratory animals (such as mice). Its advantages of not requiring direct contact and being able to work stably for extended periods have made it one of the mainstream technologies. Currently, RFID technologies used for animal identification are mainly divided into three categories: low frequency (LF, 125kHz or 134.2kHz), high frequency (HF, 13.56MHz), and ultra-high frequency (UHF, 860~960MHz). However, all of these technologies have technical limitations in small animal group identification scenarios, making it difficult to meet the efficient group reading requirements for multiple small animals (usually two or more) inside a box.

[0003] In terms of low-frequency RFID technology, although existing solutions perform well in terms of penetration and operational reliability, they are limited by the ISO 11784 / 11785 protocol and lack an effective anti-collision mechanism. When there are multiple small animals carrying low-frequency RFID tags inside the box, the simultaneous response of the tags can easily cause signal conflicts, making it impossible to achieve efficient batch identification. Furthermore, the working wavelength of low-frequency tags is relatively long, and the sensing distance of the matching micro tags (the size of tags adapted to small animals usually needs to be controlled within a small range) is usually less than 10cm, and in some scenarios it is only a few centimeters, which is difficult to cover the entire space of the box. The tags are also prone to falling out of the identification range due to animal movement.

[0004] In terms of UHF RFID technology, although it supports mature anti-collision protocols such as EPC C1G2 and can achieve high-density group reading in logistics and retail, UHF signals are significantly affected by moisture and biological tissue absorption, resulting in large penetration loss. Water sources, bedding, support structures, and animal tissues commonly found in cages and boxes can significantly attenuate the signal, causing the tag's reading and writing distance to decrease sharply, or even prevent it from working properly.

[0005] In the field of high-frequency RFID technology, its frequency falls between low and ultra-high frequencies, theoretically achieving a balance between penetration and group reading capabilities, and possessing the potential to simultaneously identify multiple tags. However, the market currently lacks high-frequency RFID group reading solutions suitable for small animals. The core issues include: First, insufficient uniformity of the magnetic field of the reader antenna. Existing high-frequency antennas mostly adopt a planar coil design, and the radiation signal intensity attenuates significantly with distance, making it impossible to form a uniform magnetic field within the three-dimensional space of the box. When small animals move freely inside the box, the tags are easily in signal blind spots, leading to missed reads. Second, tag miniaturization is difficult. Due to the insufficient uniformity of the magnetic field of the reader antenna, miniaturized tags cannot capture stable energy within a limited space to maintain tag operation. Therefore, the current high-frequency RFID tags on the market are generally large in size, making it difficult to adapt to the configuration requirements of small animals such as mice. Summary of the Invention

[0006] To address one or more technical problems in the prior art, the present invention provides a small animal group reading and identification system based on high-frequency RFID technology, comprising: The RFID tag operates at a frequency of 13.56MHz±7kHz. Each small animal is equipped with one RFID tag, and each RFID tag stores the unique identification information of the small animal to which it belongs. The box is used to hold the small animal; The reader antenna includes at least one pair of coils sleeved outside the housing. The coil pair includes a first coil and a second coil. The axes of the first coil and the second coil coincide and the current direction is the same. The resonant frequency of the coil pair is 13.56MHz±7kHz. An RFID reader / writer is used to identify and read / write RFID tags through the reader / writer antenna. The RFID reader / writer has a built-in signal processing module and an anti-collision control module. The signal processing module is used to parse the response signals of multiple RFID tags to extract the unique identification information stored in each RFID tag. The anti-collision control module is used to avoid signal conflicts caused by multiple RFID tags responding at the same time.

[0007] Optionally, the first coil and the second coil are connected in series by a wire. Both the first coil and the second coil are made of multi-turn conductive wire, and each turn of conductive wire contains 80 to 120 enameled wires.

[0008] Optionally, the RFID tag includes an RFID chip, a chip antenna, and a rod-shaped magnetic core encapsulated inside a glass tube. The chip antenna is formed by winding enameled wire around the outside of the rod-shaped magnetic core to form a solenoid structure. The two ends of the enameled wire of the chip antenna are respectively connected to the two electrodes of the RFID chip. The diameter of the glass tube is no greater than 1.25 mm and the length is no greater than 7 mm. The RFID chip stores the unique identification information of the small animal to which it belongs.

[0009] Optionally, the number of coil pairs is at least two pairs, the included angle between the axes of different coil pairs is not 0 degrees, and the RFID reader drives one coil pair at a time for identification and reading / writing.

[0010] Optionally, the signal processing module receives the RFID tag response signal from any temporarily activated coil during each round of group reading initialization phase, distinguishes the spatial sub-regions where different RFID tags are located in the box by analyzing the coupling strength value of the signal, and transmits the tag spatial distribution information to the anti-collision control module. The anti-collision control module matches the coupling strength value of each tag in the tag spatial distribution information with the pre-stored activation priority rules to determine the activation order of each pair of coils and generate the activation sequence of the current coil pair. The RFID reader outputs drive signals to each pair of coils sequentially through the anti-collision control module according to the coil pair activation sequence. Only one pair of coils is activated at a time. During the activation of the current coil pair, the signal processing module only parses the RFID tag response signal coupled to that coil pair. After the current coil pair completes identification, the anti-collision control module triggers the activation process of the next pair of coils until all coil pairs have been activated and signal acquisition has been completed.

[0011] Optionally, the RFID reader divides the activation period of a single coil pair in each round of group reading into multiple consecutive time slots of equal duration, and allows the RFID tag to send a response signal only once in each time slot; After each round of group reading, the signal processing module extracts the time slot response data of each coil pair during the activation period in this round of group reading. The time slot response data includes the number of valid response time slots, the number of collision time slots, and the number of empty time slots. The module calculates the tag response density based on the time slot response data and transmits the tag response density and time slot response data to the anti-collision control module. After receiving the tag response density and time slot response data, the anti-collision control module dynamically adjusts the total number of time slots or the duration of a single time slot in the next round of group reading, generates the time slot configuration information for the next round of group reading, and feeds the time slot configuration information back to the RFID reader. The RFID reader then performs tag response window division and group reading in the subsequent coil pair activation period according to the adjusted time slot configuration information.

[0012] Optionally, after all coil pairs have completed one round of activation and signal acquisition, the signal processing module extracts the unique identification information of the RFID tags parsed during the activation of each coil pair, generates a tag ID set for each coil pair according to the coil pair number, and stores the unique identification information of all RFID tags identified by that coil pair in each tag ID set. The signal processing module aggregates the tag ID sets corresponding to all coil pairs to form a temporary tag ID set. Then, it compares the unique identification information in the temporary tag ID set one by one, filters and removes duplicate unique identification information in the temporary tag ID set, and retains a single record of each unique identification information.

[0013] Optionally, after any coil pair is activated and the RFID reader sends a group read request signal to the RFID tag in each round of group reading, the anti-collision control module extracts the unique identification information of each RFID tag previously parsed by the signal processing module. The anti-collision control module performs hash calculations on the unique identification information of each RFID tag according to the pre-stored hash operation rules, and obtains the unique hash value corresponding to each tag; The anti-collision control module maps different hash values ​​to different response delay durations according to the pre-stored delay allocation rules. Each RFID tag's unique hash value corresponds to a unique response delay duration. The anti-collision control module sends a control signal containing the unique response delay time to each RFID tag through the RFID reader and the currently active coil pair; After receiving the control signal, each RFID tag adds a waiting time consistent with its own unique response delay between receiving the group read request signal and sending the response signal, and then sends a response signal containing unique identification information.

[0014] Optionally, the signal processing module transmits the collected reading progress data, the proportion of remaining unread tags, and the signal quality data to the anti-collision control module in real time; After receiving reading progress data, remaining unread tag ratio data, and signal quality data, the anti-collision control module matches the pre-stored parameter adjustment rules, adjusts the coil pair activation sequence and time slot configuration parameters in real time for subsequent rounds, generates the adjusted coil pair activation sequence and time slot configuration information, and feeds this information back to the RFID reader. The RFID reader activates the coil pair according to the adjusted coil pair activation sequence and time slot configuration information, and then performs subsequent coil pair activation and group reading operations.

[0015] This invention also provides a method for identifying small animal groups based on high-frequency RFID technology, comprising the following steps: Place no fewer than two small animals inside the box. Each small animal is equipped with an RFID tag with a working frequency of 13.56MHz±7kHz. Each RFID tag stores the unique identification information of the small animal to which it belongs. The box is placed within the uniform magnetic field range formed by the reader antenna. The reader antenna includes at least one pair of coils, each pair including a first coil and a second coil. The axes of the first coil and the second coil coincide and the current directions are consistent. The resonant frequency of the coil pair is 13.56MHz±7kHz. The RFID reader uses its antenna to identify and read RFID tags, enabling the identification of multiple small animals inside the box.

[0016] The beneficial effects of this invention are: This invention constructs a three-dimensional uniform magnetic field by using coil pairs with coincident axes and co-currents, and paired with a high-frequency RFID tag of 13.56MHz±7kHz, which can effectively eliminate signal blind spots, avoid multi-tag conflicts, and achieve stable and efficient group reading of small animals. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used together with the embodiments of the invention to explain the invention and do not constitute a limitation thereof.

[0018] Figure 1 This is a schematic diagram of the working state of the identification system and method according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a reader antenna according to an embodiment of the present invention. Figure 1 ; Figure 3 This is a schematic diagram of the structure of a reader antenna according to an embodiment of the present invention. Figure 2 ; Figure 4 This is a schematic diagram of the structure of the bracket according to an embodiment of the present invention; Figure 5 This is a schematic diagram showing the positional relationship between the reader antenna and the housing according to an embodiment of the present invention; Figure 6 This is a schematic diagram of the internal structure of an RFID tag according to an embodiment of the present invention.

[0019] In the picture: 1. RFID tag; 11. Glass tube; 12. RFID chip; 13. Chip antenna; 14. Rod-shaped magnetic core; 2. RFID reader / writer; 3. Reader antenna; 31. Coil pair; 311. First coil; 312. Second coil; 313. Wire; 4. Bracket; 41. First wire frame; 411. First wire groove; 42. Second wire frame; 421. Second wire groove; 43. Connecting rod; 431. Third wire groove; 5. Box body; 6. Small animals 7. Information Management System. Detailed Implementation

[0020] The present invention will now be described in detail with reference to the accompanying drawings and embodiments. Various examples are provided by way of explanation and not by way of limitation. Indeed, those skilled in the art will recognize that modifications and variations can be made to the invention without departing from its scope or spirit. For example, a feature represented or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present invention encompass such modifications and variations falling within the scope of the appended claims and their equivalents.

[0021] It should be noted that, in order to clearly show the structural relationship of the key internal components of the present invention, some pipelines, lines, support brackets and other components of the actual product are omitted in the accompanying drawings. However, the specific design schemes of these omitted components are all easily implemented by those skilled in the art based on the technical solutions currently presented in the present invention and conventional design.

[0022] In the description of this invention, the terms "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. The terms "connected," "linked," and "set up" used in this invention should be interpreted broadly. For example, they can refer to a fixed connection or a detachable connection; they can refer to a direct connection or an indirect connection through intermediate components. Those skilled in the art can understand the specific meaning of the above terms according to the specific circumstances.

[0023] Example 1: like Figures 1-6 As shown, this invention provides a small animal 6-group reading and identification system based on high-frequency RFID technology, comprising: RFID tag 1, with an operating frequency of 13.56MHz±7kHz, is used for each small animal 6. Each RFID tag 1 stores the unique identification information of the small animal 6 to which it belongs. Box 5 is used to hold the small animal 6; The reader antenna 3 includes at least one pair of coils 31 sleeved outside the housing 5. The coil pair 31 includes a first coil 311 and a second coil 312. The axes of the first coil 311 and the second coil 312 coincide and the current direction is the same. The resonant frequency of the coil pair 31 is 13.56MHz±7kHz. The RFID reader 2 is used to identify and read / write the RFID tag 1 through the reader antenna 3. The RFID reader 2 has a built-in signal processing module and an anti-collision control module. The signal processing module is used to analyze the response signals of multiple RFID tags 1 to extract the unique identification information stored in each RFID tag 1. The anti-collision control module is used to avoid signal conflicts caused by multiple RFID tags 1 responding at the same time.

[0024] In specific implementation, the axis of the first coil 311 is perpendicular to its own plane and passes through its geometric center point (e.g., Figure 3 (Point a1 in the diagram), the axis of the second coil 312 is also perpendicular to its own plane and passes through its geometric center point (e.g., point a1 in the diagram). Figure 3 Point a2 in the diagram), the axes of the first coil 311 and the second coil 312 coincide (as shown in the diagram). Figure 3 The first coil 311 and the second coil 312 are connected by a current flowing in the same direction during operation (either clockwise or counterclockwise along the coil). When the RFID reader 2 is activated, the current flows through the first coil 311 and the second coil 312. Due to the coincidence of their axes and the consistency of their current directions, the magnetic fields generated by the two coils are superimposed in space, forming a three-dimensional magnetic field region with a wider coverage and uniform intensity. The RFID tag 1 is placed within this magnetic field region, obtains energy through electromagnetic induction, establishes communication with the RFID reader 2, and realizes identification and data reading and writing.

[0025] The number of coil pairs 31 can be one pair (e.g.) Figure 2 (as shown) or multiple pairs (such as) Figure 5 As shown, when there are multiple pairs of coils (31), they can be arranged alternately in three-dimensional space, thereby further enhancing the magnetic field coverage and strength. This enables rapid, accurate, and effective identification and reading / writing of RFID tags 1 from randomly appearing directions and angles, thus improving the identification efficiency and data transmission stability of RFID tags 1. The coils located on two parallel planes have the same specifications and technical parameters, thus forming a Helmholtz coil.

[0026] The RFID reader 2 can connect to various existing information management systems 7. For example, it can transmit the information of the identified RFID tag 1 to the laboratory animal management platform in real time through wireless transmission modules such as Wi-Fi and Bluetooth to realize functions such as automated recording, animal tracking, and experimental batch management. It can also connect to the local data server through wired transmission methods such as network cable and data cable to complete data storage and subsequent analysis.

[0027] In existing technologies, RFID read / write antennas are mostly single planar coils, whose magnetic field strength decays rapidly with distance, only forming a locally non-uniform planar magnetic field. This invention uses a first coil 311 and a second coil 312 with coincident axes and aligned current directions to form a coil pair 31, which can construct a three-dimensional uniform magnetic field. The magnetic field generated by the coil pair 31 is uniformly distributed between the two coils and in the surrounding area, eliminating the signal blind spots present in single planar coils. Addressing the problem of small animals being easily trapped in signal blind spots during free movement, the three-dimensional uniform magnetic field can cover the entire space of the animal's enclosure. Regardless of the animal's direction or angle of movement, the RFID tag 1 remains within the effective magnetic field range, ensuring no omissions in identification. Using this invention, comprehensive coverage within a three-dimensional space can be achieved without increasing the number or location of antennas, reducing system deployment costs. The uniformity of the magnetic field improves identification stability, enabling efficient batch identification even when small animals are kept in groups.

[0028] Small animals (such as laboratory mice) often need to be housed in groups. This serves two purposes: firstly, it aligns with their social habits, reduces stress, and ensures the accuracy of experimental data; secondly, research often requires simultaneous monitoring of the growth status and behavioral patterns of multiple animals. For instance, some drug experiments require tracking the weight changes and drug responses of 10-20 mice. Group reading enables batch data collection, avoiding the tedious process of reading individual animals. Compared to existing technologies, this invention allows for the rapid identification of multiple animals without human intervention. The identification process is contactless, avoiding injury or stress caused by manual handling. Once the tag is attached to the animal, it can be used long-term, enabling tracking throughout the animal's entire lifespan.

[0029] In drug development experiments, mice in different experimental groups are equipped with RFID tags, which can store information such as experimental group, drug dosage, and date of birth. A swarm read system allows for rapid counting of mice in each experimental group and screening of target individuals. Data is synchronized to the experimental management platform in real time, avoiding errors from manual recording and improving the standardization of experimental procedures.

[0030] In animal behavior research, swarm reading systems can be combined with video monitoring to capture the movement trajectories and group interactions of mice within a box in real time. By correlating tagged identity information with behavioral data, the activity frequency and social preferences of different individuals can be analyzed, providing quantitative data support for behavioral research.

[0031] In infectious disease transmission research, swarm tracking systems can trace the contact relationships and infection pathways of mice within a group. Tags record the activity areas and times of the mice, and combined with detection data, the source of infection and transmission chain can be accurately located, providing technical support for disease prevention and control research.

[0032] Example 2: Furthermore, the first coil 311 and the second coil 312 are connected in series by a wire 313. Both the first coil 311 and the second coil 312 are made of multiple turns of conductive wire, and each turn of conductive wire contains 80 to 120 enameled wires.

[0033] In practical implementation, the series connection method allows the current to flow sequentially through the first coil 311 and the second coil 312, ensuring that the magnitude and direction of the current in the two coils are completely consistent, resulting in a more stable magnetic field superposition effect. If the first coil 311 and the second coil 312 are not connected in series, a power supply circuit can be configured for each coil separately, but the current synchronization of the two coils needs to be precisely controlled. The wire 313 forms a unified circuit between the two coils, fixing the current transmission path, resulting in a higher degree of matching of the magnetic field strengths of the two coils, further improving the uniformity of the superimposed magnetic field, and ensuring that the RFID tag 1 can obtain stable inductive energy at any position within the magnetic field area.

[0034] The conductive wire can be enameled wire, whose surface insulation layer can prevent inter-turn short circuits, and it has good conductivity, low cost, and wide applicability. Alternatively, strip-shaped conductive metals such as copper or aluminum strips can be used, offering excellent heat dissipation and strong current carrying capacity, suitable for high-power, long-term operation. Multi-turn winding increases the coil's inductance, enabling it to generate a stronger magnetic field after energization, improving magnetic field coverage and induction intensity, ensuring the RFID tag 1 can stably acquire energy and complete communication. Each turn of conductive wire can preferably contain 100 enameled wires. This setup uses multiple strands of enameled wire twisted together to form a single-turn conductive wire, with the diameter of each strand controlled between 0.01 and 0.03 mm. The twisted structure of 80-120 enameled wires ensures both the conductive cross-sectional area and the flexibility of the conductive wire, facilitating tight winding on the first frame 41 and the second frame 42, and allowing resonance under 50-ohm impedance conditions through a matching circuit.

[0035] Furthermore, the coil pair 31 can be sleeved on the outside of the box 5 by the bracket 4, which also provides support for the box 5. The bracket 4 includes a first wire frame 41 and a second wire frame 42, with the axis of the first wire frame 41 and the axis of the second wire frame 42 coinciding. The first wire frame 41 and the second wire frame 42 are connected by a connecting rod 43. The first coil 311 is fixed on the first wire frame 41, the second coil 312 is fixed on the second wire frame 42, and the wire 313 is fixed on the connecting rod 43. The first wire frame 41 is provided with a first wire groove 411, the second wire frame 42 is provided with a second wire groove 421, and the connecting rod 43 is provided with a third wire groove 431. The first wire groove 411 and the second wire groove 421 are both connected to the third wire groove 431.

[0036] The axis of the first wire frame 41 is perpendicular to its own plane and passes through its geometric center point. Similarly, the axis of the second wire frame 42 coincides with the axis of the first wire frame 41, and they are fixedly connected by a connecting rod 43. The first coil 311 is wound and fixed on the first wire frame 41, and the second coil 312 is wound and fixed on the second wire frame 42. The wire 313 connecting the two coils is fixed to the connecting rod 43. The bracket 4 provides stable support for the coil pair 31, ensuring that the relative positions of the first coil 311 and the second coil 312 are fixed and their axes always coincide, preventing coil displacement due to external vibrations or collisions, which would affect the uniformity of the magnetic field.

[0037] The wire of the first coil 311 can be embedded in the first slot 411, the wire of the second coil 312 can be embedded in the second slot 421, and the wire of the conductor 313 connecting the two coils can be embedded in the third slot 431. The depth, width, and space of the slots ensure that the wire fits tightly into the slots, preventing loosening. The core function of the slots is to protect the wires, preventing the conductive wires from being exposed to friction and compression, which could lead to damage to the insulation layer or breakage of the conductive wires. At the same time, the slots can limit the movement of the wires, preventing them from tangling or shifting, and ensuring the winding accuracy of the coils and the stability of the relative positions of the two coils.

[0038] Example 3: Furthermore, the RFID tag 1 includes an RFID chip 12, a chip antenna 13, and a rod-shaped magnetic core 14 encapsulated inside a glass tube 11. The chip antenna 13 is formed by winding enameled wire around the rod-shaped magnetic core 14 to form a solenoid structure. The two ends of the enameled wire of the chip antenna 13 are respectively connected to the two end electrodes of the RFID chip 12. The diameter of the glass tube 11 is no greater than 1.25 mm and the length is no greater than 7 mm. The RFID chip 12 stores the unique identification information of the small animal 6 to which it belongs.

[0039] In practical implementation, the chip antenna 13 of the RFID tag 1 is wound with enameled wire around the outside of the rod-shaped magnetic core 14, forming a solenoid structure. This winding method fixes the shape of the chip antenna 13, resulting in a compact structure. Multiple turns can be wound within a limited space, improving the antenna's inductance and signal coupling efficiency. Because the winding fixes the shape of the chip antenna 13, smaller diameter enameled wire (e.g., 0.02mm) can be used for winding, reducing the antenna size while maintaining performance, thus contributing to the miniaturization of the RFID tag 1. The rod-shaped magnetic core 14, made of magnetic material, enhances the magnetic field strength around the chip antenna 13, improving electromagnetic induction efficiency and enabling the RFID tag 1 to stably acquire energy even in weak magnetic field environments.

[0040] The RFID tag 1 is encapsulated in a glass tube 11, which can be filled with medical-grade inert adhesive or employ a vacuum protection structure. The inert adhesive fills the internal gaps of the glass tube 11, fixing the relative positions of the RFID chip 12, chip antenna 13, and rod-shaped magnetic core 14, preventing collision damage. The vacuum structure prevents the corrosion of internal components by bodily fluids and oxygen, ensuring stability for long-term implantation. The ports of the glass tube 11 can be sealed with a bio-inert sealing material to achieve an airtight seal, further enhancing the protective effect. Specifically, the glass material of the glass tube 11 can be high borosilicate glass, medical-grade borosilicate glass, or other bio-inert glasses, possessing biocompatibility and suitable for long-term subcutaneous implantation in animals.

[0041] The miniaturized design of the glass tube 11, with a diameter no greater than 1.25 mm and a length no greater than 7 mm, can be achieved through the following structural optimizations: A chip antenna 13 is wound with enameled wire of 0.02 mm diameter, paired with a nickel-zinc ferrite rod-shaped magnetic core 14 with a diameter no greater than 0.8 mm and a length no greater than 5 mm. The RFID chip 12 can be a microchip with a size no greater than 0.65 mm × 0.65 mm, with all components compactly arranged inside the glass tube 11. The rod-shaped magnetic core 14, made of nickel-zinc ferrite material, has an initial permeability of less than 1000 (H / m), ensuring stable performance in high-frequency magnetic field environments and effectively enhancing the sensing effect of the chip antenna 13. The chip antenna 13 can form a resonant matching circuit with the chip by adjusting the number of turns.

[0042] It is important to clarify that a crucial foundation for achieving this design lies in the unique reader antenna 3 of this invention. Due to the unique design of the reader antenna 3, each component can operate efficiently within a smaller space, thus enabling such extreme miniaturization. Existing glass tags typically have a diameter of 2mm or more and a length of 10mm or more, and are mostly used for larger animals such as cattle, sheep, and dogs. These tags are too large to be suitable for subcutaneous implantation or surface wearing in smaller animals such as mice. The glass tube 11 of this embodiment can be implanted subcutaneously in small animals 6, or it can be suspended or tied to the neck, ears, or feet of small animals 6 using a special strapping band. Due to its small size, it does not affect the animal's normal activities.

[0043] Example 4: Furthermore, the number of coil pairs 31 is at least two pairs, and the included angle between the axes of different coil pairs 31 is not 0 degrees. The RFID reader 2 drives one pair of coil pairs 31 for identification and reading / writing at a time.

[0044] In practical implementation, taking a common rectangular feeding box as an example, a first pair of coil pairs 31 can be set in the vertical direction of the box body 5, a second pair of coil pairs 31 in the horizontal direction, and a third pair of coil pairs 31 in the front-back direction. The axis of the vertical coil pair 31 is perpendicular to the bottom surface of the box body 5, the axis of the horizontal coil pair 31 is parallel to the bottom surface of the box body 5 and extends along the width direction, and the axis of the front-back coil pair 31 is parallel to the bottom surface of the box body 5 and extends along the length direction. The axes of the three pairs of coil pairs 31 are perpendicular to each other, forming a three-dimensional magnetic field coverage. At this time, the RFID reader 2 can adopt a time-division driving mode, activating only one pair of coil pairs 31 at a time. For example, the vertical coil pair 31 is activated first to complete the identification and signal acquisition of the tag in the magnetic field area of ​​that direction; then the horizontal coil pair 31 is activated, and so on, until all coil pairs 31 are activated and signal acquisition is completed. Time-division driving can avoid mutual interference of magnetic fields generated by different coil pairs 31, ensuring the magnetic field stability of each pair of coil pairs 31 during operation. Regardless of the small animal 6's posture or position within the box 5, it can be covered by the magnetic field of at least one pair of coils 31, significantly reducing the missed reading rate; multiple coil pairs 31 work together to improve the comprehensiveness and reliability of tag recognition; it is adaptable to different sizes of feeding boxes, and the number and layout of coil pairs 31 can be adjusted according to the size of the box 5, offering high flexibility.

[0045] Example 5: Furthermore, during each round of group reading initialization, the signal processing module receives the RFID tag 1 response signal fed back by any temporarily activated coil pair 31, distinguishes the spatial sub-regions where different RFID tags 1 are located within the box 5 by analyzing the coupling strength value of the signal, and transmits the tag spatial distribution information to the anti-collision control module. The anti-collision control module matches the coupling strength value of each tag in the tag spatial distribution information with the pre-stored activation priority rules to determine the activation order of each pair of coils 31, generating the activation sequence of this round of coils 31. The RFID reader 2 outputs drive signals to each pair of coil pairs 31 sequentially through the anti-collision control module according to the activation sequence of the coil pairs 31. Only one pair of coil pairs 31 is activated at a time. During the activation of the current coil pair 31, the signal processing module only parses the response signal of the RFID tag 1 coupled to the coil pair 31. After the current coil pair 31 completes identification, the anti-collision control module triggers the activation process of the next pair of coil pairs 31 until all coil pairs 31 have completed activation and signal acquisition.

[0046] In practice, during each round of group reading initialization, the reader temporarily activates any coil pair 31 (e.g., the left-right coil pair 31). After the coil pair 31 sends a signal, it receives the response signals from each RFID tag 1 within the housing 5. The signal processing module analyzes the coupling strength value of the response signal. The coupling strength value is positively correlated with the distance from the tag to the coil pair 31, thereby distinguishing the spatial sub-region where the tag is located. For example, tags with a coupling strength value higher than threshold A are determined to be located in the left half of the housing 5, tags with a coupling strength value lower than threshold B are determined to be located in the right half of the housing 5, and tags with a coupling strength value between thresholds A and B are determined to be located in the middle of the housing 5.

[0047] The anti-collision control module pre-stores activation priority rules, such as "coil pair 31 is activated first in the sub-region with more tags" and "coil pair 31 is activated first in the sub-region with a high proportion of unread tags". Assuming that during the initialization phase, the number of tags in the left half of the box 5 accounts for 60% and the right half accounts for 40%, then the activation priority of coil pair 31 in the left and right directions is higher than that of other coil pairs 31.

[0048] The anti-collision control module generates the activation sequence of the coil pairs 31 according to priority rules, such as "left-right coil pair 31 → up-down coil pair 31 → front-back coil pair 31". The reader activates each coil pair 31 sequentially according to the sequence. During the activation of the current coil pair 31, the signal processing module only parses the response signal coupled to that coil pair 31 to avoid signal interference across coil pairs 31. For example, when activating the left-right coil pair 31, only the response signals of the tags in the left and right halves of the region are processed to ensure the accuracy of signal parsing.

[0049] Assume there are 15 mice in the enclosure, each tagged with an RFID tag. During initialization, the up-down coil pair 31 is temporarily activated. The signal processing module analyzes the data and finds: 5 tags with high coupling strength (left half of enclosure 5), 4 tags with low coupling strength (right half of enclosure 5), and 6 tags with medium coupling strength (middle of enclosure 5). Based on historical data, 3 tags in the left half and 1 tag in the right half remain unidentified. The anti-collision control module uses a priority matching rule: "areas with more unread tags are prioritized." Therefore, the left-right coil pair 31 (corresponding to the left and right halves) has the highest activation priority; followed by the up-down coil pair 31 (corresponding to the top, bottom, and middle areas); and finally, the front-back coil pair 31. The generated activation sequence is "left-right → up-down → front-back." The reader activates the coil pair 31 sequentially, completing the identification of tags in each area, ultimately achieving complete identification of all 15 mouse tags.

[0050] Example 6: Furthermore, the RFID reader 2 divides the activation period of a single coil pair 31 in each round of group reading into multiple consecutive time slots of equal duration, and only allows the RFID tag 1 to send a response signal once in each time slot; After each round of group reading, the signal processing module extracts the time slot response data of each coil pair during the 31 activation period in this round of group reading. The time slot response data includes the number of valid response time slots, the number of collision time slots, and the number of empty time slots. The module calculates the tag response density based on the time slot response data and transmits the tag response density and time slot response data to the anti-collision control module. After receiving the tag response density and time slot response data, the anti-collision control module dynamically adjusts the total number of time slots or the duration of a single time slot in the next round of group reading, generates the time slot configuration information for the next round of group reading, and feeds the time slot configuration information back to the RFID reader 2. The RFID reader 2 then performs the division of the tag response window and group reading in the subsequent coil pair 31 activation period according to the adjusted time slot configuration information.

[0051] In practice, the RFID reader 2 can divide the activation period of a single coil pair 31 in each round of group reading into multiple consecutive time slots of equal duration. For example, the activation period of the left and right coil pairs 31 is 1 second, which is divided into 20 time slots. Each time slot lasts for 50 milliseconds, and the RFID tag 1 is only allowed to send a response signal once in each time slot.

[0052] After each round of group reading, the signal processing module extracts the time slot response data of each coil pair during the 31-hour activation period, including the number of valid response time slots (time slots where tags send response signals without collisions), the number of collision time slots (time slots where multiple tags send response signals simultaneously, causing collisions), and the number of empty time slots (time slots where no tags send response signals). The tag response density is calculated according to the formula "tag response density = number of valid response time slots / total number of time slots".

[0053] After receiving the tag response density and time slot response data, the anti-collision control module dynamically adjusts the time slot parameters for the next round of group reading. If the tag response density is higher than 70%, it indicates that the current number of time slots is insufficient and collisions are likely to occur; in the next round, the total number of time slots will be increased by 50%. If the tag response density is lower than 30%, it indicates that the current number of time slots is too large, with a large number of empty time slots; in the next round, the total number of time slots will be reduced by 30%. If the proportion of collision time slots is higher than 20%, it indicates that the duration of a single time slot is too short, and the tag response signal cannot be transmitted completely; in the next round, the duration of a single time slot will be extended by 20%.

[0054] In the first round of group reading, the left and right directional coils divided the 31-second activation period into 20 time slots (each time slot being 50 milliseconds). The signal processing module collected 8 valid response time slots, 6 collision time slots, and 6 empty time slots. The tag response density was 8 / 20 = 40%, and the collision time slot ratio was 6 / 20 = 30%. The anti-collision control module determined that the collision time slot ratio was too high and the duration of each time slot was insufficient. In the next round of group reading, the duration of each time slot in the 31-second activation period of the left and right directional coils was adjusted to 60 milliseconds, while the total number of time slots remained at 20, and the activation period was extended to 1.2 seconds. After the adjustment, the number of collision time slots in the second round of group reading decreased to 2, the number of valid response time slots increased to 12, the tag response density increased to 60%, and the recognition efficiency was significantly improved.

[0055] Example 7: Furthermore, after all coil pairs 31 have completed one round of activation and signal acquisition, the signal processing module extracts the unique identification information of the RFID tag 1 parsed during the activation of each coil pair 31, and generates a tag ID set corresponding to each coil pair 31 according to the coil pair number. Each tag ID set stores the unique identification information of all RFID tags 1 identified by that coil pair 31. The signal processing module summarizes the set of tag IDs corresponding to all coil pairs 31 to form a temporary tag ID set. Then, it compares the unique identification information in the temporary tag ID set one by one, filters and removes duplicate unique identification information in the temporary tag ID set, and retains a single record of each unique identification information.

[0056] In practice, after all coil pairs 31 complete one round of activation and signal acquisition, the signal processing module extracts the unique identification information of the RFID tags 1 obtained during the activation of each coil pair 31, and generates a corresponding tag ID set according to the coil pair 31 number. For example, if the up-down coil pair 31 identifies tag IDs "001, 002, 003, 004, 005", tag ID set 1 is generated; if the left-right coil pair 31 identifies tag IDs "003, 004, 006, 007, 008", tag ID set 2 is generated; and if the front-back coil pair 31 identifies tag IDs "005, 006, 009, 010", tag ID set 3 is generated.

[0057] The signal processing module aggregates all tag IDs to form a temporary tag ID set "001, 002, 003, 004, 005, 003, 004, 006, 007, 008, 005, 006, 009, 010".

[0058] The signal processing module compares the identity information in the temporary tag ID set one by one, removes duplicate records, and retains a single record of each unique identity information, finally obtaining the deduplicated tag ID set "001, 002, 003, 004, 005, 006, 007, 008, 009, 010".

[0059] For example, in an experimental scenario, there are 10 mice in a feeding box, labeled with IDs from 001 to 010. In one round of group reading, coil pair 31 in the up-down direction identifies 001, 002, 003, 004, and 005 (due to mouse activity, such as some mice gathering at the edge of the feeding box or hiding under the bedding, the recognition range is limited, and 006-010 are not recognized as they are at the edge of the magnetic field of coil pair 31); coil pair 31 in the left-right direction identifies 003, 004, 006, 007, and 008 (001, 002, 009, and 010 are not recognized); coil pair 31 in the front-back direction identifies 005, 006, 009, and 010 (001, 002, 003, 004, 007, and 008 are not recognized). The signal processing module aggregates the three sets to form a temporary set. After comparison and deduplication, it obtains 10 complete tag IDs to ensure that there are no duplicates or omissions, and accurately reflects the actual number and identity of the small animals 6 in the box 5.

[0060] Example 8: Furthermore, in each round of group reading, after any coil pair 31 is activated and the RFID reader 2 sends a group reading request signal to the RFID tag 1, the anti-collision control module extracts the unique identification information of each RFID tag 1 previously parsed by the signal processing module. The anti-collision control module performs hash calculation on the unique identification information of each RFID tag 1 according to the pre-stored hash operation rules to obtain the unique hash value corresponding to each tag; The anti-collision control module maps different hash values ​​to different response delay durations according to the pre-stored delay allocation rules. Each RFID tag 1 has a unique hash value corresponding to a unique response delay duration. The anti-collision control module sends a control signal containing the unique response delay time to each RFID tag 1 through the RFID reader 2 and the currently activated coil pair 31. After receiving the control signal, each RFID tag 1 adds a waiting time consistent with its own unique response delay between receiving the group read request signal and sending the response signal, and then sends a response signal containing unique identification information.

[0061] In practice, during each round of group reading, after any coil pair 31 is activated and the reader sends a group reading request signal, the anti-collision control module extracts the unique identification information of each RFID tag 1 previously parsed by the signal processing module. According to pre-stored hash operation rules (such as the SHA-1 algorithm), the identification information of each tag is calculated to obtain a unique hash value. For example, tag ID "001" yields the hash value "1A3F", and tag ID "002" yields the hash value "2B4E".

[0062] The anti-collision control module pre-stores delay allocation rules, mapping different hash values ​​to different response delay durations. For example, a hash value starting with "1" corresponds to a delay of 10 milliseconds, "2" corresponds to a delay of 20 milliseconds, "3" corresponds to a delay of 30 milliseconds, and so on. Each hash value corresponds to a unique response delay duration, ensuring that different tags have different delay durations.

[0063] The anti-collision control module sends a control signal containing a unique response delay duration to each RFID tag 1 through the currently active coil pair 31. After receiving the control signal, the tag adds a corresponding waiting time between receiving the group read request signal and sending the response signal. For example, tag ID "001" corresponds to a 10-millisecond delay; after receiving the group read request signal, it waits 10 milliseconds before sending the response signal; tag ID "002" waits 20 milliseconds before sending, avoiding conflicts caused by multiple tags responding simultaneously.

[0064] Assume there are 5 mice in box 5, with tag IDs 001, 002, 003, 004, and 005. During a round of group reading, the up / down coil pair 31 is activated, and the reader sends a group read request signal. The anti-collision control module extracts the IDs of the 5 tags and obtains their respective hash values ​​through hash calculation: 001→1A3F, 002→2B4E, 003→3C5D, 004→4D6C, 005→5E7B. According to the delay allocation rule, the first character of the hash value corresponds to the following delay duration: 1→10ms, 2→20ms, 3→30ms, 4→40ms, 5→50ms. The anti-collision control module sends a control signal to each tag, informing it of the response delay duration. After receiving the signal, each tag waits for the corresponding duration before sending its response signal: 001 sends at 10ms, 002 sends at 20ms, and so on. The signal processing module receives response signals from each tag in different time slots, resolves them without conflict, and successfully extracts all tag IDs.

[0065] Example 9: Furthermore, the signal processing module transmits the collected reading progress data, the proportion of remaining unread tags, and the signal quality data to the anti-collision control module in real time; After receiving reading progress data, remaining unread tag ratio data and signal quality data, the anti-collision control module matches the pre-stored parameter adjustment rules, adjusts the coil pair 31 activation sequence and time slot configuration parameters in real time for subsequent rounds, generates the adjusted coil pair 31 activation sequence and time slot configuration information, and feeds this information back to the RFID reader 2. RFID reader 2 performs subsequent coil pair 31 activation and group reading operations according to the adjusted coil pair 31 activation sequence and time slot configuration information.

[0066] In practice, the signal processing module collects reading progress data (number of identified tags / total number of tags), the proportion of remaining unread tags (number of unread tags / total number of tags), and signal quality data (signal-to-noise ratio of the response signal) in real time, and transmits this data to the anti-collision control module in real time. For example, if 8 tags have been identified out of a total of 10 tags, the reading progress is 80%; the proportion of remaining unread tags is 20%; and in the signal quality data, 70% of the tags have a signal-to-noise ratio higher than 30dB, and 10% have a signal-to-noise ratio lower than 20dB.

[0067] The anti-collision control module has pre-stored parameter adjustment rules, such as "If the proportion of remaining unread tags is higher than 50% and the unread tags in the coverage area of ​​a certain coil pair 31 are concentrated, adjust the activation priority of the coil pair 31 to the highest", "If the proportion of tags with signal quality lower than 20dB is higher than 30%, extend the duration of a single time slot by 20%", and "If the reading progress is higher than 90%, reduce the total number of time slots by 30%".

[0068] The anti-collision control module adjusts the activation sequence and time slot configuration parameters of coil pairs 31 in real time based on the collected data matching rules. For example, if the remaining unread tag ratio is 20%, and the unread tags are concentrated in the coverage area of ​​coil pairs 31 in the front and rear directions, then the activation priority of coil pairs 31 in the front and rear directions is raised to the top; if the tag ratio is 10% with signal quality below 20dB, no adjustment to the time slot duration is needed; if the reading progress is 80%, the total number of time slots remains unchanged. The adjusted activation sequence and time slot configuration information are generated and fed back to RFID reader 2, which then performs subsequent group reading operations according to the new parameters.

[0069] Assume there are 10 mice in the enclosure, with a total of 10 tags. After the first round of group reading, the reading progress is 60% (6 mice identified), and the remaining unread tags are 40% (4 mice not identified). In the signal quality data, 25% of the tags have a signal-to-noise ratio (SNR) below 20dB. The anti-collision control module adjusts its parameters according to the following rules: Since the remaining unread tags are 40% and concentrated in the coverage area of ​​left-right coil pair 31, the activation priority of left-right coil pair 31 is adjusted to the highest; the 25% of tags with a signal quality below 20dB is close to the 30% threshold, so the duration of a single time slot is extended by 10%. The adjusted activation sequence is "left-right → up-down → front-back," and the time slot duration is adjusted from 50 milliseconds to 55 milliseconds. The second round of group reading is executed with the new parameters, increasing the reading progress to 90% (9 mice identified), with the remaining unread tags at 10%, and the percentage of tags with a signal quality below 20dB decreasing to 5%. In the third round of group reading, the anti-collision control module adjusted the activation sequence to "front-back direction → left-right direction → up-down direction", reducing the total number of time slots by 20%, and finally completing the recognition of all 10 tags.

[0070] Example 10: This invention also provides a method for identifying small animals in groups of 6 based on high-frequency RFID technology, comprising the following steps: Place no fewer than two small animals 6 inside the box 5. Each small animal 6 is equipped with an RFID tag 1 with a working frequency of 13.56MHz±7kHz. Each RFID tag 1 stores the unique identification information of the small animal 6 to which it belongs. The box 5 is placed within the uniform magnetic field range formed by the reader antenna 3. The reader antenna 3 includes at least one pair of coils 31. The coil pair 31 includes a first coil 311 and a second coil 312. The axes of the first coil 311 and the second coil 312 coincide and the current direction is the same. The resonant frequency of the coil pair 31 is 13.56MHz±7kHz. The RFID reader 2 identifies and reads the RFID tag 1 through the reader antenna 3, so as to realize the group reading and identification of multiple small animals 6 inside the box 5.

[0071] Existing experimental animal RFID tags mostly use low-frequency (LF, 125kHz or 134.2kHz) technology. These tags perform well in terms of tissue penetration and reliability, but they have the following main shortcomings: limited reading distance. Low-frequency tags have a long operating wavelength and a small matching antenna, but the sensing distance is usually less than 10cm. In particular, for miniature implantable tags for small animals (such as the 1.25mm×7mm design proposed in the following embodiments of the present invention), the reading distance can usually only be a few centimeters. Lack of group reading and anti-collision mechanisms. Due to the limitations of the low-frequency protocol, there is almost no effective anti-collision mechanism, which makes it impossible to efficiently complete batch identification in a group breeding environment.

[0072] In contrast, ultra-high frequency (UHF, 860~960MHz) RFID tags have enabled high-density group reading in logistics and retail sectors due to their support for mature anti-collision protocols (such as EPC C1G2). However, when UHF signals propagate within an animal's body, they are significantly affected by moisture and tissue absorption, resulting in poor penetration. This leads to a sharp decrease in read / write distance in implantable applications, and may even prevent the device from functioning properly.

[0073] High frequency (HF, 13.56MHz) RFID technology lies between low frequency and ultra-high frequency, achieving a balance between tissue penetration and group reading capability: its wavelength is shorter than that of low frequency, supports protocols with anti-collision capabilities, and can realize the simultaneous identification of multiple tags; its frequency is lower than that of ultra-high frequency, and its radio frequency working principle is the same as that of low frequency, resulting in relatively small penetration loss to biological tissues and stable reading within a certain distance.

[0074] However, there is currently no mature solution on the market for applying HF RFID technology to tags of small laboratory animals (such as mice). The main reasons include: high-frequency antennas need to meet the requirements of resonance matching and sensing distance, while miniaturized RFID tags (such as glass tubes 11 with a diameter of 1.25 mm and a length of 7 mm) have difficulty capturing enough energy to maintain stable operation.

[0075] Currently, RFID reader / writer 2-antenna solutions on the market, whether for low-frequency or high-frequency RFID, all use planar coil solutions. The intensity of their radiated signal decreases with distance and cannot provide a uniform magnetic field strength in a pre-defined three-dimensional space, thus failing to enable tag identification and reading at any location within the space.

[0076] In its specific implementation, this invention addresses the issue of uniform magnetic field distribution in three-dimensional space, thus providing sufficient energy for the miniaturized RFID tag 1 to maintain stable operation. Based on this, this embodiment specifies that the RFID chip 12 operates at a frequency of 13.56MHz ± 7kHz, consistent with the resonant frequency of the reader antenna 3. This frequency range falls within the high-frequency band, with a moderate wavelength, resulting in minimal penetration loss through biological tissues and effectively avoiding signal attenuation issues caused by water and tissue absorption in animals, particularly with ultra-high-frequency signals. The 13.56MHz ± 7kHz frequency supports various protocols and possesses a mature anti-collision mechanism, enabling simultaneous identification of multiple tags. Matching the resonant frequency of the reader antenna 3 with the operating frequency of the RFID chip 12 maximizes electromagnetic coupling efficiency, reduces energy loss, and ensures that the RFID tag 1 stably acquires energy and completes data transmission within a certain distance.

[0077] When using this invention to breed experimental small animals 6 (such as experimental mice or rats), the RFID tag 1 can first be placed on the small animal 6 to be tracked and identified (e.g., by hanging or binding it outside the small animal 6, or by implanting it under the skin of the small animal 6), and the small animal 6 can be placed in an animal cage; the box 5 containing the small animal 6 (at this time, the box 5 acts as an animal cage) can be placed in the reader antenna 3; the reader antenna 3, which is connected to the RFID reader 2, emits electromagnetic signals into the space it encloses; after the RFID tag 1 on the small animal 6 is coupled with the uniform field signal of the antenna, it can obtain the electrical energy required for operation, and then it can feed back the identity information of the small animal 6 to the RFID reader 2, and can send the information stored in the storage module of the RFID chip 12 to the RFID reader 2 unit; the RFID reader 2 can transmit the relevant information to the information management system 7; the information management system 7 can also write the relevant information to be stored through the RFID reader 2 and the reader antenna 3 and store it in the RFID chip 12 coupled to the reader antenna 3.

[0078] In this invention, the 13.56MHz high-frequency signal has a moderate wavelength, and its penetration loss to biological tissues is far lower than that of ultra-high-frequency signals. The signal can penetrate tissues such as skin and muscle. The coupling efficiency between the reader antenna 3 and the tag is stable, and the reading distance can reach 15~20cm, ensuring stable identification within the enclosure and overcoming the problem of severe attenuation and malfunction of ultra-high-frequency signals within the body. Through the design of aligning the axes of coil pairs 31 and ensuring consistent current direction, combined with the layout of multiple pairs of coil pairs 31 in different directions, a three-dimensional uniform magnetic field is formed. For example, the magnetic fields of the three pairs of coil pairs 31 (top, bottom, left, right, front, and back) are superimposed, ensuring that the tag remains within the effective magnetic field range regardless of the animal's free movement and posture changes within the enclosure, avoiding the reading blind spots of traditional planar antennas.

[0079] Currently, low-frequency technologies on the market cannot perform group reading, and ultra-high-frequency technologies have poor penetration. Existing high-frequency technologies lack group reading solutions suitable for small animals. This method, through tag miniaturization design (diameter ≤ 1.25mm, length ≤ 7mm) and antenna uniform field three-dimensional design, applies HF RFID technology to the group reading management of small laboratory animals such as mice, filling a technological gap in this field.

[0080] The above are merely preferred embodiments of the present invention and are not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A small animal colony identification system based on high frequency RFID technology, characterized in that, The system comprises: RFID tags, each of which is configured with a unique identification information of a small animal; a box for carrying the small animals; a reader antenna, which comprises at least a pair of coil pairs arranged outside the box, each of the coil pairs comprising a first coil and a second coil, the axes of the first coil and the second coil coincide and the current directions of the first coil and the second coil are consistent, and the resonance frequency of the coil pair is 13.56 MHz ± 7 kHz; an RFID reader for identifying and reading and writing the RFID tags through the reader antenna, the RFID reader being internally provided with a signal processing module and an anti-collision control module, the signal processing module being used for analyzing the received response signals of the RFID tags to extract the unique identification information stored in each of the RFID tags, and the anti-collision control module being used for avoiding signal conflicts caused by the simultaneous responses of multiple RFID tags.

2. The small animal group reading and identifying system based on high-frequency RFID technology according to claim 1, wherein: the first coil and the second coil are connected in series by a wire, and each of the first coil and the second coil is wound by a plurality of turns of conductive wire, each turn of the conductive wire comprising 80-120 enameled wires.

3. The small animal group reading and identifying system based on high-frequency RFID technology according to claim 1, wherein: the RFID tag comprises an RFID chip, a chip antenna and a bar-shaped magnetic core encapsulated in a glass tube, the chip antenna is formed in a solenoid type structure by winding enameled wires outside the bar-shaped magnetic core, the two end points of the enameled wires of the chip antenna are connected to the two end electrodes of the RFID chip respectively, the diameter of the glass tube is not greater than 1.25 mm, and the length of the glass tube is not greater than 7 mm, and the RFID chip stores the unique identification information of the small animal to which the RFID chip belongs.

4. The small animal group reading and identifying system based on high-frequency RFID technology according to claim 1, wherein: the number of the coil pairs is at least two, the included angle between the axes of different coil pairs is not 0 degrees, and the RFID reader drives one pair of coil pairs at a time for identification and reading and writing.

5. The small animal group reading and identifying system based on high-frequency RFID technology according to claim 4, wherein: the signal processing module receives the RFID tag response signals fed back by any coil pair temporarily activated at present in the initialization stage of each round of group reading, distinguishes the spatial sub-regions in which different RFID tags are located in the box by analyzing the coupling strength values of the signals, and transmits the tag spatial distribution information to the anti-collision control module; the anti-collision control module matches the activation priority rules pre-stored in the tag spatial distribution information according to the coupling strength values of the tags, determines the activation sequence of each pair of coil pairs, and generates the coil pair activation sequence of the present round. The RFID reader outputs a driving signal to each pair of coil pairs in sequence according to a coil pair activation sequence through the anti-collision control module, and only one pair of coil pairs is activated each time. During the activation of the current pair of coil pairs, the signal processing module only analyzes the response signal of the RFID tag coupled with the coil pair. After the identification of the current pair of coil pairs is completed, the anti-collision control module triggers the activation process of the next pair of coil pairs, and the process is repeated until all the coil pairs complete the activation and signal collection.

6. The small animal colony identification system based on high-frequency RFID technology according to claim 4, characterized in that: The RFID reader divides the activation period of a single pair of coil pairs in each round of colony reading into a plurality of continuous time slots with equal time lengths, and only allows the RFID tag to send a response signal once in each time slot; The signal processing module extracts the time slot response data of each coil pair in the activation period in each round of colony reading after the round of colony reading is completed, and the time slot response data includes the number of valid response time slots, the number of collision time slots, and the number of empty time slots. The signal processing module calculates the tag response density according to the time slot response data, and transmits the tag response density and the time slot response data to the anti-collision control module; After receiving the tag response density and the time slot response data, the anti-collision control module dynamically adjusts the total number of time slots or the time length of a single time slot in the next round of colony reading, generates time slot configuration information for the next round of colony reading, and feeds back the time slot configuration information to the RFID reader. The RFID reader divides the tag response window period in the subsequent coil pair activation period according to the adjusted time slot configuration information.

7. The small animal colony identification system based on high-frequency RFID technology according to claim 4, characterized in that: After all the coil pairs complete a round of activation and signal collection, the signal processing module extracts the unique identity information of the RFID tag analyzed during the activation of each coil pair, and generates a tag ID set corresponding to each coil pair according to the coil pair number. Each tag ID set stores the unique identity information of all the RFID tags identified by the coil pair. The signal processing module collects all the tag ID sets corresponding to the coil pairs to form a temporary tag ID total set, and compares the unique identity information in the temporary tag ID total set one by one. The signal processing module filters and removes the repeated unique identity information in the temporary tag ID total set, and retains the single record of each unique identity information.

8. The small animal colony identification system based on high-frequency RFID technology according to claim 4, characterized in that: After any coil pair is activated and the RFID reader sends a colony reading request signal to the RFID tag in each round of colony reading, the anti-collision control module extracts the unique identity information of each RFID tag analyzed by the signal processing module; The anti-collision control module performs hash calculation on the unique identity information of each RFID tag according to the pre-stored hash calculation rule, and obtains the unique hash value corresponding to each tag; The anti-collision control module maps different hash values to different response delay time lengths according to the pre-stored time delay allocation rule, and each unique hash value of the RFID tag corresponds to an exclusive response delay time length. The anti-collision control module sends a control signal containing the exclusive response delay time length of each RFID tag to each RFID tag through the RFID reader and the currently activated coil pair; After receiving the control signal, each RFID tag adds a waiting time consistent with the exclusive response delay time length of itself between receiving the group reading request signal and sending the response signal, and then sends a response signal containing unique identity information.

9. The small animal group reading identification system based on high-frequency RFID technology according to claim 4, characterized in that: The signal processing module transmits the collected reading progress data, the proportion of remaining unread tags, and signal quality data to the anti-collision control module in real time; After receiving the reading progress data, the proportion of remaining unread tags, and signal quality data, the anti-collision control module matches the pre-stored parameter adjustment rules, adjusts the coil pair activation sequence and time slot configuration parameters of the subsequent rounds in real time, generates adjusted coil pair activation sequence and time slot configuration information, and feeds back the information to the RFID reader; The RFID reader performs subsequent coil pair activation and group reading operations according to the adjusted coil pair activation sequence and time slot configuration information.

10. A method for identifying a small animal colony based on high frequency RFID technology, characterized in that, The method comprises the following steps: Place no less than two small animals in the box, each small animal is configured with an RFID tag with a working frequency of 13.56 MHz ± 7 kHz, and each RFID tag stores the unique identity information of the small animal to which it belongs; Place the box in the uniform magnetic field formed by the reader antenna, the reader antenna comprises at least one coil pair, the coil pair comprises a first coil and a second coil, the axis of the first coil and the second coil coincide and the current direction is consistent, and the resonant frequency of the coil pair is 13.56 MHz ± 7 kHz; The RFID reader identifies and reads the RFID tag through the reader antenna to realize group reading identification of multiple small animals in the box.

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