Design method and device of frequency division multiplexing radio frequency identification tag, equipment and storage medium

Abstract

The invention provides a frequency division multiplexing radio frequency identification tag design method, apparatus and device, and a storage medium, and relates to the technical field of radio frequency identification, the method comprises the steps of obtaining a plurality of frequency division multiplexing RFID chips and determining a corresponding working frequency band, the working frequency band being a sub-frequency band; according to the preset number of sub-frequency bands and the target working frequency band of each RFID chip, determining each target surface acoustic wave filter conforming to the target quality factor; the complex impedance of each target SAW filter and the complex impedance of each RFID chip are directly matched through each matching network; each RFID chip, each target SAW filter, a matching network and an antenna are integrated on an FR4 substrate to form each frequency division multiplexing RFID tag, and each tag only responds to an excitation signal of a reader-writer in a specified sub-frequency band to realize frequency division multiplexing communication. According to the invention, frequency division multiplexing of different tags is realized by means of the SAW filter device, so that parallel radio frequency identification communication is realized.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency identification technology, and in particular to a design method, device, equipment and storage medium for a frequency division multiplexing radio frequency identification tag. Background Art

[0002] Radio Frequency Identification (RFID), renowned for its battery-free operation, offers a compelling solution for ubiquitous Internet of Things (IoT) applications, experiencing explosive growth and widespread adoption in areas such as logistics, supply chain, warehouse management, and wireless sensing.

[0003] In many applications, such as industry and logistics, real-time, high-throughput identification collection and group reading of tags are crucial. For example, on high-speed production lines, such as electronics assembly lines, product parts arrive in batches and bursts. Within a very short time window (often just a few milliseconds), a large number of tags must be read quickly to achieve real-time status updates. Furthermore, large logistics centers handle a large number of incoming and outgoing items, often transported by forklifts. These incoming and outgoing items require RFID to accurately read tags within a group every time, without misreading tags from adjacent groups.

[0004] Existing RFID methods use the Electronic Product Code (EPC) Gen-2 protocol to read tags individually. Due to the limited computing power of traditional RFID tags, they lack the ability to detect and avoid collisions. To avoid conflicts when multiple RFID tags transmit simultaneously, the EPC protocol requires the exchange of a 16-bit random number (RN16) as a handshake before reading the tag ID. To improve the efficiency of ID collection, existing methods use parallel RFID communication to allow multiple tags to transmit information simultaneously. The reader then decodes conflicting signals to retrieve the information transmitted by each tag. To accurately group and read multiple tags, existing methods either limit the antenna's operating range, designing specialized antennas to read only tags in a certain direction, or utilize RFID wireless sensing methods to group tags at different locations at the signal level.

[0005] However, none of the existing methods can achieve true parallel RFID. This is because the RN16 signal required by the EPC protocol means that tags can only transmit their RN16 data to the reader for parallel reading at most. However, the reader can then complete a handshake with only one tag. Ultimately, only one tag can send its ID information at a time. In essence, it is still time-division multiplexing rather than parallel communication.

[0006] Therefore, how to design frequency-division multiplexing RFID tags to achieve parallel RFID communication has become a technical problem that needs to be solved urgently in the industry. Summary of the Invention

[0007] The present invention provides a design method, device, equipment and storage medium for a frequency division multiplexing radio frequency identification tag, which can realize frequency division multiplexing of different tags with the help of a surface acoustic wave filter device, thereby realizing parallel radio frequency identification communication.

[0008] In a first aspect, the present invention provides a method for designing a frequency division multiplexing radio frequency identification tag, the method comprising the following steps: Acquire multiple frequency division multiplexing RFID chips and determine a target operating frequency band for each of the RFID chips; the target operating frequency band is a sub-band among multiple sub-bands; Determining target surface acoustic wave filters that meet target quality factors based on the preset number of sub-bands and the target operating frequency band of each RFID chip; the target surface acoustic wave filters (SAW) are frequency-selective antennas; the target quality factor is determined by the resonant frequency and the passband bandwidth; the higher the value of the target quality factor, the greater the number of frequency division multiple access sub-bands that can be divided by the target SAW filter; Directly matching the target SAW filters with the complex impedance of the RFID chips through matching networks designed using radio frequency simulation software. The RFID chips, target SAW filters, matching networks, and antennas are integrated on a glass fiber epoxy resin printed circuit FR4 substrate to form frequency-division multiplexing RFID tags. Each tag corresponds to a different sub-band, and each tag responds to the reader's excitation signal only within the specified sub-band to achieve frequency-division multiplexing communication.

[0009] According to a design method for a frequency division multiplexing radio frequency identification tag provided by the present invention, each target SAW filter is directly matched to the complex impedance of each RFID chip through each matching network; the matching network is designed using radio frequency simulation software, and includes: Determining parameters of a parallel inductor element in each target SAW filter based on the complex impedance of each RFID chip; the parallel inductor element is used to integrate capacitance and inductance parameters to achieve direct complex impedance matching between each RFID chip and each target SAW filter; the number of matching network elements in the parallel inductor element does not exceed two, and no additional capacitance is required; A zigzag dipole antenna is used as the other end of each target SAW filter; the size of the zigzag dipole antenna is consistent with that of an ordinary RFID antenna, and the zigzag dipole antenna is used to adjust physical parameters so that the impedance of the zigzag dipole antenna matches the complex impedance of the target SAW filter.

[0010] According to a design method for a frequency division multiplexing radio frequency identification tag provided by the present invention, each target surface acoustic wave filter that meets the target quality factor is determined based on the preset number of sub-bands and the target operating frequency band of each RFID chip: Determining a minimum value of the target quality factor based on a center frequency range, a target operating frequency band of each of the RFID chips, and the number of preset sub-frequency bands; the target operating frequency band of each of the RFID chips being a sub-frequency band within the center frequency range; Determining a first quality factor corresponding to each of the first surface acoustic wave filters according to the resonant frequencies and communication bandwidths corresponding to a preset number of first surface acoustic wave filters; Each of the first quality factors is compared with a minimum value of the target quality factors, and each of the target surface acoustic wave filters is determined based on first surface acoustic wave filters corresponding to first quality factors greater than the minimum value.

[0011] According to a design method for a frequency division multiplexing radio frequency identification tag provided by the present invention, the target SAW filter implements bidirectional filtering through a piezoelectric transducer to block radio frequency signals in non-operating frequency bands.

[0012] According to a design method of a frequency division multiplexing radio frequency identification tag provided by the present invention, the method further includes: Based on the roll-off characteristics of each target SAW filter, each tag sub-band is divided into a working area and a roll-off area; the reader operates within the working area of ​​each tag sub-band to prevent the roll-off area signal from interfering with adjacent frequency bands; Verify the frequency division multiplexing performance of each tag to ensure that the interference suppression between sub-bands is not lower than the preset threshold.

[0013] According to a design method of a frequency division multiplexing radio frequency identification tag provided by the present invention, the method further includes: Testing the communication distance and signal stability of each tag through the reader; The power parameters of each of the tags are adjusted to compensate for the insertion loss.

[0014] In a second aspect, the present invention further provides a device for designing a frequency division multiplexing radio frequency identification tag, the device comprising the following modules: A filter antenna selection module is used to obtain multiple frequency division multiplexing RFID chips and determine a target operating frequency band for each of the RFID chips; the target operating frequency band is a sub-band of the multiple sub-bands; Determining target surface acoustic wave filters that meet target quality factors based on the number of preset sub-bands and the target operating frequency band of each RFID chip; the target surface acoustic wave filters are frequency-selective antennas; the target quality factor is determined by the resonant frequency and the passband bandwidth, and the higher the value of the target quality factor, the more frequency division multiple access sub-bands the target surface acoustic wave filter can be divided into; A filter antenna matching module, configured to directly match the target SAW filters to the complex impedance of the RFID chips through matching networks designed using radio frequency simulation software. An integrated module is used to integrate each of the RFID chips, each of the target SAW filters, the matching network, and the antenna on a glass fiber epoxy resin printed circuit FR4 substrate to form frequency-division multiplexing RFID tags; each tag corresponds to a different sub-band, and each tag responds to the reader's excitation signal only within the specified sub-band to achieve frequency-division multiplexing communication.

[0015] In a third aspect, the present invention further provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, the method for designing a frequency division multiplexing radio frequency identification tag as described above is implemented.

[0016] In a fourth aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the method for designing a frequency-division multiplexing radio frequency identification tag as described in any one of the above.

[0017] In a fifth aspect, the present invention further provides a computer program product, comprising a computer program, which, when executed by a processor, implements any of the above-described methods for designing a frequency-division multiplexing radio frequency identification tag.

[0018] The present invention provides a design method, apparatus, device, and storage medium for frequency-division multiplexing (FDM) radio frequency identification tags. First, a plurality of FDM RFID chips are obtained and a target operating frequency band of each RFID chip is determined, where the target operating frequency band is a sub-band of a plurality of sub-bands. Then, target surface acoustic wave filters (SAW) that meet a target quality factor are determined based on a preset number of sub-bands and the target operating frequency band of each RFID chip. The target surface acoustic wave filters are frequency-selective antennas, and the target quality factor is determined by the resonant frequency and the passband bandwidth. The higher the value of the target quality factor, the greater the number of FDM sub-bands that the target surface acoustic wave filter can divide. Furthermore, each target SAW filter is directly matched to the complex impedance of each RFID chip through each matching network, where the matching network is designed using radio frequency simulation software. Then, each RFID chip, each target SAW filter, the matching network, and the antenna are integrated on an FR4 substrate to form each FDM RFID tag. Each tag corresponds to a different sub-band, and each tag responds to an excitation signal of a reader / writer only within a specified sub-band to achieve FDM communication.

[0019] The present invention uses an existing RFID tag chip and introduces a passive filtering surface acoustic wave device and a matching network design to ensure that the RFID tag only responds to an excitation signal of a specific frequency. With the help of the SAW filter device, frequency division multiplexing of different tags can be achieved, thereby realizing parallel RFID communication. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 The figure is a flow chart of the design method of the frequency division multiplexing radio frequency identification tag provided by the present invention.

[0022] Figure 2 This is a schematic diagram of an application scenario of the frequency division multiplexing radio frequency identification tag provided by the present invention.

[0023] Figure 3 It is a schematic diagram of the principle of the surface acoustic wave filter device and model provided by the present invention.

[0024] Figure 4 The figure is a schematic diagram comparing the working modes of a traditional radio frequency identification tag and a frequency division multiplexing radio frequency identification tag provided by the present invention.

[0025] Figure 5It is a schematic diagram comparing the decoupling matching network design provided by the present invention and the traditional impedance matching design.

[0026] Figure 6 This is a schematic diagram of impedance adjustment of the meander line dipole antenna provided by the present invention.

[0027] Figure 7 The figure is a schematic diagram comparing the frequency responses of downlink excitation signals of the frequency division multiplexing video identification tag provided by the present invention and the traditional radio frequency identification tag.

[0028] Figure 8 The figure is a schematic diagram comparing the frequency responses of uplink reflected signals of the frequency division multiplexing video identification tag provided by the present invention and the traditional radio frequency identification tag.

[0029] Figure 9 This is a schematic diagram of the passband loss and frequency band division of all types of frequency division multiplexing labels provided by the present invention.

[0030] Figure 10 It is a structural schematic diagram of a design device for a frequency division multiplexing radio frequency identification tag provided by the present invention.

[0031] Figure 11 It is a structural schematic diagram of the electronic device provided by the present invention. DETAILED DESCRIPTION

[0032] To make the objectives, technical solutions, and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0033] To address the above-mentioned problems of the prior art, the present invention proposes a frequency-division multiplexing (FDM) RFID tag based on a frequency-selective antenna. This FDM RFID tag overcomes the time-division multiplexing limitations of traditional RFID tags, enabling frequency-domain parallel reading and group reading scenarios.

[0034] The following combination Figures 1-11 The present invention describes the design method, device, equipment and storage medium of the frequency division multiplexing radio frequency identification tag.

[0035] Figure 1 FIG. 1 is a flow chart of a design method for a frequency division multiplexing radio frequency identification tag provided by the present invention. Figure 1 As shown, the method includes the following: Step 101: Acquire multiple frequency division multiplexing RFID chips and determine a target operating frequency band for each RFID chip; the target operating frequency band is a sub-band among multiple sub-bands; Specifically, it should be noted first that Figure 2 This is a schematic diagram of an application scenario of the frequency division multiplexing radio frequency identification tag provided by the present invention, such as Figure 2 As shown, the RFID reader / writer includes frequency bands F1-F5 and transmits excitation signals to frequency-division multiplexing (FDM) RFID tags. These tags only respond to signals within a specific frequency band, with Freq.Domain representing the frequency domain. This FDM RFID tag utilizes an existing RFID tag chip, such as a commercial RFID chip, and utilizes a frequency-selective antenna to respond only to excitation signals within a specific frequency band. Various types of FDM RFID tags are equipped with different frequency-selective antennas, each responding only to excitation signals specific to its own frequency, all within the RFID band (e.g., 902-928 MHz). By using multiple commercial RFID readers / writers, each configured for a specific frequency within each FDM RFID tag, it is possible to read tags of different frequencies in parallel or in groups. It should be noted that the key to achieving the functionality of this FDM RFID tag lies in the introduction of a frequency-selective antenna, while maintaining the battery-free and low-cost characteristics of RFID, namely, a fully passive, high-frequency selective filtering antenna.

[0036] Traditional tag antennas offer some filtering capabilities, but they cannot meet the high selectivity requirements of this FDM RFID tag. We discovered that surface acoustic wave (SAW) filters can meet this requirement. Furthermore, we carefully fine-tuned the decoupling matching networks at both ports of the SAW device for optimal efficiency. Analysis showed that this antenna had only a minor impact on the FDM RFID tag's read range performance. This FDM RFID tag maintains compatibility with traditional RFID systems because it is essentially a tag using a commercial RFID chip. Commercial readers can read this FDM RFID tag using either a frequency hopping mechanism or active frequency adjustment.

[0037] The following describes in detail the design method of the frequency division multiplexing radio frequency identification tag provided by the present invention: First, multiple frequency division multiplexing radio frequency identification (RFID) chips are obtained and the target operating frequency band of each RFID chip is determined.

[0038] The selected RFID chip is any type of commercial RFID chip, such as NXP UCODE 7, and the printed circuit board (PCB) is a packaged version.

[0039] RFID chips operate in the 902-928MHz ISM band. The Industrial Scientific Medical (ISM) band refers to the wireless frequency band used for industry, scientific research, and medical treatment. 902-928MHz is the radio frequency identification band. In order for radio frequency identification tags to achieve frequency division multiplexing, the radio frequency identification band needs to be divided into multiple sub-bands, and a frequency division multiplexing radio frequency identification tag only operates on one of the sub-bands, that is, the target operating band is also one of the sub-bands, for example, the target operating band is 902-907 MHz, for example, the target operating band is 908-913 MHz, and for example, the target operating band is 914-919 MHz. Correspondingly, this requires that the filtering antenna selected by the present invention must have high frequency selectivity.

[0040] Step 102: Determine target surface acoustic wave filters that meet target quality factors based on the preset number of sub-bands and the target operating frequency band of each RFID chip. The target surface acoustic wave filters (SAW) are frequency-selective antennas. The target quality factor is determined by the resonant frequency and the passband bandwidth. The higher the target quality factor, the more frequency division multiple access sub-bands the target SAW filters can divide into. Specifically, after determining the target operating frequency band of each RFID chip, i.e., the corresponding sub-band of each RFID chip, a filter antenna must be selected. The filter antenna selected in the present invention must have high frequency selectivity. Specifically, the requirements for selecting a filter antenna that meets the present invention are as follows: 1. The filtering antenna is required to have high frequency selectivity; 2. Size and cost: RFID applications require tags to be lightweight and easy to manufacture, and the filter antenna must also meet the same requirements.

[0041] In frequency division multiplexing RFID tags, we use SAW filters to implement the filtering function of the antenna, and the target SAW filter is a frequency selective antenna.

[0042] The filtering capability of RF circuits requires a certain resonant structure, and its frequency selectivity is quantified by its quality factor (Q factor): in is the resonant frequency, is the passband bandwidth, corresponding to the 3dB attenuation point. The higher the Q value, the steeper the frequency response, allowing for more FDMA sub-bands to be divided.

[0043] It can be seen from the above formula that the target quality factor is determined by the resonant frequency and the passband bandwidth. The higher the value of the target quality factor, the more frequency division multiple access sub-bands the target surface acoustic wave (SAW) filter can be divided into.

[0044] Therefore, during the design of frequency-division multiplexing RFID tags, the target SAW filters that meet the target quality factor can be determined based on the preset number of sub-bands and the target operating frequency band of each RFID chip. This means configuring the corresponding SAW filters for each tag. For example, if five sub-bands are required, the tag must have a selectivity of less than 5 MHz (megahertz), corresponding to a target quality factor of at least 200.

[0045] Step 103: Directly match each target SAW filter to the complex impedance of each RFID chip through each matching network; the matching network is designed using radio frequency simulation software; Specifically, after selecting a target SAW filter as a filter antenna, the target SAW filter needs to be applied to a frequency-division multiplexing RFID tag. It should be noted that in order to apply the above-mentioned SAW device to the RFID tag, impedance matching with the integrated circuit (IC) chip is required to maximize energy transfer. Specifically, the impedance of the filter antenna within the operating frequency band should be equal to the conjugate of the chip impedance. This precise matching is crucial for SAW-based filter antennas.

[0046] The target SAW filter converts electrical energy into sound waves through a piezoelectric transducer. Figure 3 Schematic diagram of the principle of the surface acoustic wave filter device and model provided by the present invention, such as Figure 3 As shown in Figure (a), a SAW filter made of piezoelectric material demonstrates that the transducer oscillates only when the RF signal approaches its resonant frequency, achieving a Q factor as high as 1000. The corresponding inductors are Z1, C1, Z2, and C2, while R1 and R2 are the corresponding resistors. It also provides bidirectional filtering, supporting uplink and downlink communications. Furthermore, SAW filters are compact (IC-level), low-cost, and simple to manufacture.

[0047] The target SAW filter achieves filtering through internal transducers. Each transducer consists of two interleaved metal electrodes, showing the electrical characteristics of a parallel resistor-capacitor circuit (RC), such as Figure 3 (b) The two transducers are physically disconnected, forming two distinct and independent capacitive impedances (Z1 and Z2) in the circuit. Furthermore, SAW devices operating at different frequencies also generate different impedances due to differences in transducer structure. Figure 3(c) shows examples of characteristics (impedance values) of two SAW device series. The resonant frequency of SAW device B3934 is 902.8 MHz, R1 is 400 ohms (Ω), C1 is 1.1 pF, R2 is 380 Ω, C2 is 1.2 pF, Z1 is 55.3-138.1 jΩ, and Z2 is 49.7-127.8 jΩ. The resonant frequency of SAW device B3949 is 921.4 MHz, R1 is 260 Ω, C1 is 1.6 pF, R2 is 270 Ω, C2 is 1.3 pF, Z1 is 38.2-92.1 jΩ, and Z2 is 52.6-107.0 jΩ.

[0048] Given this impedance inconsistency, a common design approach is to uniformly match both ends of the SAW device to 50 ohms. One end is connected to a standard antenna, and the other end is connected to the RFID chip via a matching circuit. However, this traditional matching method does not achieve optimal performance. The entire tag requires up to six matching components (capacitors and inductors), and their parasitic effects lead to significant energy losses. Furthermore, the presence of these components significantly increases the cost of mass production of the tag.

[0049] However, in this invention, a matching network is designed to directly match the complex impedance of the RFID chip and the SAW filter to achieve optimal performance of the SAW filter antenna. The matching network is designed using RF simulation software, such as PathWave (Advanced Design System, ADS), to simulate inductor-based matching networks. ADS is primarily used for the design, simulation, and analysis of RF, microwave, and millimeter-wave circuits. The inductor is from muRata, and its values ​​were optimized using ADS.

[0050] Step 104: Integrate each RFID chip, each target SAW filter, a matching network, and an antenna on a fiberglass epoxy resin printed circuit FR4 substrate to form frequency-division multiplexing RFID tags; each tag corresponds to a different sub-band, and each tag responds to the reader's excitation signal only within the specified sub-band to achieve frequency-division multiplexing communication.

[0051] Specifically, after completing the structural design of the filtering antenna and the application of the filtering antenna in the tag, the above-mentioned device can be further integrated into an FR4 substrate to generate a frequency division multiplexing RFID tag.

[0052] For example, frequency-division multiplexing (FDM) RFID tags are integrated onto an FR4 substrate, along with individual RFID chips, target SAW filters, matching networks, and antennas. Different tags correspond to different sub-bands. Each tag measures 100 mm x 20 mm. These tags are passive and require no external power. Each tag responds only to the reader's excitation signal within its designated sub-band, enabling FDM communication. More specifically, each tag responds to excitation signals within only one frequency band, enabling FDM of different tags.

[0053] Figure 4 This is a schematic diagram comparing the working modes of the traditional RFID tag and the frequency division multiplexing RFID tag provided by the present invention. Figure 4 (a) shows the working mode of traditional RFID tags. Figure 4 (b) Shows the working mode of the frequency division multiplexing RFID tag.

[0054] Traditional RFID tags consist of a fixed IC chip and a customizable antenna. Due to power constraints, the chip lacks the ability to distinguish between carrier frequencies. Therefore, traditional RFID tags operate within the entire RFID band (typically 902-928 MHz). Any in-band carrier signal will excite the tag and be reflected, modulating the tag's data.

[0055] The FDM RFID tag of the present invention adds a highly selective passive filtering antenna to a conventional IC chip, selectively stimulating and reflecting RF signals within a narrow band. Specifically, the filtering antenna allows RF signals within its operating frequency band to enter and exit the IC chip, while blocking RF signals outside of the operating frequency band. This allows only carrier signals with the correct frequency to stimulate and transmit information to the FDM RFID tag, and the signals modulated by the FDM RFID tag during reflection and modulation are also based solely on this carrier signal.

[0056] The method provided in this embodiment first obtains multiple frequency-division multiplexing RFID chips and determines the target operating frequency band of each RFID chip, where the target operating frequency band is a sub-band among multiple sub-bands. Then, based on the preset number of sub-bands and the target operating frequency band of each RFID chip, each target surface acoustic wave filter that meets the target quality factor is determined. The target surface acoustic wave filter is a frequency-selective antenna, and the target quality factor is determined by the resonant frequency and the passband bandwidth. The higher the value of the target quality factor, the more frequency-division multiplexing sub-bands the target surface acoustic wave filter can be divided into. Furthermore, each target SAW filter is directly matched to the complex impedance of each RFID chip through each matching network, and the matching network is designed using radio frequency simulation software. Then, each RFID chip, each target SAW filter, the matching network, and the antenna are integrated on an FR4 substrate to form each frequency-division multiplexing RFID tag. Each tag corresponds to a different sub-band, and each tag responds to the excitation signal of the reader / writer only within the specified sub-band to achieve frequency-division multiplexing communication.

[0057] The present invention uses an existing RFID tag chip and introduces a passive filtering surface acoustic wave device and a matching network design to ensure that the RFID tag only responds to an excitation signal of a specific frequency. With the help of the SAW filter device, frequency division multiplexing of different tags can be achieved, thereby realizing parallel RFID communication.

[0058] According to a design method for a frequency-division multiplexing radio frequency identification tag provided by the present invention, each target SAW filter is directly matched to the complex impedance of each RFID chip through each matching network; the matching network is designed using radio frequency simulation software and includes: Determining parameters of a shunt inductor element in each target SAW filter based on the complex impedance of each RFID chip; the shunt inductor element is used to integrate capacitance and inductance parameters to achieve direct complex impedance matching between each RFID chip and each target SAW filter; the number of matching network components in the shunt inductor element does not exceed two, and no additional capacitor is required; A meander line dipole antenna is used as the other end of each target SAW filter; the size of the meander line dipole antenna is consistent with that of a common RFID antenna, and the physical parameters of the meander line dipole antenna are adjusted to match the impedance of the meander line dipole antenna with the complex impedance of the target SAW filter.

[0059] Specifically, in some embodiments, the matching network design process in step 103 is implemented by the following steps: In frequency-division multiplexing radio frequency identification tags, we design a decoupling matching network to achieve the optimal performance of the SAW filter antenna by directly matching the complex impedance.

[0060] Figure 5This is a schematic diagram comparing the decoupling matching network design provided by the present invention and the traditional impedance matching design. Figure 5 (a) is a schematic diagram showing the design of a traditional matching circuit under standard 50Ω. Figure 5 (b) Schematic diagram of the network design for decoupling matching, as shown in Figure 5 As shown in (a), it includes capacitors 𝐶1, 𝐶2 and inductors 𝐿1, 𝐿2. In the figure, there are redundant curves in the matching path from the RFID IC chip to the SAW. Here, the impedance point of the SAW represents the conjugate of its complex impedance. Eliminating redundant matching can simplify the design of the matching network and reduce matching components. Unlike equivalently treating both ends as 50 ohms (Ω), the present invention directly matches the complex impedance of both ends. Figure 5 As shown in (b), capacitors 𝐶1 and 𝐶2 are combined with inductor 𝐿2 into a single parallel inductor 𝐿2 to achieve matching between the chip and the SAW. The 50-ohm antenna at the other end of the SAW is then replaced with a meanderline dipole antenna. This antenna has a 2dBi gain and is comparable in size to a typical RFID antenna. Its physical parameters are adjusted to precisely match the impedance of the SAW. Ultimately, only two inductors are used to achieve optimal matching.

[0061] Specifically, first, the parameters of the parallel inductor element in each target SAW filter are determined based on the complex impedance of each RFID chip. The parallel inductor element is used to integrate the capacitance and inductance parameters to achieve direct complex impedance matching between each RFID chip and each target SAW filter. The number of matching network elements in the parallel inductor element does not exceed two and no additional capacitor is required. Figure 5 As shown in (b), capacitor 𝐶1, capacitor 𝐶2 and inductor 𝐿2 are integrated into a single parallel inductor element 𝐿2, and the parameters of the parallel inductor element are adjusted to achieve direct matching between the chip and the SAW.

[0062] Furthermore, a meander line dipole antenna is used as the other end of each target SAW filter, that is, the 50 ohm antenna at the other end is replaced by Figure 6 The zigzag dipole antenna shown in the figure has the same dimensions as a common RFID antenna. Figure 6 Schematic diagram of impedance adjustment of the meander line dipole antenna provided by the present invention, as shown in FIG. Figure 6 As shown, by adjusting the physical parameters of the meander line dipole antenna such as W i , S i To make the meander line dipole antenna (such as the impedance fine-tuning antenna Z A )'s impedance is precisely matched to the complex impedance of the SAW filter.

[0063] In this paper, RF simulation and full-wave analysis software were used to construct and simulate the tag's frequency-selective antenna. For example, a commercial high-pass SAW filter, the B3300, was used as the filter component. After optimizing the inductor matching and fine-tuning the dipole antenna, the antenna operated at 916.5 MHz with a passband width of approximately 1.6 MHz.

[0064] Figure 7 FIG. 1 is a schematic diagram comparing the frequency responses of the downlink excitation signals of the frequency division multiplexing video identification tag provided by the present invention and the traditional radio frequency identification tag. Figure 7 As shown, Figure 7 The figure compares the responses of frequency-division multiplexing (FDM) tags and RFID tags to excitation signals (or downlink signals). FDM tags respond only to excitation signals within a specific frequency band, while RFID tags respond to excitation signals across the entire frequency band. The figure shows that the FDM tag responds only to excitation signals within the operating frequency band, not the rolling band.

[0065] Since the tag chip realizes binary amplitude keying OOK modulation by adjusting the absorption and reflection states, Figure 8 FIG. 1 is a schematic diagram comparing the frequency responses of the uplink reflected signals of the frequency division multiplexing video identification tag provided by the present invention and the traditional radio frequency identification tag. Figure 8 Figure 2 shows the reflection frequency responses of the two types of tags in two different states. It can be seen that the frequency-division multiplexing video identification tag achieves frequency selection in both uplink and downlink communications through the SAW filter antenna, while the traditional tag has a smaller reflection amplitude.

[0066] The method provided in this embodiment first determines the parameters of the parallel inductor element in each target SAW filter based on the complex impedance of each RFID chip. The parallel inductor element is used to integrate the capacitance and inductance parameters to achieve direct matching of the complex impedance of each RFID chip with that of each target SAW filter. The number of matching network components in the parallel inductor element does not exceed two, and no additional capacitance is required. Then, a zigzag dipole antenna is used as the other end of each target SAW filter. The zigzag dipole antenna has the same dimensions as a conventional RFID antenna, and the physical parameters of the zigzag dipole antenna are adjusted to match the impedance of the zigzag dipole antenna with the complex impedance of the target SAW filter. The decoupling matching network designed in the present invention achieves optimal performance of the SAW filter antenna by directly matching the complex impedance of the RFID chip and the target SAW filter.

[0067] According to a design method for a frequency-division multiplexing radio frequency identification tag provided by the present invention, target surface acoustic wave filters meeting a target quality factor are determined based on the number of preset sub-bands and the target operating frequency band of each RFID chip: Determining a minimum value of a target quality factor based on the center frequency range, the target operating frequency band of each RFID chip, and the number of preset sub-frequency bands; the target operating frequency band of each RFID chip is a sub-frequency band within the center frequency range; Determining a first quality factor corresponding to each first surface acoustic wave filter according to the resonant frequencies and communication bandwidths corresponding to a preset number of first surface acoustic wave filters; Each first quality factor is compared with a minimum value of the target quality factor, and each target surface acoustic wave filter is determined based on the first surface acoustic wave filters corresponding to the first quality factors greater than the minimum value.

[0068] Specifically, in some embodiments, the process of configuring the SAW filter in step 102 is exemplified as follows: First, the minimum value of the target quality factor is determined based on the center frequency range, the target operating frequency band of each RFID chip, and the number of preset sub-bands. The center frequency range is the entire radio frequency identification operating frequency band (902-928 MHz), and the target operating frequency band of each RFID chip is a sub-band within the center frequency range. According to formula (1), the higher the quality factor (Q), the steeper the frequency response, which allows for more FDMA sub-bands to be divided. Therefore, the minimum value of the quality factor can be determined based on the number of sub-bands to be divided. For example, if five sub-bands need to be used in parallel, the frequency division multiplexing tag must have a selectivity of less than 5 MHz, corresponding to a Q value of at least 200.

[0069] Furthermore, the first quality factor corresponding to each first surface acoustic wave filter is determined based on the resonant frequencies and communication bandwidths corresponding to the preset number of first surface acoustic wave filters. For example, if there are currently 10 selectable filters, the first quality factor corresponding to each filter needs to be calculated by substituting them into formula (1).

[0070] Each first quality factor is compared with a minimum value of a target quality factor, and each target surface acoustic wave filter is determined based on the first surface acoustic wave filters corresponding to the first quality factors greater than the minimum value. For example, a first surface acoustic wave filter with a first quality factor greater than 200 is determined as an available target surface acoustic wave filter and used as a filtering antenna in a frequency division multiplexing tag to achieve frequency selection.

[0071] The method provided in this embodiment first determines the minimum value of the target quality factor based on the center frequency range, the target operating frequency band of each RFID chip, and a preset number of sub-bands; the target operating frequency band of each RFID chip is a sub-band within the center frequency range; then, based on the resonant frequencies corresponding to a preset number of first surface acoustic wave filters and the communication bandwidth, the first quality factor corresponding to each first surface acoustic wave filter is determined; then, each first quality factor is compared with the minimum value of the target quality factor, and each target surface acoustic wave filter is determined based on the first surface acoustic wave filters corresponding to the first quality factor greater than the minimum value. The present invention utilizes existing radio frequency identification tag chips and implements frequency selection with the aid of a frequency selective antenna (surface acoustic wave filter), so that different tags respond only to excitation signals within a specific frequency band, thereby achieving parallel frequency division multiplexing communication.

[0072] According to a design method for a frequency division multiplexing radio frequency identification tag provided by the present invention, a piezoelectric transducer is used in a target SAW filter to implement bidirectional filtering and block radio frequency signals in non-operating frequency bands.

[0073] Specifically, the SAW filter in this invention uses a piezoelectric transducer to achieve bidirectional filtering, blocking RF signals outside the operating frequency band. The core of this method is to utilize the propagation characteristics of sound waves, the structural design of the piezoelectric transducer (IDT), and the piezoelectric effect of the material. The following are the detailed steps of its specific implementation process: (1) Signal input and electro-acoustic conversion Input signal: The RF signal is applied to the piezoelectric substrate (such as lithium niobate) through the IDT (interdigital transducer) at the input end.

[0074] Electroacoustic conversion: The interlaced electrodes of the IDT excite surface acoustic waves (SAW) on the surface of the piezoelectric material. The frequency of SAW is determined by the electrode spacing (λ) of the IDT and the sound velocity (v) of the material (f0=v / λ).

[0075] (2) Sound wave propagation and frequency selection Acoustic wave path: The acoustic wave propagates along the substrate surface to the output end IDT. During the propagation process, the acoustic wave energy in the non-working frequency band is attenuated or reflected.

[0076] Frequency selectivity: Operating frequency band: The frequencies corresponding to the acoustic wavelength (λ) that matches the IDT electrode spacing are efficiently transmitted. Non-operating frequency band: Acoustic waves with mismatched wavelengths are suppressed due to phase mismatch or reflection.

[0077] (3) Sound-to-electricity conversion and output The IDT at the output end converts the sound waves back into electrical signals, retaining only the signals in the working frequency band and filtering out the energy in the non-working frequency band.

[0078] SAW filters achieve efficient suppression of non-operating frequencies in bidirectional transmission through technologies such as IDT structural optimization (symmetrical design and apodization), reflection grating blocking, cascade filtering, and temperature compensation. Their core principle is to leverage the wavelength selectivity of acoustic waves and the energy conversion properties of piezoelectric materials, combined with precision manufacturing to ensure high-frequency stability. In the future, with the development of new materials (such as diamond substrates) and integration technologies (such as SiP), SAW filters will continue to play a key role in 5G / 6G communications.

[0079] In the method provided in this embodiment, a piezoelectric transducer is used in the target SAW filter to implement bidirectional filtering, thereby blocking radio frequency signals in non-operating frequency bands, thereby obtaining a frequency division multiplexing radio frequency identification tag.

[0080] According to a design method of a frequency division multiplexing radio frequency identification tag provided by the present invention, the method further includes: Based on the roll-off characteristics of each target SAW filter, each tag sub-band is divided into a working area and a roll-off area. The reader operates within the working area of ​​each tag sub-band to prevent the roll-off area signal from interfering with adjacent frequency bands. Verify the frequency division multiplexing performance of each tag to ensure that the interference suppression between sub-bands is not lower than the preset threshold.

[0081] Specifically, it is important to understand that the capacity of FDMA depends on the number of sub-bands into which the RFID frequency band is divided, while also requiring no interference between the sub-bands. Although the SAW filter has a steep frequency response, it is not a perfect rectangle and exhibits a roll-off as the frequency moves away from the resonant frequency.

[0082] To this end, the frequency band of the frequency division multiplexing label needs to be divided into a working area and a roll-off area, such as Figure 7 The reader should avoid reading tags in the roll-off area to avoid possible interference with adjacent sub-bands.

[0083] The method further comprises: Based on the roll-off characteristics of each target SAW filter, each tag's sub-band is divided into an operating region and a roll-off region. The reader operates within the operating region of each tag's sub-band to prevent signals in the roll-off region from interfering with adjacent frequency bands. The frequency division multiplexing performance of each tag is verified to ensure that inter-sub-band interference suppression does not fall below a preset threshold, such as 30dB.

[0084] Figure 9 This is a schematic diagram of the passband loss and frequency band division of all types of frequency division multiplexing labels provided by the present invention, such as Figure 9 As shown, Figure 9 The labels F1, F2, F3, F4, and F5 are included, and the corresponding frequency bands include F1, F2, F3, F4, and F5. The corresponding passband losses are shown in the figure. There is more than 30dB of interference suppression between different frequency bands.

[0085] The method provided in this embodiment divides the frequency band of the frequency division multiplexing tag into a working area and a roll-off area. The reader operates in the working area of ​​each tag sub-band to prevent the roll-off area signal from interfering with adjacent frequency bands.

[0086] According to a design method of a frequency division multiplexing radio frequency identification tag provided by the present invention, the method further includes: Test the communication distance and signal stability of each tag through the reader; The power parameters of each tag are adjusted to compensate for insertion loss.

[0087] Specifically, in some embodiments, the method further includes: The communication distance and signal stability of each frequency division multiplexing tag are tested using a reader / writer. Based on the test results, the power parameters of each tag are adjusted to compensate for insertion loss.

[0088] SAW filter antennas have excellent frequency selectivity, but they inevitably bring about 3dB of insertion loss, which may affect the tag's reading distance. However, the filtering characteristics can partially offset this loss. The reading distance of the RFID system is mainly determined by the downlink communication. At the critical distance, the reader can still activate the tag and receive its backscattered signal, but the tag cannot demodulate the downlink command. This is because the broadband noise introduced along with the signal forms self-mixing noise in the tag's envelope detection. The broadband characteristics of traditional tags bring up to 100MHz of thermal noise, while frequency-division multiplexing tags use filtering antennas to effectively filter this noise to about 2MHz, increasing the downlink detectable power by about 2dB. Although it cannot completely offset the shortened distance, it can still ensure an acceptable communication range in RFID applications.

[0089] For example, the test process for multi-band concurrent bit error rate testing is as follows: 1. Activate multiple frequency bands simultaneously through the reader (e.g., 4 frequency bands: 915 MHz, 920 MHz, 925 MHz, 930 MHz).

[0090] 2. Send a known data packet (such as EPC code) to the tag through the reader and calculate the bit error rate.

[0091] 3. Gradually increase the number of frequency bands (to the capacity limit) and record the BER changes.

[0092] Optimization strategy: If the BER increases significantly with the number of frequency bands, the tag's demodulation circuit or the reader's time slot allocation algorithm needs to be optimized.

[0093] For another example, the test method flow for tag dynamic range test is as follows: 1. Set the power difference between adjacent frequency bands (e.g. +30 dBm for Band A and +27 dBm for Band B).

[0094] 2. Verify whether the tag's response success rate in frequency band A is affected by the power in frequency band B.

[0095] Tolerance Standard: When the power difference is ±3dB, the tag response success rate drops by ≤5%.

[0096] The method provided in this embodiment can test the communication distance and signal stability of each tag through a reader / writer to improve tag performance.

[0097] The following describes a design device for a frequency division multiplexing RFID tag provided by the present invention. The design device for a frequency division multiplexing RFID tag described below and the design method for a frequency division multiplexing RFID tag described above can be referred to each other.

[0098] Figure 10 This is a schematic diagram of the structure of the design device of the frequency division multiplexing radio frequency identification tag provided by the present invention. Figure 10 As shown, the design device 1000 of the frequency division multiplexing radio frequency identification tag includes the following modules: The filter antenna selection module 1010 is used to obtain multiple frequency division multiplexing RFID chips and determine the target operating frequency band of each of the RFID chips; the target operating frequency band is a sub-band among the multiple sub-bands; Determining target surface acoustic wave filters that meet target quality factors based on the number of preset sub-bands and the target operating frequency band of each RFID chip; the target surface acoustic wave filters are frequency-selective antennas; the target quality factor is determined by the resonant frequency and the passband bandwidth, and the higher the value of the target quality factor, the more frequency division multiple access sub-bands the target surface acoustic wave filter can be divided into; The filter antenna matching module 1020 is used to directly match the target SAW filters with the complex impedance of the RFID chips through matching networks; the matching networks are designed using radio frequency simulation software; The integrated module 1030 is used to integrate the RFID chips, the target SAW filters, the matching network, and the antenna on a fiberglass epoxy resin printed circuit FR4 substrate to form frequency-division multiplexing RFID tags. Each tag corresponds to a different sub-band, and each tag responds to the reader's excitation signal only within the specified sub-band to achieve frequency-division multiplexing communication.

[0099] The device provided in this embodiment includes a filter antenna selection module, a filter antenna matching module, and an integration module. First, the filter antenna selection module is used to obtain multiple frequency-division multiplexing RFID chips and determine the target operating frequency band of each RFID chip. The target operating frequency band is a sub-band among multiple sub-bands. Then, based on the preset number of sub-bands and the target operating frequency band of each RFID chip, target surface acoustic wave filters that meet the target quality factor are determined. The target surface acoustic wave filters are frequency-selective antennas. The target quality factor is determined by the resonant frequency and passband bandwidth. The higher the value of the target quality factor, the more frequency-division multiplexing sub-bands the target surface acoustic wave filter can be divided into. Furthermore, the filter antenna matching module directly matches each target SAW filter to the complex impedance of each RFID chip through each matching network. The matching network is designed using radio frequency simulation software. Furthermore, the integration module integrates each RFID chip, each target SAW filter, the matching network, and the antenna on an FR4 substrate to form each frequency-division multiplexing RFID tag. Each tag corresponds to a different sub-band. Each tag responds to the excitation signal of the reader / writer only within the specified sub-band to achieve frequency-division multiplexing communication.

[0100] The present invention uses an existing RFID tag chip and introduces a passive filtering surface acoustic wave device and a matching network design to ensure that the RFID tag only responds to an excitation signal of a specific frequency. With the help of the SAW filter device, frequency division multiplexing of different tags can be achieved, thereby realizing parallel RFID communication.

[0101] According to a design device 1000 for a frequency division multiplexing radio frequency identification tag provided by the present invention, the filtering antenna matching module 1020 is specifically configured to: Determining parameters of a parallel inductor element in each target SAW filter based on the complex impedance of each RFID chip; the parallel inductor element is used to integrate capacitance and inductance parameters to achieve direct complex impedance matching between each RFID chip and each target SAW filter; the number of matching network elements in the parallel inductor element does not exceed two, and no additional capacitance is required; A zigzag dipole antenna is used as the other end of each target SAW filter; the size of the zigzag dipole antenna is consistent with that of an ordinary RFID antenna, and the zigzag dipole antenna is used to adjust physical parameters so that the impedance of the zigzag dipole antenna matches the complex impedance of the target SAW filter.

[0102] According to a design device 1000 for a frequency division multiplexing radio frequency identification tag provided by the present invention, the filtering antenna selection module 1010 is specifically used to: Determining a minimum value of the target quality factor based on a center frequency range, a target operating frequency band of each of the RFID chips, and the number of preset sub-frequency bands; the target operating frequency band of each of the RFID chips being a sub-frequency band within the center frequency range; Determining a first quality factor corresponding to each of the first surface acoustic wave filters according to the resonant frequencies and communication bandwidths corresponding to a preset number of first surface acoustic wave filters; Each of the first quality factors is compared with a minimum value of the target quality factors, and each of the target surface acoustic wave filters is determined based on first surface acoustic wave filters corresponding to first quality factors greater than the minimum value.

[0103] According to a design device 1000 for a frequency division multiplexing radio frequency identification tag provided by the present invention, the target SAW filter implements bidirectional filtering through a piezoelectric transducer to block radio frequency signals in non-operating frequency bands.

[0104] According to a design device 1000 of a frequency division multiplexing radio frequency identification tag provided by the present invention, the device further includes an interference avoidance module; The interference avoidance module is configured to: Based on the roll-off characteristics of each target SAW filter, each tag sub-band is divided into a working area and a roll-off area; the reader operates within the working area of ​​each tag sub-band to prevent the roll-off area signal from interfering with adjacent frequency bands; Verify the frequency division multiplexing performance of each tag to ensure that the interference suppression between sub-bands is not lower than the preset threshold.

[0105] According to a design device 1000 of a frequency division multiplexing radio frequency identification tag provided by the present invention, the device further includes a testing module; The test module is used to: Testing the communication distance and signal stability of each tag through the reader; The power parameters of each of the tags are adjusted to compensate for the insertion loss.

[0106] Figure 11 An example of a physical structure diagram of an electronic device is shown below. Figure 11 As shown, the electronic device may include: a processor 1110, a communications interface 1120, a memory 1130, and a communication bus 1140, wherein the processor 1110, the communications interface 1120, and the memory 1130 communicate with each other via the communication bus 1140. The processor 1110 may call the logic instructions in the memory 1130 to execute the design method of the frequency division multiplexing radio frequency identification tag, which includes: Acquire multiple frequency division multiplexing RFID chips and determine a target operating frequency band for each of the RFID chips; the target operating frequency band is a sub-band of the multiple sub-bands; Determining target surface acoustic wave filters that meet target quality factors based on the preset number of sub-bands and the target operating frequency band of each RFID chip; the target surface acoustic wave filters (SAW) are frequency-selective antennas; the target quality factor is determined by the resonant frequency and the passband bandwidth; the higher the value of the target quality factor, the greater the number of frequency division multiple access sub-bands that can be divided by the target SAW filter; Directly matching the target SAW filters with the complex impedance of the RFID chips through matching networks designed using radio frequency simulation software. The RFID chips, target SAW filters, matching networks, and antennas are integrated on a glass fiber epoxy resin printed circuit FR4 substrate to form frequency-division multiplexing RFID tags. Each tag corresponds to a different sub-band, and each tag responds to the reader's excitation signal only within the specified sub-band to achieve frequency-division multiplexing communication.

[0107] Furthermore, the logic instructions in the aforementioned memory 1130 can be implemented as software functional units and, when sold or used as independent products, can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product, stored in a storage medium, includes instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a mobile hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0108] On the other hand, the present invention further provides a computer program product, which includes a computer program. The computer program can be stored on a non-transitory computer-readable storage medium. When the computer program is executed by a processor, the computer can perform the design method of the frequency division multiplexing radio frequency identification tag provided by the above methods, which includes: Acquire multiple frequency division multiplexing RFID chips and determine a target operating frequency band for each of the RFID chips; the target operating frequency band is a sub-band among the multiple sub-bands; Determining target surface acoustic wave filters that meet target quality factors based on the preset number of sub-bands and the target operating frequency band of each RFID chip; the target surface acoustic wave filters (SAW) are frequency-selective antennas; the target quality factor is determined by the resonant frequency and the passband bandwidth; the higher the value of the target quality factor, the greater the number of frequency division multiple access sub-bands that can be divided by the target SAW filter; Directly matching the target SAW filters with the complex impedance of the RFID chips through matching networks designed using radio frequency simulation software. The RFID chips, target SAW filters, matching networks, and antennas are integrated on a glass fiber epoxy resin printed circuit FR4 substrate to form frequency-division multiplexing RFID tags. Each tag corresponds to a different sub-band, and each tag responds to the reader's excitation signal only within the specified sub-band to achieve frequency-division multiplexing communication.

[0109] In another aspect, the present invention further provides a non-transitory computer-readable storage medium having a computer program stored thereon. When the computer program is executed by a processor, the method for designing a frequency-division multiplexed radio frequency identification tag provided by the above methods is implemented, the method comprising: Acquire multiple frequency division multiplexing RFID chips and determine a target operating frequency band for each of the RFID chips; the target operating frequency band is a sub-band among the multiple sub-bands; Determining target surface acoustic wave filters that meet target quality factors based on the preset number of sub-bands and the target operating frequency band of each RFID chip; the target surface acoustic wave filters (SAW) are frequency-selective antennas; the target quality factor is determined by the resonant frequency and the passband bandwidth; the higher the value of the target quality factor, the greater the number of frequency division multiple access sub-bands that can be divided by the target SAW filter; Directly matching the target SAW filters with the complex impedance of the RFID chips through matching networks designed using radio frequency simulation software. The RFID chips, target SAW filters, matching networks, and antennas are integrated on a glass fiber epoxy resin printed circuit FR4 substrate to form frequency-division multiplexing RFID tags. Each tag corresponds to a different sub-band, and each tag responds to the reader's excitation signal only within the specified sub-band to achieve frequency-division multiplexing communication.

[0110] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, i.e., they may be located in one location or distributed across multiple network units. Some or all of the modules may be selected based on actual needs to achieve the objectives of the present embodiment. Persons of ordinary skill in the art will be able to understand and implement the present invention without inventive effort.

[0111] Through the above description of the embodiments, those skilled in the art will clearly understand that each embodiment can be implemented using software plus a necessary general-purpose hardware platform, or of course, hardware. Based on this understanding, the essence of the above technical solution, or the portion that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, a magnetic disk, or an optical disk, and includes a number of instructions for causing a computer device (such as a personal computer, server, or network device) to execute the methods described in each embodiment or certain portions of the embodiments.

[0112] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A design method for a frequency division multiplexing radio frequency identification tag, characterized in that: include: Acquire multiple frequency division multiplexing RFID chips and determine a target operating frequency band for each of the RFID chips; the target operating frequency band is a sub-band among multiple sub-bands; Determining target surface acoustic wave filters that meet target quality factors based on the preset number of sub-bands and the target operating frequency band of each RFID chip; the target surface acoustic wave filters (SAW) are frequency-selective antennas; the target quality factor is determined by the resonant frequency and the passband bandwidth; the higher the value of the target quality factor, the greater the number of frequency division multiple access sub-bands that can be divided by the target SAW filter; Directly matching the target SAW filters with the complex impedance of the RFID chips through matching networks designed using radio frequency simulation software. The RFID chips, target SAW filters, matching networks, and antennas are integrated on a glass fiber epoxy resin printed circuit FR4 substrate to form frequency-division multiplexing RFID tags. Each tag corresponds to a different sub-band, and each tag responds to the reader's excitation signal only within the specified sub-band to achieve frequency-division multiplexing communication.

2. The design method of a frequency division multiplexing radio frequency identification tag according to claim 1, characterized in that: The target SAW filters are directly matched to the complex impedances of the RFID chips through matching networks; the matching networks are designed using radio frequency simulation software and include: Determining parameters of a parallel inductor element in each target SAW filter based on the complex impedance of each RFID chip; the parallel inductor element is used to integrate capacitance and inductance parameters to achieve direct complex impedance matching between each RFID chip and each target SAW filter; the number of matching network elements in the parallel inductor element does not exceed two, and no additional capacitance is required; A zigzag dipole antenna is used as the other end of each target SAW filter; the size of the zigzag dipole antenna is consistent with that of an ordinary RFID antenna, and the zigzag dipole antenna is used to adjust physical parameters so that the impedance of the zigzag dipole antenna matches the complex impedance of the target SAW filter.

3. The design method of a frequency division multiplexing radio frequency identification tag according to claim 1, characterized in that: Determining each target surface acoustic wave filter that meets the target quality factor according to the preset number of sub-bands and the target operating frequency band of each RFID chip: Determining a minimum value of the target quality factor based on a center frequency range, a target operating frequency band of each of the RFID chips, and the number of preset sub-frequency bands; the target operating frequency band of each of the RFID chips being a sub-frequency band within the center frequency range; Determining a first quality factor corresponding to each of the first surface acoustic wave filters according to the resonant frequencies and communication bandwidths corresponding to a preset number of first surface acoustic wave filters; Each of the first quality factors is compared with a minimum value of the target quality factors, and each of the target surface acoustic wave filters is determined based on first surface acoustic wave filters corresponding to first quality factors greater than the minimum value.

4. The design method of a frequency division multiplexing radio frequency identification tag according to claim 1, characterized in that: The target SAW filter implements bidirectional filtering through a piezoelectric transducer to block radio frequency signals in non-operating frequency bands.

5. The design method of a frequency division multiplexing radio frequency identification tag according to claim 1, characterized in that: The method further comprises: Based on the roll-off characteristics of each target SAW filter, each tag sub-band is divided into a working area and a roll-off area; the reader operates within the working area of ​​each tag sub-band to prevent the roll-off area signal from interfering with adjacent frequency bands; Verify the frequency division multiplexing performance of each tag to ensure that the interference suppression between sub-bands is not lower than the preset threshold.

6. The method for designing a frequency division multiplexing radio frequency identification tag according to claim 1, wherein: The method further comprises: Testing the communication distance and signal stability of each tag through the reader; The power parameters of each of the tags are adjusted to compensate for the insertion loss.

7. A design device for a frequency division multiplexing radio frequency identification tag, characterized in that: include: A filter antenna selection module is used to obtain multiple frequency division multiplexing RFID chips and determine a target operating frequency band for each of the RFID chips; the target operating frequency band is a sub-band of the multiple sub-bands; Determining target surface acoustic wave filters that meet target quality factors based on the number of preset sub-bands and the target operating frequency band of each RFID chip; the target surface acoustic wave filters are frequency-selective antennas; the target quality factor is determined by the resonant frequency and the passband bandwidth, and the higher the value of the target quality factor, the more frequency division multiple access sub-bands the target surface acoustic wave filter can be divided into; A filter antenna matching module, configured to directly match the target SAW filters to the complex impedance of the RFID chips through matching networks designed using radio frequency simulation software. An integrated module is used to integrate each of the RFID chips, each of the target SAW filters, the matching network, and the antenna on a glass fiber epoxy resin printed circuit FR4 substrate to form frequency-division multiplexing RFID tags; each tag corresponds to a different sub-band, and each tag responds to the reader's excitation signal only within the specified sub-band to achieve frequency-division multiplexing communication.

8. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the method for designing a frequency division multiplexing radio frequency identification tag according to any one of claims 1 to 6 is implemented.

9. A non-transitory computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the method for designing a frequency division multiplexing radio frequency identification tag according to any one of claims 1 to 6 is implemented.

10. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the method for designing a frequency division multiplexing radio frequency identification tag according to any one of claims 1 to 6 is implemented.

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