A parallel helical dipole antenna base sensor tag and preparation and application thereof

Abstract

The present application belongs to the technical field of functional textiles, and relates to a parallel helical dipole antenna base sensing label yarn and a preparation and application thereof. The sensing label yarn comprises a core yarn and an interconnection body spirally integrated on the surface of the core yarn, and the interconnection body is composed of a conductor I, an RFID chip and a conductor II. In the preparation, first, two conductors are spirally wound to the surface of the core yarn according to a set parallel interval by using a wrapping process to form a helical dipole structure. Then, the RF end and the GND end of the RFID chip are respectively precisely positioned on the outer surface of the middle position of the two conductors by using a microscope up-down alignment system of a flip packaging patch machine device to respectively complete dispensing and flip bonding. After that, the interconnection part is subjected to ultraviolet curing packaging. Finally, relative to the spiral direction of the conductor, an inverse spiral wrapping process is used to coat an outer wrapping yarn on the outside to obtain the product. The present application is applied to monitoring the joint motion state. The present application has the advantages of simple preparation method, fast response speed of the product, high detection sensitivity and wide application range.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of functional textiles, and relates to a parallel spiral dipole antenna-based sensing label yarn as well as preparation and application thereof. BACKGROUND

[0002] In recent years, with the in-depth implementation of the health care strategy and the vigorous development of human-computer interaction industry, human body limb movement monitoring technology has been increasingly valued. However, through in-depth analysis of the existing technology, it is found that there are still four key technical bottlenecks in the technical implementation of the current limb movement monitoring device, which seriously restricts its wide application in the fields of sports health and human-computer interaction: (1) active monitoring device: CN221963612U discloses a knee joint monitoring knee pad device based on flexible sensing, although the patent realizes the multi-modal monitoring function, but it relies on lithium battery power supply, resulting in large device volume (thickness usually exceeds 5mm) and frequent charging (battery life is generally less than 24 hours), which seriously affects the wearing comfort and use convenience; (2) complex wiring: CN107692376A discloses an integrated textile-based stress and strain sensing network for sign language recognition intelligent gloves, which realizes comfortable monitoring of finger movements by using textile-based active flexible sensors and fabric circuits, but it needs fabric circuits to connect each sensor and battery, which is not suitable for continuous monitoring; (3) large volume: patent CN116105779A discloses a full-textile-based self-powered multi-element driving sensing system and its preparation method and application, which realizes a self-powered multi-element sensing system by integrating fabric nanogenerators and supercapacitors, and has high sensitivity, but has the disadvantages of complex structure, large volume, complex sensing signal transmission line, etc., and the wearing experience is not good; (4) difficult to prepare: CN116999055A discloses a wireless passive strain sensing yarn for limb movement state monitoring and its preparation method, the disclosed wireless passive strain sensing yarn for limb movement state monitoring realizes flexibility and long reading distance, but due to its parallel spiral dipole antenna structure and interconnection before wrapping preparation process, it presents significant linear polarization radiation characteristics and complex manufacturing process, which restricts its continuous production.

[0003] Therefore, it is of great significance to study a parallel spiral dipole antenna-based sensing label yarn and its preparation and application, which can not only maintain excellent monitoring performance, but also realize integrated wireless transmission of sensing signals and power signals and continuous large-scale production, while ensuring wearing comfort. SUMMARY

[0004] The purpose of the present application is to solve the problems in the prior art and provide a parallel spiral dipole antenna-based sensing label yarn and its preparation and application.

[0005] To achieve the above-mentioned purpose, the technical solutions adopted by the present application are as follows:

[0006] A parallel helical dipole antenna-based sensing tag yarn comprises a core yarn and an interconnect spirally integrated on the surface of the core yarn, the interconnect being composed of a conductor I, an RFID chip and a conductor II, the RF end and the GND end of the RFID chip (i.e. two antenna connection points of the RFID chip, namely a pair of electrical contacts) being connected to the same length of the conductor I and the conductor II respectively, and the connection points being the middle positions of the conductor I and the conductor II respectively, the conductor I and the conductor II being arranged in parallel, the conductor I and the conductor II both being in a helical structure, the two segments of the conductor I divided by the connection point being in an anti-symmetrical relationship, the two segments of the conductor II divided by the connection point being in an anti-symmetrical relationship, so as to form anti-symmetrical double-arm structures at the RF end and the GND end respectively, namely, two anti-symmetrical helical conductors are extended at the RF end and the GND end of the RFID chip respectively, but the two helical parallel conductors connecting the RF end and the GND end form a symmetrical dipole antenna.

[0007] The sensing principle of the present application is that the anti-symmetrical double-arm parallel helical dipole antenna-based sensing tag yarn in the radio frequency electromagnetic field is strained with the movement of the limbs, and the reflected electromagnetic wave signal strength, phase, frequency and the like are changed accordingly.

[0008] The specific sensing process is that the electromagnetic wave emitted by the reader / writer generates an alternating induced current in the conductor I and the conductor II of the sensing tag yarn to supply power for the RFID sensing system. When the limbs move, the sensing yarn is coformally bent and strained, and this mechanical deformation changes the distribution characteristics of the induced current in the conductor, so as to modulate the energy distribution of the radiated electromagnetic field. This modulation effect is directly reflected on the signal characteristic (such as received signal strength indication, RSSI) change at the receiving end. Since there is a strict functional relationship between the signal characteristic and the vector characteristics (size and direction) of the induced current, and the current characteristics are one-to-one corresponding to the strain degree, the movement state of the limbs and the deformation trajectory of the sensing tag yarn can be inversely solved by analyzing the dynamic change of the signal characteristic. The design realizes high-sensitivity wireless motion monitoring through electromagnetic-mechanical coupling.

[0009] As a preferred technical solution,

[0010] The core yarn is composed of elastic filaments, and the core yarn mainly plays two key roles in the structure: one is to serve as a bearing substrate for the chip, and the other is to provide a fulcrum for the helical winding of the conductor; the use of elastic filaments as the core yarn also endows the sensing tag yarn with good stretchability; the diameter of the core yarn is 0.5-0.9 mm, which has a super large length-diameter ratio, and meets the characteristics of flexibility, light weight, low profile, compact structure and easy invisibility.

[0011] The interconnect is spirally integrated on the surface of the RFID core yarn through a wrapping process or a weaving process.

[0012] The parallel helical dipole antenna based sensing tag yarn as described above, the conductor I is a conductive fiber or a conductive yarn, and the conductor II is a conductive fiber or a conductive yarn.

[0013] The helical length of the conductor I is 12-15 cm, and the helical length of the conductor II is 12-15 cm, and the sensing yarns in the length range can achieve the required reading distance > 5 m.

[0014] The parallel distance d between the conductor I and the conductor II is 0.6-1.1 mm, and the range is determined mainly based on the comprehensive consideration of the chip contact pitch and the interconnection process characteristics: the pitch between the two contacts of the adopted chip is 0.60-0.99 mm, and in the interconnection process, the anisotropic conductive adhesive naturally extends a certain length to achieve effective contact with the contact. Based on the above characteristics, the parallel distance d of the conductor I and the conductor II can be selected within the range of 0.6-1.1 mm.

[0015] The RFID chip is a commercial Flip ultra-high frequency radio frequency chip, which is used to realize individual identification of the monitoring object.

[0016] The parallel helical dipole antenna based sensing tag yarn as described above, the conductor I, the conductor II and the RFID chip are connected through anisotropic conductive adhesive.

[0017] The parallel helical dipole antenna based sensing tag yarn as described above further comprises an outer wrapping yarn, the interconnection body is located between the core yarn and the outer wrapping yarn, and the outer wrapping yarn is used to protect the interconnection body of the sensing tag yarn, so that the conductor I and the conductor II are prevented from being exposed to the air; the outer wrapping yarn is composed of two insulating bodies, the insulating body is a non-conductive filament fiber or a non-conductive yarn, and the two insulating bodies are spirally wound on the surface of the interconnection body in opposite directions.

[0018] The application further provides a preparation method of the parallel helical dipole antenna based sensing tag yarn as described in any one of the above, which comprises the following steps: firstly, two conductors are spirally wound on the surface of the core yarn at a set parallel distance by using a wrapping process to form a helical dipole structure; then, the RF end and the GND end of the RFID chip are respectively precisely positioned on the outer surfaces of the two conductors by using a microscope up-down alignment system of a flip packaging patch machine device, the position deviation is controlled within ±0.01 mm by alignment, and then point gluing (automatic micro-point gluing technology is adopted, a precision needle is used to apply anisotropic conductive adhesive to the chip-wire contact area, and it is ensured that the conductive particles uniformly cover the contact surface) and flip bonding are respectively completed; after bonding, the interconnection part is subjected to ultraviolet curing packaging; finally, relative to the helical direction of the conductor, an outer wrapping yarn is wrapped in the reverse helical direction to obtain the parallel helical dipole antenna based sensing tag yarn.

[0019] The application also provides an application of the parallel helical dipole antenna-based sensing label yarn as described in any of the above, which is applied to monitoring the joint movement state.

[0020] As a preferred technical solution:

[0021] The application of the parallel helical dipole antenna-based sensing label yarn as described above is that the parallel helical dipole antenna-based sensing label yarn is sewn into a cotton sports suit by using the embroidery technology to make a wireless passive arm movement monitoring suit, which is used to monitor the joint movement state.

[0022] The chip of each parallel helical dipole antenna-based sensing label yarn is located at the elbow joint.

[0023] The principle of the application is as follows:

[0024] The parallel helical dipole antenna-based sensing label yarn of the application is a reverse asymmetric double-arm parallel helical dipole antenna-based ultrahigh frequency strain sensing label yarn, which is composed of an interconnecting body, a supporting material (core yarn) and a protective material (outer wrapping yarn). The interconnecting body is connected by a conductor I, an RFID chip and a conductor II, and the conductor I and the conductor II are in a parallel helical shape; the RFID chip is located on the outer surface of the two parallel conductors, and the ideal position is the outer surface of the middle position of the respective axial direction.

[0025] The sensing yarn of the application adopts the reverse asymmetric double-arm parallel helical dipole antenna structure, the RF end and the GND end of the RFID chip are respectively connected to one conductor, and the connection point is the middle position of the conductor, so that the reverse asymmetric double-arm structure is formed at the RF end and the GND end. From the overall structure, the RFID chip of the application is configured with two parallel helical wrapping conductors on each side. The reverse asymmetric double-arm parallel helical dipole antenna structure adopted by the application not only enhances the radiation efficiency of the antenna, but also improves the sensitivity to strain changes, so that the sensing label yarn can effectively change the antenna characteristics when stretched and bent, thereby reflecting the strain state. Compared with the single-arm helical dipole antenna structure of the prior art, the reverse asymmetric double-arm parallel helical dipole antenna structure of the application has a wider bandwidth and a lower input return loss (input return loss S 11 is a parameter representing the signal reflection performance, which refers to the ratio of incident wave power to reflected power. S 11 is smaller, the better the impedance matching is), which can maintain stable transmission of signals in complex deformation environments such as human movement, thereby achieving performance improvement.

[0026] In the preparation method, the present application starts with a wrapping mechanism to prepare an anti-symmetric double-arm parallel spiral dipole antenna structure with a set interval, focuses on the pre-preparation of the antenna structure, and realizes the preparation of a parallel spiral dipole antenna base sensing label yarn with stable structure and reliable performance through an innovative "first forming and then interconnecting" process flow. The prior art such as CN116999055A focuses on the preparation of an interconnecting body, fixes the chip and two pieces of wire in the mold, interconnects and hot-press packages by using anisotropic conductive glue, cuts off the excess flexible end in the middle piece of the interconnecting body, then coats the assembly point between the packaged conductor and the chip with flexible insulating glue, and finally wraps the interconnecting body on the core yarn with a certain wrapping degree, and two non-conductive yarns are wrapped outward. CN116999055A adopts a "first interconnection and then forming" process flow. Since the conductor I, the chip and the conductor II are sequentially connected in the preparation process of the interconnecting body, the first and last connections of the two pieces of antenna conductors are realized through the chip. If the "first forming and then interconnecting" process flow is forcibly adopted, the pre-formed complete spiral structure conductor must be first stripped from the core yarn and then cut off at the middle position, so as to form two pieces of conductors I and II with equal length. This not only increases the workload, but also increases the operation difficulty, even damages the integrity of the spiral structure, causes the performance of the antenna to be damaged, and is not conducive to efficient and high-quality production.

[0027] Advantages:

[0028] (1) The preparation method of the parallel spiral dipole antenna base sensing label yarn of the present application adopts a one-dimensional yarn structure design, realizes the seamless integration of the sensing unit and the textile base through the innovative anti-symmetric double-arm spiral dipole antenna, and is not only beneficial to maintaining the original softness and air permeability of the fabric, but also suitable for dynamic deformation of various sports clothes through the large deformation of the spiral structure, and solves the technical problems of poor wearing comfort and low integration concealment of traditional rigid sensors.

[0029] (2) The preparation method of the parallel spiral dipole antenna base sensing label yarn of the present application adopts an innovative anti-symmetric double-arm spiral structure design, ensures the signal stability in a dynamic environment while maintaining high sensitivity through an optimized electromagnetic-mechanical coupling mechanism, and overcomes the technical difficulty of large strain sensing instability of rigid sensors. The structure design can effectively suppress environmental interference, so as to obtain stable and reliable monitoring signals.

[0030] (3) The preparation method of the parallel spiral dipole antenna-based sensing label yarn of the application, through the innovative double-arm parallel spiral structure design and flip-chip bonding process, realizes near-zero power consumption, long-distance sensing and high integration, and also provides the possibility for continuous and industrialized production, greatly improves the preparation efficiency of the product, provides a new solution for strain monitoring in textiles, and has a wide market application prospect.

[0031] (4) The parallel spiral dipole antenna-based sensing label yarn of the application has the advantages of fast response speed, high detection sensitivity (sensitivity of 0.3 dB / % when the reading distance is 0.5 m), long reading distance (the farthest reading distance is 10 m), and excellent textile integration characteristics. It can be directly embedded in various textiles through conventional textile and garment manufacturing processes, and a new three-in-one technical route of "passive power supply-high efficiency manufacturing-precise monitoring" is established.

[0032] (5) The application of the parallel spiral dipole antenna-based sensing label yarn of the application realizes near-zero power consumption wireless monitoring of the joint movement state of the limb through the corresponding relationship between the strain degree of the sensing label yarn generated by joint movement and the change of the electromagnetic wave energy and the resonant frequency thereof. In actual application, the sensing performance is not affected by the body temperature change of the monitored object. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The preparation process flow chart of the sensing label yarn of the application;

[0034] Figure 2 The preparation process structure schematic diagram of the sensing label yarn of the application;

[0035] Figure 3 The structure schematic diagram of the sensing label yarn of the application;

[0036] Figure 4 The structure schematic diagram of the ultra-high frequency radio frequency tag chip used for the sensing yarn of the application; wherein, RF is a radio frequency pin, NC is a null pin, and GND is a ground wire;

[0037] Figure 5 The input return loss (S 11 ) test diagram of the parallel spiral dipole antenna with a single-arm shaft length of 6.5 cm, 7 cm, 7.5 cm and 8 cm; wherein, the single-arm shaft length is 1 / 2 of the spiral length; the single-arm shaft length of 7 cm corresponds to embodiment 1, and the single-arm shaft length of 7.5 cm corresponds to embodiment 2;

[0038] Figure 6RSSI values of the parallel spiral dipole antenna based sensing tag yarn of Example 1 with arm length L of 7 cm and parallel distance d of 1 mm at different reading distances;

[0039] Figure 7 Stretching cycle test graph of the parallel spiral dipole antenna based sensing tag yarn of Example 1 when stretched by 15%;

[0040] Figure 8 Stretching cycle test graph of the parallel spiral dipole antenna based sensing tag yarn of Example 1 when stretched by 20%;

[0041] Figure 9 RSSI change graph of the parallel spiral dipole antenna based sensing tag yarn of Example 1 when monitoring elbow joint flexion under the influence of different temperatures;

[0042] Figure 10 RSSI change graph of the parallel spiral dipole antenna based sensing tag yarn of Example 1 when monitoring elbow joint flexion under the influence of different humidities;

[0043] Figure 11 S parameters of the spiral dipole antenna of Example 1 and Comparative Example 1 11 Comparison graph;

[0044] Figure 12 Schematic diagram of monitoring elbow joint movement by the parallel spiral dipole antenna based sensing tag yarn prepared in Example 1 of the present application; a represents the sensing tag yarn sewn into clothes in the diagram;

[0045] Figure 13 Corresponding relationship between elbow flexion angle and RSSI of the parallel spiral dipole antenna based sensing tag yarn prepared in Example 1 of the present application when simulating elbow joint flexion of human body;

[0046] Figure 14 S parameters of the parallel spiral dipole antenna under different bending angles of Example 1 11 ;

[0047] Figure 15 RSSI of the sensing yarn under different bending angles of Example 1

[0048] Figure 16 S parameters of the parallel spiral dipole antenna under different elongation rates of Example 1 11 ;

[0049] Wherein, 1 is core yarn, 2-1 is conductor I, 2-2 is conductor II, 3 is RFID chip, 4-1 is outer cover yarn I, and 4-2 is outer cover yarn II. DETAILED DESCRIPTION

[0050] The application will be further described below in connection with specific embodiments. It should be understood that these embodiments are only used to illustrate the application and not used to limit the scope of the application. Furthermore, it should be understood that those skilled in the art can make various modifications or changes to the application after reading the content of the application, and these equivalent forms also fall within the scope defined by the appended claims.

[0051] The performance indicators of the application involve the following test methods:

[0052] RSSI change: the parallel helical dipole antenna-based sensing yarn prepared in the examples or comparative examples is placed on the pearl cotton foam board, and in an open space, the experimenter stretches the sensing yarn to different elongations, uses the reader-writer to transceive electromagnetic waves, and the data processing system automatically outputs RSSI in real time, and calculates the difference between the average value of RSSI at different elongations and the average value of RSSI at no elongation, which is the RSSI change;

[0053] wherein the transmission power of the reader-writer antenna is 30 dBm, and the test frequency band is 860-960 MHz.

[0054] Input return loss S 11 : the helical dipole structure is placed on the pearl cotton foam, the head end of the parallel helical dipole antenna port (i.e. the connection position with the RFID chip) is attached to the test differential clamp (the inner and outer conductors are not connected), the general differential method is used, and the S 11 , S 12 , S 21 , S 22 parameters of the antenna under the condition of 50Ω matching are collected by the vector network analyzer; then the antenna impedance is calculated according to the formula , and finally the S 11 return loss value and the resonant frequency when the helical dipole structure and the RFID chip achieve impedance matching are determined; wherein, = 50Ω, S 11 is the input return loss, S 12 is the reverse transmission coefficient, S 21 is the forward transmission coefficient, and S 22 is the output return loss.

[0055] Stretching cycle test: the two ends of the parallel helical dipole antenna-based sensing yarn prepared in the examples or comparative examples are clamped on the single-axis stretching cycle test table, the initial length and the stretching length are set, the residence time is 5 s, the cycle number is 100 times, the reader-writer is used to transceive electromagnetic waves, and the data processing system automatically outputs RSSI in real time, and the difference between the maximum value and the minimum value of RSSI in each cycle is calculated to determine the change value to determine the cycle stability.

[0056] The transmitting power of the reader antenna is 30dBm, and the test frequency band is 860-960MHz.

[0057] In the embodiments and the comparative examples of the present application, the two conductors are both copper wire enameled wires, and each of the copper wire enameled wires is coated with an insulating layer.

[0058] The ultraviolet-curable polyurethane acrylate used in the embodiments of the present application is self-prepared, and the preparation process is as follows: polyurethane acrylate resin (Chengdu Light Polymer Material Technology Co., Ltd., R96), tripropylene glycol diacrylate (TPGDA), ethoxylated trimethylolpropane triacrylate (EO3-TMPTA), 2-hydroxy-2-methyl-1-phenylpropanone (photoinitiator 1173), propyltrimethoxysilane (coupling agent KH560), and an analytical grade defoaming agent (BYK Co., Ltd., BYK-065) are added into a reaction container in the proportions shown in Table 1 below, and the ultraviolet-curable polyurethane acrylate is prepared by continuously stirring at 50℃ for 30min.

[0059] Table 1

[0060] Ingredient Ratio (wt%) R96 48 TMPTA 20 TPGDA 20 1173 10 KH-560 1.5 BYK-065 0.5

[0061] Example 1

[0062] A preparation method of a double-arm parallel helical dipole antenna base sensing label yarn, and the specific steps are as follows:

[0063] (1) Material preparation;

[0064] Core yarn: spandex, manufacturer is Zhuji City Man Yue Chemical Fiber Factory, brand PU1680, specification is 1680D, diameter is 0.66mm;

[0065] Conductor I: copper wire enameled wire, manufacturer is Baixin Copper Industry (Shenzhen) Co., Ltd., brand TW0060, the copper wire enameled wire is coated with an insulating layer, the insulating layer is polyurethane, and the diameter is 0.06mm;

[0066] Conductor II: copper wire enameled wire, manufacturer is Baixin Copper Industry (Shenzhen) Co., Ltd., brand TW0060, the copper wire enameled wire is coated with an insulating layer, the insulating layer is polyurethane, and the diameter is 0.06mm;

[0067] RFID chip: commercial Alien Higgs 4 Flip ultra-high frequency radio frequency chip, impedance is 18.5-j181.3 Ω, and the structure is as shown in Figure 4 .

[0068] Outer wrapping yarn: composed of two insulating bodies, the insulating bodies are spandex multifilament, manufacturer is Zhuji City Man Yue Chemical Fiber Factory, brand PU840, and specification is 840D;

[0069] Anisotropic conductive adhesive: DELO, AC268;

[0070] Encapsulation material: UV-curable polyurethane acrylate;

[0071] (2) To wrap;

[0072] Two conductors are spirally wound onto the surface of the core yarn at a set parallel spacing using a wrapping process to form a spiral dipole structure.

[0073] The parallel spacing d between conductor I and conductor II is 1 mm;

[0074] (3) Alignment;

[0075] Using a flip-chip mounting machine, the RF and GND terminals of the RFID chip are precisely positioned on the outer surfaces of two conductors using its microscope alignment system.

[0076] (4) Applying adhesive;

[0077] The automated micro-dispensing technology uses a precision needle to apply anisotropic conductive adhesive to the chip-wire contact area to complete the dispensing operation.

[0078] (5) Inverted bonding;

[0079] The chip is flip-chip positioned using a vacuum nozzle; thermoforming is performed using an electronic tag flip-chip bonding machine.

[0080] The process parameters are: upper temperature: 120 ℃; lower temperature: 100 ℃; pressurization time: 5 s; pressure: 5 N;

[0081] (6) Packaging;

[0082] After bonding, the interconnects are encapsulated by UV curing for 10 seconds; the encapsulation material is polyurethane acrylate.

[0083] (7) Outsourcing;

[0084] Relative to the helical direction of the conductor, an outer wrapping yarn is applied using a reverse helical wrapping process, with a wrapping density of 20±2 turns / cm, to produce a double-arm parallel helical dipole antenna base sensing tag yarn.

[0085] like Figure 3As shown, the finally prepared double-arm parallel helical dipole antenna base sensing label yarn is composed of core yarn 1, interconnects integrated on the surface of core yarn 1 by wrapping process, and outer wrapping yarn, the interconnects are located between the core yarn 1 and the outer wrapping yarn; the outer wrapping yarn is composed of outer wrapping yarn I 4-1 and outer wrapping yarn II 4-2; 2 insulators are spirally wound on the surface of the interconnects, and the spiral directions are opposite; the interconnects are composed of conductor I 2-1, RFID chip 3 and conductor II 2-2, the RF end and the GND end of the RFID chip 3 are connected with the conductor I 2-1 and the conductor II 2-2 respectively, and the connection points are respectively the middle positions of the conductor I 2-1 and the conductor II 2-2, the conductor I 2-1 and the conductor II 2-2 are arranged in parallel, the conductor I 2-1 and the conductor II 2-2 are both in spiral structure, the two segments of the conductor I 2-1 divided by the connection point are in anti-symmetry relationship, the two segments of the conductor II 2-2 divided by the connection point are in anti-symmetry relationship; the spiral length of the conductor I 2-1 is 14 cm, the spiral length of the conductor II 2-2 is 14 cm; the spiral radius r is 0.33 mm; the conductor I 2-1, the conductor II 2-2 and the RFID chip 3 are connected by anisotropic conductive adhesive. The frequency band of the resonance point of the parallel helical dipole antenna under the structure parameters is 939 MHz, S 11 -21.1 dB.

[0086] As Figure 5 shown, when the single-arm axial length is 7 cm, 7.5 cm, and 8 cm, the resonance point of the parallel helical dipole antenna falls within the target frequency band (860 MHz~960 MHz). According to the miniaturization principle, the structure with the single-arm axial length of 7 cm is selected. Through the antenna port impedance test of the above-mentioned anti-symmetric double-arm parallel helical dipole antenna with the single-arm axial length L of 7 cm and the parallel distance d of 1 mm during the stretching process, the stretching elongation range is 0~50%, and the step is 5%, as Figure 16 shown, the real-time pitch, spiral radius and single-arm axial length of the parallel helical dipole antenna all change during the stretching process, and the impedance changes significantly. From the shift of the resonance frequency, it can be known that with the increase of the elongation ratio, the resonance point shifts to low frequency, and the input return loss increases.

[0087] For the ultra-high frequency radio frequency sensing label yarn, the reading distance refers to the maximum distance between the label yarn and the reader that can effectively communicate, and is one of the key indicators for evaluating the performance of the RFID sensing yarn. As Figure 6As shown in the figure, the anti-symmetrical double-arm helical dipole antenna-based sensing tag yarn with the single-arm axis length L of 7 cm and the parallel distance d of 1 mm between the conductor I and the conductor II is placed in front of the reader-writer, and the distance is slowly increased until it cannot be read. The maximum reading distance of the sensing yarn is 10 m, which meets the required reading distance (> 5 m) of the general limb joint motion monitoring sensing tag yarn. During the process of increasing the reading distance, the received signal strength RSSI of the sensing tag yarn first rapidly decreases and then tends to be flat, and the overall trend is a downward trend, and the RSSI value is 71-53 dBm.

[0088] As shown in the figure, Figure 7~8 The parallel helical dipole antenna-based sensing tag yarn of Example 1 with the single-arm axis length L of 7 cm and the parallel distance d of 1 mm is subjected to a tensile cycle test, and the tensile deformation process is 0-15%-0, 0-20%-0, respectively. The test is performed 10 times, and each time is kept for 5 s. The test results show that the sensing tag yarn is sensitive to strain, and the RSSI value changes significantly during the tensile strain process. At the same time, the fluctuation of the signal value is still stable under multiple cyclic stretching, which shows excellent tensile cycle stability.

[0089] Considering that in actual application, the change of human body temperature and the increase of sweat secretion humidity may affect the sensing performance of the sensing tag yarn, the temperature and humidity influence test is performed on the parallel helical dipole antenna-based sensing tag yarn with the single-arm axis length L of 7 cm and the parallel distance d of 1 mm. As shown in the figure, Figure 9 As shown in the figure, the sample is heated from the ambient temperature 23℃ to the set temperature 50℃ by an infrared heating lamp. It can be found that when the temperature changes in the range of 25-50℃, the RSSI value of the sensing tag yarn does not change, which shows that the sensing tag yarn is not sensitive to temperature change. As shown in the figure, Figure 10 As shown in the figure, the ambient humidity is increased from the initial value (45% RH) to 100% RH (relative humidity) by a humidifier, and the humidification is stopped after the target humidity is reached. It can be found that under smaller humidity, the RSSI value of the sensing tag yarn does not change obviously, when the humidity is larger (water droplet shape), the RSSI value drops sharply, and then the water evaporates, and the RSSI value slowly recovers, that is, the sensing performance of the sensing yarn is greatly affected under larger humidity.

[0090] As shown in the figure, Figure 12 The parallel helical dipole antenna-based sensing tag yarn is sewn into a cotton sports suit by embroidery technology to make a wireless passive arm motion monitoring suit for monitoring the joint motion state. The chip of each parallel helical dipole antenna-based sensing tag yarn is located at the elbow joint.

[0091] As shown in the figure, Figure 13As shown, the parallel spiral dipole antenna-based sensing tag yarn was subjected to a simulated human arm flexion test under the conditions of 23℃ temperature and 45% relative humidity. The arm flexion range was 0~50° with an interval of 5° and the test time was 40 s. The test results showed that as the arm flexion angle increased, the RSSI value gradually decreased from 72 dBm to 52 dBm.

[0092] like Figure 14 As shown, the port impedance of the parallel spiral dipole antenna was tested by bending the sensing tag yarn within the range of 0~180°. The results show that S 11 The CV of the value is 1.03%, indicating good stability of signal reflection loss under different bending angles; the CV of the resonant frequency is 0.285%, indicating a small frequency shift and that the resonant point of the parallel spiral dipole antenna is only slightly affected by bending. This is because the average pitch, spiral radius, and single-arm axial length of the conductor remain unchanged during bending, the impedance does not change significantly, and the magnitudes of the induced current and equivalent current remain almost unchanged, only the directions of the induced current and equivalent current change.

[0093] like Figure 15 As shown, the parallel spiral dipole antenna-based sensing tag yarn was subjected to a bending test. The bending angle ranged from 0 to 180°, with intervals of 10°, and the test time was 50 seconds. As the bending angle increased, the RSSI value remained basically unchanged, with only a fluctuation of 0.84%. This test result is consistent with the antenna port impedance test result.

[0094] Comparative Example 1

[0095] A method for preparing a single-arm spiral dipole antenna-based sensing tag yarn is basically the same as in Example 1, except that it adopts a single-arm spiral dipole structure, namely the structure of CN116999055A, and the connection points of the RF end and GND end of the RFID chip on conductor I and conductor II are one end of conductor I and conductor II, respectively.

[0096] The difference between Comparative Example 1 and Example 1 in terms of preparation method is that the process flow of "forming first and then interconnecting" is replaced by the process flow of "interconnecting first and then forming", that is, the order of step (2) is moved to after step (6), and step (5) is omitted. That is, Example 1 first wraps to form a spiral dipole antenna structure and then interconnects the chip, while Comparative Example 1 first completes the interconnection of the chip and the conductor, then cuts off the excess flexible ends at both ends, and after encapsulation, it is spirally wrapped onto the core yarn, and finally a single-arm spiral dipole antenna base sensing tag yarn is obtained.

[0097] The spiral dipole antenna-based sensing tag yarn is sewn into a cotton sports suit by using embroidery technology to make a wireless passive arm movement monitoring suit for monitoring joint movement state; the chip of each spiral dipole antenna-based sensing tag yarn is located at the elbow joint.

[0098] As shown in Figure 11 , comparing the comparative example 1 and the example 1, it can be found that the process of the example 1 is more convenient and efficient, and the innovation of the spiral dipole structure is realized, and the S 11 of the antenna at the resonance point in the example 1 is lower, and the -10 dBm bandwidth is wider, because the symmetrical design of the spiral structure of the present application makes the current distribution uniform, reduces the reflection to reduce the S 11 ; the electromagnetic coupling between the two conductors produces mutual inductance and distributed capacitance, which can adapt to wider frequency band impedance changes, thereby widening the bandwidth.

[0099] Example 2

[0100] A preparation method of a double-arm parallel spiral dipole antenna-based sensing tag yarn, which is basically the same as example 1, except that the spiral length is changed from 14 cm to 15 cm.

[0101] The finally prepared double-arm parallel spiral dipole antenna-based sensing tag yarn is composed of a core yarn, an interconnector integrated on the surface of the core yarn by a wrapping process, and an outer wrapping yarn; the interconnector is located between the core yarn and the outer wrapping yarn; two insulators are spirally wound on the surface of the interconnector, and the spiral directions are opposite; the interconnector is composed of a conductor I, an RFID chip and a conductor II, the RF end and the GND end of the RFID chip are connected to the conductor I and the conductor II respectively, and the connection points are respectively the middle positions of the conductor I and the conductor II, the conductor I and the conductor II are arranged in parallel, the conductor I and the conductor II are both spiral structures, the two segments of the conductor I divided by the connection point are in an anti-symmetrical relationship, and the two segments of the conductor II divided by the connection point are in an anti-symmetrical relationship; the spiral length of the conductor I is 15 cm, and the spiral length of the conductor II is 15 cm; the spiral radius r is 0.33 mm; the conductor I, the conductor II and the RFID chip are connected by anisotropic conductive adhesive. As shown in Figure 5 , the frequency band of the parallel spiral dipole antenna at the resonance point is 906 MHz, and the S 11 is -21.6 dBm. As shown in Figure 12 , the parallel spiral dipole antenna-based sensing tag yarn is sewn into a cotton sports suit by using embroidery technology to make a wireless passive arm movement monitoring suit for monitoring joint movement state; the chip of each parallel spiral dipole antenna-based sensing tag yarn is located at the elbow joint; the prepared wireless passive arm is monitored for arm flexion movement according to the RSSI change amount, and the RSSI change amount is 71 dBm~54 dBm under the condition of a temperature of 23℃ and a relative humidity of 45%.

[0102] Example 3

[0103] A preparation method of a double-arm parallel spiral dipole antenna-based sensing tag yarn is substantially the same as that in Example 1, except that the core yarn has a brand of PU2160, a specification of 2160D, and a diameter of 0.85 mm.

[0104] The finally prepared double-arm parallel spiral dipole antenna-based sensing tag yarn is composed of a core yarn, an interconnector spirally integrated on the surface of the core yarn by a wrapping process, and an outer wrapping yarn; the interconnector is located between the core yarn and the outer wrapping yarn; two insulators are spirally wound on the surface of the interconnector, and the spiral directions are opposite; the interconnector is composed of a conductor I, an RFID chip, and a conductor II, the RF end and the GND end of the RFID chip are connected to the conductor I and the conductor II respectively, and the connection points are respectively the middle positions of the conductor I and the conductor II, the conductor I and the conductor II are arranged in parallel, the conductor I and the conductor II are both in a spiral structure, the two segments of the conductor I divided by the connection point are in an anti-symmetrical relationship, and the two segments of the conductor II divided by the connection point are in an anti-symmetrical relationship; the spiral length of the conductor I is 15 cm, and the spiral length of the conductor II is 15 cm; the spiral radius r is 0.43 mm; the conductor I, the conductor II, and the RFID chip are connected by anisotropic conductive adhesive. The frequency band of the resonance point of the parallel spiral dipole antenna under the structural parameters is 903 MHz, and the S 11 As shown in FIG. 6, the parallel spiral dipole antenna-based sensing tag yarn is sewn into a cotton sports suit by using the embroidery technology to prepare a wireless passive arm movement monitoring suit for monitoring the joint movement state; the chip of each parallel spiral dipole antenna-based sensing tag yarn is located at the elbow joint; the finally prepared wireless passive arm is used for elbow movement monitoring according to the RSSI change amount, and the RSSI change amount is 72 dBm~56 dBm under the condition of a temperature of 23℃ and a relative humidity of 45%. Figure 12

[0105] Example 4

[0106] A preparation method of a double-arm parallel spiral dipole antenna-based sensing tag yarn is substantially the same as that in Example 1, except that the core yarn has a brand of PU2160, a specification of 2160D, and a diameter of 0.85 mm.

[0107] ​The finally prepared double-arm parallel spiral dipole antenna based sensing tag yarn is composed of a core yarn, an interconnector integrated on the surface of the core yarn by a wrapping process, and an outer wrapping yarn; the interconnector is located between the core yarn and the outer wrapping yarn; two insulators are spirally wound on the surface of the interconnector, and the spiral directions are opposite; the interconnector is composed of a conductor I, an RFID chip, and a conductor II; the RF end and the GND end of the RFID chip are connected to the conductor I and the conductor II respectively, and the connection points are the middle positions of the conductor I and the conductor II respectively; the conductor I and the conductor II are arranged in parallel; the conductor I and the conductor II are both in a spiral structure; the two segments of the conductor I divided by the connection point are in an anti-symmetrical relationship; the two segments of the conductor II divided by the connection point are in an anti-symmetrical relationship; the spiral length of the conductor I is 15 cm, and the spiral length of the conductor II is 15 cm; the spiral radius r is 0.27 mm; the conductor I, the conductor II, and the RFID chip are connected by anisotropic conductive adhesive. The frequency band of the resonance point of the parallel spiral dipole antenna under the structural parameters is 896 MHz, and S 11 -20.3 dBm. As shown in Figure 12 FIG. 6, the parallel spiral dipole antenna based sensing tag yarn is sewn into a cotton sports suit by using embroidery technology to prepare a wireless passive arm motion monitoring suit for monitoring joint motion state; the chip of each parallel spiral dipole antenna based sensing tag yarn is located at the elbow joint; the prepared wireless passive arm is monitored for arm flexion motion according to the RSSI change amount, and the RSSI change amount is 69 dBm~54 dBm under the condition of a temperature of 23℃ and a relative humidity of 45%.

[0108] Example 5

[0109] A preparation method of a double-arm parallel spiral dipole antenna based sensing tag yarn, which is basically the same as that of Example 1, except that the parallel distance d between the conductor I and the conductor II is changed from 1 mm to 0.8 mm.

[0110] The finally prepared double-arm parallel spiral dipole antenna based sensing tag yarn is composed of a core yarn, an interconnector spirally integrated on the surface of the core yarn through a wrapping process, and an outer wrapping yarn; the interconnector is located between the core yarn and the outer wrapping yarn; two insulators are spirally wound on the surface of the interconnector, and the spiral directions are opposite; the interconnector is composed of a conductor I, an RFID chip, and a conductor II; the RF end and the GND end of the RFID chip are connected to the conductor I and the conductor II respectively, and the connection points are respectively the middle positions of the conductor I and the conductor II; the conductor I and the conductor II are arranged in parallel; the conductor I and the conductor II are both in a spiral structure; the two segments of the conductor I divided by the connection point are in an anti-symmetrical relationship; the two segments of the conductor II divided by the connection point are in an anti-symmetrical relationship; the spiral length of the conductor I is 12 cm, and the spiral length of the conductor II is 12 cm; the spiral radius r is 0.33 mm; the conductor I, the conductor II, and the RFID chip are connected through an anisotropic conductive adhesive. The frequency band of the resonance point of the parallel spiral dipole antenna under the structure parameters is 958 MHz, and S 11 -19.8 dBm. As shown in Figure 12 Fig. 6, the parallel spiral dipole antenna based sensing tag yarn is sewn into a cotton sports suit using the embroidery technology to prepare a wireless passive arm motion monitoring suit for monitoring the joint motion state; the chip of each parallel spiral dipole antenna based sensing tag yarn is located at the elbow joint; the prepared wireless passive arm is monitored for arm flexion motion according to the RSSI change amount, and the RSSI change amount is 72 dBm~50 dBm under the condition that the temperature is 23℃ and the relative humidity is 45%.

[0111] Example 6

[0112] A preparation method of a double-arm parallel spiral dipole antenna based sensing tag yarn, and the specific steps are as follows:

[0113] (1) Material preparation;

[0114] Core yarn: spandex, manufacturer is Zhuji City Man Yue Chemical Fiber Factory, brand PU1680, specification is 1680D, diameter is 0.66 mm;

[0115] Conductor I: copper wire enameled wire, manufacturer is Baixin Copper Industry (Shenzhen) Co., Ltd., brand TW0100, the copper wire enameled wire is coated with an insulating layer, the insulating layer is polyurethane, and the diameter is 0.1 mm;

[0116] Conductor II: copper wire enameled wire, manufacturer is Baixin Copper Industry (Shenzhen) Co., Ltd., brand TW0100, the copper wire enameled wire is coated with an insulating layer, the insulating layer is polyurethane, and the diameter is 0.1 mm;

[0117] Wrapping yarn: cotton yarn (manufacturer), specification is 14texx2;

[0118] RFID chip: commercial Alien Higgs 4 Flip ultra-high frequency radio frequency chip, impedance is 18.5-j181.3 Ω;

[0119] Outer wrapping yarn: composed of 2 insulators, the insulator is spandex multifilament, the manufacturer is Zhuji City Man Yue Chemical Fiber Factory, the brand is PU840, and the specification is 840D;

[0120] Anisotropic conductive adhesive: DELO, AC268;

[0121] Encapsulation material: ultraviolet-cured polyurethane acrylate;

[0122] (2) A 6-line unidirectional spiral structure is prepared by using a two-step 12-yarn tube knitting machine, two conductors are spirally wound on the core yarn surface according to the set parallel spacing to form a spiral dipole structure; the parallel spacing d between conductor I and conductor II is 0.6 mm;

[0123] The specific process parameters are as follows: 6 yarn tubes in the same direction of the 12 yarn tube are selected, and an interphase arrangement mode is configured (the yarn tube moves in one direction without forming a knitting structure), among which, No. 4 and No. 10 yarn tubes adopt 0.1 mm copper wire enameled wire, No. 2, No. 6, No. 8 and No. 12 yarn tubes adopt 14 tex*2 cotton yarn (the cotton yarn is spaced in the middle, so that the two copper wires maintain a certain spacing, and also can protect the copper wire from being exposed in the air to produce oxidation), the core yarn is 1680D spandex; the motor speed is 100 r / min, the take-up coefficient is 3.00, and the upper and lower traction ratio is 0.7.

[0124] (3) Positioning;

[0125] Using the inverted packaging paster device, the RF end and the GND end of the RFID chip are respectively precisely positioned on the outer surfaces of the two conductors through the microscope up-down positioning system;

[0126] (4) Dispensing;

[0127] An automatic micro-dispensing technology is adopted, and a precision needle is used to apply anisotropic conductive adhesive to the chip-wire contact area to complete the dispensing operation;

[0128] (5) Flip bonding;

[0129] A vacuum suction nozzle is used to flip and position the chip; an electronic tag flip packaging paster is used to implement thermal compression bonding;

[0130] The process parameters are as follows: upper temperature: 120 ℃; lower temperature: 100 ℃; pressure time: 5 s; pressure: 5 N;

[0131] (6) Packaging;

[0132] After bonding, the interconnection part is subjected to ultraviolet curing for 10s for encapsulation; the encapsulation material is polyurethane acrylate;

[0133] (7) outsourcing;

[0134] With respect to the spiral direction of the conductor, the reverse spiral wrapping process is adopted to wrap the outer wrapping yarn, and the wrapping density is 20±2 turns / cm, thereby obtaining the double-arm parallel spiral dipole antenna-based sensing tag yarn.

[0135] The finally obtained double-arm parallel spiral dipole antenna-based sensing tag yarn is composed of core yarn, interconnection body integrated on the surface of the core yarn through the weaving process, and cotton yarn spaced between the core yarns; the interconnection body is composed of a conductor I, an RFID chip and a conductor II, the RF end and the GND end of the RFID chip are connected to the conductor I and the conductor II respectively, and the connection points are the middle positions of the conductor I and the conductor II respectively, the conductor I and the conductor II are arranged in parallel, the conductor I and the conductor II are both spiral structures, the two segments of the conductor I divided by the connection point are in an anti-symmetrical relationship, and the two segments of the conductor II divided by the connection point are in an anti-symmetrical relationship; the spiral length of the conductor I is 14 cm, and the spiral length of the conductor II is 14 cm; the spiral radius r is 0.33 mm; the conductor I, the conductor II and the RFID chip are connected by anisotropic conductive adhesive. The frequency band of the parallel spiral dipole antenna resonant point under the structure parameters is 886 MHz, and the S 11 The parallel spiral dipole antenna-based sensing tag yarn is sewn into a cotton sports suit by using the embroidery technology to obtain a wireless passive arm movement monitoring suit for monitoring the joint movement state; the chip of each parallel spiral dipole antenna-based sensing tag yarn is located at the elbow joint; the obtained wireless passive arm is monitored for arm flexion movement according to the RSSI change amount, and the RSSI change amount under standard temperature and humidity conditions is 68~52 dBm.

Claims

1. A method for preparing a parallel spiral dipole antenna-based sensing tag yarn, the parallel spiral dipole antenna-based sensing tag yarn comprising a core yarn and an interconnection spirally integrated on the surface of the core yarn, the interconnection being composed of conductor I, an RFID chip, and conductor II, characterized in that: First, a wrapping process is used to spirally wind two conductors onto the core yarn surface at a set parallel spacing to form a spiral dipole structure. Then, a flip-chip bonding machine is used, with its microscope alignment system, to precisely position the RF and GND terminals of the RFID chip onto the outer surfaces of the two conductors, respectively, and to complete the dispensing and flip bonding. After bonding, the interconnection area is encapsulated with ultraviolet light. Finally, a reverse spiral wrapping process is used to wrap the outer yarn relative to the spiral direction of the conductors to produce a parallel spiral dipole antenna base sensor tag yarn. The RF and GND terminals of the RFID chip are connected to conductor I and conductor II respectively, and the connection points are located at the middle of conductor I and conductor II. Conductors I and conductor II are arranged in parallel and both conductor I and conductor II have a spiral structure. The two segments of conductor I divided by the connection point are anti-symmetrical, and the two segments of conductor II divided by the connection point are also anti-symmetrical.

2. The method for preparing a parallel spiral dipole antenna-based sensing tag yarn according to claim 1, characterized in that, The core yarn is composed of elastic filaments; the diameter of the core yarn is 0.5~0.9 mm.

3. The method for preparing a parallel spiral dipole antenna-based sensing tag yarn according to claim 1, characterized in that, The interconnects are spirally integrated onto the surface of the core yarn through a wrapping or braiding process.

4. The method for preparing a parallel spiral dipole antenna-based sensing tag yarn according to claim 1, characterized in that, Conductor I is a conductive fiber or conductive yarn, and conductor II is a conductive fiber or conductive yarn; The helix length of conductor I is 12~15 cm, and the helix length of conductor II is 12~15 cm; The parallel spacing d between conductor I and conductor II is 0.6~1.1 mm; The RFID chip is a commercially available Flip ultra-high frequency radio frequency chip.

5. The method for preparing a parallel spiral dipole antenna-based sensing tag yarn according to claim 1, characterized in that, Conductor I, conductor II, and the RFID chip are connected by anisotropic conductive adhesive.

6. The method for preparing a parallel spiral dipole antenna-based sensing tag yarn according to claim 1, characterized in that, It also includes an outer sheath yarn, with the interconnect located between the core yarn and the outer sheath yarn; the outer sheath yarn consists of two insulators, which are non-conductive filament fibers or non-conductive yarns, and the two insulators are spirally wound on the surface of the interconnect, with the spiral directions being opposite.

7. The application of a parallel spiral dipole antenna-based sensing tag yarn prepared by the preparation method according to any one of claims 1 to 6, characterized in that: It is used to monitor joint movement.

8. The application of the parallel spiral dipole antenna-based sensing tag yarn according to claim 7, characterized in that, Parallel spiral dipole antenna-based sensing tag yarn is sewn into cotton sportswear using embroidery technology to create a wireless passive arm motion monitoring suit for monitoring joint movement status. The chip of each parallel spiral dipole antenna-based sensing tag is located at the elbow joint.

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