Radio frequency identification (RFID) electronic tag capable of changing frequency

Abstract

The utility model provides an RFID electronic tag capable of changing frequency, which comprises a cuboid dielectric ceramic block, an upper electrode and a lower electrode are respectively arranged on the upper surface and the lower surface of the dielectric ceramic block, a resonance body is formed among the upper electrode, the dielectric ceramic block and the lower electrode, the upper electrode is a resonance electrode, and the lower electrode is a resonance electrode. The lower electrode is a reflection ground of the tag antenna; a short-circuit electrode for electrical connection is arranged on one side surface of the dielectric ceramic block, and the upper electrode and the lower electrode are electrically connected with the short-circuit electrode; and a flexible circuit board is arranged at one end, far away from the short-circuit electrode, of the adjacent surface of the short-circuit electrode. The distance between the flexible circuit board on the ceramic edge and the short circuit electrode is adjusted to excite the working wavelength of the antenna electrode on the ceramic, so that the working tag antenna can work in different frequency bands.

Description

Technical Field

[0001] The utility model relates to a frequency-convertible RFID electronic tag. Background Art

[0002] RFID (Radio Frequency Identification) technology, also known as wireless radio frequency identification, is a communication technology that can identify specific targets and read and write related data through radio signals without establishing mechanical or optical contact between the identification system and the specific target. It can be widely used in logistics, medical equipment management, material use, library management, animal identification, production and assembly, etc. RFID systems generally consist of three parts: electronic tags, readers and writers, and application software. Electronic tags are used to store the identity information of the identified objects. The reader and writer communicate wirelessly with the electronic tag, which can realize the writing and reading of data information in the tag, and the application software analyzes and processes the data collected by the reader and writer. The electronic tag is a key component in the entire system, and the performance of the tag antenna largely determines the performance of the tag, including the read and write distance, consistency, etc. The antenna of the electronic tag mainly includes dipole antenna, microstrip antenna, planar inverted F antenna, planar L antenna and other types, which are used in different occasions.

[0003] The existing tag microstrip antennas that can work on metal surfaces are mainly based on microstrip antenna design, but the frequency bandwidth used by the tag microstrip antennas in the prior art is limited, generally 0.5%-2%. In production, it is necessary to produce tag antennas with different working frequency bands to meet different needs to meet different applications. For different application environments, the tag antenna also needs to match the working frequency of the tag antenna according to environmental factors, and then re-confirm and produce the size of the radiation surface, which undoubtedly increases the production cost and cycle of the tag antenna. During the use of the tag, if the working frequency band is changed, it can only be achieved by using two tag antennas. Utility Model Content

[0004] The purpose of the utility model is to address the above-mentioned problems in the existing technology and to propose a frequency-convertible RFID electronic tag. By adjusting the distance between the flexible circuit board and the short-circuit electrode on the ceramic edge, the working wavelength of the antenna electrode on the ceramic can be stimulated, so that the working tag antenna can operate in different frequency bands.

[0005] The purpose of the utility model can be achieved through the following technical solutions: a frequency-convertible RFID electronic tag, comprising a rectangular dielectric ceramic block, an upper electrode and a lower electrode are respectively arranged on the upper surface and the lower surface of the dielectric ceramic block, a resonant body is formed between the upper electrode, the dielectric ceramic block and the lower electrode, the upper electrode is a resonant electrode, and the lower electrode is a reflective ground for the tag antenna;

[0006] A short-circuit electrode for electrical connection is provided on one side of the dielectric ceramic block, and the upper electrode and the lower electrode are both electrically connected to the short-circuit electrode;

[0007] A flexible circuit board is provided on a surface adjacent to the short-circuit electrode and at one end away from the short-circuit electrode.

[0008] Furthermore, the upper electrode is a non-standard quadrilateral.

[0009] Furthermore, the flexible circuit board is adhered to the dielectric ceramic block by adhesive tape.

[0010] Furthermore, an RFID chip is provided on one end of the flexible circuit board away from the short-circuit electrode.

[0011] Furthermore, the upper electrode is close to the electrode edge of the flexible circuit board and is not parallel to the ceramic edge.

[0012] Furthermore, the flexible circuit board includes a first feeding electrode, a second feeding electrode and a chip pad, and the first feeding electrode is close to the upper electrode.

[0013] Furthermore, the dielectric ceramic block is made of microwave dielectric ceramic with a relative dielectric constant of 5-160.

[0014] Compared with the prior art, the advantages of the present application are: by adjusting the distance between the flexible circuit board and the short-circuit electrode on the ceramic edge to achieve the working wavelength of the antenna electrode on the exciting ceramic, the working tag antenna can be made to work in different frequency bands. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of a frequency-changeable RFID electronic tag antenna;

[0016] Figure 2 It is a frequency-convertible RFID tag antenna, and a schematic diagram of a flexible circuit board;

[0017] Figure 3 It is a schematic diagram of the radiation electrode of the RFID electronic tag antenna with variable frequency;

[0018] Figure 4 It is a schematic diagram of the distance between the flexible circuit board and the short-circuit electrode;

[0019] In the figure, 11, dielectric ceramic block; 12, upper electrode; 13, short-circuit electrode; 14, lower electrode; 15, flexible circuit board; 151, adhesive label; 16, RFID chip; 17, first feeding electrode; 18, second feeding electrode; 19, chip pad. DETAILED DESCRIPTION

[0020] The following are specific embodiments of the present invention and the accompanying drawings to further describe the technical solution of the present invention.

[0021] like Figure 1-4 As shown, a frequency-convertible RFID electronic tag comprises a rectangular dielectric ceramic block 11, an upper electrode 12 and a lower electrode 14 are respectively arranged on the upper surface and the lower surface of the dielectric ceramic block 11, a resonant body is formed between the upper electrode 12, the dielectric ceramic block 11 and the lower electrode 14, the upper electrode 12 is a resonant electrode, and the lower electrode 14 is a reflective ground of the tag antenna;

[0022] A short-circuit electrode 13 for electrical connection is provided on one side of the dielectric ceramic block 11, and the upper electrode 12 and the lower electrode 14 are both electrically connected to the short-circuit electrode 13;

[0023] A flexible circuit board 15 is disposed on a surface adjacent to the short-circuit electrode 13 and at one end away from the short-circuit electrode 13 .

[0024] Furthermore, the upper electrode 12 is a non-standard quadrilateral.

[0025] Furthermore, the flexible circuit board 15 is adhered to the dielectric ceramic block 11 by means of a self-adhesive adhesive 151 .

[0026] Furthermore, an RFID chip 16 is provided on one end of the flexible circuit board 15 away from the short-circuit electrode 13. The chip can be H3, H9 of Ali, U8, U8m, U9 of NXP, R6, M730 of Impinj, etc.

[0027] Furthermore, the upper electrode 12 is close to the electrode edge of the flexible circuit board 15 and is not parallel to the ceramic edge.

[0028] Furthermore, the flexible circuit board 15 includes a first feeding electrode 17, a second feeding electrode 18 and a chip pad 19, wherein the first feeding electrode 17 is close to the upper electrode 12. The electrode of the chip pad 19 is determined according to the chip pad 19 or pin of the adopted chip package (such as QFN, DFN, PGA, SOP, etc.) and the mounting method (such as chip bonding technology).

[0029] Furthermore, the dielectric ceramic block 11 is made of microwave dielectric ceramic with a relative dielectric constant of 5-160.

[0030] The dielectric ceramic block 11 is MgO-SiO2-TiO2 series microwave material, SiO2-CaO-B2O3 series microwave material, BaO-ZnO-TiO2 series microwave material and BaO-PbO-Nd2O3-TiO2 series microwave material, or CaO-Li2O-Ln2O3-TiO2 series microwave material, the dielectric ceramic block 11 is 95% Al2O3 series microwave material, 96% Al2O3 series microwave material and 99% Al2O3 series microwave material.

[0031] This tag antenna is designed based on a planar PIFA antenna, so the length of the long side of the upper electrode 12 is related to the lower limit frequency of the tag antenna to be designed. If the lower limit of the design frequency is 0, the length L of the long side is:

[0032]

[0033] Where L is the length of the long side of the upper electrode, is the dielectric constant of the dielectric ceramic block, and c is the speed of light.

[0034] Generally, the frequency range of RFID tags is 860M-930MHz, so the value range of 0 is <860MHz.

[0035] The tag antenna uses the first feeding electrode 17 and the second feeding electrode 18 on the flexible circuit board 15 as feeding electrodes, and the feeding method is coupled feeding;

[0036] The operating frequency of the PIFA antenna is related to the distance between the feeding position and the short circuit edge. If the distance between the flexible circuit board 15 and the short circuit edge is L1, then L-L1 is the operating frequency of the tag antenna. If the operating frequency of the tag is 1, then L-L1 is approximately

[0037]

[0038] By changing the distance L1 between the flexible circuit board 15 and the short circuit edge, the tag antenna can be operated in different frequency bands. When L1 is reduced, the tag operating frequency is reduced, and when L1 is increased, the tag antenna operating frequency is increased.

[0039] The lengths of the first feeding electrode 17 and the second feeding electrode 18 of the flexible circuit board 15 are confirmed by debugging the simulation software. After the lengths are confirmed, there is no need to make multiple versions of materials according to different frequencies. Because the length of the feeding electrode of the flexible circuit board 15 is fixed, when the size of L1 is changed on the side of the dielectric ceramic block 11, the impedance parameters of the tag antenna and the inherent impedance curve of the chip at different frequencies will be inconsistent. Therefore, by making the edge of the upper electrode 12 on one side of the flexible circuit board 15 non-parallel to the flexible circuit board 15, the coupling amount of the coupling feed is pre-adjusted according to the inherent impedance curve of the chip by pre-designing or determining the distance between the edge and the flexible circuit board 15 through simulation software, so as to achieve conjugate matching between the impedance of the tag antenna and the inherent impedance of the chip at different frequencies.

[0040] As attached Figure 3 As shown, for example, the upper electrode 12 is at a certain angle to the edge of the ceramic block, or the edge is at a certain arc change to the edge of the ceramic block, and the impedance change is achieved for different coupling amounts of the upper electrode 12 through the first feeding electrode 17 and the second feeding electrode 18 of the flexible circuit board 15.

[0041] For example, if you need to design a tag antenna with a center frequency of 915MHz, design the electrode size L of the tag antenna according to the frequency of 850MHz. First, determine the size of L1 at a frequency of 915MHz through pre-simulation. Test the actual operating frequency of the tag through network distribution or reader-writer and other related equipment, adjust the value of L1 until the tag antenna works at 915MHz, and record the value of L1, A. Then, by changing the pasting position of the flexible circuit board 15, such as reducing the value of L1, the operating frequency band of the tag antenna can be lowered. After moving a certain range, a tag antenna with a center frequency of 828MHz can be achieved. Measure and record the value of L1 as B. When you need to produce tag antennas of these two frequency bands in the future, you only need to paste the flexible circuit board 15 according to the recorded value A or B to make a tag antenna working at 915MHz or 868MHz.

[0042] The technical solution of the above utility model provides a solution that is significantly different from the prior art to address the technical problem that the prior art solution is too single. The parts not involved in the technical solution of this application are the same as the prior art or can be implemented by using the prior art and will not be described in detail.

[0043] The technical solutions in the above embodiments have clearly and completely described the contents of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of them. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

Claims

1. A frequency-convertible RFID electronic tag, characterized in that: It comprises a rectangular dielectric ceramic block (11), an upper electrode (12) and a lower electrode (14) are respectively arranged on the upper surface and the lower surface of the dielectric ceramic block (11), a resonant body is formed between the upper electrode (12), the dielectric ceramic block (11) and the lower electrode (14), the upper electrode (12) is a resonant electrode, and the lower electrode (14) is a reflective ground of a tag antenna; A short-circuit electrode (13) for electrical connection is provided on one side of the dielectric ceramic block (11), and both the upper electrode (12) and the lower electrode (14) are electrically connected to the short-circuit electrode (13); A flexible circuit board (15) is provided on a surface adjacent to the short-circuit electrode (13) and at one end away from the short-circuit electrode.

2. The frequency-convertible RFID electronic tag according to claim 1, characterized in that: The upper electrode (12) is a non-standard quadrilateral.

3. The frequency-convertible RFID electronic tag according to claim 1, characterized in that: The flexible circuit board (15) is adhered to the dielectric ceramic block (11) by means of a self-adhesive adhesive.

4. The frequency-convertible RFID electronic tag according to claim 3, characterized in that: An RFID chip (16) is provided on one end of the flexible circuit board (15) away from the short-circuit electrode (13).

5. The frequency-convertible RFID electronic tag according to claim 4, characterized in that: The upper electrode (12) is located close to the electrode edge of the flexible circuit board (15) and is not parallel to the ceramic edge.

6. The frequency-convertible RFID electronic tag according to claim 5, characterized in that: The flexible circuit board (15) comprises a first feeding electrode (17), a second feeding electrode (18) and a chip pad (19), wherein the first feeding electrode (17) is close to the upper electrode (12).

7. The frequency-convertible RFID electronic tag according to claim 1, characterized in that: The dielectric ceramic block (11) is made of microwave dielectric ceramic with a relative dielectric constant of 5 to 160.

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