CN104866894A - Coupling capacitor RFID tag with isolation slot - Google Patents

Abstract

The present invention discloses a coupling capacitor RFID tag with an isolation groove, comprising a first antenna and a second antenna, wherein the distance between the first antenna and the second antenna can be adjusted telescopically; the reading distance is long, and after testing, the reading distance can reach 11-13m; the tag is stretchable, i.e., the length is adjustable, and the tag can be used for a set of packaging with a basically fixed width but an indefinite length, and has great practical value, good antenna performance, a small standing wave ratio, a low return loss, a high gain, and omnidirectionality.

Description

Coupling capacitor RFID tag with isolation slot

technical field

The invention relates to a coupling capacitance RFID tag provided with an isolation groove.

Background technique

At present, radio frequency identification is RFID (Radio Frequency Identification) technology, also known as electronic tags and radio frequency identification. Optical contact communication technology. Commonly used passive RFIDs include low frequency (125k~134.2K), high frequency (13.56Mhz), and ultrahigh frequency (860-960MHz). As an important part of the RFID system, the RFID tag antenna's performance will greatly affect the efficiency and quality of the entire RFID system. The main factors affecting the performance of RFID antennas include antenna size, operating frequency band, impedance and gain. Commonly used RFID antennas often adopt the form of bent-line dipoles, which is convenient for reducing the size of the antenna and processing the antenna. This type of antenna pattern is perpendicular to the antenna surface, so it is attached to the vertical outer surface of the target object when used; when the length of the object changes, the antenna is required to change accordingly, and its gain also changes, so it is necessary to design An antenna that can be changed according to the length. In addition, its various antenna performances also need to meet the requirements.

Contents of the invention

The object of the present invention is to overcome the above-mentioned shortcomings, and provide a coupling capacitance RFID tag provided with isolation grooves.

In order to achieve the above object, the specific scheme of the present invention is as follows: comprising a substrate, and a coupling capacitive RFID tag antenna provided with an isolation groove for insertion on the substrate, a dielectric plate is provided on the second antenna, and a dielectric plate is provided on the dielectric plate. a tag chip, the tag chip is electrically connected to the antenna;

The tag antenna includes a first antenna and a second antenna, and the distance between the first antenna and the second antenna can be adjusted telescopically.

The first antenna includes a strip-shaped first body, one end of the first body is provided with a first booster rod, the free end of the first booster rod is provided with an arc-shaped first booster antenna, and two Coupling grooves, the openings of the two coupling grooves face the other end of the first body, the two coupling grooves are arranged in parallel in the first body, and the upper and lower sides of each coupling groove are provided with serrated grooves; The second antenna includes a second body, the length of the first body is greater than that of the second body, and one end of the second body is provided with a second gain rod, and the free end of the second gain rod is provided with an arc-shaped The second booster antenna also includes two coupling strips arranged at the other end of the second body and matched with the coupling groove, the two coupling strips are arranged in parallel, and the upper and lower sides of each coupling strip are provided with sawtooth grooves The matching saw-toothed protrusions, when mated, the saw-tooth protrusions are located in the saw-tooth grooves;

It also includes a T-shaped adjustment rod, an adjustment notch with an opening facing the first body is provided in the second body, and the horizontal section of the T-shaped adjustment rod is located in the adjustment notch;

Let the distance between the free end of the coupling strip and the inner side of the coupling groove be L, and set the horizontal distance between the free end of the horizontal section of the T-shaped adjustment rod and the inner side of the adjustment notch as M, and the L=M*3.75.

Wherein, one end of the first body is an arc surface, and the arc is the same as that of the first booster antenna.

Wherein, one end of the second body is an arc surface, and the arc is the same as that of the second booster antenna.

Wherein, the radians of the first booster antenna and the second booster antenna are the same, 60°-80°.

Wherein, one side of the first booster antenna is further provided with a third booster rod, and a free end of the third booster rod is provided with a third booster antenna.

Wherein, the curvature of the third gain rod is the same as that of the first gain rod.

Wherein, the height of the first body is less than 10 cm.

Wherein, the first antenna is provided with a strip-shaped isolation slot,

Wherein, the second antenna and the first antenna are provided with frequency increasing notches.

Beneficial effects of the present invention: 1. The reading distance is long, and the reading distance can reach 11-13m after testing. The reading distance of ordinary RFID tag antennas is less than 10m. 2. Stretchable; that is, the length can be adjusted. It can be used for complete packaging with a basically constant width but variable length, and has great practical value. 3. Various antennas have good performance, small standing wave ratio, low return loss, high gain and omnidirectionality. Its performance is high when it is used at ultra-high frequency (860-960MHz), especially at a frequency around 925MHz.

Description of drawings

Fig. 1 is the schematic diagram of tag antenna of the present invention;

Fig. 2 is a schematic diagram of the elongated tag antenna of the present invention;

Fig. 3 is a schematic diagram of the first antenna of the present invention;

Fig. 4 is a schematic diagram of the second antenna of the present invention;

Fig. 5 is a schematic diagram of utilizing the present invention;

Fig. 6 is the impedance test data figure of the present invention;

Fig. 7 is a return loss test data diagram of the present invention;

Fig. 8 is a directional test data diagram of the present invention;

Explanation of reference numerals among Fig. 1 to Fig. 8:

1-first antenna; 11-coupling slot; 12-sawtooth slot; 13-first booster rod; 14-first booster antenna; 15-third booster rod; 16-third booster antenna; 17-isolation slot; 18 - boost notch;

2-Second antenna; 21-Coupling bar; 22-Sawtooth protrusion; 23-Second gain rod; 24-Second gain antenna; 25-Adjustment notch;

3-T-shaped adjustment lever;

4-Medium board;

5-Tag chip;

6- Substrate.

Detailed ways

The present invention will be described in further detail below in conjunction with the accompanying drawings and specific embodiments, and the implementation scope of the present invention is not limited thereto.

As shown in Figures 1 to 8, a coupling capacitive RFID tag antenna with an isolation slot described in this embodiment includes a first antenna 1 and a second antenna 2, the first antenna 1 and the second antenna The distance between the two antennas 2 can be telescopically adjusted. The RFID tag made by it includes a substrate 6, and a coupling capacitive RFID tag antenna which is arranged on the substrate 6 and is provided with an isolation groove. The second antenna 2 is provided with a dielectric plate 4, and the dielectric plate 4 is provided with a label. Chip 5, the tag chip 5 is electrically connected to the antenna.

In the coupling capacitive RFID tag antenna described in this embodiment, the first antenna 1 includes a strip-shaped first body, and one end of the first body is provided with a first gain rod 13. The free end of the first booster rod 13 is provided with an arc-shaped first booster antenna 14, and also includes two coupling slots 11, the openings of the two coupling slots 11 are facing the other end of the first body, and the two coupling slots The grooves 11 are arranged in parallel in the first body, and the upper and lower sides of each coupling groove 11 are provided with serrated grooves 12; the second antenna 2 includes a second body, and the length of the first body is Greater than the second body, one end of the second body is provided with a second booster rod 23, and the free end of the second booster rod 23 is provided with an arc-shaped second booster antenna 24, and also includes two other antennas located on the second body. The coupling bar 21 that matches with the coupling groove 11 at one end, the two coupling bars 21 are arranged in parallel, and the upper and lower sides of each coupling bar 21 are provided with saw-toothed protrusions 22 that match the saw-tooth groove 12. , the sawtooth protrusion 22 is located in the sawtooth groove 12; the coupling capacitive RFID tag antenna described in this embodiment is provided with an isolation groove, and also includes a T-shaped adjustment rod 3, and the inside of the second body There is an adjustment notch 25 with an opening facing the first body, and the horizontal section of the T-shaped adjustment rod 3 is located in the adjustment notch 25; a coupling capacitance RFID tag antenna with an isolation groove inserted in this embodiment , the distance between the free end of the coupling strip 21 and the inner surface of the coupling groove 11 is L, and the horizontal distance between the free end of the horizontal section of the T-shaped adjusting rod 3 and the inner surface of the adjustment notch 25 is M, and the L= M*3.75.

This solution achieves a long reading distance through the above features, and its reading distance can reach 11-13m after testing. The reading distance of ordinary RFID tag antennas is less than 10m. In addition, it can be stretched; that is, the length can be adjusted, and it can be used in a complete set of packaging with a basically constant width but an indeterminate length. Finally, its various antennas have good performance, small standing wave ratio, low return loss, high gain and omnidirectionality. ; Its performance is higher when it is used at a frequency of about 925MHz. In the coupling capacitive RFID tag antenna provided with isolation slots in this embodiment, one end of the first body is an arc-shaped surface, and the arc is the same as that of the first booster antenna 14 . With such setting, the gain performance is further improved, the return loss is reduced, the omnidirectionality of radiation is increased, and the optimization result is better. In the coupling capacitive RFID tag antenna provided with isolation slots in this embodiment, one end of the second body is an arc surface, and the arc is the same as that of the second booster antenna 24 . The same radian can reduce the standing wave formation between the two antennas, reduce wave interference, and reduce the standing wave ratio. In the coupling capacitive RFID tag antenna provided with isolation slots in this embodiment, the arcs of the first booster antenna 14 and the second booster antenna 24 are the same, both being 60°-80°. Through simulation and actual experiments, the performance of the radian antenna is the best.

A coupling capacitive RFID tag antenna that is inserted with an isolation slot described in this embodiment, one side of the first booster antenna 14 is also provided with a third booster rod 15, and the free end of the third booster rod 15 is A third booster antenna 16 is provided; a coupling capacitive RFID tag antenna provided with an isolation slot is inserted in the present embodiment, and the arc of the third booster rod 15 is the same as that of the first gainer rod 13; In this way, the gain performance is further improved, the return loss is reduced, the radiation omnidirectionality is increased, and the optimization result is better.

In the coupling capacitive RFID tag antenna provided with isolation slots in this embodiment, the height of the first body is less than 10 cm. A coupling capacitive RFID tag antenna with isolation slots inserted in this embodiment, said first antenna 1 is provided with strip-shaped isolation slots 17, and said isolation slots 17 are located in two coupling slots Between 11, a kind of coupling capacitive RFID label antenna that is provided with an isolation slot described in this embodiment, the second antenna 2 is close to the two corners of the first antenna 1 side and the first antenna 1 is close to the second Two corners of one side of the antenna 2 are provided with frequency increasing notches 18 . The frequency-increasing notch 18 can increase the isolation, reduce the formation of standing waves, and make the standing wave ratio close to 1. The antenna of this solution also has good performance in omnidirectionality, as shown in FIG. 8 , it has excellent performance in omnidirectionality, and has 360-degree equidistant omnidirectionality with no dead angle. As shown in Figure 7, its return loss performance is outstanding, especially at 925MHz, the minimum value of return loss reaches -65dB, and the return loss in the entire high frequency band remains below -10dB, which exceeds the level of other similar antennas.

According to the test and design, its effective distance can reach 11-13m under different stretching lengths. The test results are as follows:

In addition, the input impedance of the antenna test is shown in Figure 6. The measured impedance is 11+144j ohms at 925MHz, which is conjugate matched with the impedance 11+143j of the chip Monza4 Dura. The label can achieve the best effect at 925MHz.

The above is only a preferred embodiment of the present invention, so all equivalent changes or modifications made according to the structure, features and principles described in the patent application scope of the present invention are included in the protection scope of the patent application of the present invention.

Claims (8)

1. A coupling capacitance RFID tag provided with an isolation groove, characterized in that: it comprises a substrate (6), and a coupling capacitance RFID tag antenna provided with an isolation groove inserted on the substrate (6), the second The antenna (2) is provided with a dielectric board (4), the dielectric board (4) is provided with a label chip (5), and the label chip (5) is electrically connected to the antenna; The tag antenna includes a first antenna (1) and a second antenna (2), and the distance between the first antenna (1) and the second antenna (2) is scalable and adjustable; The first antenna (1) is provided with a strip-shaped isolation slot (17). 2. A coupling capacitive RFID tag with isolation slots according to claim 1, characterized in that: the first antenna (1) includes a strip-shaped first body, and one end of the first body is provided with a second A booster rod (13), the free end of the first gain rod (13) is provided with an arc-shaped first booster antenna (14), and also includes two coupling slots (11), the two coupling slots ( 11) The opening faces the other end of the first body, the two coupling grooves (11) are arranged in parallel in the first body, and the upper and lower sides of each coupling groove (11) are provided with serrated grooves (12 ); the second antenna (2) includes a second body, the length of the first body is greater than the second body, and one end of the second body is provided with a second gain rod (23), the second gain rod The free end of (23) is provided with an arc-shaped second booster antenna (24), and also includes two coupling strips (21) arranged at the other end of the second body to match the coupling groove (11). The coupling strips (21) are arranged in parallel, and the upper and lower sides of each coupling strip (21) are provided with serrated protrusions (22) matching with the serrated grooves (12). When mated, the serrated protrusions ( 22) Located in the sawtooth groove (12); It also includes a T-shaped adjustment rod (3), the second body is provided with an adjustment notch (25) with an opening facing the first body, and the horizontal section of the T-shaped adjustment rod (3) is located in the adjustment notch (25 )Inside; Let the distance between the free end of the coupling strip (21) and the inner side of the coupling groove (11) be L, and set the horizontal distance between the free end of the horizontal section of the T-shaped adjustment rod (3) and the inner side of the adjustment notch (25) is M, the L=M*3.75. 3. A coupling capacitive RFID tag with an isolation slot according to claim 2, characterized in that: one end of the first body is an arc-shaped surface, and the arc is the same as that of the first booster antenna (14) . 4. A coupling capacitive RFID tag with an isolation slot according to claim 2, characterized in that: one end of the second body is an arc-shaped surface, and the arc is the same as that of the second booster antenna (24) . 5. A coupling capacitive RFID tag with an isolation slot according to claim 2, characterized in that: the arc of the first booster antenna (14) and the second booster antenna (24) are the same, both are 60° -80°. 6. A coupling capacitive RFID tag with an isolation slot according to claim 2, characterized in that: a third gain rod (15) is provided on one side of the first booster antenna (14), and the The free end of the third gain rod (15) is provided with a third gain antenna (16). 7. A coupling capacitive RFID tag provided with isolation slots according to claim 6, characterized in that: the arc of the third gain bar (15) is the same as the arc of the first gain bar (13). 8. A coupling capacitive RFID tag provided with isolation slots according to claim 2, characterized in that: the height of the first body is less than 10 cm.