KR100820545B1 - RFID antennas and RDF tags - Google Patents

Abstract

The present invention provides an RFID antenna and an RFID tag having the same.

RFID antenna according to an embodiment of the present invention is a plate-shaped first conductor made of a polygon; A second conductor formed side by side with the same size as the first conductor; Third and fourth conductors formed on one side of the first and second conductors; It includes a slot formed between the first to fourth conductors.

RFID tag according to the present invention comprises a plurality of conductors formed in the shape of a polygonal plate and an RFID antenna having a cross-shaped open slot formed between the conductors; An IC chip is connected between two conductors connected to two center conductors of the RFID antenna.

Description

Rfid antenna and rfid tag {RFID antenna and RFID tag}

1 is a block diagram showing a conventional RFID tag.

2 is a diagram illustrating an RFID tag according to an embodiment of the present invention.

3 is a view showing the surface current flow of the RFID antenna according to an embodiment of the present invention.

4 is a view showing an antenna of another shape of the RFID tag according to an embodiment of the present invention.

5 is a diagram illustrating a current distribution in an RFID tag according to an embodiment of the present invention.

6 is a view showing a radiation pattern of the RFID antenna according to the embodiment of the present invention.

7 is a view showing the E plane of the RFID antenna according to the embodiment of the present invention.

8 is a view showing the H plane of the RFID antenna according to the embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100,200: RFID tag 101,201: support

110,210: IC chip 120,220: antenna

121,123,125,126,221,223,225,226: Conductor

127,128,227,228: slots

The present invention relates to a radio frequency identification (RFID) antenna and an RFID tag.

In general, radio frequency identification (RFID) is a technology for non-contact recognition or recording of a tag's information using radio frequency. It recognizes and tracks a tagged object, animal, or person. , Technology that can be managed. Such an RFID system has a unique identification information and includes a tag (tag or transponder) attached to an object or animal, and a reader (reader or interrogator) for reading or recording the identification information of the tag. The RFID system is being developed with RFID / USN (Ubiquitous Sensor Network) technology in combination with a sensor.

In addition, RFID tags are used in various frequency bands such as low frequency (125 kHz and 135 kHz), high frequency (13.56 MHz), ultra high frequency (433 MHz, 860 to 960 MHz), and microwave (2.45 GHz). Here, most countries require the use of readers operating at different carrier frequencies in consideration of the interference with wireless communication to suit the situation of the country.

1 is a diagram illustrating a conventional radio frequency identification tag.

Referring to FIG. 1, the RFID tag 10 includes an IC chip 20 and an antenna 30. The IC chip 20 includes an RF transmission / reception circuit, a control logic, a memory, and the antenna 30. Transmit and receive radio frequency through.

The RFID tag 10 reflects a signal of an ultra high frequency (UHF) band transmitted from a reader (not shown) and modulates information including identification information in the reflected RF signal and transmits the information to the reader.

The antenna 30 used for the RFID tag 10 has a form of a dipole antenna printed on a film. That is, the characteristics of the antenna applied to the RFID tag 10 are designed in the form of a radiation pattern of the dipole antenna.

Since the radiation pattern of the RFID antenna 30 has a radiation pattern of a half-wavelength dipole antenna, nulls exist in a specific direction. Accordingly, the recognition rate of the RFID tag is reduced.

The present invention provides an RFID antenna and an RFID tag.

The present invention provides an RFID antenna having a slot of a cross shape and formed in a planar shape and an RFID tag having the same.

The present invention provides an RFID antenna and an RFID tag in which a cross-shaped slot is formed in a flat conductor to guide current flow in up, down, left and right directions.

RFID antenna according to an embodiment of the present invention is a plate-shaped first conductor made of a polygon; A second conductor formed side by side with the same size as the first conductor; Third and fourth conductors formed on one side of the first and second conductors; It includes a slot formed between the first to fourth conductors.

RFID tag according to the present invention comprises a plurality of conductors formed in the shape of a polygonal plate and an RFID antenna having a cross-shaped open slot formed between the conductors; An IC chip is connected between two conductors connected to two center conductors of the RFID antenna.

Hereinafter, with reference to the accompanying drawings as follows.

2 is a block diagram showing an RFID tag according to the present invention, Figure 3 is a surface current distribution diagram of FIG.

2 and 3, the RFID tag 100 includes an antenna 120 including an IC chip 110, four conductors 121, 123, 125, and 126 and cross slots 127, 128, and a support 101 for supporting the RFID antenna. ).

The IC chip 110 has a built-in RF transmission and reception circuit, a control logic and a memory, and transmits and receives radio frequencies through the antenna 120. The IC chip 110 provides identification information recorded through communication with a reader, and may be classified into an active type including an internal power source or a passive type operating by receiving energy from a radio signal of the reader without an internal power source.

The IC chip 110 may be connected to the center portion of the antenna 120 by a wire or flip chip bonding method, and may be connected by another connection method according to an application.

The antenna 120 operates in the UHF band, has a total lambda / 2 size, and emits an isotropic radiation pattern.

The antenna 120 includes conductors 121, 123, 125, and 126 formed in the shape of a polygonal plate on the support 101, and open slots 127, 128. The conductor may include first and second conductors 121 and 123 formed side by side in a rectangular plate structure, and third and fourth conductors 125 and 126 formed on one side (upper or lower side) of the first and second conductors 121 and 123. Include.

Here, the size of the first or second conductors 121 and 123 may be about 2 to 3 times the size of the third and fourth conductors 125 and 126, and the third and fourth conductors 125 and 126 may be square or rectangular. It may be formed into a structure. In addition, the lines of the outer sides of the first to fourth conductors 121, 123, 125, and 126 may be bent.

The slots 127 and 128 are formed with upper and lower slots 127 open between the first and second conductors 121 and 123, and between the first and third conductors 121 and 125 and between the second and fourth conductors 123 and 126. Open left and right slots 128 are formed. That is, the upper and lower slots 127 and the left and right slots 128 are formed in a cross shape, for example, in a cross shape.

In addition, the centers of the first and second conductors 121 and 123 are electrically connected at both ends of the IC chip 110, and the outer side of the first and second conductors 121 and 123 may be electrically connected to the left and right directions of the conductors 121 and 123 based on the portion where the IC chip 110 is connected. Open auxiliary slots 122 and 124 are formed. At this time, the auxiliary slots 122 and 124 guide the current to the first conductor 121 or the second conductor 123 so that the current easily flows in the vertical direction based on the IC chip 110 when the current is supplied.

Referring to FIG. 3, when the current is supplied from the IC chip 110, the current may be formed by the auxiliary slots 122 and 124 formed in the first and second conductors 121 and 123) of the first and second conductors 121 and 123. Induced in the upper and lower portions, the induced current flows in the up and down direction along the upper and lower slots 127 by the coupling effect between the first and second conductors 121 and 123, and the first and third Due to the coupling effect between the conductors 121 and 125 and between the second and fourth conductors 123 and 126, they flow in the left and right directions along the left and right slots 128.

As such, the electric current supplied to the first and second conductors 121 and 123 by the slots 127 and 128 formed in the cross shape flows in the vertical and horizontal directions along the slots 127 and 128, so that the dipole antenna radiation pattern has Since the current is excited to the null portion, it can be radiated in an isotropic pattern.

In addition, each conductor 121, 123, 125, and 126 of the antenna 120 may be implemented in a polygonal plate or a polygonal planar shape on one surface (upper or lower surface) of the support 101, and the support 101 may be formed of a film member or a dielectric. Can be. Here, the film member is, for example, PET film, polyimide (PI), polyethylene naphtharate (PEN), polyvinyl chloride (PVC), paper, acetate, polyester, polyethylene, polypropylene, poly with calcium carbonate Propylene, acrylonitrile butadiene styrene (ABS) or plastics. The selection of the material of the film member may be made of one or two or more of the above materials, or a combination of the above materials, and may be variously changed depending on the application.

In addition, the conductors 121, 123, 125, and 126 may be printed on the upper surface of the support 101 at once by conductive ink, so that mass production is easy and the production cost thereof can be lowered. In addition, a protective cover may be attached on the RFID tag 100.

Here, the widths of the slots 127 and 128 are adjusted to match different impedances according to the company in which the IC chip is manufactured.

4 is an example of another embodiment of an antenna of the RFID tag according to the present invention. This embodiment is the same as the embodiment of FIG. 2, and the lines 231, 232, 233, and 234 of the outer sides of the first to fourth conductors may be bent in the RFID antenna 220. Since the RFID tag 200 and the RFID antenna 220 of FIG. 4 operate in the same manner as in FIG. 2, detailed descriptions thereof will be omitted.

FIG. 5 is a surface current distribution of the RFID antenna of FIG. 4, in which the H field is monitored. Here, the frequency is in the 900MHz band, the phase is 0 degrees.

FIG. 6 is a diagram illustrating a radiation pattern in an RFID antenna (FIG. 4) according to the present invention, and is characterized by an isotropic radiation pattern in a frequency band of 900 MHz.

FIG. 7 illustrates the E plane in the RFID antenna (FIG. 4) according to the present invention, in which the frequency is 900 MHz, the main lobe magnitude is 0.7 dB, and the main lobe direction is 30.0. Degrees.

FIG. 8 shows the H plane in the RFID antenna (FIG. 4) according to the present invention, in which the frequency is 900 MHz, the main lobe size is 0.0 dB, the main lobe direction is 180 degrees, and the angular width is 3 dB. ) Is 160.3 degrees.

The RFID tag of the present invention as described above is a passive or active RFID tag of the UHF band, and by providing an isotropic pattern, it can improve the reliability of the product by minimizing the shadow recognition interval of the RFID tag when communicating with the RFID reader. have.

Although the present invention has been described above with reference to the embodiments, these are only examples and are not intended to limit the present invention, and those skilled in the art to which the present invention pertains may have an abnormality within the scope not departing from the essential characteristics of the present invention. It will be appreciated that various modifications and applications are not illustrated.

For example, each component shown in detail in the embodiment of the present invention may be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

According to the RFID antenna and the RFID tag according to the present invention, by providing an antenna having an isotropic radiation pattern in the RFID tag, it is possible to improve the reliability of the product by eliminating the shadow recognition section of the RFID tag.

In addition, by printing the shape of the RFID antenna in a simple flat form, there is an effect that the production is easy.

In addition, by minimizing the restriction on the installation position of the RFID tag, it is possible to improve the product reliability for the RFID system.

Claims (16)

A plate-shaped first conductor made of a polygon; A second conductor formed side by side with the same size as the first conductor; Third and fourth conductors formed on one side of the first and second conductors; RFID slot comprising a slot formed between the first to fourth conductors. The method of claim 1, And the first and second conductors are formed in a rectangular shape. The method of claim 1, And the third and fourth conductors are formed in a square or rectangular shape. The method of claim 1, The slot is an RFID antenna formed in the cross shape. The method of claim 1, The center of the first and the second conductor RFID antenna including a slot which is open on the other side to induce a current to be supplied flows in the vertical direction. The method of claim 1, RFID antennas, characterized in that the outer sides of the first and second conductors, the third and fourth conductors are bent. The method of claim 1, RFID antenna including a support of an insulating material for supporting the first to fourth conductors. The first and second conductors having a polygonal shape, and the third and fourth conductors formed on one side of the first and second conductors, and an open slot having a cross shape is formed between the first and fourth conductors. A formed RFID antenna; And an IC chip coupled between a first conductor and a second conductor of the RFID antenna. An RFID antenna having a plurality of conductors formed in a polygonal plate shape and an open slot having a cross shape between the conductors; An IC chip connected between two center conductors of the RFID antenna, And the RFID antenna has an isotropic radiation pattern in the UHF band. The method of claim 9, The RFID antenna includes a first conductor and a second conductor of which polygonal ends are connected to both ends of an IC chip at a central portion thereof; An RFID tag comprising a third and fourth conductor formed on one side of the first conductor and the second conductor, the cross-shaped open slot is formed between the first conductor and the fourth conductor. The method of claim 8 or 10, The RFID tag, characterized in that the electric current flows in the vertical direction along the slot formed between the first and second conductors, and flows in the left and right directions by the slot formed between the third and fourth conductors. The method of claim 8 or 10, The first tag and the second conductor RFID tag including an open slot on one side for dividing the first and the second conductor up / down based on the portion of the IC chip connected. The method of claim 8, The RFID antenna has an isotropic radiation pattern in the UHF band. The method of claim 8 or 10, RFID tag including an insulating film or a support of dielectric material formed on the RFID antenna. The method of claim 14, RFID support includes an RFID antenna formed in a printed pattern of conductive ink. The method of claim 8 or 10, And the IC chip is passive or active.

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