WO2019212070A1 - Empty space-type cavity uhf rfid tag antenna for long-distance recognition, applicable to steel - Google Patents

Abstract

A UHF RFID tag antenna enabling long-distance recognition comprises: a printed circuit board provided with a UHF chip, and an antenna electrode for receiving a UHF-band wireless signal; a dielectric layer attached to the lower surface of the printed circuit board; and a metal thin film layer for forming a cavity structure by simultaneously surrounding the lower and lateral surfaces of the dielectric layer and the lateral surface of the printed circuit board.

Description

[Correction 28.05.2018] according to Rule 26. 피 Caption UHF RFID tag antenna in the form of empty space for long-range recognition applicable to steel

The present invention relates to a HF RFID tag antenna, and more particularly, to a HF RFID tag antenna of a long space recognition blank space applicable to steel.

Information in the tag is transmitted by transmitting a signal of about 1 W from the reader / writer using a UHF band (860 to 960 MHz) radio signal, and returning a response signal to the reader / writer when the signal is received from the tag (tag) side. A radio frequency identification (RFID) system is known that reads a by a reader / writer.

The communication distance also varies depending on the gain of the tag side antenna, the operating voltage of the IC (integrated circuit) chip in the tag, and the surrounding environment, but is generally about 3 m.

RFID (Radio Frequency Identification) system is a technology that recognizes objects using RF wireless communication, and is currently applied in various fields such as inventory management, material distribution, livestock management, and safe food.

RFID (Radio Frequency Identification) is largely composed of a reader system and a tag. The reader system includes a host computer, a reader and a reader antenna. RFID tag consists of RF chip and tag antenna. The passive tag without its own power source operates the RF chip using the signal transmitted from the reader, and transmits the tag information to the reader.

The radiated output of the reader system is limited to 36dBm by the International Standard Organization (ISO) -18000-6, so the tag recognition distance of the general dipole structure is limited. The recognition distance of a typical commercial tag is about 5-6 m. Therefore, if the passive tag is designed to be recognized at a long distance (more than 10m), the antenna structure should be designed as a high gain antenna structure or a structure that increases the gain.

High-gain antenna structures include horn antennas, antenna antennas, and patch antennas, and the gain-enhancing structures include cavity models, meta-materials, and array structures. When the Yagi-Uda antenna is applied to the tag antenna, the recognition distance is about 8m.

The UHF band (840 to 960 MHz) RFID transmits information in a back scattering method using electromagnetic waves in a far field. The general label tag does not operate when subjected to electromagnetic interference from the surrounding environment or when the impedance of the tag chip and the tag antenna are mismatched. Therefore, when the general label tag is attached to the metal, the tag antenna's impedance is changed and mismatched with the chip impedance, so the tag does not operate normally.

That is, when the generic label tag is attached to the metal, parasitic capacitance occurs between the tag antenna and the metal surface. Due to the influence of parasitic capacitance, the tag antenna's impedance is changed and mismatched with the chip's impedance, so the tag does not operate normally. Therefore, the metal tag must be designed with a special structure that is different from the general label tag structure.

In order to solve the above problems, the prior art reference paper (Y.-K. Park, Y. Kim, K. Lee, YC Chung, "Various UHF RFID tag for metallic object," IEEE International Symposium on Antenna and Propagation, pp. 2258-2288, June 2007.) introduced a variety of small metal tags on a PCB, made from a combination of vias, meander lines, and patches. The recognition distance of commercial metal tag is 3 ~ 5m, and it is used in the field of short-range recognition such as notebook and cabinet management.

However, in the case of managing large metals at long distances (5 to 10 m) such as large steel plates, large metal material warehouses, heavy equipment management, commercial metal tags cannot be used at present due to the limitation of recognition distance. Therefore, RFID application in such an environment requires a special tag design that can be recognized over a long distance without significant change in performance even when attached to metal.

The present invention has been proposed to solve the above technical problem, and provides a UHF RFID tag antenna having a cavity structure that can have a high gain even when attached to a metal and can be recognized even at a long distance.

According to an embodiment of the present invention, a border region protruding in an inner surface direction is formed along an edge, and a substrate to which an H electrode chip and an antenna electrode for receiving a radio signal of the H band are attached to an inner surface thereof; And a side metal layer attached to the edge region and simultaneously surrounding side surfaces of the antenna electrode to form a cavity structure.

In addition, the cover metal thin film layer is attached to the inner surface direction of the substrate in contact with the end of the edge region while maintaining a predetermined distance from the antenna electrode; characterized in that it further comprises.

The antenna electrode may further include a left port line 21 connected to a left side of the HFC chip 10; A left antenna line 23 connected to the left port line 21 and extending in a left direction; A left loop line 25 connected to an end of the left antenna line 23 and extending downward; A right port line 31 connected to the right side of the HFC chip 10; A right antenna line 33 connected to the right port line 31 and extending in a right direction; A right loop line 35 connected to an end of the right antenna line 33 and extending downward; A teematline (27A) connecting between the left roof line (25) and the right roof line (35); A left m-loop line 22 connected to the left antenna line 23 and extending downward; A right m-loop line 32 connected to the right antenna line 33 and extending downward; And a mat line 20A connecting between the left m-loop line 22 and the right m-loop line 32.

HF RFID tag antenna according to an embodiment of the present invention,

It is formed of a cavity structure and can have a high gain even if it is attached to a nonmetallic material or a metal material, so that it can be recognized at a long distance.

1 is a block diagram of a HF RFID tag antenna 6 according to an embodiment of the present invention

2, 2A, and 3 are front, side, rear, and perspective views of the HF RFID tag antenna 6 of FIG.

4 is a perspective view of the HF RFID tag antenna 6

5 shows antenna simulation and measured return loss (S | 11 |)

6 illustrates an antenna parameter sweep.

7 illustrates an antenna gain pattern

8 is a diagram illustrating an antenna measurement recognition distance pattern.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art may easily implement the technical idea of the present invention.

RFID is a technology that recognizes an object by attaching the tag to an object and then reading the information of the electronic tag using a radio frequency.

The UHF RFID (860 to 960 MHz) passive tag transmits the information of the tag to the antenna reader by back scattering using electromagnetic waves of the signal transmitted from the reader to the antenna. .

While the recognition distance of a Cavity type UHF band RFID tag antenna is 15m, there is a disadvantage that the material filled in the cavity is not easily produced and easily damaged by using styrofoam.

In the present invention, because the antenna is configured in the antenna cover (Cover) of the PLA material, without the RF board or FR4 board simply configured a cavity structure antenna in the empty space, and using the Higgs-4 chip to extend the recognition distance.

Therefore, there is an advantage that there is no large performance change even if attached to the metal. The present invention describes an antenna design having a recognition distance of 20 m or more measured by the recognition distance LP antenna.

FIG. 1 is a block diagram of a HF RFID tag antenna 6 according to an embodiment of the present invention, and FIGS. 2, 2A and 3 are front views, side views, of the HF RFID tag antenna 6 of FIG. FIG. 4 is a rear view and a perspective view, and FIG. 4 is an actual view of the RF tag tag antenna 6.

The HF RFID tag antenna 6 according to the present embodiment includes only a brief configuration for clearly describing the technical idea to be proposed.

Referring to FIGS. 1 to 4, the HF RFID tag antenna 6 includes a substrate 500, an antenna electrode, a side metal layer 600, and a cover metal thin film layer 700.

Looking at the detailed configuration and main operation of the RF tag tag antenna 6 configured as described above is as follows.

For reference, the cover metal thin film layer 700 may be selectively provided according to an embodiment.

That is, when the H.F. ID tag antenna 6 is attached to the metal material, the metal material itself may play a role of the cover metal thin film layer 700, and thus similar performance may be achieved even if the metal thin film layer 700 is not provided. .

Therefore, the cover metal thin film layer 700 is provided when the HF RFID tag antenna 6 is attached to a nonmetal material (non-ferrous material), reflects the incident signal and returns the signal back to the antenna electrode of the substrate, thereby providing It has a structure that the recognition distance is increased by increasing the size of the arriving signal. The width of the cover metal thin film layer 700 may vary depending on the embodiment.

The dielectric constant of air is 1, and the substrate 500 may use ABS (Acrylonitrile, Butadiene, Styrene) or PLA (Poly Lactic Acid) having a dielectric constant of about 1.1 to 1.5. In this embodiment, a substrate 500 having a dielectric constant of 1.3 is used.

The substrate 500 is formed with an edge region 510 protruding in an inner surface direction along an edge. The HFC chip 10 and an antenna electrode for receiving a radio signal of the HFC band are attached to an inner surface of the substrate 500.

In addition, the side metal layer 600 is attached to the edge region 510 and simultaneously surrounds the side surface of the antenna electrode to form a cavity structure together with the cover metal thin film layer 700.

In addition, the cover metal thin film layer 700 is attached to the inner surface direction of the substrate 500 to contact the end 510 of the edge region while maintaining a predetermined distance from the antenna electrode.

Therefore, the side metal layer 600 and the cover metal thin film layer 700 form a cavity structure, thereby reflecting the incident signal and returning the signal back to the antenna electrode of the substrate 500, thereby preventing the signal reaching the antenna electrode. As the size increases, the recognition distance increases.

In this embodiment, the antenna electrode is attached to the inner surface of the substrate 500, the antenna electrode is formed using a copper tape, and the copper structure is attached to the edge region 510, which is an inner side surface of the substrate 500, to form a cavity structure. Formed.

In the present embodiment, the side metal layer 600 and the cover metal thin film layer 700 are made of a copper metal, but according to the embodiment, a single material of silver, aluminum, gold, platinum, and nickel, or an alloy material containing any one or more thereof. This could be used.

Looking at the antenna electrode formed on the substrate 500 in detail, the antenna electrode,

A left port line 21 connected to the left side of the HFC chip 10,

A left antenna line 23 connected to the left port line 21 and extending in a left direction;

A left loop line 25 connected to an end of the left antenna line 23 and extending downward;

A right port line 31 connected to the right side of the HFC chip 10,

A right antenna line 33 connected to the right port line 31 and extending in a right direction;

A right loop line 35 connected to an end of the right antenna line 33 and extending downward;

A teematline 27A connecting between the left roof line 25 and the right roof line 35,

A left m-loop line 22 connected to the left antenna line 23 and extending downward;

A right m-loop line 32 connected to the right antenna line 33 and extending downward;

And a mat line 20A connecting between the left m-loop line 22 and the right m-loop line 32.

In the present embodiment, the right line and the left line are formed to be symmetrical to each other with the HFC chip 10 interposed therebetween-their lengths and widths are symmetrical to each other, and specific values thereof are shown in Table 1 below.

tmat_w	loop_w	tmat_h	loop_h	gap	ant_L	ant_h	port_w
100 mm	15 mm	2 mm	50 mm	1 mm	15 mm	8 mm	2 mm
ant_w	mloop_w	mloop_h	mat_w	mat_h
47.5mm	5 mm	20 mm	80 mm	8 mm

The HF RFID tag antenna 6 of the embodiment is

A cavity structure is formed using the side metal layer 600 and the cover metal thin film layer 700.

In the present invention, the tag is a tag that can be mainly used at 915MHz and 920MHz in the UHF RFID band, and the size of the inside of the antenna cover is designed to easily configure the cavity structure as 140 x 60 x 10 mm ³ .

In an embodiment of the present invention, the reusable space is easily configured so that the attached steel becomes the bottom surface of the cavity when the empty cavity is attached to the steel by using the copper tape.

The parameters of the antenna are tmat_w = 100mm, loop_w = 15mm, tmat_h = 2mm, loop_h = 50mm, gap = 1mm, ant_L = 15mm, ant_h = 8mm, port_w = 2mm, ant_w = 47.5mm, mloop_w = 5mm, mloop_h = 20mm, mat_w = 80 mm, mat_h = 8 mm.

The designed antenna was simulated by CST's program and the antenna impedance was designed to be conjugated to the impedance of RFID Higgs4 chip.

The design of the antenna of the present invention is characterized by using a cavity structure using a plastic cover made of PLA material and at the same time used for protecting the antenna, and by designing a cavity structure to be formed by attaching a metal tag to mass production. To facilitate.

Previewing the simulation results, the antenna is designed to operate at 915 and 920MHz in the UHF band, the RFID frequency. The reflection coefficient in that band is about -12.86 dB in the simulation and about -17.47 dB in the measurement using the Network Analyzer. 10m with Circular Polarization (CP), and long distance recognition with Linear Polarization (LP) antenna is about 21m.

The RFID chip uses Alien's Higgs-4 Chip on board (COB) chip and is designed so that the antenna impedance is conjugated to the chip's impedance. At 920MHz the chip impedance is Zc = 18.25-j180.34 and at 915MHz Zc = 18.45-j181.31.

5 shows antenna simulation and measured return loss (S | 11 |).

Referring to FIG. 5, a graph showing reflection coefficient magnitudes through simulation of an antenna having a designed empty cavity structure is shown. Simulation results show that the return loss value is -7.48dB at 915Mhz and -12.13dB at 920MHz.

That is, a graph showing the return loss of the antenna measured by the simulation of the antenna and the network analyzer is shown. In this graph, the simulated antenna has a return loss of about -12.6 dB at 970 MHz and an antenna measured with Agilent's E5071B network analyzer at-970 MHz.

6 is a diagram illustrating an antenna parameter sweep.

Referring to FIG. 6, the antenna sweep ant_h was simulated using 2, 5, 8, 10, and 11 parameters to measure the return loss according to the frequency for each value.

ant_h = 5 The simulated antenna was about -12.3dB at the resonant frequency of 920MHz and the antenna was fabricated and measured by Alien's 920MHz ALR-9900-KOR reader. The recognition distance was measured 8m.

In addition, ant_h = 8 simulated antenna is about -12.6dB at the resonant frequency of 970MHz, and the antenna was manufactured by myself and measured by Alien's ALR-9900-KOR reader that can be used at 920MHz. The longest recognition distance was 20.786m.

The reason for this result was that the optimum S | 11 | was obtained when ant_h was 8 due to errors in the bonding glue used in the process of bonding the antenna chip and the adhesion of the copper tape.

7 is a diagram illustrating an antenna gain pattern.

Referring to FIG. 7, the antenna value ant_h = 5 antenna gain patterns. Due to the antenna structure, the beam pattern of the antenna is directed. Expressed numerically, the main lobe gain is 6.43dBi and the main lobe beam width is 123.8 degrees at 3dB at 920MHz. The pattern shape of ant_h = 8 is similar.

8 is a diagram illustrating an antenna measurement recognition distance pattern.

Referring to FIG. 8, two values of Pi and Theta directions were measured using a simulation and a beam pattern with the gain pattern of the actually measured ant_h = 8 antenna.

As a result of the measurement, there is almost no antenna beam pattern in the part attached to the steel, and it can be seen that the recognition distance appears only in the part where the antenna is located. In other words, the recognition distance measured by the LP antenna theta direction recognition distance is as shown in the figure, the produced tag has a recognition distance of 0 to 20.786 m, and the Phi direction recognition distance is produced at 0 degrees to about 20.786 m. I am showing the distance. It came out at least 2.67m at 180 degrees.

 In the present invention, an empty cavity UHF RFID tag in the form of a cavity for long-range recognition applicable to steel is designed. The antenna operates at frequencies 920 and 915 MHz in the UHF band and shows a recognition distance of about 21 m even when attached to steel. The present invention is relatively inexpensive and easy to manufacture by not using unnecessary styrofoam and FR-4 board.

As described above, the HF RFID tag antenna 6 according to an embodiment is a UHF RFID tag antenna that can be recognized at a long distance even when attached to steel or non-ferrous metal.

Manufacturing distance is simple while maintaining long distance. Long distance recognition can be achieved regardless of whether the medium to be tagged is steel or non-ferrous.

The bottom surface of the cavity structure is removed so that the metal body to be attached to the tag antenna can be used as a reflector, and the metal structure is attached to the inside of the edge area of the substrate by the metal tape. Thus, the steel structure itself, which is tagged when a signal enters the front of the tag, can act as part of the cavity structure.

HF RFID tag antenna according to an embodiment of the present invention,

It is formed of a cavity structure and can have a high gain even if it is attached to a nonmetallic material or a metal material, so that it can be recognized at a long distance.

In this embodiment, a UHF band tag capable of long-range recognition that can be attached to an iron cart or pallet for automotive parts logistics is designed. This is to check the movement of the product in real time by managing the information such as basic information, goods receipt, warehousing, inventory, etc. when moving the exported product by recognizing the tag.

In addition, it is possible to increase the recovery rate of carts or pallets that are missed in the recovery of carts or pallets exported with parts overseas, and to recover the customs duties of carts or pallets paid to the exporting country at the time of recovery.

The steel cart or pallet tag of the UHF band is a metal tag that can be recognized at a long distance using a cavity structure, and the cavity antenna has a metal reflector at the rear to extend the recognition distance than a conventional passive tag. The antenna to perform the.

Many companies export their auto parts overseas by including pallets and carts for their export. Pallets and carts are also required to pay customs duties at customs clearance and can be reclaimed when they are recovered overseas. (Article 99 of the Customs Act and Article 27-12 of the Value Added Tax Act).

In fact, most carts and pallets are not high in actual recovery rates because they are often lost locally and are often difficult to be recognized as belonging to the exported company. In addition, it is difficult not only to check the information of many parts of the vehicle, but also to check the position of the product in real time in the process of transportation, goods receipt and delivery of logistics.

The RFID UHF long-range identification tag antenna is attached to the cart or pallet to reduce the loss of cart or pallet, increase the recovery rate, and increase the efficiency of logistics through logistics movement and product management.

As such, those skilled in the art will appreciate that the present invention can be embodied in other specific forms without changing the technical spirit or essential features thereof. Therefore, the above-described embodiments are to be understood as illustrative in all respects and not as restrictive. The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included in the scope of the present invention. do.

Claims (4)

1. A substrate having a border region protruding inwardly along an edge, and having an antenna chip for receiving a radio frequency signal of a HFC chip and a HFC band attached to an inner surface thereof; And

   A side metal layer attached to the edge region to simultaneously surround side surfaces of the antenna electrode to form a cavity structure;

   HF RF tag antenna comprising a.
2. The method of claim 2,

   The HF RFID tag antenna further comprising a cover metal thin film layer attached to an inner surface direction of the substrate and in contact with an end of the edge region and maintaining a predetermined distance from the antenna electrode.
3. The method of claim 1,

   The antenna electrode,

   A left port line 21 connected to the left side of the HFC chip 10;

   A left antenna line 23 connected to the left port line 21 and extending in a left direction;

   A left loop line 25 connected to an end of the left antenna line 23 and extending downward;

   A right port line 31 connected to the right side of the HFC chip 10;

   A right antenna line 33 connected to the right port line 31 and extending in a right direction;

   A right loop line 35 connected to an end of the right antenna line 33 and extending downward;

   A teematline (27A) connecting between the left roof line (25) and the right roof line (35);

   A left m-loop line 22 connected to the left antenna line 23 and extending downward;

   A right m-loop line 32 connected to the right antenna line 33 and extending downward; And

   UHF RFID tag antenna, comprising: a mat line (20A) connecting between the left m-loop line (22) and the right m-loop line (32).
4. The method of claim 2,

   The antenna electrode,

   A left port line 21 connected to the left side of the HFC chip 10;

   A left antenna line 23 connected to the left port line 21 and extending in a left direction;

   A left loop line 25 connected to an end of the left antenna line 23 and extending downward;

   A right port line 31 connected to the right side of the HFC chip 10;

   A right antenna line 33 connected to the right port line 31 and extending in a right direction;

   A right loop line 35 connected to an end of the right antenna line 33 and extending downward;

   A teematline (27A) connecting between the left roof line (25) and the right roof line (35);

   A left m-loop line 22 connected to the left antenna line 23 and extending downward;

   A right m-loop line 32 connected to the right antenna line 33 and extending downward; And

   UHF RFID tag antenna, comprising: a mat line (20A) connecting between the left m-loop line (22) and the right m-loop line (32).

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