KR101194070B1 - Planar Folded Transmission Line Loop Antenna - Google Patents

Abstract

The present invention relates to a flat panel grid transmission line loop antenna. Square shaped printed circuit board; It is formed on the printed circuit board and it is a loop antenna of mesh type mesh structure. It is a diagonal mesh structure of square pattern, and a rectangular and diagonal structure of 45 ° angle of closed loop and monopole antenna structure of copper (Cu). A radiator for wiring a metal body such as a back and radiating radio waves of an RFID reader in an ommi-directional UHF band; And a feed terminal formed at the center of the mesh type mesh structure (a point where electric field = 0) and to which a coaxial cable for feeding is connected, and a mesh type mesh on a printed circuit board. Connect the coaxial cable (feeding line) to the feeding point (feeding point) formed at the center of the square pattern of the loop antenna of the radiator, which is wired with metal such as copper (Cu), and shield the coaxial cable The shield line is connected to the reflector ground by soldering, and the cable terminal (connector) at the end of the power supply coaxial cable is connected to the port of the RFID reader. Therefore, the RFID reader antenna provides the omni-directional radial direction with the RFID tag, thereby reducing the error rate of tag recognition and omitting the omni-directional omni-directional direction to improve the radiation characteristics of the RFID tag recognition. It is effective to increase.

Description

Planar Folded Transmission Line Loop Antenna

The present invention relates to a flat-grid grid transmission line loop antenna, and more specifically, a radiator made of copper wiring is a loop antenna of a mesh type mesh structure having a closed loop and a monopole antenna structure having an angle of 45 °, The coaxial cable is connected to the feeding point formed at the center, and the shield line of the coaxial cable is connected to the reflective ground, and the terminal (connector) of the coaxial cable is connected to the port of the RFID reader. The present invention relates to a flat-grid grid-type transmission line loop antenna for use in a UHF band RFID reader that provides an omnidirectional Near Field Antenna.

RFID (Radio Frequency Identification) technology is an automatic identification and data capture (AIDC) technology applied to ubiquitous computing of RFID / USN rather than simply a barcode replacement technology. tag (electronic tag) 10, attach a RFID tag at a short distance using an RFID reader (RFID reader) to recognize the RF carrier signal for each frequency band, and contactless information about the product or object from the RFID tag (contactless) A technology that manages tag information on a computer by recognizing it as a.

RFID tag includes a small wireless IC chip, memory and antenna, and is usually attached to products, foods, and objects, and embeds the whole process information into a small IC chip in production, product release, distribution, and sale. Based on this, distribution and logistics information is managed by remote server through mobile communication network, internet and satellite communication network.

RFID tags are classified as passive tags without power, active tags with power, or CPU. In a passive RFID system architecture, an RFID reader transmits an RF carrier frequency signal to an RFID tag on a forward link. When the RFID tag receives an RF signal, amplitude modulation or phase modulation is used to return data stored in the RFID tag to the RFID reader via a carrier frequency through a reverse link. The RFID reader demodulates the returned modulated signal to decrypt the RFID tag information and is connected to a server on a PC or the Internet to manage the information.

RFID readers are classified into fixed RFID readers and portable RFID readers. The fixed RFID reader is fixed to doors, checkout counters, production lines, etc., and provides a function of reading or writing the information of the RFID tag. Portable RFID readers support mobility in the form of gun type or handheld.

RFID reader sends RF signal to RFID tag attached to the product, reads the information of the tag by decoding data from RFID tag, and communicates with the application of computer through RFID middleware through communication interface such as TCP / IP, USB, CDMA, etc. It transmits the information and manages the information including the unique number of the product.

The RFID frequency used for the air interface between the RFID reader and the RFID tag uses 125kHz, 135KHz, 13.56MHz, 433MHz, 860 ~ 960MHz, 2.45GHz bands, and the 860 ~ 960MHz band is mainly used for product distribution and logistics. .

125kHz and 135KHz low frequency (LF) band RFID frequency is the oldest technology, recognition distance is less than 60cm, slow recognition speed and not easy to read a lot, mainly access control, security, animal recognition and tracking, task automation, inventory management This is used in the field of inventory asset tracking.

The 13.56 MHz high frequency (HF) band RFID frequency is used in applications such as traffic cards, access control security, and smart cards, which are limited in data storage and weak in metal environments, but require short recognition distances.

The 433.92MHz Ultra High Frequency (UHF) band RFID frequency works only with active RFID tags and is used for defense with a wide recognition distance of 50m to 100m and in the United States for container management.

The 860 to 960 MHz microwave band RFID frequency offers wide recognition and reading distances and fast data transfer rates and is used for distribution and logistics.

The 2.45GHz microwave band RFID frequency is similar to the RFID tag in the 900MHz band with a recognition distance of less than 1m. The small tag size is used for product management and vehicle control.

RFID tag is the most produced product in the domestic market of 13.56MHz, 860 ~ 930MHz frequency band.

RFID      900 MHz (UHF RFID)             13.56 MHz RFID reader Long range recognition (~ 1m)
-Short distance recognition
-Library, parking management, inventory management RFID tag -Logistics, B2B companies use RFID tags for B2C
-Not suitable for ID identification due to security problem by RF leakage -Widely used for ID card of transportation card, financial card, smart card, ID card
-Mobile RFID information service using mobile phone

The Working Group of ISO / IEC / JTC1 / SC31 has already established international standards using RFID usage frequencies of 125 kHz, 135 KHz, 13.56 MHz, 433 MHz, 900 MHz and 2.45 GHz, storing information in RFID-tags, and A standard specification for reading information from RFID readers and transmitting information data to application systems was also established. In addition, EPCglobal uses 900MHz frequency RFID technology to search the product's unique number, production information, and distribution history by attaching EPC codes such as 96bit or 128bit for each product. The international standard is established as ISO / IEC 18000-6 Type-C.

RFID technology for product management is mainly promoted in ISO / IEC / JTC1 / SC31, and in ISO / IEC 15961, 15962 (Encoder, Decoder, Command / Response Unit, Local Memory), 15962 Annexes (Tag Driver and Mapping Rules). Define data protocol between application and RFID reader, define air interface protocol for each frequency between RFID-tag and RFID reader in ISO / IEC 18000 series, ISO / IEC 18000-6 Is pushing EPCglobal's Air Interface protocol, Class1 Gen2, to type C.

While ISO / IEC / JTC1 / SC31 and EPCglobal use RFID tags mainly for distribution and logistics, the Near Field Communication (NFC) Forum, which appeared in 2004, provides wireless communication to provide mobile-based mobile RFID services with RFID readers. Standardization of standards was established, and international standards were established in ISO / IEC 18092,21481.

The NFC (Near Field Communication) Forum provides mobile RFID information service using 13.56MHz RFID frequency band by linking with EPCglobal's distribution logistics field (B2B, B2C) of UHF band 900MHz RFID frequency band.

UHF (Ultra High Frequency) Bandwidth RFID is used in major countries by using the Industrial, Scientific, and Medical (ISM) band of 860-960 MHz as the RFID frequency band, and the occupying bandwidth of one channel is 500 kHz. In Europe, 865-868MHz is used as the RFID frequency band, Australia uses 918-926MHz, 910-914MHz in Korea and 200kHz occupied bandwidth similar to Europe, and Japan uses 950-956MHz. .

The UHF band RFID system uses different radio technology standards in different countries, and in a dense reader environment, since the number of readers is as high as the number of channels, the probability of reader interference is high, thus preventing frequency interference between the RFID reader and RFID-tag. For this purpose, it is recommended to strictly separate the spectral mask on the forward link and to use the Miller sub-carrier method on the reverse link.

1 is a configuration diagram of an RFID system using a passive tag.

The RFID system consists of an RFID-Tag 10, an RFID reader 20, and a host computer 30 that supports the RFID reader 20.

The RFID-tag 10 includes a small IC chip, a memory, and an antenna, and stores ID information, product information, shipping information, production and distribution history information of a product, food, or thing in an electronic memory device.

When the passive tag is used as the RFID-tag 10, the passive tag generates energy by using an electric wave through a radio frequency in a power supply required for the operation of the RFID tag.

In the case of the passive tag, the RFID reader 20 generates energy using radio waves (carrier frequency) in the forward link direction through NFC (Near Field Communication) to the RFID tag attached to the product, and the RFID tag When the RF signal is received, amplitude modulation or phase modulation returns the data stored in the RFID tag to the RFID reader 20 through a carrier frequency through a reverse link. The RFID reader 20 decrypts the returned modulation signal to decrypt the RFID tag information and transmits the decrypted information to the PC 30 or a server on the Internet.

The host computer 30 wired to the RFID reader 20 collects the data recognized from the RFID reader 20 using an RFID middleware, stores the data in the DB, and transfers the information read from the tag to an application. Manage information such as product information, production history and distribution history.

FIG. 2 is a diagram illustrating a conventional near field UHF RFID antenna formed in a circular shape.

Conventional circular UHF RFID antenna includes a radiator (23) for forming a radiation line of a radiator in which a metal body such as copper (Cu) is wired in the form of two rows of circular bands, and radiates radio frequency radio waves of the RFID reader according to the radiation direction; Ground 21 formed on one inner side of the two-row circular strip-shaped radiator formed on the printed circuit board 24 and connected to the ground, and the other side inside the circular strip-shaped radiator formed on the substrate 24. And a feeding terminal 22 for connecting a coaxial cable for feeding power.

Near field UHF band RFID reader antennas formed in the shape of a circular band have a feed terminal biased in one direction and radiate by the coupling effect. In order to distribute the radio waves evenly, the feed point is located in the center and the radio waves are radiated forward from the center of the center so that the radio waves are omni-directional. Purpose.

An object of the present invention for solving the problems of the prior art is a loop antenna of a mesh type mesh structure in a UHF (Ultra High Frequency) RFID reader antenna of the 900MHz band and a closed loop of 45 ° angle and Form a radiation line of copper-wired radiator with a monopole antenna structure, and feed point and coaxial cable formed at the center of the mesh type mesh structure (electric field = 0). The shield line of the coaxial cable is connected to the reflective ground and the terminal of the coaxial cable is connected to the port of the RFID reader to provide omni-directional radiation of the antenna. It is to provide a flat grid grid transmission line loop antenna that directionally improves antenna radiation characteristics.

In order to achieve the object of the present invention, a flat plate grid-type transmission line loop antenna is a square-shaped printed circuit board; It is formed on the printed circuit board and is a loop antenna of a mesh type mesh structure, which forms a grid with a diagonal mesh structure of a square pattern, and a closed loop and a monopole of 45 ° angle in a square shape and a diagonal structure, respectively. A radiator for wiring a metal body such as copper (Cu) as an antenna structure and radiating radio waves of an RFID reader in an UHF band in an ommi-directional manner; And a feed terminal formed at a center of a grid-type transmission line loop antenna having a mesh type mesh structure of the printed circuit board (a point at which electric field = 0) and connected to a feeding coaxial cable. .

A coaxial cable (feeding line) is connected to a feeding part (feeding point) formed at the center of a grid transmission line loop antenna on the printed circuit board, and the shield line of the coaxial cable is a reflector ground ( ground) and soldering.

The end of the power supply coaxial cable further comprises a cable terminal (connector) 36 for connecting with the port of the RFID reader.

In the RFID reader antenna, a feeding type is located at the center of the center in a hybrid form of a spiral structure and a loop intersecting the shape.

The flat grid type transmission line loop antenna according to the present invention is a mesh antenna mesh loop structure in a 900 MHz band UHF RFID tag antenna, and radiates radiated copper wired with a closed loop and monopole antenna structure having a 45 ° angle. Radiation line is formed, power is supplied by connecting coaxial cable with feeding point formed in the center of mesh type mesh structure, and shield line of coaxial cable is reflected ground It is connected to (Ground, Ground), and the terminal (connector) of the coaxial cable is connected to the port of the RFID reader to provide the radial direction of the RFID reader antenna with the RFID tag, thereby reducing the error rate of tag recognition and omitting in all directions Ommi-directionally improve the radiation characteristics of the antenna (radiation features) has the effect of improving the RFID tag recognition quality.

The flat grid type transmission line loop antenna developed by the present invention recognizes tag information more accurately in all directions from RFID tags attached to products within a distance of 1m, and applies RFID / USN technology in the distribution / logistics field of 900 MHz band products. It effectively manages distribution / logistics information including product information and production history for B2C and B2B purposes.

1 is a configuration diagram of an RFID system using a passive tag.
2 is a view showing a conventional circular Near Field UHF RFID antenna.
3 is a planar grid transmission line loop antenna for a near field according to the present invention.
4 is a diagram illustrating a system configuration having a flat grid transmission line loop antenna according to an exemplary embodiment of the present invention.

Hereinafter, with reference to the accompanying drawings, preferred embodiments of the present invention will be described in detail the configuration and operation.

3 is a planar grid transmission line loop antenna according to the present invention.

The structure of the flat lattice transmission line loop antenna for RFID tag of UHF (Ultra High Frequency) band is seen from above.

The flat grid type transmission line loop antenna for a near-field long-range 900MHz UHF band RFID tag according to the present invention includes a rectangular printed circuit board 33; A loop antenna of a mesh type mesh structure formed on the printed circuit board 33 and a closed loop and monopole antenna structure of 45 ° angle in a square shape and a diagonal structure in a diagonal mesh structure in a square pattern. A radiator 32 for wiring a metal body such as copper (Cu) and radiating radio waves of an RFID reader in an UHF band in an ommi-directional manner; And a feed terminal 31 formed at the center of the mesh type mesh structure of the printed circuit board 33 and connected to a coaxial cable for feeding.

Holes are formed at four ends of the upper substrate 33 and the lower substrate 39 used as the printed circuit boards 33 and 39 so as to be connectable with bolts and nuts.

4 is a diagram illustrating a system configuration including a spiral centered cross loop RFID reader antenna for a near-field long range UHF RFID tag according to an exemplary embodiment of the present invention.

A system having a spiral-centered cross-loop RFID reader antenna for a long-distance UHF RFID tag has a mesh type mesh structure on a printed circuit board 33 and a radiator 32 wired with a metal body such as copper (Cu). Connect the coaxial cable (feeding line) 35 to the feeding part (feeding point) 31 formed in the center of the square pattern center of the loop antenna of the loop antenna, and the shield line of the coaxial cable is UHF band. By connecting to the ground (ground) of the reflecting plate 39 reflecting the radio wave of the RFID reader and the solder (34). The cable terminal (connector) 36 at the end of the power feeding coaxial cable is used in connection with the port of the RFID reader 37.

The feature of this structure is that it is a hybrid of the spiral shape and the intersected loop in the RFID reader antenna, and the feeding position is located at the center of the center.

The line of the radiator 32 of the antenna of the RFID reader is UHF band (860 to 960 MHz) through the radiator 32 which is branched and copper-wired in various directions, such as a square shape and a diagonal line, as shown in FIG. RFID tag attached to the product more accurately by providing omni-directional radiation pattern in the center and any direction of antenna radiator in near field of 20 ~ 30cm distance because the radio wave of RFID reader is radiated in various polarization. It can recognize (RFID Tag) and can be used as antenna of RFID reader even in far field within 1m distance.

When using the Near Field Antenna technology of this product to recognize the RFID tag in the 900 MHz band used for product information and distribution / logistics information, the mesh type can be used in all directions without having to read the RFID tag information in a specific direction. type) by omni-directionally radiating radio waves through the radiator line 32 of the RFID reader antenna formed in a mesh structure, thereby reducing tag recognition error and improving the radiation feature of the RFID reader antenna.

The RFID reader antenna thus formed operates as follows.

A carrier frequency signal of a UHF specific band is transmitted to an RFID tag attached to a product by a forward link from an RFID reader antenna in a forward link. When the RFID tag receives an RF signal, the RFID tag returns the data stored in the RFID tag to the RFID reader through a carrier frequency of a specific band in a UHF band through a reverse link.

The RFID reader demodulates the RFID tag information by demodulating the modulated signal returned through the antenna, and uses the RFID middleware as a computer application through a communication interface of a wired network (TCP / IP) or a mobile communication network (CDMA). It is connected to the company to manage distribution / logistics information including product information and production history using RFID for B2C and B2B using RFID / USN technology in the distribution / logistics field.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art without departing from the spirit and scope of the present invention described in the claims In the present invention can be carried out by various modifications or variations.

21: Ground 22: Feeding Terminal
23: radiator 24: printed circuit board
31: Feeding Point 32: Radiator
33: substrate 34: feed cable ground (ground)
35: coaxial cable 36: cable terminal (connector)
37: RFID Reader 39: Reflector

Claims (4)

In the flat grid transmission line loop antenna (Planar Folded Transmission Loop Antenna),
A square printed circuit board 33;
It is formed on the printed circuit board 33, and it is a loop antenna of a mesh type mesh structure. It is a diagonal mesh structure of a square pattern. A radiator 32 for wiring a metal body such as copper (Cu) and radiating radio waves of an RFID reader in a UHF band in an ommi-directional manner; And
A feed terminal 31 formed at the center of the mesh type mesh structure of the printed circuit board 33 and connected to a coaxial cable for feeding;
Flat lattice transmission line loop antenna comprising a. The method of claim 1,
Feed point formed at the center of the square (conter) of the square pattern of the loop antenna of the radiator 32 wired by a metal such as copper (Cu) in a mesh type mesh structure on the printed circuit board 33 and a coaxial cable (feeding line) 35 to the feeding point 31, and a shield line of the coaxial cable is connected to the ground of the reflector 39 reflecting the radio wave of the RFID reader to the UHF band. Flat grid grid transmission line loop antenna, characterized in that connected by soldering (34). The method of claim 1,
The end of the power supply coaxial cable further comprises a cable terminal (connector) (36) for connecting to the port of the RFID reader (37) flat grid type transmission line loop antenna. The method of claim 1,
Flattened grid transmission line loop antenna, characterized in that the position of the feeding (Feeding) is located in the center (Center) in the form of a spiral intersecting the loop shape in the antenna included in the RFID reader.

Images