KR100857031B1 - Radio frequency identification reader/writer and rfid system - Google Patents

Abstract

Disclosed are an RFID reader including a linear dual polarization antenna and a radio recognition means, and an RFID system using the same. RFID readers include dual linearly polarized antennas to improve recognition distance and recognition rate, and wireless recognition means are switched between two polarizations, reducing manufacturing costs. In addition, the RFID reader includes an antenna and includes a wireless communication means, and can be freely applied to various systems without establishing a separate transmission line.

Antenna, Radio Reader, Radio Reader, Host, Wireless Communication

Description

RDF reader / writer and RDF system {RADIO FREQUENCY IDENTIFICATION READER / WRITER AND RFID SYSTEM}

1 is a block diagram showing a conventional RFID system.

2 is a side view showing a configuration of an RFID reader according to an embodiment of the present invention.

3 illustrates a power supply circuit of an RFID reader antenna according to an embodiment of the present invention.

4 is a block diagram of radio recognition means of an RFID reader according to one embodiment of the present invention;

5 is a block diagram of radio recognition means of an RFID reader according to another embodiment of the present invention.

6 is a block diagram illustrating an RFID system according to another embodiment of the present invention.

TECHNICAL FIELD The present invention relates to an RFID system, and more particularly, to an RFID system including an RFID reader having a dual polarized antenna and having a wireless communication function.

Recently, RFID (Radio Frequency IDentification) systems have been actively studied. 1 is a block diagram illustrating a general RFID system. The RFID system transmits / receives signals to / from a transponder 110, also called an RF tag, an antenna 120 for transmitting and receiving wireless signals to and from the transponder 110, and an antenna 120. And a reader (and / or lighter) 130 for processing. Reader 130 is also connected to host 140 for transmitting / receiving signals to and from one or more readers and processing signals. The transponder 110 is attached to an object to be identified, such as a product, an automobile, a human body, an animal, and stores data such as identification information of the object and state information of the object. In this manner, the reader 130 transmits electromagnetic waves through the antenna 120 to activate the transponder 110 and read data stored in the transponder 110 or write new data to the transponder 110. . Data is also collected at the host 140 and processed in the required manner.

In a conventional system, the antenna 120 is installed at a position advantageous for reading the transponder 110 and the reader 130 is connected by the antenna 120 and the transmission line 150. Therefore, the signal between the antenna 110 and the reader 130 is attenuated by the transmission line 150, the reader 130 should include a separate amplifier. In addition, when a plurality of antennas 120 are connected to the reader 130, the attenuation degree of the signal is different depending on the length of the transmission line 150, so that the reader 130 may read differently even with the same signal. have. Of course, there is a problem that a separate cost occurs for the installation of the track 150. In addition, since the host 140 is also connected to the reader 130 through the transmission line 160, the same problem as described above may occur between the host 140 and the reader 130.

On the other hand, in the conventional system, the antenna 120 generally uses a circularly polarized antenna. This is because the reading is impossible when the transponder 110 to be read is arranged perpendicular to the antenna polarization when horizontal polarization is used. However, the circularly polarized antenna has a problem in that its gain is low and the recognition distance of the reader 130 is shortened.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an RFID system which can minimize transmission loss between an antenna and a reader and between a reader and a host. In addition, an object of the present invention is to provide an RFID system having an increased recognition distance without using a circularly polarized antenna.

In order to achieve the above object, according to an aspect of the present invention, an antenna having a feed circuit and an antenna radiator connected to the feed circuit, and connected to the antenna via the feed circuit, and from or to the antenna; An RFID reader is provided that includes radio recognition means for processing a signal.

The antenna is a linear dual polarization antenna for transmitting and receiving signals of vertical polarization and horizontal polarization, and preferably includes a first port for the vertical polarization and a second port for the horizontal polarization.

Further, the power supply circuit includes a first power divider for outputting two power supply signals having a phase difference of 90 degrees from a signal from the first port, and two two having a phase difference of 90 degrees from a signal from the second port. A second power divider for outputting a feed signal, wherein a line connecting the points at which the feed signals from the first power divider are fed to the antenna radiator and the feed signals from the second power divider are fed to the antenna radiator It is desirable that the lines connecting the holes are orthogonal.

The antenna radiator is substantially square, the feed signals from the first power divider are fed to the antenna radiator at a symmetrical position within the antenna radiator, and the feed signals from the second power divider are symmetrical within the antenna radiator. It is more preferable to feed the antenna radiator in position.

On the other hand, it is preferable to further include polarization switching means for switching the connection between the radio recognition means and the first port and the second port.

Further, it is preferable that the radio recognition means comprises a transmitting means and a receiving means, and the RFID reader further comprises a polarization switching means and transmission and reception switching means for switching a connection between the transmitting means and the receiving means.

The polarization switching means and the transmission and reception switching means, wherein the radio recognition means is connected to each of the first port and the second port one or more times while the transmission means is connected to the polarization switching means, and the reception means It is preferable that the radio recognition means is switched so as to be connected to each of the first port and the second port one or more times while connected to the polarization switching means.

On the other hand, the antenna further comprises a ground conductor of a conductive material disposed substantially parallel to the radiator, the radio recognition means is preferably disposed on the ground conductor.

Preferably, the radio recognition means includes radio communication means for communicating with a host.

In order to achieve the above object, according to another aspect of the present invention, an antenna having a feeding circuit and an antenna radiator connected to the feeding circuit, and connected to the antenna via the feeding circuit, from or to the antenna; And an RFID reader including a wireless recognition means for processing a signal, and a host for processing data read by the RFID reader or processing data to be recorded by the RFID reader, and communicating data with the RFID reader. This is provided.

Preferably, the radio recognition means comprises radio communication means for communicating with the host.

EMBODIMENT OF THE INVENTION Hereinafter, specific embodiment of this invention is described with reference to attached drawing. In the present specification, an RFID reader for reading a tag is mainly described, but the description of the RFID reader may be equally applied to an RFID writer for recording data in a tag. The term "RFID reader" is not limited to an RFID reader, It is used to include both an RFID writer and an RFID reader / writer with which they are coupled.

2 is a side view showing the configuration of the RFID reader 200 according to the embodiment of the present invention. The RFID reader 200 of the present embodiment largely includes an antenna for transmitting and receiving signals to and from a tag, and radio recognition means for processing signals to and from the antenna.

The antenna includes a radiator 210 which is formed of a conductive material and emits a signal, and a circuit board 230 having a feeding circuit for feeding the radiator 210, the radiator 210 having a feeding circuit on the circuit board 230. And via a feed conductor 220. In addition, the antenna may further include a ground conductor 240 formed of a conductive material to function as a ground plane of the antenna. Ground conductor 240 may direct the antenna by reflecting electromagnetic waves emitted from radiator 210. However, the antenna may be used as the antenna ground plane by forming a ground plane on the circuit board 250 without separately including the ground conductor 240. The antenna may be a linear dual polarized antenna, which will be described later.

The radio recognition means includes a substrate 250 and signal processing means 260, 270 mounted on the substrate. The signal processing means 260, 270 are preferably modular, but may be individual electronic elements. Although two components 260 and 270 are illustrated as signal processing means in the figure, this is for convenience of description and the number of components is not limited thereto. For example, the wireless recognition means may include three or more components according to its function, and may be configured as a single module or element by implementing a plurality of components in one module or one integrated circuit. . The signal processing means 260, 270 processes the signal to / from the antenna to convert the data read from the tag into a form suitable for communication with the host, or identifies and organizes data simultaneously obtained from multiple tags to the host. send.

The radio recognition means of the RFID reader of this embodiment is integrally coupled with the antenna. Specifically, the substrate 250 is fixed to the rear surface of the ground conductor 240, and the circuit of the substrate 250 and the power feeding circuit of the circuit board 230 may be connected through a through hole or the like. As the RFID reader includes both the antenna and the radio recognition means, the connection between the antenna and the radio recognition means is almost lost and there is no need to install a separate transmission line to connect the antenna and the reader, thereby reducing the overall system construction cost. Can be. Alternatively, it is also possible for the substrate 250 to be fixed to the front surface of the ground conductor 240, or the substrate 250 is not provided separately from the circuit board 230, and radio recognition means may be provided in the circuit board 230.

Meanwhile, the RFID reader of the present embodiment may use a linear dual polarized antenna to increase the recognition distance, which will be described with reference to FIGS. 3 and 4. 3 is a diagram illustrating a power supply circuit of an RFID reader antenna according to an embodiment of the present invention. As described above, the power feeding circuit of the antenna may be formed on the circuit board 230. In order to allow the antenna to operate as a linear dual polarized antenna, the feed circuit has two ports: a horizontal polarization port (H.P) and a vertical polarization port (V.P). The signals of the ports are input to the first power divider 232 and the second power divider 234, respectively, and split into two input signals.

The signal of the horizontal polarization port H.P is separated into a signal of the first terminal 232a and a signal of the second terminal 232b through the first power divider 232. The first power divider 232 allows the signal of the first terminal 232a and the signal of the second terminal 232b to have a phase difference of 90 degrees by adjusting the length of the line, and the first terminal 232a and the second terminal. 232b is connected to the radiator at a symmetrical position to generate a signal of a predetermined polarization.

Further, the signal of the vertical polarization port V.P is separated into a signal of the third terminal 234a and a signal of the fourth terminal 234b through the second power divider 234. The second power divider 234 allows the signal of the third terminal 234a and the signal of the fourth terminal 234b to have a phase difference of 90 ° by adjusting the length of the line, and the third terminal 234a and the fourth terminal. 234b is connected to the radiator at a symmetrical position to generate a signal of a predetermined polarization.

On the other hand, the line connecting the points where the first terminal 232a and the second terminal 232b are connected to the radiator (in the present embodiment, the same as the positions of the terminals) has a third terminal 234a and a fourth terminal 234b. It is arranged to be orthogonal to the line connecting the points connected to the radiator (in this embodiment, the same as the position of the terminals). Therefore, the signal by the horizontal polarization port (H.P) and the signal by the vertical polarization port (V.P) have a polarization orthogonal to each other. The radiator of the antenna may have a substantially square shape for efficiency of double polarization operation.

In this way, the antenna operates as a linear dual polarized antenna, so that the tag can be recognized by another polarization even if the tag arrangement direction is orthogonal to one polarization, and even if the tag arrangement direction is not parallel to the antenna polarization, both polarizations Since the tag is recognized, the recognition rate of the tag can be improved. In addition, by using linear polarization, the gain of the antenna can be increased and the recognition distance of the RFID reader can be increased compared with the case of using circular polarization.

In the RFID reader employing the linear dual polarization antenna of the present embodiment, since the antenna has two ports for two polarizations, the radio recognition means communicating therewith must also have two ports. However, in order to have two ports, two signal processing means in the radio recognition means must exist or further include a circuit for distributing a signal from one signal processing means. In addition, two antennas for transmitting / receiving are required in order to handle both signal transmission to and from the tag, thereby increasing the manufacturing cost of the circuit. The configuration of the radio recognition means for solving this problem will be described with reference to FIG.

4 is a block diagram of radio recognition means of an RFID reader according to an embodiment of the present invention. The wireless recognition means includes signal processing means 320 for processing signals to / from the tag, and the signal processing means 320 includes a transmitter 324 and a receiver 326 for transmitting and receiving signals. Transmitter 324 and receiver 326 communicate with controller 328 to control operation. Controller 328 processes the signals to / from transmitter 324 and receiver 326 to extract data to be read or written and convert it to communicate with a host (not shown). The wireless recognition means may further comprise an interface which enables the signal to / from the controller 328 to communicate with an external device via RS232 or TCP / IP protocol. This allows the RFID reader to be used in conjunction with various devices.

The signal processing means 320 comprises transmission and reception switching means 322 for selectively connecting the transmitter 324 and the receiver 326 to the antenna. The transmit / receive switching means 322 switches to connect the antenna 324 when the transmitter 324 and the receiver 326 each operate under the control of the controller 328. Therefore, the manufacturing cost can be reduced by using one antenna for both transmission and reception. Alternatively, the transmission / reception switching means 322 may not be included in the signal processing means 320 but may exist as a separate component.

The radio recognition means also comprises polarization switching means 310. The polarization switching means 310 connects the transmitted or received signal to / from the signal processing means 320 to ports V.P and H.P for each polarization of the antenna. Therefore, the signal can be supplied to the dual polarized antenna using only one signal processing means 320. In more detail, operations of the transmission and reception switching means 322 and the polarization switching means 310 are as follows.

While the switching means 310 is connected to, for example, a vertically polarized port V.P, the transmission and reception switching means 322 is switched between the transmitter 324 and the receiver 326. The switching of the polarization switching means 310 may be performed continuously at predetermined time intervals, while the transmission / reception switching means 322 is controlled by the controller 328. The transmitter 324 or the receiver 326 in the signal processing means 320 may be controlled. Can be switched independently of the polarization switching means 310 in accordance with the operation time of Therefore, both polarizations may be used during transmission or both polarizations may be used during reception. In particular, the switching interval of the polarization switching means 310 is very short compared to the transmission / reception operation execution time, that is, the switching interval of the transmission / reception switching means 322, so that the effect of dual polarization transmission and reception can be improved.

By such a configuration, it is possible to efficiently perform both transmission and reception with a dual polarized signal using a single signal processing means and a single antenna.

Next, with reference to FIG. 5, wireless recognition means of an RFID reader according to another embodiment of the present invention will be described. In FIG. 5, the same reference numerals are used for the same components as in the previous embodiment, and detailed description thereof will be omitted.

The radio recognition means of this embodiment is different from the previous embodiment in that it includes a WiFi interface 330 for communication with a host. The WiFi interface 330 converts signals to / from the signal processing means 320 to communicate with the WiFi protocol, and performs communication with the host. Accordingly, the RFID reader of the present embodiment can not only communicate with the host wirelessly, but also can configure a separate network without using an existing wireless Internet network or a mobile communication network to communicate with the host at no additional cost. In addition, since the antenna and the radio recognition means are integrally formed, the RFID reader of the present embodiment eliminates the need to establish a transmission line at all, thereby reducing the installation cost of the RFID system and freely determining the installation position of the RFID reader without restriction of the transmission line. It can make the design of the leader beautiful. In this embodiment of the WiFi interface 330 is to be described by way of example WiFi protocol, Bluetooth ^®, UWB, Zigbee, etc. replacement is available in the interface that can communicate with a variety of short-range wireless communication protocol, and the invention is limited to a specific protocol, It will be readily appreciated by those skilled in the art.

Hereinafter, an RFID system according to another embodiment of the present invention will be described with reference to FIG. 6. The RFID system of the present embodiment communicates with an RF tag 410 that is a transponder, an RFID reader 420 that reads the tag 410 or writes data to the tag 410, and collects data by communicating with the RFID reader 420. A host 430 for processing / processing. The configuration of the tag 410 is the same as that of the conventional tag 410 and will not be described in detail.

The RFID reader 420 includes radio recognition means 424 having an antenna 422 for directly transmitting and receiving signals to and from the tag 410 and signal processing means for processing signals to and from the antenna 422. The specific configuration of the antenna 422 and the radio recognition means 424 of the RFID reader 420 is the same as the previous embodiments described with reference to FIGS. 2 to 6 and will not be described in detail. The RFID reader 420 may be equipped with middleware for communication with the host 430.

The host 430 collects data from the RFID reader 420, processes it for application purposes, and processes it as necessary. For example, in the RFID system for inventory management, the host 430 collects data read by the RFID reader from tags attached to various items to extract information such as the type of goods loaded in the warehouse, the quantity of the goods, and the like. Based on this, the type and quantity of goods to be procured are determined. In addition, in the charging system, the host 430 receives information such as the amount and account stored in the tag from the RFID reader and pays the amount in the account, or information in which the amount charged in the amount information stored in the tag is reduced through the RFID reader. Update to. In addition, payment information for each period / region may be extracted and provided to the user according to the billing history. The host 430 may be equipped with a suitable application according to various service purposes such as this, and middleware for communicating with the RFID reader 420 may be mounted. In addition, the host 530 may be implemented using a small PC, a large computer, a server, or the like according to the amount of processing data.

The RFID reader 520 of the present embodiment may communicate via a wireless link (air link) in a variety of short-range wireless communication protocol, such as a host 530 and a WiFi, Zigbee, UWB, Bluetooth ^®. To this end, the RFID reader 420 and the host 430 may include a wireless communication interface.

This configuration eliminates the need to establish a transmission line for communication between the RFID reader 420 and the host 430, and reduces the installation cost of the system. In addition, since the installation position of the system is not limited by the transmission line, the application range of the RFID system can be expanded. In addition, since the antenna 422 is integrated into the RFID reader 420, a separate transmission line for connecting the RFID reader and the antenna is not required, and thus, the standalone type in which the RFID reader 420 is not substantially connected to the transmission line. Implementation frees readers from being placed and moved, reducing installation costs.

Although the present invention has been described above in connection with specific embodiments, this is only an example and the present invention is not limited to these embodiments. Those skilled in the art can modify and modify these embodiments without departing from the scope of the present invention. For example, two or more components shown in each functional block in the block diagram may be integrated to form a single block, and a plurality of unspecified components may be included in each functional block. In addition, when one function block performs two or more functions, it is also possible to implement a separate function block for each function. The functional blocks may actually be implemented in hardware, software, firmware, etc., such as integrated circuits, and a person skilled in the art will be able to easily implement the functional blocks based on known techniques. Accordingly, the scope of the invention should be defined only by the following claims, not by the description.

According to the present invention, an RFID reader can be obtained without the necessity of a transmission line between the antenna and the RFID reader. In addition, according to the present invention, an RFID reader having both a recognition distance and a recognition rate can be obtained using dual linear polarization.

In addition, according to the present invention can obtain an RFID system that does not require the establishment of a transmission line.

Claims (18)

An antenna having a feed circuit and an antenna radiator connected to the feed circuit; And An RFID reader connected to the antenna via the power feeding circuit and including radio recognition means for processing a signal from or to the antenna, The antenna is a linear dual polarization antenna for transmitting and receiving signals of vertical polarization and horizontal polarization, and includes a first port for the vertical polarization and a second port for the horizontal polarization, The power supply circuit, A first power divider which outputs two feed signals having a phase difference of 90 ° from the signal from the first port and supplies them to the first point and the second point of the antenna radiator, respectively; And A second power divider which outputs two feed signals having a phase difference of 90 ° from the signal from the second port and supplies them to third and fourth points of the antenna radiator, respectively; And the line connecting the first and second points and the line connecting the third and fourth points are orthogonal to each other. delete delete The method of claim 1, The antenna radiator is square, The first point and the second point are symmetric about a first straight line, The third point and the fourth point are symmetric about a second straight line perpendicular to the first straight line, And the first straight line passes through the center of the rectangle and is parallel to one side of the rectangle. The method according to claim 1 or 4, And a polarization switching means for switching the connection between the radio recognition means and the first port and the second port. The method of claim 5, wherein The radio recognition means comprises a transmitting means and a receiving means, The RFID reader further includes transmission and reception switching means for switching a connection between the polarization switching means and the transmission means and the reception means. The method of claim 6, The polarization switching means and the transmission and reception switching means, wherein the radio recognition means is connected to each of the first port and the second port one or more times while the transmission means is connected to the polarization switching means, and the reception means And the wireless recognition means switches so as to be connected to each of the first port and the second port one or more times while connected to the polarization switching means. The method of claim 1, The antenna further includes a ground conductor of a conductive material disposed in parallel with the radiator, And the radio recognition means is disposed on the ground conductor. The method of claim 1, And the wireless recognition means comprises wireless communication means for communicating with a host. An RFID reader having a feed circuit and an antenna radiator connected to the feed circuit, and an RFID reader connected to the antenna via the feed circuit, the radio recognition means processing a signal from or to the antenna; And An RFID system comprising a host for processing data read by the RFID reader or processing data to be recorded by the RFID reader and communicating data with the RFID reader. The antenna is a linear dual polarization antenna for transmitting and receiving signals of vertical polarization and horizontal polarization, and includes a first port for the vertical polarization and a second port for the horizontal polarization, The power supply circuit, A first power divider which outputs two feed signals having a phase difference of 90 ° from the signal from the first port and supplies them to the first point and the second point of the antenna radiator, respectively; And A second power divider which outputs two feed signals having a phase difference of 90 ° from the signal from the second port and supplies them to third and fourth points of the antenna radiator, respectively; And the line connecting the first and second points and the line connecting the third and fourth points are orthogonal to each other. delete delete The method of claim 10, The antenna radiator is square, The first point and the second point are symmetric about a first straight line, The third point and the fourth point are symmetric about a second straight line perpendicular to the first straight line, And the first straight line passes through the center of the rectangle and is parallel to one side of the rectangle. The method according to claim 10 or 13, The RFID reader further comprises polarization switching means for switching the connection between the radio recognition means and the first port and the second port. The method of claim 14, The radio recognition means comprises a transmitting means and a receiving means, And the RFID reader further comprises transmission and reception switching means for switching a connection between the polarization switching means and the transmission means and the reception means. The method of claim 15, The polarization switching means and the transmission and reception switching means, wherein the radio recognition means is connected to each of the first port and the second port one or more times while the transmission means is connected to the polarization switching means, and the reception means And the radio recognition means switches to be connected to each of the first port and the second port one or more times while connected to the polarization switching means. The method of claim 10, The antenna further includes a ground conductor of a conductive material disposed in parallel with the radiator, And the radio recognition means is disposed on the ground conductor. The method of claim 10, And the wireless recognition means comprises wireless communication means for communicating with the host.

Images