KR101231473B1 - Radio Frequency IDentification system - Google Patents

Abstract

According to an aspect of the present invention, there is provided an RFID system including a transmitting processor, a receiving processor, and a plurality of antennas, comprising: a first switching unit including a plurality of switches for switching the antenna to the transmitting processor or the receiving processor; A second switching unit including one or more switches for selectively switching the switches of the first switching unit with the receiving processing unit; A third switching unit including one or more switches for selectively switching the switches of the first switching unit with the transmission processing unit; And a controller configured to selectively transmit / receive a transmission signal by applying a control signal to the first switching unit, the second switching unit, and the third switching unit.

According to the present invention, the transmit / receive path of the antenna can be controlled according to the user's setting command, the strength of the received signal, the error bit rate, etc., thereby improving the error rate, stability, recognition distance, etc. There is an effect that enables the design of the system. In addition, it is possible to effectively use the antenna and to facilitate the antenna arrangement, and the isolation probability between the transmission and reception paths is improved by controlling the plurality of switching units, thereby reducing the probability of malfunction.

Description

RFID system {Radio Frequency IDentification system}

1 is a schematic illustration of some components of a conventional RFID system.

2 is a block diagram exemplarily illustrating an antenna arrangement form of an RFID system according to an exemplary embodiment of the present invention.

3 is a block diagram schematically illustrating components of an RFID system according to an embodiment of the present invention;

4 is a circuit diagram schematically illustrating a connection structure of switches among components of an RFID system according to an exemplary embodiment of the present invention.

5 is a block diagram exemplarily illustrating a form in which an RFID system is connected to an external terminal according to an embodiment of the present invention.

6 is an experimental graph measuring waveforms of signals processed by a transmission processor and a reception processor of an RFID system according to an embodiment of the present invention in units of 200 μs.

7 is an experimental graph measuring waveforms of signals processed by a transmission processor and a reception processor of a RFID system according to an embodiment of the present invention in units of 10 μs.

Description of the Related Art

100: RFID system 112: first antenna

114: second antenna 116: third antenna

118: fourth antenna 121: first switch

122: second switch 123: third switch

124: fourth switch 125: fifth switch

126: sixth switch 127: seventh switch

130: reception processing unit 140: signal separation unit

150: transmission processor 160: baseband unit

170: Q-RSSI section 180: I-RSSI section

190: control unit 300: external terminal

The present invention relates to a radio frequency identification (RFID) system having a multiple antenna structure.

Currently, ubiquitous network technology has attracted the attention of many people, ubiquitous network technology means a technology that can be connected to various networks regardless of time and place.

Ubiquitous network technology can be implemented in various ways by using communication technologies such as telematics communication, short-range wireless communication, and mobile communication. By using this, a natural connection environment is provided in spaces such as automobiles, homes, and public places. The use of information and technology will increase, and the overall IT industry is expected to develop more rapidly.

As the next generation technology of the ubiquitous network technology, RFID technology may be cited. Among them, RFID technology introduced in commerce is representative.

Generally, a commercial RFID system includes an RFID tag attached to a product and embedded with detailed information, an RFID reader that reads information of the electronic tag using RF communication, an information server that collects information from the RFID reader, and builds a database. The RFID tag attached to the product passes through the area where the RFID reader is located and transmits information by using RF communication, so the logistics / distribution management such as distribution, assembly, price change, and sale of the product can be efficiently handled. Provides a foundation to be

In the case of an RF receiving circuit provided in such an RFID system, it is generally implemented through envelope detection using ASK (Amplitude Shift Keying), FSK (Frequency Shift Keying), and PSK (Phase Shift Keying) modulation. According to the present invention, there is a disadvantage in that the data recognition rate is lowered because the bit error rate is lowered.

Since the RFID reader targets a tag moving at a high speed, a change in the radio wave environment is severe, and a change in the reception signal is greatly caused by an external environment change.

FIG. 1 is a view schematically showing some components of a conventional RFID system 10. According to FIG. 1, a conventional RFID system 10 includes an antenna 12 and a low noise amplifier (LNA) 14 ), A summer 16, and a baseband portion 18.

The antenna 12 receives an RF signal transmitted from a tag through a wireless channel in the 800 MHz to 900 MHz band, for example, in which the RF signal is affected by factors such as propagation attenuation, multipath loss, interference, and Doppler effect. To various signal components.

The antenna 12 is provided in plural to receive signals whose characteristics are differentiated according to the radio wave environment, and each antenna 12 receives various signals.

That is, since the strength of the signal is weak and the recognition rate is changed due to the characteristics of the conventional RFID reception method, the antenna has a structure for accommodating each signal through the plurality of antennas 12 and utilizing the same to improve the recognition rate of the data.

The low noise amplifier 14 is also provided in plural and connected to each antenna 12, and amplifies the filtered RF signal while suppressing the low noise component.

The summer 16 collects, sums and amplifies the amplified RF signals to the baseband unit 18 to reflect the received signal components as much as possible to increase the recognition rate of the data.

That is, since the characteristics of the signal required by the RF receiver are not phases but phases, the signals are summed to increase the accuracy of the phases. As a result, the strength of the RF signal received in real time becomes irregular (for example, too large or small), Since the baseband unit 18 including the AD converter occupies only a part of the voltage range processed, the conversion efficiency is reduced.

This uses only a part of the dynamic processing range of the AD converter of the baseband unit 18, which means that the conversion range of the AD converter is smaller.

In addition, when the gain having a constant value is multiplied and multiplied by the low noise amplifier 14, the RF signal having an irregular size is very likely to cause the receiver saturation, and thus the reception state of the signal is not maintained stably. Since it is not possible to simultaneously set the transmit and receive paths for a plurality of antennas, there is a limitation in the efficient use of the antennas.

Therefore, when processing a large number of tags and communication, the computational burden of the control unit may increase, a communication delay may occur, or may miss if the tag is not recognized.

The present invention provides an RFID system capable of performing RFID communication between a larger number of terminals in a wider area with a smaller number of antennas than by efficiently switching a plurality of antennas.

In addition, the present invention can set the real-time transmission and reception paths for the common antenna stage, improve the isolation between the transmission and reception paths, and can control the antenna in real time by grasping the receiving environment, thereby extending the recognition area of the tag and stable propagation energy Provides an RFID system that can supply.

According to an aspect of the present invention, there is provided an RFID system including a transmitting processor, a receiving processor, and a plurality of antennas, comprising: a first switching unit including a plurality of switches for switching the antenna to the transmitting processor or the receiving processor; A second switching unit including one or more switches for selectively switching the switches of the first switching unit with the receiving processing unit; A third switching unit including one or more switches for selectively switching the switches of the first switching unit with the transmission processing unit; And a controller configured to selectively transmit / receive a transmission signal by applying a control signal to the first switching unit, the second switching unit, and the third switching unit.

In addition, at least one switching unit of the second switching unit and the third switching unit of the RFID system according to the present invention is composed of a multi-opening switch, and further comprises a divider circuit.

In addition, the control unit of the RFID system according to the present invention is connected to an external terminal equipped with an interface for receiving an antenna setting information from a user and a communication means for processing a predetermined communication protocol. Processing to receive the antenna setting information, and apply the control signal according to the antenna setting information.

Hereinafter, an RFID system according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

2 is a block diagram exemplarily illustrating an antenna arrangement form of an RFID system 100 according to an exemplary embodiment of the present invention.

2, the RFID system 100 according to an embodiment of the present invention has four antennas 112, 114, 116, 118, the electronic tag 200 is attached to the goods passing through the logistics inspection area The antennas 112, 114, 116, and 118 are disposed to the left and right of the region (inspection region) in which the electronic tag 200 is moved. At this time, each of the antennas 112, 114, 116, 118 may be installed with different radio wave transmission and reception angles.

According to an embodiment of the present invention, the RFID system 100 may group four antennas 112, 114, 116, and 118 to switch one group to a transmission path and the other group to a reception path. The type of group may be variously set according to the number and type of antennas 112, 114, 116, and 118 forming a group.

A structure in which the antennas 112, 114, 116, and 118 are grouped and switched will be described in detail with reference to FIGS. 3 and 4.

As the antennas 112, 114, 116, and 118 are switched for each transmission path according to the reception environment, the RFID system 100 according to the embodiment of the present invention may maintain a stable communication state while having a minimum number of antennas.

For example, according to the present invention, in order to control a plurality of antennas, as in the prior art, a plurality of RFID systems are provided, or a large amount of antennas allocated to transmission paths and reception paths are not required.

3 is a block diagram schematically illustrating components of an RFID system 100 according to an embodiment of the present invention.

Referring to FIG. 3, the RFID system 100 according to the embodiment of the present invention may include a first antenna 112, a second antenna 114, a third antenna 116, a fourth antenna 118, and a first switch ( 121, the second switch 122, the third switch 123, the fourth switch 124, the fifth switch 125, the sixth switch 126, the seventh switch 127, and the reception processor 130. , The signal separation unit 140, the transmission processing unit 150, the baseband unit 160, the Q-RSSI (Received Signal Strength Indicator) unit 170, the I-RSSI unit 180, and the controller 190. .

First, the antennas 112, 114, 116, and 118 convert electrical signals into radio signals when transmitting signals, and convert radio signals into electrical signals when receiving signals, and transmit the signals to the reception processor 130. do.

The antennas 112, 114, 116, and 118 may include a dipole antenna, a monopole antenna, a microstrip antenna (also called a "patch antenna"), a horn antenna, and a parabolic. A parabolic antenna, a helical antenna, a slot antenna, or the like may be used.

Usually, as the RFID signal, when the electronic tag 200 and the RFID system 100 operate in an active manner, a UHF signal having a frequency band of 400 MHz to 900 MHz is used, and in the case of a passive manner, a UHF (800 MHz to 900 MHz) is used. Nationally allocated frequency) signals are used.

The third switch 123, the fourth switch 124, the fifth switch 125, and the sixth switch 126 are respectively the first antenna 112, the second antenna 114, and the third antenna 116. And a fourth antenna 118, wherein the third switch 123 to the sixth switch 126 are connected to one side end of the first switch 121 and the first switch 121 connected to the antennas 112, 114, 116, and 118. The switch element has two other path ends connected to the second switch 122 or the seventh switch 127.

The two other side ends are used as a transmit (Tx) pass and a receive (Rx) pass, respectively, and the third switch 123 to the sixth switch 126 are, for example, a single pole double throw (SPDT). It may be provided as a switch element.

In addition, the seventh switch 127 connects the reception path ends of the third switch 123 to the sixth switch 126 with the reception processing unit 130. The reception processing unit 130 is connected to the third switch 123 through the third switch 123. One or more switches of the sixth switch 126 may be selectively connected.

That is, the seventh switch 127 is a multi-switch switch device that can connect one to five signal paths at the same time, unlike the third switch 123 to the sixth switch 126.

In addition, the first switch 121 and the second switch 122 connects the transmission path ends of the third switch 123 to the sixth switch 126 with the signal separation unit 140. ) Selectively connects transmission paths of the fifth switch 125 and the sixth switch 126 with the signal separation unit 140, and the second switch 122 connects the third switch 123 and the fourth switch ( The transmission path of 124 is selectively connected to the signal separator 140.

The first switch 121 and the second switch 122 may be provided as a switch element of the same series as the third switch 123 to the sixth switch 126, as in the seventh switch 127 Since the fifth switch 125 and the sixth switch 126 connected to the first switch 121 cannot configure the transmission path at the same time.

Similarly, since the third switch 123 and the fourth switch 124 connected to the second switch 122 cannot form a multipath like the seventh switch 127, a transmission path cannot be configured at the same time.

On the other hand, the signal separation unit 140 connects the first switch 121 and the second switch 122 with the transmission processing unit 150, branching the signal transmitted from the transmission processing unit 150 to the first switch ( 121 and the second switch 122 at the same time.

Accordingly, since the first switch 121 and the second switch 122 may receive the same transmission signal by the signal separation unit 140 and selectively transmit the same transmission signal, the third switch 123 and the fourth switch 124. The group may be combined with the group of the fifth switch 125 and the sixth switch 126 to form a transmission path.

In this way, the switching structure for the received signal is implemented by one multi-opening switch element, and the switching structure for the transmission signal is implemented by two SPDT switch elements and the signal separation unit 140, which is more unstable than the transmission environment. Because it is passive.

However, the switching structure may be modified. For example, the switching structure for the transmission signal may be implemented by one multiple switching device, or the switching structure for the reception signal may be implemented by the two SPDT switch elements and the signal separation unit 140. Could be.

The first switch 121 to the seventh switch 127 according to the present invention is a semiconductor-based switching element, and usually performs the switching operation several times or more than ten times, so that the antennas 112, 114, 116, and 118 are electronic The effect of monitoring the entire area where the tag 200 is moved at the same time can be seen.

In addition, the processor or memory operation speed of the conventional RFID system is slower than the hundreds of electronic tag propagation speed (640Kbps), the overload occurs, but the RFID system 100 according to the present invention is largely by the above-described multiple switching structure Can reliably receive the signal, so that the hardware resources can be used efficiently.

Therefore, the RFID system 100 according to the present invention does not need to include a plurality of controllers 190 and memory resources.

The reception processor 130 includes a low noise amplifier, a band pass filter, a matching circuit, and the like, and receives the transmissions through one or more of the third switch 123 to the sixth switch 126 and the seventh switch 127. The noise component of the signal is suppressed and amplified, and the amplified signal is transmitted to the baseband unit 160.

In the embodiment of the present invention, the signal separator 140 is implemented as a divider circuit, which may be implemented as a coupler circuit, a splitter circuit, or the like.

The transmission processor 150 adjusts and amplifies the power gain of the transmission signal transmitted from the baseband unit 160, filters the mixed signal in the process of processing the received signal, and transmits the mixed signal to the signal separation unit 140.

The baseband unit 160 is connected to the transmission processing unit 150 and the reception processing unit 130, respectively, and consists of two parts for processing the transmission signal and the reception signal (the components of the baseband unit 160 are not shown), Received signal processing part includes I / Q demodulator, low pass filter (LPF), intermediate frequency amplifier, modulator, A / D converter, etc. It handles signal generation, filtering, amplification / modulation and A / D conversion.

In addition, a portion of the baseband processing unit 160 that processes the transmission signal includes a D / A converter, a low pass filter, a demodulator, an intermediate main gain amplifier, an intermediate frequency filter, and the like to convert the digital signal into an intermediate frequency signal and an RF signal. After the conversion, the gain of the power is adjusted and transmitted to the transmission processor 150.

The digital signal transmitted from the baseband unit 160 is transferred to the controller 190, the I-RSSI unit 180, and the Q-RSSI unit 170.

The I-RSSI unit 180 is a circuit for measuring the reception strength of an in-phase signal. The I-RSSI unit 180 detects and corrects that an intensity of a signal increases and becomes irregular due to an interference or a mixture of noise components. Means a circuit used for the purpose.

The Q-RSSI unit 170 is a circuit for measuring reception strength of a quadrature (Q) signal, and performs a function similar to that of the I-RSSI unit 180.

The controller 190 includes a communication protocol to control wireless communication with the electronic tag 200 and periodically transmits an information request signal to determine the location of the electronic tag 200.

In addition, the controller 190 analyzes the code of the tag identification information received from the electronic tag 200 and demodulated by the baseband unit 160, and converts the data format and processes filtering to extract necessary information.

Here, the control unit 190 may be implemented using a field programmable gate array (FPGA) circuit or a digital signal processing (DSP) circuit, and the FPGA circuit may be used to perform the function of the RFID system 100 outside the production process of the chip. If implemented, it means a gate array circuit (logical integrated circuit) to which programming can be added as needed. The characteristics of the gate array and programmable logic devices (PLD) are implemented.

These FPGA circuits have the advantages of being able to use multiple I / Os like a gate array, programmable at a time, and increasing the utility of the gate by 95%.

In addition, the DSP (Digital Signal Processing) circuit processes algebraic operations on digital data obtained by A / D (Analog / Digital) conversion of an analog signal to perform signal processing such as filtering or spectrum analysis.

The controller 190 applies a control signal to the control voltage terminal of the first switch 121 to the seventh switch 127 so that the signal paths of the switches 121, 122, 123, 124, 125, 126, and 127 The controller 190 determines whether the antenna having the best sensitivity is currently determined based on the strength of the received signal measured from the RSSI unit 170 or 180 or is transmitted from the baseband unit 160. By calculating the bit error rate of the digital signal, the antenna that has received the signal having the lowest error rate may be identified as the antenna having the highest sensitivity.

The controller 190 may be connected to an external terminal 300 (refer to FIG. 5) to receive antenna setting information. For example, the external terminal 300 may include an antenna of an administrator of the RFID system 100 according to the present invention. After the arrangement, the antenna to be used for transmission may be set according to the arrangement, and the input configuration information may be transmitted to the controller 190 through a wired / wireless network.

The connection relationship between the external terminal 300 and the controller 190 will be described later with reference to FIG. 5.

4 is a circuit diagram schematically illustrating a connection structure of the switches 121, 122, 123, 124, 125, 126, and 127 among the components of the RFID system 100 according to an exemplary embodiment of the present invention.

Referring to FIG. 4, as described above, the RFID system 100 according to the present invention includes a total of seven switches 121, 122, 123, 124, 125, 126, and 127, and combines the switching circuits of the switches. By controlling, the four antennas 112, 114, 116, and 118 can be connected to a transmission path and a part of the four antennas 112, 114, 116, and 118.

The first switch 121 to the sixth switch 126 include two control voltage terminals A and B, an antenna terminal RFC, a power terminal Vdd, a transmission and reception path terminal RF1 and RF2, and a ground terminal ( A pin map (GND) or the like, and includes a high frequency switch circuit and a decoder inside the switch package.

The first switch 121 to the sixth switch 126 receive a control signal from the control unit 190 through control voltage terminals A and B, and accordingly, the high frequency switch circuit selectively opens and closes a signal path. The decoder interprets the control signal and logically controls the switching operation.

In addition, the seventh switch 127 includes five control voltage terminals V1, V2, V3, V4, and V5, five ground terminals GND, a receiving processor connection terminal J6, and third switches 123 to. A pin map such as connection terminals J1, J2, J3, and J4 with the sixth switch 126 is formed, and a high frequency switch circuit and a decoder are included in the switch package.

The high frequency switch circuit and the decoder are similar to the first switch 121 to the sixth switch 126 described above, but are connected to the third switch 123 to the sixth switch 126 (J1, J2, J3, J4) is different from the point that is selectively switched to each of the allocated ground terminals or the receiving processor connection terminal (J6 (connected by a common line)).

In general, the transmission processor 150 transmits a signal having a high power of 1W (EIRP = 4W), and some of the transmission signals (signal components of about 5 dBm out of about 30 dBm in total) are received via the reception path 130. Inflow to the side.

Therefore, in the process of switching from the transmission mode to the reception mode, the unwanted wave component is introduced into the reception processing unit 130, and the magnitude of the input power of the reception signal is changed.

When the magnitude of the input power is changed in this way, the reference voltage is shaken, and the receiving processor 130 is influenced to restore the data transmitted from the electronic tag 200.

However, according to the RFID system 100 according to the present invention, the seven switches 121, 122, 123, 124, 125, 126, and 127 collectively constitute a transmission / reception path, and the manager selects or receives the environment. Therefore, even if different transmission and reception paths are configured in real time, each switching device suppresses mutual influx of signals, and thus attenuation effects of 25 dB or more can be seen without a separate blocking circuit.

Hereinafter, the transmission and reception path configuration of an antenna will be described with reference to some examples.

First, as described above, the controller 190 may receive antenna setting information from the external terminal 300. When one antenna is largely set, two antennas are set, and four antennas are set. Can be classified as

First, when one antenna is set, when any one transmission path antenna is set, the controller 190 selects the antenna having the strongest received signal strength among the remaining three antennas and switches 121, 122, 123, and 124. , 125, 126, 127 to transmit the control signal. Therefore, one receiving antenna and one transmitting antenna are used.

Second, when the two antennas are set, if the first antenna 112 and the second antenna 114 are set, the second switch 122 switches the RF2 terminal, and the third switch 123 switches the RF1 terminal. By switching, the first antenna 112 constitutes a transmission path.

Then, the fourth switch 124 switches the RF2 terminal, and the seventh switch 127 switches the J3 terminal so that the second antenna 114 configures the reception path.

Hereinafter, a description of another case in which the two antennas are set is shown in a table (refer to the contents described in the first case and the second case).

Number of cases Antenna type Path type Switching behavior

two
dog

within
rim
I
end

doxy
tablet
Be
The

circa
Right First case  1st antenna  Rx 3rd switch RF2 terminal, 7th switch J4 terminal switched  Second antenna  Tx 4th switch RF1 terminal, 2nd switch RF1 terminal switched Second case  1st antenna  Tx 3rd switch RF1 terminal, 2nd switch RF2 terminal switched  Third antenna  Rx 5th switch RF1 terminal, 7th switch J2 terminal switched Third case  1st antenna  Rx 3rd switch RF2 terminal, 7th switch J4 terminal switched  Third antenna  Tx 5th switch RF2 terminal, 1st switch RF2 terminal switched Case 4  1st antenna  Tx 3rd switch RF1 terminal, 2nd switch RF2 terminal switched  4th antenna  Rx 6th switch RF1 terminal, 7th switch J1 terminal switched Case 5  1st antenna  Rx 3rd switch RF2 terminal, 7th switch J4 terminal switched  4th antenna  Tx 6th switch RF2 terminal, 1st switch RF1 terminal switched Case 6  Second antenna  Tx 4th switch RF1 terminal, 2nd switch RF1 terminal switched  Third antenna  Rx 5th switch RF1 terminal, 7th switch J2 terminal switched 7th case  Second antenna  Rx Fourth switch RF1  Third antenna  Tx 5th switch RF2 terminal, 1st switch RF2 terminal switched 8th case  Second antenna  Tx 4th switch RF1 terminal, 2nd switch RF1 terminal switched  4th antenna  Rx 6th switch RF1 terminal, 7th switch J1 terminal switched 9th case  Second antenna  Rx  4th antenna  Tx 6th switch RF2 terminal, 1st switch RF1 terminal switched

Third, when four antennas are set, the controller 190 may set four antennas as transmission paths and select antennas to be used as reception paths by using a non-transmission period of the transmission signal.

In this case, the controller 190 selects the antenna to be used as a reception path in consideration of the strength of the received signal, the error bit rate, and the like by grouping the antennas 112, 114, 116, and 118 as shown in Table 1 above. You can set up a credit antenna.

5 is a block diagram exemplarily illustrating a form in which an RFID system 100 according to an embodiment of the present invention is connected to an external terminal 300.

Referring to FIG. 5, the external terminal 300 connected to the control unit 190 includes a user interface 310 and a communication unit 320. In an embodiment of the present invention, the external terminal 300 may include a user interface ( 310 may be implemented by loading a program to function the communicator 320.

The user interface 310 receives a setting information of an antenna to be used as a transmission path or a reception path by providing a graphical user interface (GUI) to the user, and the communication unit 320 processes a communication protocol to set the input antenna. The information is transmitted to the controller 190.

The control unit 190 and the communication unit 320 both have analysis information of the communication protocol, and process data processing, transmission, and analysis by the communication protocol.

The control unit 190 and the communication unit 320 may include, for example, a UART port and may be connected through an RS-232 cable. The UART may include a microchip equipped with a program for controlling an interface with a serial device connected to a processor. By providing an RS-232C DTE interface to the processor, it controls data transmission and reception with serial devices.

The ports of the UART are connected to each other through an RS-232 cable, and operate in synchronous mode (half duplex transmission and reception) and asynchronous mode (full duplex transmission and reception) with a serial control register, a serial status register, and a transmission / reception buffer.

The UART converts the byte data transferred from the parallel circuit into a single serial bit stream (in case of internal communication, converts the serial bit stream into byte data), adds a parity bit to transmit, or checks / removes the parity of the received byte. Function, add / remove start bit and stop bit, and interrupt processing function.

6 is an experimental graph in which waveforms of signals processed by the transmission processor 150 and the reception processor 130 of the RFID system 100 are measured in units of 200 μs, and FIG. 7 is an embodiment of the present invention. According to an example, an experimental graph in which waveforms of signals processed by the transmission processor 150 and the reception processor 130 of the RFID system 100 are measured in units of 10 μs, wherein the x coordinate of each graph represents a time axis, and the y coordinate represents a time axis. It means the voltage axis.

"Channel 1 (C1)" in FIG. 6 is a waveform when a reference voltage of 5 V is provided, and "Channel 2 (C2)" is a waveform when a reference voltage of 500 mV is provided, for example, a time interval of 432 μs is 160 mV. Corresponds to the voltage interval.

In addition, "channel 1 (C3)" in Fig. 7 is a waveform when a reference voltage of 5V is provided, "channel 2 (C4)" is a waveform when a reference voltage of 500mV is provided, for example, a time interval of 128μs Corresponds to a voltage interval of 120 mV.

"D1" in FIG. 6 and "D3" in FIG. 7 are regions in which the waveforms of the transmission signal are shown, and "D2" in FIG. 6 and "D4" in FIG. 7 are regions in which the waveforms of the received signal are shown. In comparison with the two regions in FIG. 7, it can be seen that the reception signal is processed with little change in the reference voltage of the reception signal when the transmission mode is switched to the reception mode.

That is, it can be seen that the RFID system 100 according to the embodiment of the present invention has excellent isolation characteristics between the transmission path and the reception path.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, It will be understood that various modifications and applications not illustrated in the drawings are possible. For example, each component specifically shown in the embodiments of the present invention can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

According to the RFID system according to the present invention, the transmit / receive path of the antenna can be controlled according to the user's setting command, the received signal strength, the error bit rate, etc. ), The recognition distance can be improved, and the stable system can be designed.

In addition, according to the present invention, it is possible to configure the transmit and receive paths by grouping the antennas at the same time, which enables efficient use of the antenna and facilitates the antenna arrangement. Can be reduced.

Claims (10)

An RFID system comprising a transmission processor, a reception processor, and a plurality of antennas, A first switching unit including a plurality of switches for switching the antennas to the transmission processing unit or the reception processing unit; A second switching unit including one or more switches for selectively switching the switches of the first switching unit with the receiving processing unit; A third switching unit including one or more switches for selectively switching the switches of the first switching unit with the transmission processing unit; And A control unit for selecting at least two of the antennas, controlling the first switching unit, the second switching unit, and the third switching unit to set transmission / reception paths to the selected antennas; The control unit At least one of the antennas is selected according to antenna setting information received from an external terminal, and at least one of the other antennas is selected according to the strength of a received signal corresponding to each of the antennas. The switch of claim 1, wherein the switches of the first switching unit are RFID system connected to each of the antennas. The method of claim 1, wherein the first switching unit RFID system comprising a single pole double throw (SPDT) series of switches. The method of claim 1, wherein the switching unit of at least one of the second switching unit and the third switching unit RFID system comprising a multi-switch switch. The method of claim 4, wherein the switching unit of at least one of the second switching unit and the third switching unit RFID system comprising a divider circuit. The method of claim 1, And a detector circuit for sensing the strength of the received signal. delete delete The method of claim 1, wherein the control unit And a multiple of two in the antennas according to the antenna setting information. The method of claim 1, wherein the control unit An RFID system, characterized in that at least one of the other antennas is selected by determining an error bit rate of a signal received by each of the antennas.

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