TWI428835B - Radio frequency identification transmitting and receiving device - Google Patents

Description

Radio frequency identification transceiver

The present invention claims priority from Korean Patent No. 10-2009-0019673, filed on March 09, 2009, and Korean Patent No. 10-2009-0020636, filed on March 11, 2009. This is incorporated herein by reference.

The invention relates to a radio frequency identification transceiver capable of transmitting and receiving a radio frequency identification (RFID) signal.

At present, ubiquitous technology is gradually attracting attention from public businesses and industries. Ubiquitous technology is a technology that provides relevant content and information to the user's network of interactive devices regardless of the user's location or time.

An example of ubiquitous technology is radio frequency identification (RFID) technology, in which wireless radio frequency technology is introduced into commercial transactions as the most representative example.

The disclosure of the present invention provides a radio frequency identification transceiver device that can automatically adjust a voltage standing wave ratio (VSWR) between a radio frequency identification reader (RFID reader) and an antenna.

In some embodiments, the present invention provides a radio frequency identification transceiver device that can control an impedance between a connection terminal between an antenna and a radio frequency identification reader, thereby effectively controlling the reading. One of the output loss, and automatically controls the phase of a label identity (ID) preamble error caused by the phase change of the reflected wave characteristic to adjust the recognition rate Reduce the phenomenon.

The descriptions herein are not intended to limit the scope of the invention, and other undescribed problems may be apparent from the following description.

According to a general consideration of the present invention, a radio frequency identification transceiver device is characterized by: an antenna, a directivity coupler, a voltage standing wave ratio (VSWR) detector, a voltage standing wave ratio controller, and a Phase/impedance controller. The pointing coupler outputs a progressive wave signal input from the antenna and a reflected wave signal reflected from the antenna; the voltage standing wave ratio detector uses the forward wave signal and the reflected wave signal to detect Measuring a voltage standing wave ratio; the voltage standing wave ratio controller controls a voltage standing wave ratio characteristic of the voltage standing wave ratio; the phase/impedance controller uses the controlled voltage standing wave ratio characteristic to adjust a phase and an impedance .

In some embodiments, the RFID device can further include a standard signal detector that utilizes a signal output from the directional coupler to detect a voltage standing wave ratio standard signal, and the radio frequency identification transceiver The device may further include a main signal processor, and the main signal processor outputs the voltage standing wave ratio and the voltage standing wave ratio standard signal input by the respective voltage standing wave ratio detector and the standard signal detector to the Voltage standing wave ratio controller.

In some embodiments, the voltage standing wave ratio controller controls the voltage standing wave ratio characteristic by using the detected voltage standing wave ratio and the voltage standing wave ratio standard signal, and wherein the phase/impedance controller adjusts A phase between the antenna and the RFID reader and an impedance.

In some embodiments, the voltage standing wave ratio detector detects the voltage standing wave ratio based on Equation 1 below, and when the voltage standing wave ratio is close to Equation 1, a transmission line impedance and an end impedance are completely matched to Prevents an incident wave from being reflected and allows all of the incident wave to pass.

Equation 1:

Voltage standing wave ratio (VSWR)=(1+|ρ|)/(1-|ρ|)

Where ρ is a reflection coefficient.

In some embodiments, the phase/impedance controller adjusts the phase and the impedance to adjust the reflection coefficient to automatically adjust the voltage standing wave ratio to meet environmental requirements.

The invention utilizes a band control module to automatically adjust a voltage standing wave ratio between a radio frequency identification reader and an antenna according to an environment, thereby improving a receiving of the radio frequency identification transceiver device. Sensitivity and the use of compensation for an output to reduce power consumption.

The invention can automatically adjust a voltage standing wave ratio between a radio frequency identification reader and an antenna according to the environment, so as to effectively control the output of the radio frequency identification transceiver device, the receiving sensitivity and the label recognition rate are reduced. And, the present invention can automatically adjust the voltage standing wave ratio characteristic of a region to improve the tag identification rate and utilize the compensation to reduce the power consumption.

The above described objects, features, and characteristics of the present invention will become more apparent from the aspects of the invention. For the sake of brevity, details of functions, configurations, or structures that are well known are omitted in order to avoid obscuring the present invention. Further, in the drawings, the same reference numerals will be given to the same elements.

Please refer to FIG. 1. FIG. 1 is a block diagram showing the control of a radio frequency identification transceiver device according to an embodiment of the invention.

As shown in FIG. 1, a radio frequency identification (RFID) transceiver device according to the present invention may include an antenna 100, a phase/impedance controller 200, a directivity coupler 300, and a voltage standing wave. Ratio (VSWR) detector 400 and a voltage standing wave ratio controller 500.

The antenna 100 receives a received signal input to a radio frequency identification reader (RFID reader) and transmits a transmission signal output by the radio frequency identification reader.

The directional coupler 300 is coupled between the antenna 100 and the RFID reader to couple a progressive wave signal input to the antenna 100 for monitoring an RF signal and a reflected wave signal reflected by the antenna 100 and outputting the forward wave signal and the reflected wave signal.

The voltage standing wave ratio detector 400 utilizes the forward wave signal outputted to the coupler 300 and the reflected wave signal to detect a voltage standing wave ratio (VSWR).

In telecommunication, a standing wave ratio (SWR) is an amplitude of a standing wave in one part of the antinode (maximum) to an adjacent node (minimum) in an electron transmission line. The ratio of the amplitude. The standing wave ratio is usually defined as a voltage ratio and is called a Voltage Standing Wave Ratio (VSWR).

For example, a forward wave in two media having two different impedances is divided into a forward wave and a reflected wave due to impedance mismatch, in which case, One difference between the two waves is the so-called voltage standing wave ratio. If the reflection coefficient is defined as ρ, the voltage standing wave ratio can be calculated via Equation 1 below.

Equation 1:

VSWR=(1+|ρ|)/(1-|ρ|)

That is to say, for example, the value of the voltage standing wave ratio is 1.2:1, which means that a maximum standing wave amplitude is 1.2 times larger than the minimum standing wave value. In another example, the value of the voltage standing wave ratio of 1 indicates that a transmission line impedance is perfectly matched with the impedance of one end to allow all incident waves to pass, and if the value of the standing wave ratio of the voltage is greater than 1, it indicates that the incident is more reflected. The wave makes the voltage standing wave ratio an important indicator for judging whether an antenna is functioning properly.

As shown in FIG. 2, the voltage standing wave ratio detector 400 can compare a standard signal A according to an output control of one of the RFID readers 700 and an impedance according to an impedance of an antenna 100 and an external reflected wave. Change B to detect the voltage standing wave ratio between the antenna 100 and a radio frequency identification reader 700.

The voltage standing wave ratio controller 500 can control a voltage standing wave ratio characteristic based on the voltage standing wave ratio detected by the voltage standing wave ratio detector 400, and can be configured in an analog circuit. The phase/impedance controller 200 utilizes the controlled voltage standing wave ratio characteristic to adjust a phase and impedance between the antenna 100 and the RFID reader 700.

3a to 3c are diagrams illustrating a phase control method of the phase/impedance controller of Fig. 1.

As shown in Figure 3a, it can be noted that this phase and power level can vary due to the generation of reflected waves between the RFID reader 700 and the antenna 100.

Figure 3b illustrates a phase/impedance controller controlling a phase waveform at 40% of the phase, and Figure 3c illustrates a phase/impedance controller controlling the phase at 90% of the phase waveform.

4 is a functional block diagram showing a radio frequency identification transceiver device according to another embodiment of the present invention. The same operation of the radio frequency identification transceiver device of FIG. 4 will be omitted in the description.

Referring to FIG. 4, the voltage standing wave ratio detector 400 can include an RF detector 410, an analog converter (AD converter) 420, and a signal processor 430.

The RF detector 410 detects an RF signal pulse output from the pointing coupler 300. In general, the radio frequency communication uses the Amplitude Shift Keying (ASK) modulation method, so that the radio frequency detector 410 is used to identify a transmission command signal to facilitate reading from the radio frequency identification as shown in FIG. The instruction of the extractor 700 is identified to mitigate the transition of the transmission/reception state.

As shown in FIG. 5, FIG. 5 is a schematic diagram showing signal waveforms detected by the RF detector of FIG. 2 according to an embodiment of the invention.

The signal processor 430 performs the operation of Equation 1 to calculate a voltage standing wave ratio, wherein the calculated voltage standing wave ratio is input to a main signal processor 800. The radio frequency identification transceiver device according to the present invention may further include a standard signal detector 600 that uses a signal output from the pointing coupler 300 to detect a voltage standing wave ratio standard signal.

As shown in FIG. 4, the standard signal detector 600 can include a pair of log detectors 610, an amplifier 620, and an analog converter (AD converter) 630 to operate. The voltage standing wave ratio standard signal confirmed by the standard signal detector 600 is input to the main signal processor 800.

The main signal processor 800 outputs the voltage standing wave ratio and voltage standing wave ratio standard signal to voltage standing wave ratio controller 500 input by the voltage standing wave ratio detector 400 and the standard signal detector 600, wherein the voltage station is The wave ratio controller 500 controls the characteristic such that the detected voltage standing wave ratio matches the voltage standing wave ratio standard signal.

FIG. 6 is a schematic diagram showing voltage standing wave ratio characteristics of a radio frequency identification transceiver device according to an embodiment of the invention.

As illustrated in FIG. 4, the voltage standing wave ratio controller 500 can include a radio frequency detector 510, a signal processor 520, and an analog-to-digital converter 530.

The phase/impedance controller 200 adjusts a phase and an impedance between the antenna 100 and the RFID reader 700 in response to the voltage standing wave ratio controlled by the voltage standing wave ratio controller 500. For example, the phase/impedance controller 200 can adjust the phase and the impedance to correct the reflection coefficient according to the controlled voltage standing wave ratio, so that the voltage standing wave ratio is automatically adjusted according to the environment. The analog-to-digital converter 530 converts a type of analog signal detected by the RF detector 510 into a digital signal.

FIG. 7 is a schematic diagram showing signal waveforms transmitted by a radio frequency identification transceiver device according to an embodiment of the invention.

As shown in FIG. 7, in order to prevent a transmission signal higher than, for example, 30 dBm (1 W) from entering a receiving end, the phase/impedance controller 200 can control the phase and impedance to adjust the reflection coefficient so that the transmission signal can be Reflected. Further, the query response and the tag backscattering signal as shown in FIG. 7 can be changed to the receiving state and the phase correction is performed in a label preamble section. The phase correction is performed by a phase converter of the reader via an erroneous section of the erroneous input signal generated by the inverted input signal due to the reflected wave signal.

FIG. 8 is a functional block diagram showing a radio frequency identification transceiver device with a frequency band module installed according to an embodiment of the invention.

Referring to FIG. 8, the RFID device may include a multi-band antenna 900 capable of transmitting and receiving signals of different frequency bands, for example, an ultra high frequency (Ultra High Frequency) of about 900 MHz to about 2 GHz. UHF) band.

Further, different from FIG. 8, the radio frequency identification transceiver device according to the present invention may be installed with a plurality of antennas capable of transmitting and receiving mutually different frequency band signals, that is, a signal capable of transmitting and receiving a 900 MHz frequency band signal. An antenna and a second antenna capable of transmitting and receiving signals of a frequency band of approximately 2 GHz.

As shown in FIG. 8, the radio frequency identification transceiver device according to the present invention may include a plurality of frequency band control modules (910, 920, 930) capable of automatically adjusting the voltage standing wave ratio in the radio frequency identification reader 940.

For example, the first frequency band control module 910 can automatically adjust a voltage standing wave ratio of the first frequency band signal in different frequency broadband signals transmitted and received via a multi-band antenna 900, and the second frequency band control module 920 can automatically Adjusting a voltage standing wave ratio of the second frequency band signal in different frequency broadband signals transmitted and received via a multi-band antenna 900, and an nth band control module 930 can automatically adjust via a multi-band antenna 900 A voltage standing wave ratio of the nth band signal of one of the different frequency broadband signals transmitted and received.

The configuration and operation of each of the plurality of frequency band control modules (910, 920, 930) installed in the radio frequency identification transceiver device according to the present invention are the same as those of the frequency identification transceiver devices described in FIGS.

That is, each of the first through nth control modules (910, 920, 930) may include the phase/impedance controller 200 as described in FIG. 1, the pointing coupler 300, the voltage standing wave ratio detection The detector 400 and the voltage standing wave ratio controller 500 may further include a standard signal detector 600 and the main signal processor 800 in addition to the constituent elements described in FIG.

The number of frequency band control modules installed in the radio frequency identification transceiver device according to the present invention is the same as the number of signal bands transmitted and received by the multi-band antenna 900.

For example, in one example, the multi-band antenna 900 transmits and receives 900 MHz and 2 GHz frequency band signals, and the RFID device can include a first band control module 910 that automatically adjusts a voltage standing wave ratio of one of the 900 MHz frequency bands. And a second band control module 920 that automatically adjusts a voltage standing wave ratio of one of the 2 GHz frequency bands.

Further, in one example, the radio frequency identification transceiver device is equipped with a plurality of antennas for transmitting and receiving frequency band signals, and each of the plurality of antennas can be connected to a frequency band control module corresponding to an associated frequency band. For example, in one example, the radio frequency identification transceiver device is equipped with a first antenna for transmitting and receiving a 900 MHz frequency band signal, and a second antenna for transmitting and receiving a frequency band of about 2 GHz, and automatically adjusting 900 MHz. The first frequency band control module 910 of the voltage standing wave ratio of the frequency band can be connected to the first antenna, and the second frequency band control module 920 that automatically adjusts the voltage standing wave ratio of the 2 GHz frequency band can be connected to The second antenna.

The industrial applicability of the present invention lies in: from a practical point of view, a reflected wave and an impedance mismatch are generated according to a reader, an antenna, and an object to be recognized during radio frequency identification (RFID) field placement. Therefore, a portion of the reader output is reduced, and a recognition rate caused by the change of the label phase based on the reflection characteristic is reduced, and the RFID device can control the connection between the reader and one of the antennas. An impedance that effectively manages the output loss of the reader such that the phenomenon of the recognition rate reduction can be adjusted by automatically controlling the phase of a portion of the label preposition error caused by the phase change based on the reflected wave characteristic.

In summary, the present invention is only described as a preferred embodiment or embodiment of the technical means for solving the problem, and is not intended to limit the scope of the invention. That is, the equivalent changes and modifications made in accordance with the scope of the patent application of the present invention or the scope of the invention are covered by the scope of the invention.

100. . . antenna

200. . . Phase/impedance controller

300. . . Pointing coupler

400. . . Voltage standing wave ratio detector

410. . . Radio frequency detector

420. . . Analog digital converter

430. . . Signal processor

500. . . Voltage standing wave ratio controller

510. . . Radio frequency detector

520. . . Signal processor

530. . . Analog digital converter

600. . . Standard signal detector

610. . . Logarithmic detector

620. . . Amplifier

630. . . Analog digital converter

700. . . Radio frequency identification reader

800. . . Main signal processor

900. . . Multi-band antenna

910. . . First band control module

920. . . Second band control module

930. . . The nth band control module

940. . . Radio frequency identification reader

A. . . Standard signal

B. . . Impedance change

1 is a block diagram showing the control of a radio frequency identification transceiver device according to an embodiment of the invention;

2 is a schematic diagram illustrating a method for detecting a voltage standing wave ratio of the voltage standing wave ratio detector of FIG. 1;

3a to 3c are diagrams illustrating a phase control method of the phase/impedance controller of FIG. 1;

4 is a block diagram showing the function of a radio frequency identification transceiver device according to another embodiment of the present invention;

FIG. 5 is a schematic diagram showing signal waveforms detected by the RF detector of FIG. 2 according to an embodiment of the invention; FIG.

FIG. 6 is a schematic diagram showing a voltage standing wave ratio characteristic of a radio frequency identification transceiver device according to an embodiment of the invention; FIG.

7 is a schematic diagram showing signal waveforms transmitted by a radio frequency identification transceiver device according to an embodiment of the invention;

FIG. 8 is a functional block diagram showing a radio frequency identification transceiver device with a frequency band module installed according to an embodiment of the invention.

100. . . antenna

200. . . Phase/impedance controller

300. . . Pointing coupler

400. . . Voltage standing wave ratio detector

500. . . Voltage standing wave ratio controller

Claims (12)

A radio frequency identification transceiver device comprising: an antenna; a directional coupler for outputting a forward wave signal input from the antenna and a reflected wave signal reflected from the antenna; a standard signal detector, the standard signal The detector uses a signal output from the pointing coupler to detect a voltage standing wave ratio standard signal; a voltage standing wave ratio detector uses the forward wave signal and the reflected wave signal to detect a voltage station a voltage standing wave ratio controller that controls a voltage standing wave ratio characteristic in response to the detected voltage standing wave ratio; and a phase/impedance controller that utilizes the controlled voltage standing wave ratio characteristic to adjust a phase and an impedance, wherein the standard signal detector comprises: a pair of detectors for detecting a pair of signals for detecting a voltage standing wave ratio standard signal; and an amplifier for amplifying by the log detector The detected logarithmic signal; an analog-to-digital converter that converts a type of analog signal amplified by the amplifier. The radio frequency identification transceiver device of claim 1, further comprising a main signal processor, wherein the main signal processor output is respectively The voltage standing wave ratio detector and the standard standing signal ratio input by the voltage standing wave ratio detector and the voltage standing wave ratio standard signal to the voltage standing wave ratio controller. The radio frequency identification transceiver device according to claim 1, wherein the voltage standing wave ratio controller uses the detected voltage standing wave ratio and the voltage standing wave ratio standard signal to control the voltage standing wave ratio characteristic. . The radio frequency identification transceiver device of claim 1, wherein the directional coupler is connected between the antenna and a radio frequency identification reader. The radio frequency identification transceiver device of claim 4, wherein the phase/impedance controller adjusts the phase and the impedance between the antenna and the radio frequency identification reader. The radio frequency identification transceiver device according to claim 1, wherein the voltage standing wave ratio detector detects the voltage standing wave ratio according to Equation 1 below, and wherein the voltage standing wave ratio is close to 1 When a transmission line impedance is perfectly matched with one end impedance to prevent an incident wave from being reflected and allowing all of the incident wave to pass, Equation 1 is: voltage standing wave ratio = (1 + | ρ |) / (1-| ρ|) where ρ is a reflection coefficient. The radio frequency identification transceiver device of claim 6, wherein the phase/impedance controller adjusts the phase and the impedance to adjust the reflection coefficient such that the voltage standing wave ratio can be automatically adjusted to meet environmental requirements. . The radio frequency identification transceiver device according to claim 1, The phase/impedance controller is coupled between the antenna and the directional coupler. The radio frequency identification transceiver device of claim 1, wherein the phase/impedance controller adjusts a reflection coefficient to allow reflection of a transmission signal having more than a predetermined level. The radio frequency identification transceiver device of claim 1, wherein the voltage standing wave ratio controller comprises: a radio frequency detector for detecting a signal output from the directional coupler; and an analog-to-digital converter Converting a type of signal detected by the RF detector into a digital signal; and a signal processor calculating a power level value of the converted digital signal. The radio frequency identification transceiver device of claim 1, wherein the antenna is a multi-band antenna, and the radio frequency identification transceiver device further comprises a control module comprising a plurality of control modules corresponding to a frequency band control module. A control module, the band control module corresponding to an associated frequency band. The radio frequency identification transceiver device according to claim 11, wherein the multi-band antenna transmits and receives a frequency signal including an ultra-high frequency band of a frequency band signal from 900 MHz to 2 GHz.