CN104573772B

CN104573772B - Radio frequency identification positioning and tracing equipment and mode

Info

Publication number: CN104573772B
Application number: CN201510054794.4A
Authority: CN
Inventors: 周立明
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-02-02
Filing date: 2015-02-02
Publication date: 2019-03-01
Anticipated expiration: 2035-02-02
Also published as: CN107403120A; CN104573772A

Abstract

The present invention relates to field of radio frequency identification, and in particular to radio frequency identification positioning and tracing equipment and method essentially disclose a kind of radio-frequency identification reader/writer and RFID tag with phased array antenna, to position and track reader and label；Also disclose a variety of technologies for improving reading/writing distance, comprising: for eliminating the transmitting leakage technology in reader and in antenna；For improving the technology of RFID tag scattering modulation efficiency；Reader and label polarization mode are adjusted to improve the technology of channel loss；The technology of channel loss is reduced using repeater.Further include in the technical solution being disclosed a novel reflective vector attenuator construction and its in frequency read/write with the application method in label.The present invention is the comprehensive improvement to existing based on radio-frequency identification reader/writer and electronic labelling system, systematically solve the problems, such as it is existing it is short based on radio-frequency identification reader/writer and reading/writing distance present in electronic labelling system, trace ability is weak.

Description

Radio frequency identification positioning and tracing equipment and mode

Technical field

The present invention relates to field of radio frequency identification, it particularly relates to a kind of positioning of radio frequency identification and tracing equipment and mode.

Background technique

The background technique is the general implementation in order to illustrate different video identifying system, and viewpoint cannot be simple equivalent In the prior art.Correspondingly, specific implementation described in background note also should not be simply equivalent to have proved or publicity The prior art implementation method.

Radio frequency identification (RFID) label and reading and writing device system are read using electromagnetic field transmission data, including RFID label tag and RFID Write device.RFID label tag is also referred to as electronic tag, transponder, identification label.RFID reader is used to exchange coding with RFID label tag Rear information simultaneously positions label.RFID label tag can absorb the radio wave that neighbouring reader is emitted, and to the received nothing of institute Line electric wave is modulated by varying load will identify that the identification information in label passes frequency read/write back.

Existing identification label is broadly divided into three types: the first kind is active electronic label, itself generates radio frequency letter Number and can independently generate modulated signal, work capacity is provided by battery；Second class is passive electronic label, itself does not have battery, It needs to obtain energy from the electromagnetic wave received, and modulation is scattered to the radiofrequency signal received；The third is half nothing Source electronic tag includes the battery for powering to chip, but cannot generate independent radio frequency signal, needs to the radio frequency received Signal does scattering modulation.In general, the semi-passive electronic tag of charged pool has lower radio frequency activation power and longer Read and write range.Electromagnetic wave has biggish loss during long distance transmission, to guarantee sufficiently long reading distance, it is desirable that penetrate Frequency identification reader has enough sensitivity.

Passive label uses an antenna, while for sending and receiving, by changing the load impedance of antenna when transmission It is scattered modulation.Back scattered signal energy is only a part of input signal energy, and another part energy is used for passive The in-line power of electronic tag.Amplifier and circulator can scatter tag combination with single antenna and form loop to increase modulation effect Rate.But this structure is very easy to oscillation, because of the presence of circulator and gain loop, holds that the impedance of RFID antenna very Easily affected by environment, the reflection coefficient of antenna can directly become loop gain, when oscillation loop gain is 1 or more, this circuit It can shake.Therefore the electronic tag with radio frequency amplifier needs more reliable, more stable circuit structure, to efficiently use amplification High scattering efficiency is realized in device gain.

RFID reader not only sends but also receives electromagnetic wave, for carrying out information exchange with neighbouring electronic tag.To read-write For device and electronic tag this system, read range is damaged by the transmission power of reader, the activation power of electronic tag, transmission Consumption, antenna polarization matching determine.Successful electronic tag reading is necessary to ensure that electronic tag receives sufficiently high radio-frequency power, And the scattering modulated signal that receives of reader is higher than the sensitivity of reader.In the actual environment, reader and electronics mark There are multiple propagation paths between label.Mobile electronic tag due to composite wave propagation path more than and also it is unstable, cause to connect The signal strength received is also more unstable, and the ratio between the polarization tilt angle of the wave after combination and polaxis can also change. For the reader and electronic label antenna that polarization is fixed, if reading/writing distance is different, multipath fading effect will be remarkably reinforced, Except the reader and electronic label antenna of non-polarized fixation are in the free space or electromagnetic anechoic chamber of single propagation path. In order to overcome this fading effect, guarantee can effectively read electronic tag distance, need to improve the sensitivity of reader. The sensitivity of reader is determined by its noise coefficient and dynamic range and the ability of anti-transmitting leakage.Electronic tag swashs Distance living can activate power to realize by increasing to send power or reduce electronic tag.Increasing transmission power will lead to more sternly The transmitting leakage of weight, and reduce noise coefficient and dynamic range that electronic tag activation power needs to improve reader.Therefore, this Two methods require to reduce sensitivity of the transmitting leakage to improve reader receiving part.

In the RFID system of full duplex, the leakage of reader transmitting signal is likely to occur in inside reader, antenna draws During Ambient in the coupling process risen or around antenna is coupled to the receiving part of reader.Hair in reader Penetrating leakage may be caused by coupling, power supply coupling, capacitive coupling, Mutual Inductance Coupling, the wave resonance etc. between internal circuit board.Single-shot list Couple leak caused by the antenna of reader is received to be determined by the reflection coefficient of antenna, and the antenna of bistatic formula reader causes Couple leak determined by the mutual coupling factor between two antennas.It is using an antenna while to be responsible for that single-shot list, which receives formula reader, Transmission and reception signal, and bistatic formula reader is to be each responsible for sending and receiving using two antennas.Single-shot list receives formula Reader is often used the duplexer of a circulator or directional coupler as discrete transmitting and reception signal.In addition, environment Variation, such as being toward or away from for vehicle or people, antenna can also generate transmitting leakage, because a part transmitting signal is by Ambient Into receiving antenna.The leakage for solving these three types needs kinds of schemes to cooperate.The transmitting leakage and ring that antenna introduces Transmitting leakage pace of change caused by border needs relatively quick tracking speed all than very fast.Existing leakage removing method is to make It is combined with adjustable attenuator and adjustable phase shifter the copy for sending signal to be adjusted, to generate transmitting leakage Negative sample.But existing reflection-type phase shifter lacks continuous tuning range, thus can not accomplish 360 degree or more not between Disconnected adjusting.In addition, attenuator is restricted tuning resolution ratio because there is the limitation of tuning precision and range.This structure Transmitting leakage eliminates infrastructure cost height, tuned speed slowly and needs complicated control algolithm, and is not available classical negative-feedback Control algolithm controls.

Although industrial applications ratios such as radio frequency identification and positioning system gate inhibition's access control in daily life, asset managements It is wide, but do not applied sufficiently.To find out its cause, a portion is limited by physical factor, such as multi-spread path Decline, because of chip activation power limited system, the energy of passive and semi-passive Scattering Communication caused by transistor size and design problem Measure conservation limitation, etc..Consider from engineering viewpoint, needs to allow reader in full-duplex mode using the electronic tag of Scattering Communication Lower work, that is, allow its transmitter and receiver to work at the same time.Because the transmitting signal of radio-frequency identification reader/writer and receive signal without Method is separated in radio band with filter, and transmitting signal can leak in the reception circuit of same reader, to reduce reader The sensitivity of receiver and the noise coefficient for improving reader.If can significantly improve radio-frequency identification reader/writer sensitivity and The scattering modulation efficiency of label will greatly improve the reading distance for reading electronic tag, and develop many new RFID applications Mode.The application mode not being available at present by the limitation of reading/writing distance can be developed after reading/writing distance increases at multiple It uses.

Summary of the invention

The first purpose of the invention is to provide a kind of radio frequency identification positioning systems, existing based on RFID's to improve The orientation distance and trace ability of positioning system.

Above-mentioned first goal of the invention that the invention is realized by the following technical scheme: the radio frequency identification positioning system Including radio-frequency identification reader/writer and its phased antenna array, which at least contains there are two radiating element, each spoke Penetrate element has dedicated upconverter and low-converter, and the phase between at least two radiating elements in radio-frequency identification reader/writer Delay can be adjusted, for generating the adjustable radiation lobe of antenna in direction to phased antenna array to retrieve aerogram Number direction；The radio-frequency identification reader/writer with phased antenna array is used to detect the angle of at least two RFID tags, The label position coordinate being stored in two labels is obtained, and the position coordinates of label and angle are calculated described in acquisition The location information of radio-frequency identification reader/writer.

A second object of the present invention is to provide a kind of electronic tags, strong for solving the signal that existing electronic tag emits Spend the weak and short problem of reading/writing distance.

Above-mentioned second goal of the invention that the invention is realized by the following technical scheme；The electronic tag, comprising:

Receiving antenna, for receiving the external radio-frequency signal transmitted from reader；

Amplifier is connected with the receiving antenna, for amplifying external radio-frequency signal；

Envelope detector is connected with the amplifier, for demodulating the radiofrequency signal of amplification, and generates demodulated signal；

Digital processing unit is connected with the envelope detector, for handling the signal after demodulation and execution is previously written Program controls the element being connected with number；

Radio-frequency modulator is connected with the amplifier with the envelope detector, by digital processor controls, is used to radio frequency Amplified radiofrequency signal is modulated, modulated radiofrequency signal is generated；

Transmitting antenna is connected with the radio-frequency modulator, for emitting modulated radiofrequency signal, concurrently return reader with Information is exchanged with reader.

Third object of the present invention is to provide it is a kind of feedforward and open loop radio-frequency leakage eliminate circuit and it is a kind of feedback and The radio-frequency leakage of closed loop eliminates circuit, and for solving, existing transmitting leakage elimination infrastructure cost is high, tuned speed is slow, needs complexity Control algolithm, and be not available classical negative feedback control algorithm come the problem of control.

Above-mentioned third goal of the invention that the invention is realized by the following technical scheme: the radio-frequency leakage of the feedforward and open loop Eliminate circuit, comprising:

Quadrature down converter, the quadrature down converter are used for secondary by the first of radio frequency receiving signal and radio frequency transmissions This orthogonal frequency conversion, generates with mutually defeated signal and positive blending output signal；

First low-pass filter is connected with the quadrature down converter, is used to the above-mentioned In-phase output signal of low-pass filtering simultaneously It generates with phase reference voltage；

Second low-pass filter is connected with the quadrature down converter, is used to the above-mentioned positive blending output signal of low-pass filtering simultaneously Generate orthogonal reference voltage；

Linear combination circuits are connected with first low-pass filter and the second low-pass filter, for generating the first control Voltage processed and second control voltage, it is described first control voltage be equal to the same phase reference voltage, the orthogonal reference voltage and First can be zero constant linear combination；The second control voltage is equal to the same phase reference voltage, the orthogonal ginseng Examine voltage and second can be zero constant linear combination；

Quad upconverter is connected with the linear combination circuits, is used to the first control voltage, the second control electricity Orthogonal with the triplicate of radio frequency transmissions mixing is pressed, generates a radio frequency output signal and by itself and letter to be received Number superposition, with eliminate transmitting leakage.

It includes quadrature down converter, the first low-pass filter, second that the radio-frequency leakage of the feedback and closed loop, which eliminates circuit, Low-pass filter, at least two analog-digital converters, DSP unit, at least two digital analog converters, vector decaying Device, amplifier, at least two high-pass filters, wherein

Quadrature down converter, for producing after radio frequency receiving signal frequency conversion orthogonal with the first authentic copy of radio frequency transmissions Raw In-phase output signal and positive blending output signal；

Second low-pass filter, is connected with the quadrature down converter, is used to the above-mentioned positive blending output signal of low-pass filtering And generate orthogonal reference voltage；

At least two analog-digital converters are respectively intended to the same phase reference voltage and orthogonal reference voltage being converted to number Reference voltage signal；

DSP unit is connected with the analog-digital converter, is used to operation and handles the reference voltage believe Number, and generate digital control voltage signal；

At least two digital analog converters are connected with the DSP unit, and being used to will be described numerically controlled Voltage signal is converted into same phase analog control voltage and orthogonal simulation controls voltage；

Vector attenuator is coupled at least two digital analog converter, carries out for the triplicate to transmitting signal Phase and amplitude are aligned, and the Signal averaging tieback adjusted collection of letters number is leaked with eliminating the transmitting mixed with it；

Amplifier is placed at the transmitting leakage superposition between the quadrature down converter, for reducing reception circuit Noise coefficient；

At least two high-pass filters are connected with the quadrature down converter, for provide same phase fundamental frequency output signal with Quadrature baseband output signal, the high-pass filter is for filtering out the direct current formed after radio-frequency leakage is converted by quadrature down converter Leakage residual.

Fourth object of the present invention is to provide a kind of reflective vector attenuator, for solving existing vector attenuator tune The discontinuous problem of adjusting range.

Above-mentioned 4th goal of the invention that the invention is realized by the following technical scheme, the reflective vector attenuator include Hybrid coupler, this hybrid coupler include the first port 3dB and the 2nd port 3dB, and it is negative that the first port 3dB is connected to first It carries, this first load is that impedance adjustable formula loads, and the 2nd port 3dB is connected to the second load, this second load can be solid Constant impedance can also load for impedance adjustable formula.

Fifth object of the present invention is to provide a kind of radio signal modulators, for improving the scattering of radio signal Modulation efficiency guarantees its stability.

Above-mentioned 5th goal of the invention that the invention is realized by the following technical scheme: the radio signal modulator includes First antenna, vector attenuator and the second antenna, vector attenuator are connected with first antenna, the second antenna, and the second antenna is used to Secondary transmission is by the modulated signal of vector attenuator.

Sixth object of the present invention is to provide a kind of radio relay devices, with radio-frequency identification reader/writer and electronic tag It is used cooperatively, improves reading/writing distance.

Above-mentioned 6th goal of the invention that the invention is realized by the following technical scheme: the radio relay transceiver is used By Secondary Emission after the radio wave received amplification, comprising:

Receiving antenna, for receiving external radio-frequency signal；

Amplifier is connected with the receiving antenna, for generating amplified radiofrequency signal；

Transmitting antenna is connected with the amplifier, for emitting amplified radiofrequency signal；

It is put for the circuit of monitoring amplifier working condition including the envelope detector being connected with amplifier for monitoring The amplitude of radiofrequency signal after big；The digital processing unit being connected with envelope detector, for judging whether amplifier is saturated or shakes It swings, and executes the program being previously written and operate coupled element.

The invention has the advantages that the present invention is to the positioning and tracking currently based on radio-frequency identification reader/writer and electronic tag The comprehensive improvement of equipment systematically solves existing positioning and tracing system based on radio-frequency identification reader/writer and electronic tag Present in reading/writing distance is short, trace ability is weak problem.

Detailed description of the invention

Fig. 1 is the schematic diagram of the radio-frequency location system based on RFID.

Fig. 2A is to leak elimination circuit containing reader/writer module to leak showing for the RFID reader for eliminating circuit with Anneta module It is intended to.

Fig. 2 B is the schematic diagram that circuit is eliminated in feedforward transmitting leakage.

Fig. 3 A is with the schematic diagram for the reflective vector attenuator that suitching type inductance and capacitance resistance is load.

Fig. 3 B is the schematic diagram using the reflective vector attenuator with distributed short circuit load in parallel.

It is that the reflective vector that the port 3dB loads declines that Fig. 3 C, which is with series connection and parallel-connection adjustable inductance and capacitance resistance (LRC), Subtract the schematic diagram of device.

Fig. 3 D is the schematic diagram with the distributed reflective vector attenuator of variable resistance again.

Fig. 3 E is using the field-effect tube with difference as the schematic diagram of the reflective vector attenuator of variable load.

Fig. 3 F is with the schematic diagram of the discrete component equivalent circuit of transmission line phase-shifter.

Fig. 3 G is the schematic diagram of the discrete component equivalent circuit of left hand transmission line phase-shifter.

Fig. 4 A is the schematic diagram of adjustable dual-polarized antenna of polarizing.

Fig. 4 B is the schematic diagram of the adjustable poliarizing antenna of the list with impedance matching circuit.

The schematic diagram for the variable load match circuit that Fig. 4 C is 25 or 50 ohm.

Fig. 4 D be matched using selective branch 25 or 50 ohm variable load schematic diagram.

Fig. 5 A is the schematic diagram for including the bistatic formula electronic tag of radio frequency amplifier and switching regulator modulator.

Fig. 5 B is using amplifier as the bistatic formula electronic tag schematic diagram of modem devices.

Fig. 5 C is the double schematic diagrames for receiving electronic tag of double hairs adjusted with polarization.

Fig. 5 D is the amplifying device of variable gain and phase shift.

Fig. 5 E is the adjustable radio relay repeater array in dual-mode antenna direction.

Fig. 5 F is the adjustable radio relay repeater of transmitted antednna beam.

Fig. 5 G is the adjustable radio relay repeater of receiving antenna wave beam.

Specific embodiment

The similar statement such as " one embodiment ", " technical solution " in this specification refers to described specific spy Property, structure or feature at least exist in one embodiment of the invention.And the same table in above-mentioned similar form of presentation It states not necessarily referring to same embodiment.

With reference to the accompanying drawing, it elaborates to the present invention:

Fig. 1 gives the schematic diagram of a radio-frequency location system based on RFID.System is positioned in the radio frequency based on RFID In system 100, the RFID reader 105 with direction finding phased array is for reading electronic tag 135, electronic tag 140, electronics mark The information of label 145.The phased array of electron scanning obtains the relative angle of above three electronic tag signal.Due to each electricity The coordinate information of subtab is stored in its internal memory, so the coordinate using each electronic tag can be extrapolated The position of RFID reader 105, method are: RFID reader 105 retrieves each electronic tag to obtain their coordinate and phase To angle, coordinate and the direction of RFID reader 105 itself are then calculated.

A technical solution of the invention is: RFID reader 105 and directional aerial 120, directional aerial 125 and orientation day Line 130 is coupled.Directional aerial 120 can be used to send and receive transmitting (TX) signal 111 of RFID reader 105 and receive (RX) signal 112.Another technical solution is: directional aerial 125 can be used to send and receive the TX letter of RFID reader 105 Number 113 and RX signal 114.Another technical solution of the invention is: directional aerial 130 can be used to send and receive reader TX signal 115 and RX signal 116.

In another technical solution of the invention, the phased array of RFID reader 105 contains at least two radiation element Part, and each radiating element by dedicated radio-frequency-up-converter drive transmit signal and by radio-frequency-down-converter driving Lai Receive signal.Variable phase delay can be applied between adjacent radiating element to adjust the beam positional angle of phased array The direction of electronic tag is determined with the elevation angle.

The position of RFID reader 105 and angle can use principle of triangulation to determine.As long as RFID reader 105 Not point-blank with three electronic tags, user can use three electronic tags (such as electronic tag 135,140 and 145) position and angle information calculate the three-dimensional coordinate of RFID reader 105.This requires RFID reader 105 to have in itself Two-dimentional direction finding ability, that is, be configured with two dimensional phased antenna array.If RFID reader 105 is configured with one-dimensional phased array, The position of two electronic tags is only needed to can be obtained the two-dimensional coordinate of RFID reader 105.It is continuously fixed to RFID reader 105 It can be obtained movement speed and the track of RFID reader 105 behind position.

Other information can be also stored in above-mentioned electronic tag, such as vehicle driving speed limit and condition of road surface.This information quilt After RFID reader 105 obtains, navigating processor or host can be transmitted to.The information stored on electronic tag can use wired programming Device 150 is rewritten, and wireless programmer 160 can also be connected to electronic tag by wireless data interface.Electronic tag and Ying Te Netcom is crossed after wireless data interface is connected, and user can information inside long-range real-time update electronic tag.

In one embodiment, electronic tag 140, electronic tag 135, electronic tag 145, directional aerial 125 and orientation The relative position information of antenna 130 can be calculated by the above method and be obtained.In one embodiment, electronic tag 135 and electricity The distance between subtab 140 177 can be determined.In one embodiment, between electronic tag 135 and electronic tag 145 Distance 178 can be determined.In one embodiment, the distance between electronic tag 145 and electronic tag 140 179 can be with It is determined.In one embodiment, the distance between electronic tag 135 and directional aerial 125 174 can be determined.At one In embodiment, the distance between electronic tag 140 and directional aerial 125 175 can be determined.In one embodiment, electronics The distance between label 145 and directional aerial 125 176 can be determined.In one embodiment, electronic tag 135 and orientation Angle a1171 between antenna 125 can be determined.In one embodiment, between electronic tag 140 and directional aerial 125 Angle a2172 can be determined.In one embodiment, the angle a3173 between electronic tag 145 and directional aerial 125 can It is determined.

Fig. 2A is that circuit is eliminated in a leakage containing reader/writer module and the RFID reader of circuit is eliminated in Anneta module leakage Schematic diagram.In a technical solution, RFID reader 200 includes digital processing unit 201 and the memory being attached thereto 202.Digital processing unit 201 can be connected with control host 207 to exchange information, be connected with keyboard 208 and display 209 to input With display information.

In one embodiment, digital processing unit 201 will need the signal sent to be sent to digital analog converter (DAC) 203. DAC203 can export fundamental frequency (BB) transmitting signal 205.Fundamental frequency, which receives signal 206, can be passed to analog-digital converter (ADC) In 204.The digital signal that ADC 204 is exported can be demodulated and decoded in digital processing unit 201.Fundamental frequency emits signal 205 Signal is sent for modulating the reference signal of local oscillator (LO) to generate radio frequency.In one embodiment, RFID reader 200 contain phaselocked loop (PLL) local oscillator (an abbreviation phaselocked loop local oscillator) 213 to generate local oscillator signals.In phase It controls in antenna array, local oscillator signals are shared by all radiating elements.Radio frequency receiving signal is put by low-noise amplifier 224 Greatly, by 212 frequency reducing of quadrature down converter, signal 217 is received to generate fundamental frequency.In one embodiment, fundamental frequency reception signal is Signal 206.Memory 202 is connected to store label data, control program and configuration settings information with digital processing unit 201.It is logical It crosses the keyboard 208 being connected with processor 201 and display 209 can be to RFID reader 200 in the state of being not connected to computer Carry out manual operation.It, can be from control after radio-frequency identification reader/writer is connected with computer by cable data chain or wireless data chain Host 207 remotely operates RFID reader.

In one embodiment, RFID reader 200 further includes quad upconverter 211, this 211 quilt of quad upconverter For fundamental frequency transmitting signal 216 is converted to radio frequency transmissions.

In one embodiment, vector modulator 214 and radio frequency power detector 215 be used to eliminate from transmit circuit It is coupled to the transmitting signals leakiness 218 for receiving circuit.Vector modulator 214, which is equivalent to one, can receive direct current and positive and negative fundamental frequency is defeated Enter the quad upconverter of signal.Radio frequency power detector 231 is detected by directional coupler 219 is transferred into orthogonal lower change The transmitting of frequency device 212 leaks, directional coupler 222 be used to by received radiofrequency signal with from the leakage of vector modulator 214 Thermal compensation signal is superimposed.Directional coupler 219 is between directional coupler 222 and quadrature down converter 212.Radio-frequency power inspection The output valve for surveying device 231 can be used to calibrate the control parameter of vector modulator 214.Such as in radio-frequency identification reader/writer 200 Just in the case where booting, when transmitting leadage coefficient random device heats up and changes, the output signal of radio frequency power detector 231 It is digitally processed after device 201 detects, vector modulator 214 can be adjusted accordingly.After machine preheating, in module group Transmitting leakage signal it is relatively stable, only be easy influenced by module group temperature, digital processing unit 201 can also pass through memory Temperature correction information inside 202 directly adjusts vector modulator 214 in the case where environment temperature changes, this work shape The function using radio frequency power detector 231 is not needed under state.

In one embodiment, the radio frequency that RFID reader sends reader to label (T2R) using antenna 250 is believed Number, the radiofrequency signal of label to reader (R2T) is received using antenna 255.The reader 200 of this operating mode is to receive and dispatch Separated type reader.In the Anneta module 230 of bistatic formula reader, a part of transmitting signal 251 can be because of capacitor With mutual inductance effect by near-field coupling to receiving antenna 255, another part reflexes to receiving antenna 255 by far field.

Transmitting signal on the radio frequency emitting component and transmission line of RFID reader duplexer would generally be because of galvanomagnetic-effect It is coupled in receiving part and transmission line.Reader uses length to be connected much larger than the cable of 1 wavelength more.In the case, The transmitting leakage signal that transmitting leak compensation built in module group can not be introduced with the antenna after cable delay carries out the time Delay matching, and can only guarantee unifrequency point phase delay matching, thus cannot achieve wideband leakage eliminate function, system because This and become complicated and high cost.In one embodiment of the invention, in order to eliminate at antenna from being emitted to received let out Leakage, a copy for emitting signal pass through directional coupler 234,233 and the direct coupling of vector modulator 240 from transmitting antenna 250 It is bonded to reception circuit, it is superimposed with the reception signal of receiving antenna 255.The control parameter of vector modulator 240 is set to lead to The transmitting signal that the transmitting signal in this signal compensation circuit leaks from from antenna is crossed to offset.Radio frequency power detector 231 is logical Reception signal after crossing the detection leakage compensation of directional coupler 232 is to judge remaining transmitting leakage.In the shape of no reception signal Under state, the output of the radio frequency power detector 231 is the power indicator of residual transmitting leakage.Therefore under align mode, This power detector 231 can be used to the control coefrficient of setting vector modulator 214.

In another embodiment, radio frequency amplifier 224 is used to amplify the reception signal in RF frequency band, is read with reducing Take the noise coefficient of device.Because the transmitting signal power of leakage is relatively large, radio frequency amplifier 224 will be placed in reader/writer module group After interior transmitting leakage cancellation element, to prevent the saturation of amplifier here.Transmitting in reader/writer module group leaks cancellation element packet Include the radio frequency power detector 215 of both direction coupler 223 and 222, a vector modulator 214 and a calibration.It puts Reception signal after big is transferred into quadrature down converter 212 to generate fundamental frequency and receive signal.This receives the noise coefficient of circuit Because containing radio frequency amplifier, it can be achieved that than without containing the lower noise coefficient of radio frequency amplifier, because quadrature down converter is that have There are the nonlinear device of lower third order intermodulation intercept point (IP3) and higher noise coefficient.In general, becoming under active orthogonal Frequency device is higher than the noise coefficient of passive device, and third order intermodulation intercept point is lower.

In one embodiment, the Anneta module 270 that single-shot list receives reader can be used to send simultaneously radio frequency R2T and connect Receive radio frequency T2R signal.The Anneta module 270 includes a transmit/receive antenna 263, and transmit/receive antenna 263 can be sent out simultaneously It send and receives signal.Antenna diplexer 262 is connected with transmit/receive antenna 263, and there are also for receiving and sending out for this duplexer 262 Penetrate the rf inputs mouth of signal and for exporting the radio frequency output port for receiving signal.Antenna diplexer 262 and transmitting/reception Antenna 263 is integrated in a module, and connects both parts using short transmission line to realize leak path and compensation way The delay of diameter matches.It is similar with the Anneta module group of aforementioned bistatic formula reader, with both direction coupler 268 and 269, The transmitting that one radio frequency power detector 260 and a vector modulator 261 form an inner antenna leaks cancellation element. The distance of coupler 268 and 269 to duplexer 262 is no more than quarter-wave.Power detector 260 passes through directional coupler 271 detect the reception signal after leakage compensation to judge remaining transmitting leakage.The emission port and Anneta module of reader Input port 264 between with cable 230 be connected；And between the receiving port of reader and the output port 265 of Anneta module It is connected with cable 221.Compared with single leak compensation, the transmitting leak compensation of the reader in the present embodiment has Higher bandwidth and more stable control structure.In the antenna modules extremely transmitting leakage arrester can match leakage path and The bandwidth and compensation depth for this compensation device for compensating the time delay in channel, thus optimizing.Compensate bandwidth and depth certainly Qualitative factor is the delay matching in this leakage path and compensation channel.

Elimination system is leaked using distributed emission, i.e., is equipped with the excellent of arrester in Anneta module and in reader/writer module Point is: can reach lower in the case where being greater than Installation Modes of the radio-frequency cable of a wavelength to connect transceiver and antenna using length Receiver noise coefficient and higher leakage compensation bandwidth and depth.One single transmitting leakage eliminates design using super When crossing the RF cable of a wavelength length can only matched-phase delay, therefore cannot achieve wideband leakage compensation.It is compensated in height Under the requirement of depth, single compensation circuit enables to realize high compensation depth in unifrequency, also vulnerable to the influence of environment, and needs Dynamic regulation compensating parameter.The present embodiment can reach broader compensation bandwidth while keeping compensation depth, to reduce Adjust the number of compensating parameter.

In the frequency read/write using multiple antennas, the length of cable is likely to be breached decades of times wavelength, and only 10 degree of phase Compensation depth can be limited to 15 decibels by position error.Therefore, the control of vector modulator and regulative mode disappear for transmitting leakage Except the compensation depth of circuit is most crucial, emit leakage in order to compensate for the dynamic change that antenna end introduces, needs an energy basis Environmental change and the dynamic leakage arrester accordingly changed.

Fig. 2 B shows the schematic diagram that circuit is eliminated in a feedforward transmitting leakage.In one embodiment, feedforward transmitting is let out Leakage is eliminated circuit 290 and can be used in Anneta module or in reader/writer module, is used to dynamic and eliminates transmitting leakage, and this leakage disappears Except circuit has adaptive ability.In one embodiment, it includes five direction couplings that circuit 290 is eliminated in feedforward transmitting leakage Device.First coupler 291 and the second coupler 292 are located on transmission channel, for extracting input terminal transmitting signal 296 or output The copy of end transmitting signal 297.Third coupler 293, the 4th coupler 294 and the 5th coupler 295 are in receiving channel. Coupler 295 is used to extract the copy for receiving signal and leakage signal, and coupler 294 is used to leak thermal compensation signal with transmitting Reception Signal averaging, and coupler 293 then be used to extract the reception signal after leakage compensation, for radio-frequency power detect.Coupling Clutch 293 is selectable unit (SU).

In one embodiment, emit the copy of signal 297 in quadrature down converter and with the reception for emitting leakage The copy of signal 299 makees down mixes.The fundamental component of the output signal of this quadrature down converter is by low-pass filter 283 and low Bandpass filter 284 filters, to generate two reference voltage EVI 285 and EVQ 286 containing DC component.Reference voltage it is linear Combination device circuit 287 is used to combine reference voltage EVI 285 and EVQ 286, generates two control voltage CVI 288 and CVQ 289, to drive quad upconverter 281.The local oscillator (LO) of quad upconverter 281 is the hair that directional coupler 294 is quoted Penetrate another copy of signal.Radio frequency power detector 272 is used to monitor the amplitude of residual transmitting.This radio frequency power detector It applies on baseband circuit, i.e., the amplitude of monitoring transmitting residual signal in the baseband receiver of back segment.It is penetrated for directly converting For frequency receiver, the virtual value of the direct-flow output signal of quadrature down converter, i.e. quadratic sum as emit the power of leakage.

In one embodiment, the function of linear combiner 287 is control voltage CVI 288, the CVQ 289 to product Operation is carried out according to following equation,

CVI=A*EVI+B*EVQ+C

CVQ=D*EVI+E*EVQ+F.

A in equation, B, E and D are coefficient, and to eliminate dynamic emission leakage, C and F are also coefficient, to eliminate static transmitting Leakage.A kind of structure of linear combiner 287 be include four analog multipliers and two analog signal summers, wherein every two A analog multiplier and an analog adder are used to generate a control signal.Another structure of linear combiner 287 is The control signal of number is generated with conversion reference voltage, a DSP unit including two analog-digital converters, And two digital analog converters are to generate two control signals simulated.

Fixed control signal, the control signal that the environment of variation needs to change are needed in static environment.Control signal Frequency determined by antenna relative to the relative moving speed of environment.In different signalk coupling loop borders, 285 He of error voltage 286 numerical value is also had nothing in common with each other.Control voltage 288 and 289 is can not change control required for quad upconverter 281 It is automatically generated in the case where parameter A, B, C, D, E, F by linear combiner, and self calibration is carried out according to the change of error signal.It is dynamic The advantages of state arrester are as follows: it has adaptive ability, and transmitting leakage can be eliminated with the change of environment and in real time, is one Stable open-loop control system；Environment tracking velocity is determined by the bandwidth of low-pass filter 283 and 284, therefore can pass through increase The bandwidth of low-pass filter tracks swiftly passing object and reader itself.In contrast, existing feedback transmitting leakage Elimination system is latent instability, especially in the case where high loop gain.The bandwidth of feedback control system similarly by Stability is limited, therefore bandwidth is lower than open cycle system stability, cannot achieve identical environment tracking speed.

The transmitting leakage arrester slowly adjusted can be used for cancelling in reader or inside Anneta module due to temperature Transport leaks caused by the coefficient of coup caused by changing changes.Depth is eliminated in order to improve leakage, is needed using high precision And dull adjustable vector modulator.The present invention describes multiple passive reflective vector modulators, for open loop type with close Ring type leaks cancellation element.Because these vector modulators do not depend on amplifier, alternatively referred to as vector attenuator.These are anti- The vector setting for penetrating formula vector attenuator (RVA) is continuously adjustable, and has the characteristics that structure simply and high reliablity.Each reflection Formula vector attenuator all includes a 3dB hybrid coupler, and for this hybrid coupler altogether there are four port, two of them are mixed for 3dB Miscellaneous port, and other two port then input port and isolated port each other.Since this hybrid coupler works in reflective-mode, Therefore two ports 3dB are all set to reflector port, and other two port then inputs each other and output port.

Fig. 3 A is a schematic diagram with the reflective vector attenuator that suitching type inductance and capacitance resistance is load.This is anti- Penetrating formula vector attenuator 300 includes the first input/output end port 304, and the second input/output end port 301, this two ports are each other Input and output port.This reflective vector attenuator 300 also includes a 3dB hybrid coupler 317, and the of coupler 317 One port 3dB is A, and second port 3dB is B.The load of the port 3dB A includes at least the resistance of first switch control 311, the capacitor 309 of first switch control, the inductance 310 of first switch control and first short circuit load 312.The end 3dB The load of mouth B includes at least the resistance 315 of second switch control, the capacitor 313 of second switch control, second switch control The inductance 314 of system and second short circuit load terminal 316.The impedance that the port load of these switch controls is used to generate at least is wrapped Containing 0, J50 ,-j0.02,50 or infinitely great ohm, or equal to the load for dividing equally a circle with reflection amplitudes in Smith's original image Value.The transmission coefficient T 305 and reflection coefficient Γ 306 of this RVA is defined as foloows:

Wherein Γ a 307 and Γ b308 is the local reflection coefficient of the port 3dB A and B, and c is this hybrid coupler 317 Phase difference.For example, the c value of 90 degree of hybrid couplers is 90 degree.It therefore, can be by changing two ports 3dB of this RVA Load value to make the amplitude and phase of the transmission coefficient T 305 and reflection coefficient Γ 306 of RVA independent adjustment.Shown in Fig. 3 A Reflective vector attenuator select capacitor, inductance and resistance using switch, the transmission coefficient to RVA and reflection can be realized The discrete adjustment of coefficient.

Fig. 3 B is a schematic diagram using the reflective vector attenuator with distributed short circuit load in parallel.It is reflective to Measuring attenuator 319 includes a 3dB hybrid coupler 329, and the load of first port 3dB includes: first segment a quarter The short circuit load 323,324 and 325 of wavelength transmission line, first 50 ohm of end load 322 and multiple switch control；Its The load of second port 3dB also includes the quarter-wave transmission line of second segment, second 50 ohm of end load 321 And the short circuit load 326,327 and 328 of multiple switch control.The other end of load 322 and 321 is grounded 320.Because of transmission The load transfer benefit of line is in the short circuit load role of different location: equivalent input impedance at the port 3dB is 0, 50, J50, infinity, or be a round multiple equivalent impedances in one Smith's original image of equal part.Shown in Fig. 3 B it is reflective to Amount attenuator can also realize the discrete adjustment to transmission coefficient and reflection coefficient.

Fig. 3 C be one with series connection and parallel-connection adjustable inductance and capacitance resistance (LRC) be the port 3dB load it is reflective to Measure the schematic diagram of attenuator.This reflective vector attenuator 339 includes the first adjustable LRC load and the second adjustable LRC negative It carries and is loaded as the port 3dB of hybrid coupler 330.First adjustable LRC load includes adjustable resistor 331, adjustable electric Container 333 and adjustable electric sensor 332, and the second adjustable LRC load includes adjustable resistor 336, adjustable capacitor 334 With adjustable electric sensor 335.To be connected in series, the second tunable LRC is to be connected in parallel for first adjustable LRC load.The first, The other end of two adjustable LRC is grounded 337 and 338 respectively.To realize biggish reflected phase adjustable range, it can choose and allow often Group at least one resonance point of inductor and capacitor.The impedance of adjustable LRC is equal to the resistance value of resistance at resonance point, and The load of the load of series connection adjustment and adjustment in parallel can provide two orthogonal adjustment of load ranges in Smith's original image.Cause This, this reflective vector attenuator can realize the continuously adjustable transmission coefficient and reflection coefficient of phase and amplitude.In addition, adjusting The limited occasion of device washability, this RVA can also only use two tuned elements, such as only adjust two resistance or only adjust Two capacitors can equally reach the orthogonal continuous adjustment to the transmission coefficient and reflection coefficient of RVA.

Fig. 3 D is the schematic diagram with the distributed reflective vector attenuator of variable resistance again.In one embodiment, this Reflective vector attenuator 349 includes the 3dB of a fixed load 346 and an adjustable load as hybrid coupler 340 Port load.The other end of fixed load 346 is connected with ground 347.Adjustable load includes by one section of 1/8th wavelength transmission The trimmable resistance device 341 and trimmable resistance 343 that line 345 separates.This two trimmable resistances are connected with ground 342 and ground 344, Therefore the change of resistance value can carry out Orthogonal modification to transmission coefficient and reflection coefficient in Smith's original image.It is adjusted using electricity continuous When adjustable resistance or its equivalent devices are as adjustment element, can transmission coefficient to this RVA and reflection coefficient carry out it is continuous Adjustment.This RVA is adapted for use with transmission line and trimmable resistance is easier to the occasion realized.

Fig. 3 E is one using the field-effect tube with difference as the schematic diagram of the reflective vector attenuator of variable load.? In one embodiment, field-effect transistors (FET) 354 realize the function of trimmable resistance device, i.e., by changing gate source Interpolar bias voltage changes resistance between source drain.This reflective vector attenuator 319 includes that there are two the adjustable of the port 3dB Formula load, first adjustable load is the FET 354 of a source electrode ground connection 355, its adjusting voltage is its gate-source Between bias voltage, and its drain electrode is then connected to the port 3dB of hybrid coupler.Another adjustable load is to pass through one section eight Another FET 352 that the transmission line 351 of/mono- wavelength connects.The ground connection of FET 352 353.The transmission of this 1/8th wavelength The phase-shift circuit that the function of line 351 is one 45 degree, therefore, even if two adjusting means are resistive load, this RVA can also be right Its transmission coefficient and reflection coefficient carry out orthogonal continuous adjustment.In one embodiment, the first FET354 and 1/8th wavelength Transmission line 351 is coupled to 3dB hybrid circuit 350.Its source electrode and drain electrode can be interchanged without influencing its function in FET in this circuit Energy.

The realization device of trimmable resistance in heretofore described RVA includes but is not limited to FET, PIN diode, magnetic The variable resistance of field control, or the resistor array controlled by RF switch.The selection of adjustable capacitor includes but unlimited In the array of capacitors that varactor or RF switch control.Heretofore described any analog tuner device can all pass through The help of DAC or switch arrays is digital regulated to carry out, without influencing function of the invention.

Fig. 3 F is with the schematic diagram of the discrete component equivalent circuit of transmission line phase-shifter.This phase-delay network can replace The transmission line of aforementioned 1/8 wavelength.In one embodiment, a phase-delay network 360 includes a concatenated inductor 361 and a capacitor 362 in parallel.One end of capacitor 362 is connected to inductor 361, and the other end is connected to ground 363. The input of radiofrequency signal and delivery outlet are the both ends of inductor 361.

Fig. 3 G is the schematic diagram of the discrete component equivalent circuit of a left hand transmission line phase-shifter, this phase-delay network 1/8 wavelength transmission line in aforementioned RVA can be replaced, to realize identical RVA function.In one embodiment, a phase Position delay circuit 370 includes a concatenated capacitor 371 and an inductance 372 in parallel.372 one end of capacitor is connected to capacitor Device 371, and the other end is connected to ground 373.Likewise, the input of radiofrequency signal and output port are the both ends of capacitor 371.

Be from the advantages of RVA described in Fig. 3 A to Fig. 3 G: have continuous adjustable range, simple structure with it is higher Reliability.The hybrid coupler can be 90 degree or 180 degree coupler, can be realized by transmission line, can also be by inductance capacitor Part replaces transmission line.Existing vector attenuator structure includes one 360 degree of phase shifter and three resistance attenuators.It It can not achieve continual phase adjustment, and device used is more, at high cost, reliability is low.Traditional vector amplifier is then It needs the power supply of direct current and structure is more complicated, reliability is lower.

Radio frequency efficiency transmission between radio transmitter and receiver depends greatly on their antenna Polarization matching.The Polarization match factor between them can be improved by adjusting the polarization mode of reader or label, to optimize letter The power of the reception signal of number label and the power for improving the echo that reader receives.

Fig. 4 A is the schematic diagram of an adjustable dual-polarized antenna of polarization.The adjustable dual-polarized antenna 400 that polarizes wraps Include a 3dB hybrid coupler 430, the first RVA405, the 2nd RVA410 and transmitting module 401.Transmitting module 401 includes first Polarized antenna radiation unit 402 and orthogonal polarized second polarized antenna radiation unit 403.

The dual-polarization cells of cross polarization each other include but is not limited to following methods: two dipoles are to orthogonal Construction, two polarizing angles be each other the monopole antenna of 90 degree of angles, one with the round, rectangular of cross polarization port, ring The micro-band resonance element of shape, "+" shape or other any symmetric shapes.The radiating element 402 of first poliarizing antenna shown in Fig. 4 A Polarization with the excitation wave in the second cross polarization radiating element of antenna 403 is orthogonal.The polarization mode of first radiating element Labeled as CO-POL, and the polarization mode of orthogonal polarized second radiating element is labeled as X-POL.RVA405 and RVA 410 are respectively used to carry out CO-POL and X-POL component amplitude and phase shift adjustment.3dB hybrid coupler 430 and RVA405, RVA Antenna element CO-POL 435 and X-POL440 polarization mode are converted into two new polarization modes jointly by 410 to be sent to antenna end Mouth 420 and 425.The equivalent polarization mode shown at antenna port according to the adjustment parameter of RVA can be different from CO-POL and X-POL.For example, a dual circularly polarized antenna can be converted from dual-linear polarization antenna.In this case, new polarization side The polarization tilt angle and axis of formula by the RVA phase shift applied and attenuation coefficient than then being determined completely.3dB hybrid coupler in figure 3dB hybrid coupler in 430 and RVA all can be 90 degree of hybrid couplers or 180 degree hybrid coupler.Cause is thus in antenna Element have reciprocity, therefore the port 420 and 425 of antenna can be used simultaneously in transmitting or receive signal.

Using the ratio of the attenuation coefficient of RVA405 and RVA 410, effective pole of adjustable antenna port 420 and 425 The polarization dependence of change form.For example, working as, X-POL RVA is set as hypersorption mode and CO-POL RVA is set as phase shifting modes When, port 420 and 425 is all CO-POL polarization, their polarization dependence is 100%.Conversely, when CO-POL RVA is set as When hypersorption mode and X-POL RVA are set as phase shifting modes, port 420 and 425 is all X-POL polarization.As RVA405 and RVA When 410 attenuation coefficient is equal, port 420 and the cross polarization each other of port 425, and the polarization correlated of them is 0.Radio frequency is known After the poliarizing antenna 400 that other reader has used this variable, the polarization mode of reader can be adjusted according to channel, or to every A electronic tag for needing to read distributes an arbitrary polarization mode.When reading the electronic tag of single polarization, the pole of reader The relevant antenna of the settable polarization of change mode；When reading dual-polarized electronic tag, reader may be configured as not having polarization phase The dual polarized antenna of closing property.The applied widely, structure of reader polarization adjuster in the present invention is simple, high reliablity, and The polarization tilt angle and axis ratio of each antenna can individually be fully controlled.

Fig. 4 B is the schematic diagram of an adjustable poliarizing antenna of the list with impedance matching circuit.In one embodiment, single Adjustable polarized antenna 450 is suitable for the radio-frequency identification reader/writer that single-shot list is received.This single polarization adjustable antenna 450 includes one double Polarized transmitting module 461, the orthogonal polarization mode of this 461 at least one group of transmitting module.This single polarization adjustable antenna 450 is also Including the first RVA 453, the 2nd RVA454 and power divider 452.Passive power splitter in radio circuit is alternatively referred to as Power combiner.In one embodiment, power divider 452 includes at least a changeable match circuit, to realize extremely Lack two kinds of impedance matchings and aerial signal is matchingly connected with input signal port 451.First RVA453 is by CO-POL antenna The Co-POL signal 456 that unit 459 is sent makees phase and is coupled with after amplitude adjustment with antenna input port 451；And the 2nd RVA 454 by the X-POL signal 455 that X-POL antenna element 460 is sent make after the adjustment of phase and amplitude with 451 phase coupling of antenna input port It closes.If Anneta module 461 provides 459 signal of CO-POL of a vertical polarization and the X-POL 460 of a horizontal polarization believes Number, after the attenuation coefficient and the phase shift that apply equivalent on RVA 453 and RVA 454, it can be generated at the input terminal 451 of antenna 45 degree of linear polarization mode.Horizontal polarization or vertical polarization are such as realized at 451, then RVA 453 need to be set as hypersorption, Or RVA 454 is set as hypersorption.Because hypersorption is different from the input impedance of the RVA of phase shifting modes, single adjustable polarized day Line 450 is needed comprising an impedance matching circuit, to guarantee reflection coefficient of this antenna at signal port 451.In order to optimize The efficiency of signal transmission, the RVA of hypersorption mode may be configured as the big input impedance of reflection coefficient, to allow the letter of port 451 It number can be efficiently transmitted in another radiated element.In another embodiment, the reception of circular polarisation can be by will be from The signal that CO-POL459 and X-POL460 comes obtains after being superimposed with RVA453 and RVA454 orthogonal phase shift.

The schematic diagram for the variable load match circuit that Fig. 4 C is one 25 or 50 ohm.In one embodiment, impedance Two 50 ohm of signal source can be matched superposition by match circuit 470, or by 50 ohmages and an infinite-impedance Hypersorption mode RVA Signal Matching superposition.The impedance matching circuit 470 includes one without matched radio frequency threeway 473, One 50 ohm of 1/10th wavelength transmission lines 474 are connected with threeway 473, the capacitor 476 of a matching and a switch 475.Remaining port of threeway 473 is connected with CO-POL RVA 471 and X-POL RVA 472.The input impedance of threeway can be 50 Ohm or 25 ohm, 1/10th wavelength transmission lines 474 of matching capacitor 476 and 50 ohm are connected by switch 475, because of energy Enough impedances for being 50 ohm by 25 ohm of impedance matching, to realize the low reflection coefficient in port 478.Matching capacitor 476 The other end ground connection 477.

There are two types of impedance modes by the RVA being connected with threeway 473: 50 ohm or infinite-impedance.When CO-POL's and X-POL When signal equal proportion combines, the input impedance of threeway is 25 ohm.When one of them of CO-POL or X-POL are absorbed by RVA, This RVA input impedance is arranged to infinite-impedance, and the input impedance of threeway is 50 ohm.Achievable nothing in actual circuit Poor big impedance can be with 500 ohm or more of equivalent impedance come approximate.

Fig. 4 D is the schematic diagram of a variable load that 25 or 50 ohm are matched using selective branch.Implement at one In scheme, impedance matching circuit 480 contains at least one radio frequency threeway 483, the first single-pole double throw (SPDT) switch 484, and second Single-pole double-throw switch (SPDT) 487,50 ohm transmission lines 485 and a segment length of random length are 35 ohm of quarter-wave The transmission line 486 of impedance.One end of threeway 473 is connected with the first single-pole double throw (SPDT) switch 484, remaining port and CO-POL RVA 481 is connected with X-POL RVA482.Two throwing points of the first single-pole double throw (SPDT) switch 484 are respectively 50 Ohm transmissions One end of the transmission line 486 of 35 ohmage of line 485 and quarter-wave.One end of second single-pole double-throw switch (SPDT) 487 and receipts It sends out device 488 to be connected, two throwing point is respectively the transmission line of 35 ohmage of 50 ohm transmission lines 485 and quarter-wave 486 other end.Similar with Fig. 4 C, the input impedance of this threeway 483 is also 25 ohm or 50 ohm.It is in threeway input impedance At 25 ohm, switch 484 and switch 487 cut 35 ohm of transmission line 486, are impedance-matched to 50 Europe for 25 ohm Nurse.When threeway input impedance is 50 ohm, then the transmission line 485 of 50 ohmage of the other end is selected.Because of the reflection of antenna The transmitting leadage coefficient that coefficient receives reader to single-shot list has a significant impact, and both the above match circuit can provide lower reflection Coefficient, and while adjusting the Research of Antenna Polarization keep antenna and reader effectiveness.

Amplifier can be applied to scattering modulation RFID system in, with improve electronic tag signal strength and read-write away from From.Fig. 5 A is the schematic diagram of a bistatic formula electronic tag for including radio frequency amplifier and switching regulator modulator.It is semi-active Electronic tag 500 is the long-distance electronic tag that a scattering modulation efficiency is higher than 1.This label 500 include receiving antenna 501, Radio frequency amplifier 502, envelope detector 503, single-pole single-throw(SPST (SPST) switch 508, transmission antenna 509, memory cell 511, Microprocessor 510 and battery 512.In one embodiment, the electronic tag 500 read and write connects from antenna 501 It receives external R2T signal and is sent to radio frequency amplifier 502, amplified signal is by 503 detection of envelope detector.Envelope inspection Wave device 503 includes at least a diode 504 and a low pass RC being made of the resistance 506 and capacitor 505 of earth 507 Filter, the output of this filter are fundamental frequency R2T signal.R2T signal after detection is handled by microprocessor 510, to execute Next step program behavior, such as memory cell 511 is read or write, modulation control signal 515 is generated to operate control modulator 508, it is communicated to distance host 516, receives the input of keyboard 517 or send display information to display 518.Mould is modulated in scattering In formula, the modulated signal of T2R is issued by microprocessor 510, and is executed by spst switch 508.Modulated radiofrequency signal quilt It is sent to a transmission antenna 509, T2R signal is sent back into reader.Battery 512 is used to microprocessor 510 and amplifier 502 power supplies.When electronic tag is connected with distance host 516 by cable, this electronic tag can also be from the cable of distance host Take electricity.

In some embodiments, this active electronic label sends and receivees antenna cross polarization each other.At this point, receiving The polarization mode of antenna is designated as CO-POL, and the polarization mode of transmitting antenna is designated as X-POL.Cross polarization each other Two antennas have lower coupling efficiency compared with the antenna of non-orthogonal polarization.Because of material accompanying by electronic tag and object It is mostly uncontrollable, the electromagnetic isolation between transmitting and receiving antenna can be improved using the antenna of cross polarization each other.Assuming that signal from Transmitting antenna leaks to receiving antenna, and total loop gain reaches 1, and in the case that amplifier vibrates, envelope detector 503 can be detected To a powerful radiofrequency signal and it is sent to microprocessor 510.In order to inhibit this concussion, microprocessor 510 can be reduced and be put The gain of big device 502, until the output of envelope detector 503 is less than some setting value.If because reader is closely put Be placed in electronic tag nearby and to cause envelope detector 503 to export excessively high, microprocessor 510 also can reduce the increasing of amplifier Benefit, with the normal work of hold amplifier and demodulator.This automatic gain adjustment, can not only inhibit because of environment bring electronics Inside tags oscillation, but also the signal value for exporting RFID is defined within the power bracket that a suitable reader is read. Compared with the existing active electronic label using circulator, the electronic tag of this bistatic has stronger stability, because This can obtain higher scattering modulation efficiency.

Fig. 5 B is one using amplifier as the bistatic formula electronic tag schematic diagram of modem devices.In this electronic tag Leak compensation containing spontaneous emission.In one embodiment, semi-active electronic tag 520 includes the polarized reception day CO-POL The polarized antenna 531 of line 526, RVA 521, radio frequency amplifier 522, X-POL, single-pole single-throw switch (SPST) 523, power supply device 524 with Envelope detector 529.In one embodiment, a part for the R2T signal that electronic tag 520 is passed to from receiving antenna 526 RVA 521 is sent to carry out amplitude and phase adjustment, and then signal amplifies another part R2T via radio frequency amplifier 522, This two paths of signals is transferred into transmitting antenna 531 after being then coupled together.The transmitting signal of a part is by envelope detector 529 demodulation, to obtain fundamental frequency R2T signal.The modulation system of this electronic tag is to change amplifier 522 by switch 523 Gain, to generate the scattered signals of different amplitudes to transmitting antenna 531.Envelope detector 529 can also be used to detection amplifier 522 working condition.When amplifier concussion or label are from reader hypotelorism, the processor in label can pass through change The phase shift and decaying of RVA controls the gain and phase shift of reader, to allow amplifier 522 in linear mode of operation.Control The advantages of mode is that amplifier can be allowed in full gain and without switching between gain, to optimize the scattering modulation effect of electronic tag Rate, and guarantee its stability.

The gain of amplifier 522 or phase can be corrected by the RVA521 being attached thereto, then by changing revised put The gain and phase shift of big device, it is possible to implement Different Modulations.Compared with on-off type, in the case where same data rate, amplitude The bandwidth that modulation and phase-modulation occupy is smaller.The another method of modulation R2T signal is the phase shift application phase-modulation for controlling RVA Or frequency modulation(PFM).Therefore, the signal of retransmission can be phase-modulated or frequency modulation(PFM).In addition, switch 523 is connected to and puts The bias of big device executes depth on-off modulation to switch between two gain stages.

In RFID system, the characteristic of reader or electronic tag is not fixed.In general, reader is to fix Formula, and electronic tag is movable type；Reader may be connected to data host, and electronic tag is not connected with any host.Certain In a little situations, the characteristic of reader and electronic tag be can be interchanged, such as in security guard patrol or automobile navigation, electronic tag It can be fixed, and reader can be movable type.Reader can be by the content of the one or more electronic tags of reading, to obtain About routing information or for operating access control.Electronic tag can be connected with data host, and content can be by reader Or data host read-write.

Electronic tag shown in Fig. 5 A and Fig. 5 B of the invention may serve to realize phase and amplitude modulation or more complicated Modulation.The reflection coefficient that also can change the receiving antenna of electronic tag by adjusting vector attenuator 521, thus receiving The back-scattered signal that the lesser single-shot list of modulation amplitude receives mode is carried out at antenna.Radio frequency identification is received with common single-shot list to read Write unlike device, RVA 521 can be used to control the phase shift of reflection coefficient, thus at receiving antenna implementing phase modulation or Frequency modulation(PFM).Apply the bandpass signal of out of phase by two input ports in RVA 521, it can also be to this electronic tag reality Apply the frequency modulation(PFM) of single-side belt.It similarly, can be by double-side band phase modulation and frequency modulation, or by single-side belt by the amplified signal of amplifier Phase modulation and frequency modulation.

Fig. 5 C is the double schematic diagrames for receiving electronic tag of double hairs adjusted with polarization.In one embodiment, double hairs are double The electronic tag of receipts includes dual polarization modulator 540, the polarized dual-mode antenna 543 of CO-POL and the polarized dual-mode antenna of X-POL 544.Antenna 543 and antenna 544 are connected with dual polarization modulator 540.Amplifier 542 be coupled to dual polarization modulator 540 with Amplify the R2T signal received.This electronic tag also includes envelope detector 541, modulation control 547 and the hilted broadsword list for controlling it Throw switch 548, power supply 546.A kind of structure of dual polarization modulator 540 is the same as structure shown in Fig. 4 A.It is presented by external polarizing control 549 Enter dual polarization modulator 540.R2T signal is received jointly by two antennas, is sent by dual polarization modulator 540 to amplifier 542. Amplified R2T signal becomes T2R signal after modulating using modulator 548.A part of this T2R signal passes through dual polarization tune After device 540 processed, by dual polarization modulator 540 distribute to two dual-mode antennas 543 and 544, each antenna will receive simultaneously with Signal is sent, and the polarization mode between them is then controlled by a microprocessor.Another part is solved by envelope detector 529 It adjusts, to obtain fundamental frequency R2T signal 545.One embodiment of dual polarization modulator 540 is the schematic diagram using Fig. 4 A, that is, is wrapped Containing two RVA405 and 430 and a 3dB hybrid coupler 425.There are two use for polarization modulation: first is that being used to improve label Polarization between the receiving and transmitting signal of reader matches, to improve reading/writing distance；Second is that being used to enhance the stability of label, because not Like-polarized transceiver mode can change transmitting leakage decaying and phase shift, and processor detected by radio frequency detector it is unstable Loop settings, thus adjust polarization adjuster with inhibit may show concussion.

The structure chart of component 500,520 and 550 described in the invention may be alternatively used for manufacturing radio relay repeater.These Repeater can be used cooperatively with existing radio-frequency identification reader/writer and electronic tag to improve reading/writing distance.With semi-active electronics Label is similar, and the function of a repeater is re-emitted away again after the radio signal for receiving it is amplified, to be turned up The reading/writing distance of reader or label.Because function is identical, the structure chart of Fig. 5 A, Fig. 5 B and Fig. 5 C can be used directly construction one Or multiple repeaters.Repeater 500,520 or 550 can be used to amplification R2T signal, also can be used to amplification T2R signal.One In a embodiment, repeater 500 be used to enhance aerial R2T signal, therefore the receiving antenna 501 of the repeater is used to It is directed at the transmitting antenna of reader.And the transmitting antenna 509 of repeater is used to refer to electronic tag.In another configuration, in It is used to enhance aerial T2R signal after device 500, therefore the relay reception antenna 501 is directed toward electronic tag, and the hair of repeater The receiving antenna of the direction reader of antennas 509.The repeater of simulation does not re-modulate received RF wave, so on-off modulation Device 508,523 and 548 can be removed from circuit.The stability of repeater can also by RF envelope wave detector 503,529 or 571 monitor, to control the phase shift or gain in entire circuit, so that the amplifying circuit of repeater be kept to stablize in linear work shape Under state.Polar modulator 540 can also be used to change the reception of repeater and send polarization mode, so as to improve Wireless transceiver channel Gain or repeater stability.

Fig. 5 D is the amplifying device of a variable gain and phase shift.This adjustable amplifier 570 includes RVA 571 and common Amplifier 572 is connected.According to the requirement of power consumption, RVA571 can be connect before or after amplifier 572.By changing RVA571 Decaying and phase shift, that is, adjustable apparatus 570 total variable gain and variable phase.The amplifying device 570 of cascaded structure with it is in parallel The RVA 521 of structure is identical as 522 function of amplifier, but the former stability is higher.

Fig. 5 E is the schematic diagram of the adjustable radio relay repeater array in dual-mode antenna direction.In one embodiment, 590 are The adjustable radio relay repeater array in one direction, it includes first transceiver 591 and second transceiver 592.Transceiver 591 include a receiving antenna 601, the signal amplifier 602 of a phase shift and adjustable gain section, with a transmitting antenna 603. Transceiver 592 contains a receiving antenna 611, and the signal amplifier 612 of a phase shift and adjustable gain section emits with one Antenna 613.One embodiment of the amplifier 602 and 612 of phase shift and adjustable gain section is RVA 571 shown in Fig. 5 D. By adjusting the phase shift of first transceiver 591 and second transceiver 592, transmitting signal can be guided to different from incoming signal Direction.This repeater array can also be made of the transceiver of three or more, to improve this array directivity.Each receipts The gain for sending out device can be separately adjustable, to change the main lobe beamwidth of antenna array or reduce minor lobe gain.

Fig. 5 F is the schematic diagram of the adjustable radio relay repeater of transmitted antednna beam.In one embodiment, from reception day The radio signal received at line 641, after being amplified by signal amplifier 642, after signal distributor 643, a part is put Signal after big is transferred to first vector attenuator 644, is then launched from first transmitting antenna 645.And it is another The amplified signal in part is transferred to second vector attenuator 646, is then launched from second transmitting antenna 647. The effect in this of vector attenuator is to signal phase shift, so that the radio wave after two antennas transmittings increases in certain directions By force, and other direction offsets each other, be equivalent to launching antenna array beam direction adjust.Signal distributor can pass to use The lossless power divider of defeated line, or power divider is damaged using resistance.

Fig. 5 G is the schematic diagram of the adjustable radio relay repeater of receiving antenna wave beam.In one embodiment, from first The first reception signal received at receiving antenna 661, with second reception received from second receiving antenna 664 Signal passes through signal combiner respectively by after first vector attenuator 662 and second independent phase shift of vector attenuator 665 663 superpositions.After superimposed signal is amplified the amplification of device 666, it is launched from transmitting antenna 667.By adjusting 662 and 665 Phase shift, this radio relay repeater can change receiving antenna array beam direction adjust.The structure of signal combiner can be with letter Number distributor is identical, and only input/output port definition is different.

Claims

1. a kind of radio frequency identification positioning system, including radio-frequency identification reader/writer, phased array and at least two radio frequencies are known Other electronic tag, the radio-frequency identification reader/writer is interior to eliminate circuit containing leakage, and the radio frequency recognizing electronic label includes vector Attenuator, it is characterized in that: the radio-frequency leakage elimination circuit that circuit is feedforward and open loop is eliminated in the leakage, comprising:

Quadrature down converter, the quadrature down converter are used for the first authentic copy of radio frequency receiving signal and radio frequency transmissions just Alternation frequency, generates In-phase output signal and positive blending output signal；

First low-pass filter is connected with the quadrature down converter, for In-phase output signal described in low-pass filtering and generates With phase reference voltage；

Second low-pass filter is connected with the quadrature down converter, for positive blending output signal described in low-pass filtering and generates Orthogonal reference voltage；

Linear combination circuits are connected with first low-pass filter and second low-pass filter, for generating the first control Voltage processed and second control voltage, it is described first control voltage be equal to the same phase reference voltage, the orthogonal reference voltage and First can be the linear combination of zero constant；The second control voltage is equal to the same phase reference voltage, the orthogonal reference Voltage and second can be zero constant linear combination；

Quad upconverter is connected with the linear combination circuits, be used to will it is described first control voltage, second control voltage and The orthogonal mixing of the triplicate of the radio frequency transmissions generates a radio frequency output signal and folds it with signal to be received Add, to eliminate transmitting leakage.

2. radio frequency identification positioning system as described in claim 1, it is characterized in that: the effect of the linear combination circuits is The same phase reference voltage EVI and the orthogonal reference voltage EVQ are converted into the first control voltage according to the following formula CVI and the second control voltage CVQ:

CVI=A*EVI+B*EVQ+C,

CVQ=D*EVI+E*EVQ+F,

Wherein A, B, E and D are the coefficient that can be zero, numerical value is related to dynamic emission leakage, and it can be zero to be that C and F, which are also, Number, numerical value are related to static transmitting leakage.

3. radio frequency identification positioning system as claimed in claim 1 or 2, it is characterized in that: also contain radio frequency power detector, The effect of circuit or the parameter of calibrated linear combinational circuit are eliminated for monitoring leakage.

4. radio frequency identification positioning system as described in claim 1, it is characterized in that: the leakage eliminate circuit be feedback and The radio-frequency leakage of closed loop eliminates circuit, comprising:

Quadrature down converter, it is same for after radio frequency receiving signal frequency conversion orthogonal with the first authentic copy of radio frequency transmissions, will generate Phase output signal and positive blending output signal；

At least two analog-digital converters are respectively intended to the same phase reference voltage and the orthogonal reference voltage being converted to number Reference voltage signal；

DSP unit is connected with the analog-digital converter, is used to operation and handles the reference voltage signal, and Generate digital control voltage signal；

At least two digital analog converters are connected with the DSP unit, for believing the digital control voltage It number is converted into same phase analog control voltage and orthogonal simulation controls voltage；

Vector attenuator is coupled at least two digital analog converter, carries out phase for the triplicate to transmitting signal It is adjusted with amplitude, and the Signal averaging tieback adjusted collection of letters number is leaked with eliminating the transmitting mixed with it；

Amplifier is placed at the transmitting leakage superposition between the quadrature down converter, receives making an uproar for circuit for reducing Sonic system number；

At least two high-pass filters are connected with the quadrature down converter, for filtering out radio-frequency leakage by the orthogonal lower change The direct current leakage residual formed after the conversion of frequency device, and be used to provide same phase fundamental frequency output signal and quadrature baseband output signal.

5. radio frequency identification positioning system as claimed in claim 4, it is characterized in that: the high-pass filter is series capacitance Or shunt inductance.

6. radio frequency identification positioning system as described in claim 4 or 5, it is characterized in that: the same phase of the vector attenuator The numerical value of analog control voltage and orthogonal simulation control voltage is equal to the linear of the same phase reference voltage and orthogonal reference voltage Combination.

7. radio frequency identification positioning system as claimed in claim 4, it is characterized in that: the vector of the control voltage combines behaviour Make through digital signal processor come operation.

8. radio frequency identification positioning system as described in claim 1, it is characterized in that: the vector attenuator be it is reflective to Measure attenuator, comprising:

One hybrid coupler, there is the first port 3dB and the 2nd port 3dB, and it is negative to be connected with first at the first port 3dB It carries, first load is the first tunable load；The second load is connected at 2nd port 3dB, second load is Fixed load or the second tunable load.

9. radio frequency identification positioning system as claimed in claim 8, it is characterized in that: first tunable load or second can Adjusting load includes the resistor of switch control, the capacitor of switch control, the inductor of switch control and connecing for switch control Ground.

10. radio frequency identification positioning system as claimed in claim 8, it is characterized in that: first tunable load or second Tunable load includes being equivalent to 1/8th wavelength or longer transmission line, and the line end is connected with 50 ohm of electricity Resistance, and parallel connection distributed at least one short switch on the transmission line.

11. radio frequency identification positioning system as claimed in claim 8, it is characterized in that: first tunable load or second Tunable load includes resistor, capacitor and inductor, at least one in the resistor, capacitor and inductor is adjustable.

12. radio frequency identification positioning system as claimed in claim 8, it is characterized in that: first tunable load or second Tunable load includes the transmission line for being equivalent to 1/8th wavelength, and the both ends of the transmission line are respectively parallel with adjustable resistor.

13. radio frequency identification positioning system as claimed in claim 8, it is characterized in that: first tunable load is first Adjustable resistor, second tunable load are the transmission line for being equivalent to 1/8th wavelength, and the end of the transmission line is in parallel Adjustable resistor.

14. radio frequency identification positioning system as described in claim 12 or 13, it is characterized in that: the adjustable resistor is field Effect transistor.

15. radio frequency identification positioning system as claimed in claim 8, it is characterized in that: the reflective vector attenuator is also Including amplifier, the amplifier is coupled to the hybrid coupler, and the hybrid coupler and the comprehensive of the amplifier increase Benefit is 1 or more.

16. radio frequency identification positioning system as described in claim 1, it is characterized in that: the radio frequency recognizing electronic label is also Including antenna polarization adjuster, the polarization adjuster is connected with receiving antenna, transmitting antenna, amplifier, described for adjusting Signals leakiness between antenna of the reception polarization mode or transmitting polarization mode of electronic tag to reduce the electronic tag is to mention The stability of high electronic tag, or improve the polarization matching degree of electronic tag and tag read-write equipment to improve the property of electronic tag Energy.

17. radio frequency identification positioning system as claimed in claim 16, it is characterized in that: the transmitting antenna and receiving antenna Polarization mode be cross polarization, the combination of the cross polarization including but not limited to: one vertically with a horizontal polarization；One A+45 degree and one -45 degree linear polarization；One left-handed and right-handed circular polarization；One left-handed ellipse and a dextrorotation Elliptic polarization.

18. radio frequency identification positioning system as claimed in claim 16, it is characterized in that: the receiving antenna and transmitting antenna Polarization mode for dual polarized antenna, the dual polarized antenna is adjustable.

19. radio frequency identification positioning system as claimed in claim 16, it is characterized in that: the adjustable gain of the amplifier.

20. radio frequency identification positioning system as claimed in claim 16, it is characterized in that: the phase shift of the amplifier is adjustable.