CN110598497A - Long-distance passive wireless magnetic field quantity sensing label - Google Patents
Long-distance passive wireless magnetic field quantity sensing label Download PDFInfo
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- CN110598497A CN110598497A CN201910868810.1A CN201910868810A CN110598497A CN 110598497 A CN110598497 A CN 110598497A CN 201910868810 A CN201910868810 A CN 201910868810A CN 110598497 A CN110598497 A CN 110598497A
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- 239000003381 stabilizer Substances 0.000 claims description 7
- 239000013078 crystal Substances 0.000 claims description 6
- 229910052715 tantalum Inorganic materials 0.000 claims description 6
- GUVRBAGPIYLISA-UHFFFAOYSA-N tantalum atom Chemical group [Ta] GUVRBAGPIYLISA-UHFFFAOYSA-N 0.000 claims description 6
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- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R33/00—Arrangements or instruments for measuring magnetic variables
- G01R33/02—Measuring direction or magnitude of magnetic fields or magnetic flux
- G01R33/06—Measuring direction or magnitude of magnetic fields or magnetic flux using galvano-magnetic devices
- G01R33/063—Magneto-impedance sensors; Nanocristallin sensors
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- G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
- G06K7/00—Methods or arrangements for sensing record carriers, e.g. for reading patterns
- G06K7/10—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation
- G06K7/10009—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves
- G06K7/10158—Methods or arrangements for sensing record carriers, e.g. for reading patterns by electromagnetic radiation, e.g. optical sensing; by corpuscular radiation sensing by radiation using wavelengths larger than 0.1 mm, e.g. radio-waves or microwaves methods and means used by the interrogation device for reliably powering the wireless record carriers using an electromagnetic interrogation field
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Abstract
The invention discloses a magnetic field characteristic sensing and acquisition circuit and a magnetic field characteristic sensing label based on the same, which are applied to the technical field of electronic communication technology and sensors and aim at the problems of high power consumption, difficult maintenance, large volume and high manufacturing cost of the existing magnetic field quantity sensing equipment; the magnetic field characteristic sensing and collecting circuit adopts a passive magnetic field sensor to output an output signal related to the surrounding magnetic field strength under the excitation of an excitation signal; compared with the prior art, the magnetic field quantity sensing tag has small volume, strong concealment, high precision and high sensing and transmission distance reaching 4 meters through testing, and is very beneficial to the layout and realization of a wireless sensing network.
Description
Technical Field
The invention belongs to the technical field of electronic communication technology and sensors, and particularly relates to RFID (radio frequency identification) and wireless sensor network technology.
Background
The passive electronic tag, namely the passive radio frequency tag, adopts a frequency hopping working mode, has the anti-jamming capability, can self-define and read standard data by a user, and has the reading distance of more than ten meters. The passive radio frequency tag has a wide working frequency band, not only accords with relevant industry regulations, but also can be developed and applied flexibly, and a special reader-writer can read and write a plurality of tags simultaneously. Due to the passive working characteristic, a battery is not needed in the design of the tag, and the memory of the tag can be repeatedly erased and written for more than 100000 times. Because the passive electronic tag is not provided with a built-in battery, when the passive electronic tag is within the communication identification range of the reader-writer, the electronic tag collects electric energy required by the work of the passive electronic tag from radio frequency energy emitted by the reader-writer. The passive electronic tag generally adopts a backscattering mode to complete the transmission of electronic tag information to a reader-writer, so the passive electronic tag can also be called as a passive tag.
The magnetic field sensor is an inductive passive sensor that can sense the magnetic field strength in the environment. After the magnetic field is excited by a specific frequency signal, the magnitude of an output signal can be changed linearly along with the change of the magnetic field intensity in the environment. After the output signal is processed, the process and the degree of the magnetic field intensity change can be truly embodied.
A Wireless Sensor Network (WSN) is a distributed Sensor network whose distal end is a Sensor that can sense and detect the outside world. The sensors in the WSN communicate in a wireless mode, so that the network setting is flexible, the position of equipment can be changed at any time, and the equipment can be connected and communicated with the Internet in a wired or wireless mode.
Radio Frequency Identification (RFID) technology is a traditional wireless communication Identification technology, can realize non-line-of-sight communication, and is widely applied to the fields of intelligent logistics, traffic, multi-target Identification, direction tracking and the like. The RFID technology is applied to the wireless sensor network, can have the technical characteristics of both the RFID and the wireless sensor network, and can automatically identify the target through the characteristic of the RFID radio frequency signal, thereby realizing the functions of sensing information and communicating of the wireless sensor network.
The main defects of the existing magnetic field sensing technology generally comprise: the equipment generally has higher consumption, adopts active mode operation work basically, and this has proposed certain requirement to fixed power or portable battery, has also increased the cost of periodic maintenance, and in some special environment that can't install the power or can't change the battery, prior art has embodied considerable limitation. And the existing magnetic field quantity sensing equipment is relatively large in size and high in manufacturing cost, and large-area sensing network layout cannot be realized.
Disclosure of Invention
In order to solve the problems that the conventional magnetic field quantity sensing equipment is large in size, high in power consumption and cost, a wireless transmission system based on an RFID (radio frequency identification) technology is not realized, and the precision of measuring magnetic field quantity parameters is low, the invention provides a remote passive magnetic field quantity sensing label, which can realize the effect of obtaining high-precision magnetic field quantity parameters under extremely low power consumption.
One of the technical schemes adopted by the invention is as follows: a magnetic field pattern sensing and acquisition circuit comprising: the device comprises an alternating current excitation source circuit, a magnetic field sensor, a sensor output signal conditioning circuit and a sensor output signal acquisition circuit; the alternating current excitation source circuit is used for outputting excitation signals, the magnetic field sensor outputs output signals related to the surrounding magnetic field intensity under the excitation of the excitation signals, the sensor output signal conditioning circuit processes the output signals of the sensor, and the output signals of the sensor processed by the sensor output signal conditioning circuit are subjected to magnetic field characteristic collection by the sensor output signal collection circuit.
Further, the alternating current excitation source circuit comprises: the passive band-pass filter comprises an active crystal oscillator, a passive band-pass filter and a current-limiting resistor; the active crystal oscillator is powered by direct current electric energy to start oscillation, outputs 200KHz square wave signals, transmits the 200KHz square wave signals into the passive band-pass filter, filters unnecessary frequency components, and outputs 200KHz sinusoidal signals, and the 200KHz sinusoidal signals flow through the current-limiting resistor and then are output as excitation signals.
Further, the sensor output signal conditioning circuit comprises: the device comprises a first-stage operational amplifier, a first-stage RC low-pass filter, a second-stage operational amplifier, a pair-tube detector, a second-stage RC low-pass filter, a third-stage operational amplifier and a third-stage RC low-pass filter; the output signal of the magnetic field sensor is used as the input of a first-stage operational amplifier, the output of the first-stage operational amplifier is used as the input of a first-stage RC low-pass filter, the output of the first-stage RC low-pass filter is used as the input of a second-stage operational amplifier, the output of the second-stage operational amplifier is used as the input of a pair tube detector, the output of the pair tube detector is used as the input of a second-stage RC low-pass filter, the output of the second-stage RC low-pass filter is used as the input of a third-stage operational amplifier, the output of the third-stage operational amplifier is used as the input of a third-stage RC low-pass filter, and.
Further, the sensor output signal acquisition circuit is a 12-bit precision ADC.
The second technical scheme adopted by the invention is as follows: a magnetic field characteristic sensing label at least comprises the magnetic field characteristic sensing and collecting circuit.
Further, the tag further comprises: the device comprises an antenna, an impedance matching and backscattering modulation circuit, a rectification and energy management circuit, a demodulation circuit and a baseband processing unit circuit;
the radio frequency signal and energy sent by an external reader-writer are input into an impedance matching and backscattering modulation circuit through an antenna; the impedance matching and backscattering modulation circuit comprises two paths of outputs, wherein one path of output enters the rectification and energy management circuit, and the other path of output enters the demodulation circuit;
the rectification and energy management circuit converts the input radio frequency energy into direct current electric energy; the converted direct current electric energy is used for supplying power to the demodulation circuit, the baseband processing unit circuit and the magnetic field characteristic sensing and collecting circuit;
the demodulation circuit transmits the demodulated baseband signal into a baseband processing unit circuit for processing; the baseband processing unit circuit analyzes the input baseband signal, converts the acquired magnetic field intensity parameter into a modulation signal, transmits the modulation signal into the impedance matching and backscattering modulation circuit, and then transmits the magnetic field intensity parameter back to the reader-writer in a backscattering mode.
Further, the rectification and energy management circuit comprises: the device comprises a voltage doubling rectifying circuit, a DC-DC energy management chip, an energy storage capacitor and an LDO linear voltage regulator; the voltage doubling rectifying circuit converts input radio frequency energy into direct current electric energy, the direct current electric energy is boosted through the DC-DC energy management chip and stored in the energy storage capacitor, when the electric energy stored in the energy storage capacitor reaches a set threshold value, 2.4V direct current electric energy is output through an output port of the DC-DC energy management chip and is transmitted to the LDO linear voltage stabilizer, and high-precision 2V direct current electric energy is output through the LDO linear voltage stabilizer.
Further, the baseband processing unit further includes: when receiving a command that a reader-writer requires to collect electromagnetic field quantity parameters, inputting an enabling signal to a corresponding linear voltage stabilizer in a rectification and energy management circuit; the rectification and energy management circuit supplies power to the magnetic field characteristic sensing and collecting circuit.
Further, the energy storage capacitor is a tantalum capacitor.
Further, the label is based on an ISO/IEC18000 international ultrahigh frequency RFID standard protocol.
The invention has the beneficial effects that: the magnetic field characteristic sensing and collecting circuit has the advantages that through the circuit structure of innovative design and the optimization of device elements, the magnetic field characteristic sensing and collecting circuit has the effect of obtaining high-precision (1% precision) magnetic field quantity parameters under extremely low power consumption (1.1 milliwatt), has the advantages of reflecting static magnetic field characteristics and 1Hz-100Hz alternating magnetic field quantity characteristics, and can draw a waveform diagram with 1Hz-100Hz alternating magnetic field quantity changing periodically on MATLAB software and other software according to data returned by a label; the remote passive wireless magnetic field quantity sensing label based on the magnetic field characteristic sensing and collecting circuit has the following advantages that:
1. the total volume of the passive wireless magnetic field quantity sensing label is only 8cm3The problem that the magnetic field quantity sensing equipment is large in size in the prior art is solved;
2. the passive wireless magnetic field quantity sensing label is an energy automatic collection type passive electronic label, does not need a battery, has total peak power consumption less than 2.1 milliwatts and total average power consumption less than 1.7 milliwatts, and solves the problem of high power consumption of magnetic field quantity sensing equipment in the prior art;
3. the passive wireless magnetic field quantity sensing label has low total cost, and a single label is not more than 90 yuan RMB, thereby solving the problem of high cost of magnetic field quantity sensing equipment in the prior art;
4. the passive wireless magnetic field quantity sensing label is simple in structure, convenient to maintain and low in maintenance cost, does not need to replace a battery, and solves the problem that magnetic field quantity sensing equipment is difficult to maintain in the prior art;
5. the passive wireless magnetic field quantity sensing label has small volume and strong concealment, the sensing and transmission distance can reach 4 meters through testing, the layout and the realization of a wireless sensing network are very facilitated, and the problem that the magnetic field quantity sensing equipment in the prior art is difficult to be widely laid is solved
6. The passive wireless magnetic field quantity sensing label also has the advantage of high precision of sensing and collecting magnetic field quantity parameters, and the error of the sensing magnetic field quantity parameters is effectively controlled to be below 1 percent, so that the problem that the magnetic field quantity sensing equipment cannot realize high-precision sensing in a low-power-consumption running state in the prior art is solved;
7. the passive wireless magnetic field quantity sensing label has the advantages of reflecting static magnetic field characteristics and 1Hz-100Hz alternating magnetic field characteristics, and can realize real-time monitoring and detection of static magnetic fields and alternating magnetic fields around power transmission equipment and power transmission line pipes in large power transmission units.
Drawings
Fig. 1 is an equivalent circuit diagram of a passive magnetic field sensor according to an embodiment of the present invention;
FIG. 2 is a diagram of a magnetic field sensing and acquisition circuit according to an embodiment of the present invention;
fig. 3 is a circuit diagram of a remote passive magnetic field quantity sensing tag according to an embodiment of the present invention;
fig. 4 is a flowchart of the operation of the baseband signal processing unit according to the embodiment of the present invention.
Detailed Description
In order to facilitate the understanding of the technical contents of the present invention by those skilled in the art, the present invention will be further explained with reference to the accompanying drawings.
This embodiment provides an implementation manner of a magnetic field sensor, specifically, as shown in fig. 1, the magnetic field sensor is made of an amorphous magnetic film (Fe-Ni-Mo amorphous film), and is encapsulated in a lamination manner, which is equivalent to a transformer structure. When an external magnetic field acts on the sensor, the magnetic conductivity of the magnetic film of the sensor changes correspondingly due to the movement of the magnetic domain wall and the domain rotation, so that the equivalent inductance value (impedance value) of the sensor changes, and the peak-peak value of an output sinusoidal signal after being excited by a 200KHz sinusoidal excitation signal is in negative correlation with the surrounding magnetic field intensity. Since the permeability of the magnetic film of the sensor changes rapidly in the change of the amount of the magnetic field. The characteristic can facilitate the tag circuit to quickly sense and collect the magnetic field quantity parameters in the environment, thereby realizing the real-time and sensitive sensing effect on the magnetic field quantity in the environment. Compared with the existing magnetic field sensor, the magnetic field sensor has lower power consumption, and the power consumption of the magnetic field sensor adopted in the invention is only 400 microwatts during working.
The magnetic field characteristic sensing and collecting circuit of the present invention is shown in fig. 2, and comprises: the device comprises an alternating current excitation source circuit, a magnetic field sensor, a sensor output signal conditioning circuit and a sensor output signal acquisition circuit. And the magnetic field characteristic sensing and acquisition circuit receives the direct current electric energy converted and collected by the tag circuit to supply power and operate after the tag receives an acquisition command sent by the reader-writer. Here, the tag receives the dc power converted and collected by the tag circuit after receiving the acquisition command sent by the reader/writer, and is specifically completed by the rectification and energy management circuit module in the tag, which is specifically described in the following detailed description about fig. 3.
The alternating current excitation source circuit comprises: the passive band-pass filter comprises an active crystal oscillator, a passive band-pass filter and a current-limiting resistor; the active crystal oscillator receives direct current electric energy converted and collected by the tag circuit to supply power and start oscillation, outputs 200KHz square wave signals, the 200KHz square wave signals are transmitted into a rear-connected passive band-pass filter, 200KHz sinusoidal signals are output after unnecessary frequency components are filtered, and the 200KHz sinusoidal signals are input into the magnetic field sensor after flowing through the current-limiting resistor. The current limiting resistor fixes the output current of the ac excitation source circuit to about 200 microamperes, which is the magnitude of the current of the minimum excitable field sensor. Since the magnetic field sensor is equivalent to an inductor, the internal resistance is as low as 10 ohms, and the effect of the current-limiting resistor is to reduce the excessive power consumption generated when the magnetic field sensor is excited.
After the magnetic field sensor is excited by the output signal of the alternating current excitation source circuit, a tiny same-frequency signal with a peak-to-peak value about one twentieth of the peak-to-peak value of the excitation signal is output, and the output signal of the sensor is transmitted into the sensor output signal conditioning circuit in fig. 2 to be processed.
The sensor output signal conditioning circuit includes: the device comprises a first-stage operational amplifier, a first-stage RC low-pass filter, a second-stage operational amplifier, a pair-tube detector, a second-stage RC low-pass filter, a third-stage operational amplifier and a third-stage RC low-pass filter; the first-stage operational amplifier and the second-stage operational amplifier are powered by a double power supply (a positive power supply and a negative power supply); the third-stage operational amplifier is powered by a single power supply. When the circuit works, the output signal of the magnetic field sensor is amplified by the first-stage operational amplifier and then enters the first-stage RC low-pass filter, the first-stage RC low-pass filter outputs the sensor output signal after high-frequency noise is filtered and transmits the sensor output signal into the second-stage operational amplifier, the second-stage operational amplifier amplifies the sensor output signal again and then inputs the amplified sensor output signal into the subsequent pair tube detector and the second-stage RC low-pass filter, so that an envelope signal amplified by the sine signal output by the sensor is obtained, the envelope signal is transmitted into the third-stage operational amplifier and the third-stage RC low-pass filter, and the signal-to-noise ratio of the envelope signal is improved to.
The sensor output signal acquisition circuit is a 12-bit precision ADC (analog-to-digital converter) carried by a single chip microcomputer in the tag circuit, the ADC (single chip microcomputer) receives direct current electric energy converted and collected by the tag circuit and supplies power, receives an output signal from the sensor output signal conditioning circuit, performs analog-to-digital conversion, and finally transmits a digital signal after the analog-to-digital conversion to the single chip microcomputer for processing, so that the sensing and acquisition of the magnetic field characteristics are realized.
The magnetic field characteristic sensing and collecting circuit uses a micro-power operational amplifier, a passive low-pass filter and a pair tube detection circuit to build a low-power consumption sensor output signal conditioning circuit and a sensor output signal collecting circuit realized by using a low-power consumption 12-bit precision ADC of a single chip microcomputer, so that the effect of obtaining high-precision magnetic field quantity parameters under the low power consumption of only 1.1 milliwatt of the magnetic field characteristic sensing and collecting circuit is realized.
The structure of the remote passive wireless magnetic field quantity sensing tag is shown in fig. 3, and the remote passive wireless magnetic field quantity sensing tag comprises an antenna and 5 functional module circuits: the device comprises an impedance matching and backscattering modulation circuit module, a rectification and energy management circuit module, a demodulation circuit module, a baseband processing unit circuit module and a magnetic field characteristic sensing and acquisition circuit module.
When the remote passive magnetic field quantity sensing tag circuit works, radio-frequency signals and energy of a frequency band of 920MHz-928MHz sent by a reader-writer are transmitted into an impedance matching and backscattering modulation circuit module through an antenna port, and the circuit module consists of an impedance matching circuit, a backscattering modulation circuit and a power divider circuit. The radio frequency signal and the energy transmit about four fifths of input radio frequency energy into the rectification and energy management circuit module through the impedance matching circuit and the power divider circuit, perform RF-DC conversion and collection, and transmit about one fifth of input radio frequency signal into the demodulation circuit module for demodulation.
The voltage-multiplying rectifying circuit in the rectifying and energy management circuit module converts the transmitted radio frequency energy into direct current energy, the direct current energy is boosted by the DC-DC energy management chip and stored in the energy storage tantalum capacitor in the rectifying and energy management circuit module, when the electric energy stored in the tantalum capacitor reaches a set upper limit threshold, 2.4V electric energy is output by an output port of the DC-DC energy management chip and transmitted into the LDO linear voltage regulator, finally the LDO linear voltage regulator outputs high-precision 2V direct current electric energy to be supplied to the tag circuit for operation, when the voltage of the electric energy in the energy storage tantalum capacitor is reduced to a set lower limit threshold due to discharge, the rectifying and energy management circuit module stops supplying power to the tag circuit until the electric energy in the energy storage tantalum capacitor at the next time is charged to the set upper limit threshold. The upper limit threshold value refers to a specific discharge voltage value controlled by the DC-DC energy management chip, that is, when the voltage in the capacitor is charged to the threshold value, the DC-DC energy management chip starts to supply power to the subsequent circuit, and the electric energy in the capacitor is released. The lower threshold value refers to a specific discharge stopping voltage value which is also controlled by the DC-DC energy management chip, namely when the voltage in the capacitor is discharged to the threshold value, the DC-DC energy management chip stops supplying power to a subsequent circuit. In this embodiment, the upper threshold is 4.8V, and the lower threshold is 2.4V.
The demodulation circuit module consists of an envelope detection circuit, an average value circuit and a comparator. The demodulated signal processed by the envelope detection circuit and the output signal of the mean value circuit are transmitted into the comparator together, and after the comparator receives power supply of the rectification and energy management circuit module, the comparator outputs a baseband signal and transmits the baseband signal into the baseband processing unit circuit module for processing.
The single chip microcomputer in the baseband processing unit circuit module receives power supply of the rectification and energy management circuit module, processes and analyzes a reader-writer command transmitted by the demodulation circuit module, and transmits a collection enabling signal to a corresponding LDO linear voltage regulator in the rectification and energy management circuit module from the single chip microcomputer in the baseband processing unit circuit module after receiving a command that the reader-writer requires to collect magnetic field quantity parameters, and simultaneously processes the magnetic field quantity parameters transmitted by the magnetic field characteristic sensing and collection circuit module, converts the collected parameters into modulation signals, transmits the modulation signals to the impedance matching and backscattering modulation circuit module, and transmits the magnetic field quantity parameters back to the reader-writer in a backscattering mode.
The magnetic field characteristic sensing and collecting circuit module is also supplied with power by the rectifying and energy management circuit module. The premise that the power is supplied is that after the tag receives a magnetic field quantity acquisition command sent by the reader-writer, and the baseband processing unit circuit module enables the rectification and energy management circuit module to operate the corresponding linear voltage stabilizer, the magnetic field characteristic sensing and acquisition circuit module starts to operate, and the operation mode is as shown in fig. 2, and finally the acquired magnetic field quantity parameters are transmitted to the baseband processing unit circuit for processing.
The software working flow of the circuit module of the baseband processing unit is shown in fig. 4, and the baseband processing unit mainly realizes an RFID protocol based on ISO/IEC 18000. When the rectification and energy management circuit module starts to supply power to the baseband processing unit circuit module, the baseband processing unit module circuit starts to work, firstly, the working state of each pin of the singlechip is initialized, the module for receiving data is correspondingly configured, and then, the command of the upper computer is started to be received. After the upper computer sends a universal RFID command, the magnetic field quantity sensing tag executes the command like a universal RFID tag and determines whether to return a signal according to a protocol; when the upper computer sends a magnetic field parameter acquisition command, the tag analyzes the command and obtains acquisition times, then the magnetic field characteristic sensing and acquisition circuit is enabled, the magnetic field characteristic sensing and acquisition circuit is waited for stabilization, then the ADC is configured, data is acquired, the acquired data is stored so as to be read at any time, then the acquisition times are reduced by 1, whether the acquisition times are zero or not is judged, if the acquisition times are not zero, the acquisition is continued, and if the acquisition times are not zero, the acquired data is returned to the reader-writer.
It will be appreciated by those of ordinary skill in the art that the embodiments described herein are intended to assist the reader in understanding the principles of the invention and are to be construed as being without limitation to such specifically recited embodiments and examples. Various modifications and alterations to this invention will become apparent to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.
Claims (10)
1. A magnetic field pattern sensing and acquisition circuit, comprising: the device comprises an alternating current excitation source circuit, a magnetic field sensor, a sensor output signal conditioning circuit and a sensor output signal acquisition circuit; the alternating current excitation source circuit is used for outputting excitation signals, the magnetic field sensor outputs output signals related to the surrounding magnetic field intensity under the excitation of the excitation signals, the sensor output signal conditioning circuit processes the output signals of the sensor, and the output signals of the sensor processed by the sensor output signal conditioning circuit enter the sensor output signal acquisition circuit to acquire the magnetic field characteristics.
2. The magnetic field pattern sensing and acquisition circuit of claim 1, wherein the ac excitation source circuit comprises: the passive band-pass filter comprises an active crystal oscillator, a passive band-pass filter and a current-limiting resistor; the active crystal oscillator is powered by direct current electric energy to start oscillation, outputs 200KHz square wave signals, transmits the 200KHz square wave signals into the passive band-pass filter, filters unnecessary frequency components, and outputs 200KHz sinusoidal signals, and the 200KHz sinusoidal signals flow through the current-limiting resistor and then are output as excitation signals.
3. The magnetic field pattern sensing and acquisition circuit of claim 2, wherein the sensor output signal conditioning circuit comprises: the device comprises a first-stage operational amplifier, a first-stage RC low-pass filter, a second-stage operational amplifier, a pair-tube detector, a second-stage RC low-pass filter, a third-stage operational amplifier and a third-stage RC low-pass filter; the output signal of the magnetic field sensor is used as the input of a first-stage operational amplifier, the output of the first-stage operational amplifier is used as the input of a first-stage RC low-pass filter, the output of the first-stage RC low-pass filter is used as the input of a second-stage operational amplifier, the output of the second-stage operational amplifier is used as the input of a pair tube detector, the output of the pair tube detector is used as the input of a second-stage RC low-pass filter, the output of the second-stage RC low-pass filter is used as the input of a third-stage operational amplifier, the output of the third-stage operational amplifier is used as the input of a third-stage RC low-pass filter, and.
4. The magnetic field sensing and acquisition circuit of claim 3 wherein the sensor output signal acquisition circuit is a 12-bit precision ADC.
5. A magnetic field pattern sensing tag comprising at least a magnetic field pattern sensing and acquisition circuit according to any of claims 1-4.
6. A magnetic field property sensing tag according to claim 5, further comprising: the device comprises an antenna, an impedance matching and backscattering modulation circuit, a rectification and energy management circuit, a demodulation circuit and a baseband processing unit circuit;
the radio frequency signal and energy sent by an external reader-writer are input into an impedance matching and backscattering modulation circuit through an antenna; the impedance matching and backscattering modulation circuit comprises two paths of outputs, wherein one path of output enters the rectification and energy management circuit, and the other path of output enters the demodulation circuit;
the rectification and energy management circuit converts the input radio frequency energy into direct current electric energy; the converted direct current electric energy is used for supplying power to the demodulation circuit, the baseband processing unit circuit and the magnetic field characteristic sensing and collecting circuit;
the demodulation circuit transmits the demodulated baseband signal into a baseband processing unit circuit for processing; the baseband processing unit circuit analyzes the input baseband signal, converts the acquired magnetic field intensity parameter into a modulation signal, transmits the modulation signal into the impedance matching and backscattering modulation circuit, and then transmits the magnetic field intensity parameter back to the reader-writer in a backscattering mode.
7. A magnetic field pattern sensing tag according to claim 6, wherein said rectifying and energy management circuit comprises: the device comprises a voltage doubling rectifying circuit, a DC-DC energy management chip, an energy storage capacitor and an LDO linear voltage regulator; the voltage doubling rectifying circuit converts input radio frequency energy into direct current electric energy, the direct current electric energy is boosted through the DC-DC energy management chip and stored in the energy storage capacitor, when the electric energy stored in the energy storage capacitor reaches a set threshold value, 2.4V direct current electric energy is output through an output port of the DC-DC energy management chip and is transmitted to the LDO linear voltage stabilizer, and high-precision 2V direct current electric energy is output through the LDO linear voltage stabilizer.
8. The magnetic field property sensing tag of claim 7, wherein said baseband processing unit further comprises: when receiving a command that a reader-writer requires to collect magnetic field quantity parameters, inputting an enabling signal to a corresponding linear voltage stabilizer in a rectification and energy management circuit; the rectification and energy management circuit supplies power to the magnetic field characteristic sensing and collecting circuit.
9. A magnetic field property sensing tag according to claim 7 wherein said energy storage capacitor is a tantalum capacitor.
10. The magnetic field sensing tag of claim 8, wherein said tag is based on the ISO/IEC18000 international uhf RFID standard protocol.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910868810.1A CN110598497A (en) | 2019-09-16 | 2019-09-16 | Long-distance passive wireless magnetic field quantity sensing label |
| PCT/CN2020/115438 WO2021052340A1 (en) | 2019-09-16 | 2020-09-16 | Passive wireless magnetic field characteristic sensing tag and sensing system |
| US17/388,278 US11797814B2 (en) | 2019-09-16 | 2021-07-29 | Passive wireless magnetic field characteristic sensing tag and system, and magnetic field quantity acquisition method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910868810.1A CN110598497A (en) | 2019-09-16 | 2019-09-16 | Long-distance passive wireless magnetic field quantity sensing label |
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| WO2021052340A1 (en) * | 2019-09-16 | 2021-03-25 | 电子科技大学 | Passive wireless magnetic field characteristic sensing tag and sensing system |
| CN113472382A (en) * | 2021-06-29 | 2021-10-01 | Oppo广东移动通信有限公司 | Wireless communication method, wireless communication device, electronic tag, and storage medium |
| CN115733522A (en) * | 2022-11-18 | 2023-03-03 | 大连理工大学 | Zero-power-consumption high-gain remote sensing tag based on energy collection |
| CN116996103A (en) * | 2023-09-26 | 2023-11-03 | 华南理工大学 | Intelligent reflecting surface auxiliary communication system and method with electromagnetic energy collection function |
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