Passive Wireless Magnetic Field Sensing Tag for Low-Power Monitoring
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Solution Overview
Problem
Existing magnetic field quantity sensing technologies face challenges with high power consumption, large size, and limited suitability for wireless transmission and large-area sensor network layouts, as well as low measurement accuracy and sensitivity in RFID-based systems.
Innovation Solution
A passive wireless magnetic field characteristic sensing tag and system incorporating a first antenna, impedance matching network power divider circuit, rectification and energy management circuit, low dropout group, demodulation circuit, microprocessor, magnetic field characteristic sensing circuit, select switch circuit, and back-scattering circuit, enabling high-precision and intelligent monitoring of magnetic fields with RFID technology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic field intensity measuring apparatuses are used, then measurement accuracy is improved, but device size and power consumption increase
Solution Approach 1:
The patent combines RFID technology with magnetic field sensing by integrating a magnetic field sensor into the RFID tag structure. The tag includes a magnetic field sensor, RFID circuit, and processing unit that work together to sense magnetic field intensity and wirelessly transmit the data, eliminating the need for separate power supply and communication systems
Solution Approach 2:
The RFID tag is designed to perform multiple functions: it serves as both an identification device and a magnetic field sensor. The same RFID tag that can be used for wireless communication and identification also contains the magnetic field sensing capability, allowing one device to fulfill multiple roles
2Measurement precision
If conventional magnetic field measuring apparatuses are used, then measurement accuracy is improved, but device size increases
Solution Approach 1:
The patent combines RFID technology with magnetic field sensing by integrating a magnetic field sensor into the RFID tag structure. The tag includes a magnetic field sensor, RFID circuit, and processing unit that work together to sense magnetic field intensity and wirelessly transmit the data, eliminating the need for separate power supply and communication systems
Solution Approach 2:
The magnetic field sensor is integrated within the RFID tag structure, with the sensor embedded in the tag body. The RFID circuit and processing unit are nested within the same compact housing, creating a hierarchical integration where smaller components are contained within larger systems
3Ease of operation
If RFID-based magnetic field sensing system is used, then wireless transmission capability is improved, but measurement accuracy and sensitivity deteriorate
Solution Approach 1:
The patent introduces a processing unit as an intermediary between the magnetic field sensor and the RFID communication system. This processing unit processes the raw sensor signals, performs calibration and compensation, and then transmits the processed data via RFID, ensuring that measurement accuracy is maintained while enabling wireless transmission
Solution Approach 2:
The system incorporates feedback mechanisms where the processing unit continuously monitors and adjusts the sensor readings based on calibration data and environmental conditions. This feedback loop compensates for potential accuracy losses and maintains high measurement precision throughout wireless operation
4Use of energy by moving object
If passive RFID tag is used, then power consumption is reduced, but measurement accuracy deteriorates
Solution Approach 1:
The passive tag operates in periodic measurement cycles, remaining in low-power sleep state between measurements. When triggered by the reader or based on time intervals, the tag activates the magnetic field sensor, performs measurements, transmits data, and then returns to sleep mode, achieving low average power consumption while maintaining measurement capability
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves high-precision and low-power magnetic field monitoring with reduced size and cost, enabling long-distance wireless transmission and efficient sensor network deployment, overcoming the limitations of existing systems in terms of power consumption and accuracy.
Implementation Method 1
a first antenna; the first antenna is configured to receive a radio frequency signal sent by a reader
Implementation Method 2
a magnetic field characteristic sensing circuit; the magnetic field characteristic sensing circuit is configured to sense a magnetic field quantity at a position where the passive wireless magnetic field sensing tag is located
Implementation Method 3
a back-scattering circuit; the back-scattering circuit is configured to send a signal to the reader by backscattering
Data Source
AI summary
Provided is a passive wireless magnetic field characteristic sensing tag and system, and a magnetic field quantity acquisition method, which integrates a passive magnetic field quantity sensor in a passive electronic tag and cooperates with a reader and a host computer to build a magnetic field sensing system, so as to realize high-precision and high-intelligence monitoring of the magnetic field quantity.