Inductively-Coupled Extender for Resonant Sensor Read Range
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Solution Overview
Problem
Current soil moisture monitoring technologies, particularly in situ sensors, face limitations such as requiring a permanent power supply, high individual costs, and limited deployment due to centralized data acquisition and power hubs, which restricts the number of measurement nodes and hinders monitoring of heterogeneous soil moisture content.
Innovation Solution
The introduction of an inductively-coupled extender (ICE) in an LC-resonant sensor architecture, which allows for a wireless and passive activation of the sensor, eliminating the need for a tethered power supply and enabling holistic measurement of heterogeneous environments by maintaining a fixed position relative to the LC sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a permanent power supply and centralized data acquisition system are used, then measurement reliability is improved, but device complexity and deployment cost increase
Solution Approach 1:
The patent extracts the power supply and data acquisition functions from the sensor node itself, eliminating the need for permanent power supplies, batteries, and centralized data acquisition systems at each measurement point. The sensor becomes a passive element that is powered and interrogated wirelessly by an external reader, significantly simplifying the sensor node architecture while maintaining measurement reliability through wireless power transfer and data communication
Solution Approach 2:
The patent introduces an external reader device as an intermediary that provides both power and data acquisition capabilities. This mediator wirelessly couples to the passive sensor, transferring energy and enabling measurements without requiring the sensor to have its own power source or communication infrastructure, thus resolving the contradiction between reliability and complexity
2Length of stationary object
If the read range is increased to monitor deeper soil layers, then measurement coverage is improved, but signal strength and detection accuracy deteriorate
Solution Approach 1:
The patent employs dynamic tuning of the resonant circuit parameters (inductance and capacitance values) to optimize the resonant frequency and quality factor at different depths. By adjusting the circuit characteristics to match the operating conditions at various soil depths, the system maintains both extended read range and high signal detection accuracy, as the resonant peak becomes more pronounced and easier to detect despite increased distance and signal attenuation
Solution Approach 2:
The patent changes the electrical parameters of the resonant circuit (specifically the inductance L and capacitance C values) to achieve different resonant frequencies optimized for specific measurement depths. This parameter adjustment allows the sensor to adapt to varying soil conditions and depths, maintaining measurement precision while extending the effective read range into deeper soil layers where signal strength would otherwise be insufficient
3Ease of operation
If the sensor is made position-independent to ease deployment, then ease of operation is improved, but alignment sensitivity and measurement accuracy worsen
Solution Approach 1:
The patent utilizes resonant vibration at a specific frequency to enable position-independent operation. The external reader excites the passive sensor at its resonant frequency, creating a strong, detectable response that is independent of the sensor's orientation or position relative to the reader. This resonant coupling mechanism eliminates alignment sensitivity, allowing the sensor to be deployed freely without requiring precise positioning while maintaining measurement accuracy
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
This solution effectively increases the read range of the sensor and reduces the impact of reader/sensor misalignment, allowing for robust signal detection in lossy soil substrates up to one meter deep, while maintaining sensitivity and accuracy in soil moisture content measurements.
Implementation Method 1
perform the interrogating of the resonant sensor using a reader having a reader coil to wirelessly interrogate the resonant sensor
Implementation Method 2
resonant sensor having an inductive element and a capacitive element... monitor frequency responses from the interrogation
Implementation Method 3
the capacitive element can include dielectric material between conductive lines of the electrically conductive coil
Data Source
AI summary
An inductive-capacitive resonant sensor architecture includes an inductively-coupled extender (ICE) that can both increase read range and lessen the effects of reader/sensor misalignment. The ICE can include a first coil configured with respect to a resonant sensor and a second coil separated from the first coil and coupled to the first coil by electrical wires. An external reader can be arranged with respect to the second coil. This architecture can nearly eliminate misalignment issues between the external reader and the resonant sensor. The ICE can be implemented with a closed circuit design. Additional apparatus, systems, and methods are disclosed.