Resonance Frequency Sweeping for Distance-Independent Passive Sensor Readout
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Solution Overview
Problem
Current remote sensing systems face challenges in designing a wireless, energy-efficient, handheld reader that can accurately read data from passive sensors without being sensitive to distance, often requiring complex and power-hungry circuitry, which complicates the reader architecture and compromises accuracy.
Innovation Solution
A resonance circuit-based system that uses a negative resistance circuit in parallel or series with a resonance circuit to form an oscillator core, allowing for distance-independent data readout by sweeping the resonance frequency and detecting a jump or transition in the oscillating signal, eliminating the need for bulky lab equipment and complex correction techniques.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic coupling through a coil is used to perform sensor readout, then data can be obtained from passive sensors, but the system requires bulky and expensive lab equipment such as vector network analyzers or impedance analyzers
Solution Approach 1:
The patent replaces complex electronic measurement systems (vector network analyzers, impedance analyzers) with a simplified resonance-based detection system. Instead of using bulky lab equipment to characterize input impedance profiles, the invention uses a resonance circuit that naturally oscillates at the sensor's resonant frequency, allowing detection with simple frequency measurement rather than complex impedance analysis
Solution Approach 2:
The sensor circuit itself provides the measurement information through its resonant frequency. The passive sensor contains information in its resonance frequency and Q-factor, allowing the system to self-characterize without external measurement equipment. The resonance circuit automatically oscillates and reveals sensor parameters through its natural response
2Device complexity
If complicated electronic circuits are used to perform measurements based on amplitude of coupled signal, then the design might be simpler and more energy efficient, but the devices become sensitive to distance between sensor and readout coil
Solution Approach 1:
The patent transitions from measuring signal amplitude (which is distance-dependent) to measuring resonant frequency and Q-factor (which are intrinsic sensor properties independent of distance). By sweeping through a range of frequencies and detecting the resonant peak, the system obtains distance-independent measurements of the sensor's natural characteristics rather than coupling-strength-dependent amplitude signals
Solution Approach 2:
The invention uses resonance vibration of the LC circuit at its natural frequency to detect sensor parameters. The resonance circuit oscillates at frequencies near the sensor's resonant frequency, and the coupling between them reveals sensor information through frequency shifts and Q-factor changes rather than through distance-sensitive amplitude attenuation
3Measurement precision
If resonance frequency sweeping is used to achieve distance-independent measurements, then accurate data readout is obtained, but the system requires negative resistance circuitry and oscillator core components
Solution Approach 1:
The patent combines the negative resistance circuit, resonance circuit, and sensor interface into a unified oscillator core. Rather than separate measurement and oscillation components, the system integrates these functions so that the oscillator naturally sweeps through frequencies and detects resonance through its own operating characteristics, reducing overall system complexity despite the specialized components required
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 system achieves accurate and efficient data readout from passive sensors, reducing reader complexity and power consumption while maintaining independence from distance, enabling applications like point-of-care health monitoring and food safety monitoring.
Implementation Method 1
The first and second resonance circuits are communicatively coupled via the first and second inductive elements or circuitry by way of an inductively-coupled oscillating signal
Implementation Method 2
A resonance circuit-based system that uses a negative resistance circuit in parallel or series with a resonance circuit to form an oscillator core
Implementation Method 3
sweeping the resonance frequency and detecting a jump or transition in the oscillating signal
Data Source
AI summary
One example is directed to a reader device having a first resonance circuit and being configured to interrogate one or more other remotely-located resonance circuits, each associated with a second resonance circuit which may be part of a passive sensor circuit. The first resonance circuit is operated to cause the inductively-coupled oscillating signal to be swept over a range of frequencies and therein cause a jump or sudden transition in a frequency of the oscillating signal while the first and second resonance circuits are in sufficient proximity for inductively-coupling via an oscillating signal via their respective resonance circuits. Sensing circuitry may be used to detect the jump or sudden transition in the frequency of the oscillating signal and, by way of or in response to an indication of timing and/or a set of inductively-related parameters, data is conveyed from the sensor to the reader device via the inductively-coupled oscillating signal.