High-Frequency Sensor Circuit for Bulk Water Detection
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Solution Overview
Problem
Current sensor ICs are unable to effectively evaluate the motion of water molecules in aqueous solutions due to limited frequency evaluation capabilities, specifically at frequencies above 10 GHz, which is necessary to assess hydration states and dielectric constant changes.
Innovation Solution
A sensor circuit with an oscillation unit having a resonance frequency of 30 to 200 GHz, allowing for the detection of changes in bulk water and eliminating the need for magnetic particles by utilizing a differential circuit with an inductor and capacitor to estimate oscillation frequency changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetic particles are used to detect inspection targets at frequencies below 2 GHz, then magnetic polarization can be generated, but the magnetic polarization becomes opposite to the external magnetic field and shows almost no variation at higher frequencies exceeding 10 GHz
Solution Approach 1:
The patent changes the operating frequency parameter from below 2 GHz to 30-200 GHz to detect bulk water motion. This frequency change enables detection of dielectric constant variations in bulk water while avoiding the limitations of magnetic particle behavior at high frequencies.
Solution Approach 2:
The patent replaces the magnetic detection mechanism with a dielectric-based detection mechanism. Instead of using magnetic particles and magnetic polarization, the invention uses the dielectric constant of bulk water to detect inspection targets, substituting magnetic field interactions with electromagnetic field interactions at microwave frequencies.
2Reliability
If oscillators are formed on a semiconductor substrate with protection films, then the semiconductor substrate is protected, but the inspection target cannot come in direct contact with the inductor
Solution Approach 1:
The patent forms the inductor on the highest metal layer of the semiconductor substrate, utilizing the vertical dimension to maximize the inductor's exposure to the inspection target. This dimensional arrangement allows the inspection target to approach as closely as possible to the inductor while the protection film maintains substrate protection.
3Measurement precision
If the oscillation frequency is increased to 30-200 GHz to detect bulk water motion, then hydration state detection becomes possible, but the device complexity increases
Solution Approach 1:
The patent merges the oscillation unit and detection unit onto a single semiconductor substrate, integrating multiple functions into one device. This integration reduces overall system complexity while enabling high-frequency operation for bulk water motion detection.
Solution Approach 2:
The oscillation unit's oscillation frequency naturally changes in response to dielectric constant variations caused by bulk water motion. This self-changing frequency serves as the detection signal, eliminating the need for additional complex detection circuitry and enabling automatic detection of hydration states.
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
Enables the detection of changes in inspection targets containing moisture by accurately measuring dielectric constant variations at high frequencies, simplifying the detection process and eliminating the requirement for magnetic particles.
Implementation Method 1
it is possible to replace a change of an inspection target with a change of bulk water and to detect the change of the bulk water
Implementation Method 2
an oscillation unit 20 having a resonance frequency of 30 to 200 GHz
Data Source
AI summary
Provided is a technology for detecting a change in an inspection target containing moisture. A sensor circuit (1) for inspecting property of an inspection target includes an oscillator (20) having a resonance frequency of 30 to 200 GHz, and a detection circuit (3) that estimates an oscillation frequency of the oscillator.