A Direct-Reading MEMS Conductivity Sensor with a Parallel-Symmetric Four-Electrode Configuration.

Area of Science:

• Electrochemistry
• Sensor Technology
• Materials Science

Background:

• Accurate in-situ monitoring of marine environmental parameters is crucial.
• Existing conductivity sensors may lack the required accuracy, range, or real-time compensation capabilities for marine applications.

Purpose of the Study:

• To design and fabricate a direct-reading conductivity sensor with a parallel symmetrical four-electrode structure.
• To achieve high accuracy, a broad measurement range, and integrated temperature compensation for marine applications.

Main Methods:

• Finite element simulations (COMSOL Multiphysics) were used to optimize electrode parameters.
• Micro-Electro-Mechanical Systems (MEMS) technology was employed for sensor chip fabrication.
• A dedicated conductivity measurement circuit was designed and implemented for performance testing.

Main Results:

• The optimal AC excitation frequency was determined to be 1.067 kHz.
• The sensor demonstrated a wide measurement range of 0-107.41 mS/cm.
• High measurement precision of ±0.1 mS/cm (0-76.422 mS/cm range) and a maximum error of ±0.073 mS/cm were achieved.

Conclusions:

• The developed conductivity sensor exhibits high accuracy, a broad measurement range, and miniaturization.
• The sensor enables real-time conductivity readings with integrated temperature compensation.
• This technology is significant for on-site observation of marine physical parameters.