A Surface Acoustic Wave-Based PM 1.0 Fine Dust Detection System Using Full Digital Time-Interleaved Counters

Area of Science:

• Sensor Technology
• Environmental Monitoring
• Integrated Circuits

Background:

• Surface Acoustic Wave (SAW) sensors are sensitive to mass loading, exhibiting changes in resonance frequency upon exposure to particulate matter.
• Accurate detection of fine dust is crucial for environmental monitoring and public health.
• Existing detection methods may lack the sensitivity or real-time capabilities required for comprehensive monitoring.

Purpose of the Study:

• To propose and validate a fine dust detection system employing SAW sensors and time-interleaved counters.
• To achieve high-resolution frequency measurements for sensitive fine dust detection.
• To demonstrate the feasibility of integrating this system into a standard CMOS process.

Main Methods:

• Utilized SAW sensors whose resonance frequency shifts upon fine dust adhesion.
• Implemented a dual-channel system with sensing and reference SAW oscillators.
• Employed 20-bit asynchronous counters to convert oscillation frequencies to digital data.
• Calculated frequency difference between channels to quantify fine dust presence.

Main Results:

• Achieved a frequency resolution of 0.95 ppm at an operating frequency of 460 MHz.
• Demonstrated the system's capability to detect the presence of fine dust by measuring frequency shifts.
• Successfully implemented the proposed circuit in a TSMC 130 nm CMOS process.

Conclusions:

• The proposed fine dust detection system effectively utilizes SAW sensor frequency shifts and time-interleaved counters for accurate detection.
• The system offers high resolution and is suitable for integration into standard semiconductor manufacturing processes.
• This technology holds promise for advanced environmental monitoring and air quality assessment.