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Updated: Feb 2, 2026
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Method Development for Contactless Resonant Cavity Dielectric Spectroscopic Studies of Cellulosic Paper
Published on: October 4, 2019
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Contactless Investigation of Dielectric Samples with a High-Q Millimeter-Wave Sensor
Summary
This study presents a novel on-chip sensor for dielectric measurements at 120 GHz. The sensor successfully monitors yeast cultivation progress in real-time without contact or labels.
Area of Science:
- Electrical Engineering
- Biotechnology
- Materials Science
Background:
- Dielectric measurements are crucial for material characterization.
- On-chip sensors offer miniaturized solutions for real-time monitoring.
- Millimeter-wave frequencies provide high sensitivity for detecting subtle changes.
Purpose of the Study:
- To develop and demonstrate an on-chip sensor for dielectric measurements at 120 GHz.
- To utilize the sensor for label-free, non-contact monitoring of yeast cultivation.
- To validate the sensor's capability in characterizing biological processes.
Main Methods:
- Fabrication of a coplanar strip line (CPS) bandpass filter on silicon technology.
- Enhancement of the filter's quality factor using edge-coupled lines and silicon back-side etching.
- Application of the sensor to monitor yeast in a glucose medium via S-parameter measurements.
- Utilizing RF probes for millimeter-wave measurements at 120 GHz.
Main Results:
- The fabricated on-chip sensor exhibited an unloaded quality factor of 11.
- A shift in the S21 center frequency from 124 GHz to 125 GHz was observed over 22 hours of yeast cultivation.
- Millimeter-wave monitoring confirmed the dynamic behavior and cultivation phases of yeast.
- Successful label-free, non-contact detection and characterization of dielectric samples in small volumes.
Conclusions:
- The developed on-chip sensor is effective for dielectric measurements at 120 GHz.
- The sensor enables real-time, label-free monitoring of biological processes like yeast cultivation.
- This technology holds promise for applications in biotechnology and material science requiring precise dielectric characterization.
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