A Non-Invasive Phase Sensor for Permittivity and Moisture Estimation Based on Anomalous Dispersion

Area of Science:

• Electrical Engineering
• Materials Science
• Physics

Background:

• Traditional microwave resonance sensors rely on amplitude spectrum measurements (frequency shift, bandwidth).
• These methods can be susceptible to noise and environmental variations, impacting accuracy.
• Characterizing sample losses requires complex bandwidth determination.

Purpose of the Study:

• To propose and demonstrate a novel microwave sensing scheme utilizing phase spectrum analysis.
• To enhance accuracy and reduce detection errors in resonance sensing.
• To simplify the characterization of material dielectric properties and losses.

Main Methods:

• Developed a phase sensing technique exploiting double phase reversal in anomalous dispersion regions.
• Designed and experimented with a microstrip open stub resonator operating in the anomalous dispersion region.
• Extracted dielectric characteristics from resonant frequency and phase response slope.

Main Results:

• Phase sensing demonstrated significant reduction in detection errors compared to traditional amplitude-based methods.
• The technique offers improved noise immunity and reduced environmental dependence.
• Simplified bandwidth determination for characterizing sample losses.
• Successfully detected changes in dielectric characteristics and moisture levels.

Conclusions:

• Phase sensing provides a more robust and accurate method for microwave resonance sensing.
• The developed technique simplifies material characterization and is applicable to moisture detection.
• This approach offers a promising alternative to traditional amplitude-based sensing methods.