Work

A dielectric spectrometer based on the quasi-static coaxial probe model and a miniature vector network analyser

Year: 2026

Type: article

Abstract: Due to its fast and non-destructive characteristics, dielectric spectroscopy has been widely applied in the detection of agricultural and food products. However, traditional dielectric measurement system, which rely on large and expensive vector network analyser (VNA) and accompanying software, is expensive and restricted to laboratory. To enable in-situ dielectric spectra, a quasi-static model for the relative complex permittivity was derived and its performance verified. Then, a dielectric spectrometer was developed, integrating a miniaturised VNA, a coaxial probe, and self-developed data acquisition software. Its stability and accuracy were evaluated using anhydrous ethanol and normal saline over the 200-6,000 MHz frequency range. Finally, the potential of the developed dielectric spectrometer for component analysis and adulteration identification was evaluated. The results indicated that the model’s relative errors were within ±7% for both the dielectric constant (

Source: Journal of Agriculture and Food Research

DOI: 10.1016/j.jafr.2026.102891