Permittivity measurement using coaxial resonators

The paper presents a coaxial resonator based permittivity measuring system for plane materials, which measures in a non-destructive way. The system is working in frequency range of 700-850 MHz and based on ISM band RF transceivers controlled by microcontroller and the data collected using serial UART-USB interface. The article introduces the coaxial resonator which has a resonance frequency of 780MHz without load. The system measures the scalar scattering parameter |S21} over the resonance region. The resonance frequency and the quality factor are considered to evaluate the complex dielectric constant of the measured material. The small, simple, and cheap measuring system makes this sensor system particularly usable for dielectric parameter measurement for radio wave propagation models.