Cross-Polarized Chipless RFID Sensor: A Novel Approach for Measuring Dielectric Constants in Solid Minerals and Rocks

This article introduces an innovative approach to measure the dielectric constants of solid geological samples using a cross-polarized chipless radio frequency identification (RFID) sensor. Co-polarized RFID sensors often face interference from the material under test (MUT), resulting in significant deviations in resonance frequency. To address this issue, we developed a cross-polarized chipless RFID sensor that transmits and receives signals in different polarization directions, enhancing measurement accuracy. Our sensor features resonator-integrated ground plane cylindrical capacitors designed to detect variations in the dielectric properties of minerals and rocks. Both simulation and experimental validation indicate that the sensor can identify dielectric constant variations ranging from 1 to 10, with a frequency shift sensitivity of 63.5 MHz per dielectric unit. The sensor was tested on various mineral and rock samples, demonstrating alignment with established dielectric values. Operating effectively across a wide frequency range of 3.1–10.6 GHz, the system is well-suited for ultrawideband (UWB) applications. This proposed method is cost-effective, compact, and compatible with remote sensing platforms, presenting a promising alternative for mineralogical and geophysical testing applications.