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

This paper introduces an innovative approach to measuring the dielectric constants of solid geological samples using a crosspolarised chipless radio frequency identification (RFID) sensor. Copolarised 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-polarised chipless RFID sensor that transmits and receives signals in different polarisation directions, enhancing measurement accuracy. Our sensor features resonatorintegrated 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 to 10.6 GHz, the system is well-suited for ultra-wideband (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.