Ultrasensitive Planar Metamaterials for Material Characterization Using Tapered CSRR with Application to NDT of 3D Printed Structures

This paper proposes miniaturized, ultrasensitive, flexible planar metamaterials for dielectric constant measurement with a wide dynamic range of the sensing related frequency. The proposed sensors are designed using a thin-substrate microstrip line loaded with tapered complementary split ring resonator (CSRR). The sensors' configuration can be easily integrated with RFID tags for future Internet of Things (IoT) applications. The minimum transmission frequency shifts 56% as the dielectric constant of the material under test (MUT) changes from 1 to 10. Compared to similar state-of-the-art planar sensors, the proposed sensors are almost 50% more sensitive. This extraordinary sensitivity level is of great importance for the development of high-precision near-field based sensors. Sensors' performance were verified numerically and experimentally. To further demonstrate the proposed sensor's practicality, one of the proposed sensors was used to characterize 3D printed dielectric. It was also used as a crack detector for 3D printed samples designed with artificial cracks.