A Dual-Band Microwave Sensor Based on EIT-Like Effect for Differential Sensing Applications

In this article, a differential dual-band sensor is proposed based on the electromagnetically induced transparency-like (EIT-like) effect, which is used for the dielectric characterization of solid materials. The proposed sensor is designed with two identical resonant units consisting of open-circuited stubs and split-ring resonators (SRRs), which are loaded on both sides of the microstrip line. Based on the equivalent circuit, the differential and dual-band measurements are analyzed, and the resonance frequencies can be controlled to realize dual-band measurement by changing the equivalent capacitance and inductance of the SRR. The proposed sensor is further simulated, fabricated, and measured. The unloaded sensor measurement shows the proposed sensor operates at two resonance frequencies of 1.719 and 2.712 GHz, and the dielectric constant measurement shows the proposed sensor exhibits high sensitivities of 4.4% and 3.7% at the two resonance frequencies, respectively. This design is a good candidate in the field of solid detection.