Quad‐Band Terahertz Electromagnetically Induced Transparency‐Like Metasurface Sensor With Geometry‐Constrained Inversion

ABSTRACT

This study proposes a quad‐band terahertz electromagnetically induced transparency (EIT)‐like metasurface sensor with geometry‐constrained parameter inversion. The device consists of three concentric ring resonators and a bottom U‐shaped resonator. A gap in the inner ring breaks symmetry, while cooperative bright–dark and dark–dark mode coupling produces four transparency windows at 0.49, 0.59, 0.76, and 0.86 THz. Refractive‐index sensing simulations yield a maximum sensitivity of 269.8 GHz/RIU (RIU, refractive index unit) and a maximum Q factor of 66.4. Further experiments with antibiotic samples are required to validate practical detection performance. An improved multiscale temporal convolutional network (Improved‐TCN) captures multiscale local features and cross‐band correlations in the multimode‐coupled spectra. By integrating multiscale dilated convolutions and self‐attention, it predicts a geometrically feasible candidate set of five parameters from 201‐point linear transmission amplitude spectra. Across five independent runs, the full model achieves a standardized mean squared error (MSE) of 0.028 ± 0.001 and a coefficient of determination (R ² ) of 0.969 ± 0.003, demonstrating stable performance on the held‐out test set. The method provides a practical reference for rapid, geometrically feasible parameter inversion of multiband terahertz sensors with predefined topologies.