Theoretical Investigation of the Sensitivity—Q Trade‐off in Terahertz Graphene Metamaterial Sensors via Interdigitated Design and Complex‐Frequency Waves

ABSTRACT Terahertz (THz) technology holds great promise in biomedical imaging, non‐destructive testing, biosensing, and telecommunications, but its adoption is limited by weak light–matter interactions and strong dissipative losses in conventional metamaterials. To overcome these limitations, a dual strategy is introduced that combines interdigitated electric split‐ring resonators (ID‐eSRRs) with the complex‐frequency wave (CFW) technique. Electrical gating from 0–200 V tunes the graphene Fermi level from 0.3756 to 0.6505 eV, providing a wide and continuous resonance shift for fingerprint‐aligned sensing. The CFW method reconstructs loss‐compensated spectra from real‐frequency data, generating virtual gain and markedly sharpening resonances. Simulations show that the optimized ID‐eSRR achieves a refractive index sensitivity of 196 GHz/RIU for 100 nm analytes, while CFW amplification increases the quality factor from 8.54 to 427.96, a 50.1‐fold enhancement. This improvement enables reliable discrimination of DNA variants with refractive index differences as small as at . The demonstrated approach provides a generalizable route to simultaneously enhance sensitivity and ‐factor, thereby overcoming the long‐standing sensitivity– trade‐off and advancing the development of high‐performance THz sensors for ultrasensitive biomedical diagnostics.