Metamateri̇als applications for microwave and terahertz frequencies

In this thesis, sharp resonance dips ranging from -40 dB to -120 dB in the THz band demonstrate that metamaterial-based structures can exhibit extremely selective behavior at high frequencies, and that small geometric adjustments can sensitively target a desired frequency. Studies conducted in the X-band have also shown that noticeable differences in reflection occur in various environments (dielectric materials). Notably, both branded and unbranded fuels displayed significant deviations in dip depth and resonance frequency. This finding suggests that FSY or similar resonator structures can be effectively used to distinguish fuel quality and potential additives. The resonance and dip characteristics identified through S-parameters (especially S₂₂) enable high-precision and real-time measurements in many fields such as industrial automation, quality control, and security screenings. All these studies carried out in both the microwave and terahertz regimes have demonstrated that metamaterial-based structures offer a powerful approach to understanding the electromagnetic interaction properties of different liquid and gas environments (fuels, air, etc.) and to developing highly sensitive sensor systems. Shifts in resonance frequencies and sharp changes in reflection/transmission coefficients can reveal even minor differences in material properties, thereby offering practical and innovative solutions across a broad range of applications, from fuel quality to security.