A dual-band perfect terahertz metamaterial absorber for environmental monitoring applications

Abstract

Abstract This paper shows a dual-band, symmetric lantern-shaped metamaterial absorber (MMA). The proposed absorber has been designed on a Lead glass substrate having electrical dimensions of 1.36 λ × 1.36 λ × 0.081 λ , for calculating the wavelength the first frequency 9.7 THz has been considered. The proposed absorber exhibits tremendous performance with peak absorption values of 99.997% at 9.7 THz ( f 1 ) and 98.46% at 10 THz ( f 2 ). Meanwhile, as the working range is in THz, the actual behavior of copper is also tested using the Drude model. Additionally, the design was validated using HFSS and an equivalent circuit model, both of which produced results closely matching those obtained from CST simulations. Moreover, this MMA is evaluated across a wide temperature range to assess its thermal stability. Compared to recently reported MMA, the proposed design offers a prominent improvement by significantly greater sensing performance. While several current designs have demonstrated triple or quad band absorption capabilities, their sensitivity commonly remains below 500 GHz RIU −1 , with FOMs under 100 and Q-factors generally below 75. These designs are typically optimized for multi substance sensing detection, but often at the cost of reduced selectivity or limited thermal robustness. In contrast, the proposed absorber achieves much higher sensitivities of 2720 and 2500 GHz RIU −1 , FOMs of 27.53 and 64.10 and Q-factors of 98.2 and 256.4. The high FOM enables accurate detection, while the Q-factor ensures narrow and well-defined resonance peaks for precise sensing. Furthermore, NO 2 has been selected as the key gas to check the effect of analyte thickness to find the absorption behavior as it is a major air pollutant. Besides, the MMA maintains polarization and incident angle insensitivity confirming practical applicability in environmental monitoring.

Topics & Concepts