Experimentally validated dual-band GHz metamaterial perfect absorber biosensor with negative-index response and...

A dual-band GHz metamaterial absorber (MPA) biosensor is presented as a proof-of-concept platform for dielectric-sensitive electromagnetic sensing integrated with AI-assisted broadband spectral analysis. The proposed three-layer copper-FR-4-copper structure exhibits near-unity absorption at 6.0 GHz and 9.1 GHz and demonstrates engineered negative-index behavior, which enhances electromagnetic field confinement and sensitivity to dielectric perturbations. The biosensor was fabricated using standard PCB technology and experimentally validated through free-space microwave measurements, showing excellent agreement with simulations and absorption exceeding 92.5% and 99.8% at the two resonant frequencies. For dielectric-sensitive analysis, the sensor response was evaluated under simulation-based loading conditions using low-loss COC/COP coverslip layers and literature-reported electromagnetic properties representative of healthy-like and malignant-like breast environments. Distinct broadband spectral perturbations were observed across the 5-10 GHz frequency range, demonstrating sensitivity to dielectric-property variations. Sensor performance was assessed using quality factor, sensitivity, and figure-of-merit metrics. An AI-assisted spectral interpretation framework was developed using distance- and correlation-based analysis of the broadband electromagnetic response. The results demonstrate that the proposed platform combines dual-band high-Q absorption, engineered triple-negative electromagnetic characteristics, and AI-assisted spectral analysis within a unified microwave biosensing framework. No biological samples were evaluated in this study; therefore, the reported results should be interpreted as simulation-based dielectric-loading analyses rather than validated cancer-detection outcomes.