Modeling Blood Permittivity with a Modified Cole-Cole Framework

Accurate, non-invasive estimation of blood glucose and glycated hemoglobin (HbA1c) remains a key challenge in biomedical sensing. This study introduces a novel electromagnetic framework for modeling the dielectric response of blood to glucose variations, focusing on the real part of permittivity (ε') across 0.1-20 GHz. The HbA1c-related analysis was limited to the frequency range of 0.1-10 GHz. A modified Cole-Cole model is developed, expressing dielectric relaxation parameters as polynomial functions of glucose concentration, allowing precise reconstruction of broadband complex permittivity. A sensitivity extraction technique is proposed to compute the partial derivative of ε' with respect to glucose levels. Results reveal a critical frequency band 5-7 GHz where ε' demonstrates maximum sensitivity to glycemic variations, providing a basis for optimal frequency selection in sensor design. Additionally, a physiology-based model links permittivity to HbA1c levels, accounting for red blood cell turnover and glucose accumulation. This dual-focus modeling approach is, to our knowledge, the first to integrate glucose and HbA1c into a unified dielectric characterization using a modified Cole-Cole framework. The proposed method enables improved spectral targeting for microwave biosensors, offering enhanced resolution and biomedical relevance. This work paves the way for future development of multi-marker, real-time, non-invasive EM-based diagnostic systems.