Frequency and strain dependencies in fragmented electrode capacitive strain sensors: A simulation study

Nesser and Lubineau proposed an electrode fragmentation strategy to address the limitations of capacitive strain sensors in wireless sensing due to insufficient sensitivity and limited strain range. However, the theoretical model ignores the coupling effect of nonlinear material deformation and the asymmetry of electrode conductivity, resulting in inaccurate results. At the same time, there is a lack of experimental data under conditions of large strain. To address these, we develop a 3D multiphysics model to analyze transmission line-dominated capacitive responses for the fragmentation strategy. By integrating a dynamic distributed capacitance network with conductivity evolution, the model simulates high-sensitivity behavior. Results indicate strain- and frequency-dependent sensitivity, with multi-frequency analysis identifying optimal bands. A low-frequency sub-model predicts capacitance changes for large strains (40–100%), bridging experimental gaps. A dynamic Poisson’s ratio model improves accuracy, emphasizing nonlinear deformation’s role. Electrode conductivity asymmetry induces up to 25% capacitance deviation at low frequencies, aiding fabrication optimization. Incorporating inductance replicates S11 frequency shifts in LC resonant sensors, validating model versatility. This study provides an efficient simulation evaluation method for designing high-sensitivity capacitive sensors and contributes analytical insights applicable to wireless sensing systems.