Note: Hybrid-π model and parameter extraction method for electrode-electrolyte interface characterization with...

This paper presents an equivalent circuit model for the electrode-electrolyte interface and aims at improving the modeling accuracy of the parasitic effects at frequencies up to 300 MHz. Different from the conventional model, the electrode inductances, body loss capacitances, and body loss resistances are all included in the proposed hybrid-π model. In addition, the S-parameters obtained by a vector network analyzer are innovatively used to extract the parameters of the electrode-electrolyte interface model for a frequency range from 10 Hz to 300 MHz. Since reactance is proportional to frequency, the proposed technique can precisely calculate the parasitic effects at higher frequencies. Verified by experiments, the hybrid-π model presents better accuracies when fitted to both the phases and magnitudes of S11 and S21. The superb modeling accuracy of this work is beneficial for biomedical applications that have an electrode-electrolyte interface.