Performance evaluation of surface biopotential dry electrodes based on PSD and EIS

The surface biopotential dry electrodes (SBPDE) are an important part in wearable health monitoring system (WHMS). In this paper, electrical impedance spectra (EIS) and power spectra density (PSD) are presented for evaluating the dynamic performance of SBPDE, several kinds of fabric structure surface biopotential electrodes fabricated in our lab are utilized for measuring the surface ECG of volunteers, and the PSD and summary of power spectra density difference (SPSDD) of ECG at static and running state are computed. Subsequently, EIS of these electrodes were measured on dynamic measurement system (DMS) developed in our lab, the parameters of constructed equivalent circuit (EC) of all SBPDEs are fitted by measured EIS, Experimental result shows SPSDD of ECG is negative correlative with equivalent capacitance of EIS. In general, a novel method which static EIS are utilized for predicting the dynamic performance of SBPDEs is presented.