Estimating Cole-Impedance Parameters from Limited Frequency-Band Impedance Measurements

Particle-swarm optimization is applied to estimate the parameters of 4 different Cole-impedance models using impedance measurements limited to frequencies within 1 kHz to 1 MHz, representative of typical ranges for bioimpedance applications. The accuracy of extracted parameters are compared for cases with N = 201, 25, and 5 datapoints collected using a Keysight E4990A impedance analyzer and N = 8 collected using a MAX30001 integrated circuit. The Cole-impedance estimations using the 201 and 25 frequency datasets show < 0.5% relative error compared to the ideal values. Estimations using 5 and 8 frequency datasets do show significant deviations when measurements do not capture plateauing impedance regions at low and high frequency.