Arterial Windkessel parameter estimation: a new frequency-domain method

New accurate and easily applied frequency-domain formulas are presented for calculating the parameters of the linear three-element windkessel. Besides model linearity, the main assumption is steady-state periodicity. The aortic characteristic impedance is estimated using the (active) energy-balance method, proposed previously. An equivalent frequency-domain version of that method is presented, involving Fourier harmonics of aortic pressure and flow. Finally, the arterial compliance is estimated following a new approach, based on the balance of reactive energy, which leads to a new closed-form expression. The results obtained by processing both simulated and experimental data are presented and discussed also in comparison with parameter optimisation.