A general multi-mode lumped equivalent circuit model for circular cMUT cells

In this work, we present a general multi-mode lumped equivalent circuit model for an arbitrary excited circular cMUT cell operated in a small signal regime. It can be considered as a model extension of the modal analysis based equivalent circuit model already presented in [1]. In order to derive this model, a comprehensive description of the radiation impedance by the Bouwkamp's impedance theorem [2] is provided. Comparing with other existing lumped equivalent circuit models, this model can simulate a wide frequency range, i.e., containing those harmonic modes, response of cMUTs under an unconventional excitation. A case study based on a half electrode excited circular cMUT cell is presented, and frequency response results from the modelling are well validated by COMSOL simulation. Potentially, this method can also handle the problem of a group of cMUT cells.