Improvement of micro-bubble sizing using multi-harmonic excitations under the transducer bandwidth constraint

A microbubble sizing method based on the use of the odd harmonics of square-like excitations is presented. The microbubble resonance signature is determined by measuring the backscattered signals using the Dual Frequency Method combined with a time-frequency representation. The efficiency and the limitations of this method are described in the case of sine-like excitations. It is then established that the harmonics of square-like excitations can be used to significantly enlarge the range of microbubble detection and sizing. These findings were confirmed and explained by theoretical studies on microbubble dynamics based on the Keller-Miksis formulation.