Loading Mechanism of Ultrasonic Biomedical Transducer

In this paper, an integrated loading model of ultrasonic transducer is established to explain the phenomenon that different tissue loads have different effect on resonance frequency of ultrasonic transducer. Mechanical loss of ultrasonic transducer is taken into consideration in the model and mass-spring-damping tissue model and contact impedance between ultrasonic transducer and tissues are given. Experiments show that this model is accurate enough to analyze loading characteristic of ultrasonic transducer. Effect of tissue elastic module on resonance frequency of ultrasonic transducer is studied. Results show that soft tissue with low elastic module make resonance frequency of ultrasonic transducer lower than unloaded condition, while tissue with large elastic module make resonance frequency larger.