The Influence of Temperature on the Performance of Ultrasonic Transducer

We all know that the main parameters of ultrasonic transducers are resonant frequency, anti-resonant frequency, resonant impedance, anti-resonant impedance, output amplitude, static capacitance, and so on. The long-term operation of the transducer itself will cause loss, in addition to its wear and tear, it will also be affected by the external environment. For example, the temperature difference between indoor and outdoor will cause the working environment temperature of the transducer to be unstable and affect performance. The following is about the effect of temperature on the ultrasonic transducer. Contact BBT medical for more ultrasonic transducer price info!


Ⅰ. The influence of temperature on the resonance frequency of the ultrasonic transducer


The size of the optimal working frequency of the transducer is related to the thickness of the transducer, the density ρ of the piezoelectric ceramics, and the elastic constant component of the constant electric displacement. The relationship between frequency and temperature of piezoelectric ceramics is usually expressed by frequency-temperature stability. Since the linear expansion coefficient and the density temperature coefficient are both negative values, when the operating temperature rises, the resonance frequency of the waterproof ultrasonic transducer will drop. Therefore, the frequency of the transducer will change with temperature, and it is mainly caused by the change of elastic constant with temperature. The change in the size of the transducer caused by the linear expansion has a minor effect on the frequency.


Ⅱ. The influence of temperature on the static capacitance of the ultrasonic transducer


The size of the static capacitance of the medical ultrasonic transducer is related to the thickness and diameter of the piezoelectric ceramic and the dielectric constant component of the constant strain. Because the piezoelectric transducer is rigidly clamped, the temperature coefficient of the vibrator's diameter is almost unchanged, and the linear expansion coefficient of the vibrator is much smaller than the temperature coefficient of the dielectric constant component. Therefore, the relationship between static capacitance and temperature is only related to the dielectric constant of the piezoelectric material. As the operating temperature increases, the dielectric constant increases, and the static capacitance of the waterproof ultrasonic transducer increases.


Ⅲ. The influence of temperature on the resonance impedance of the ultrasonic transducer


Due to temperature changes, the dielectric isolation rate and elastic constant components increase with increasing temperature, the operating frequency decreases with increasing temperature, and the static capacitance increases with increasing temperature. Therefore, the impedance of the ultrasonic transducer decreases as the temperature increases.


In short, temperature changes will change the parameters of the transducer such as increased temperature, lower resonant frequency, increased static capacitance, and reduced impedance. The influence of temperature will be taken into account and compensated when the transducer is designed and used.

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