Up to now, low-frequency ultrasonic transducers have been manufactured using different materials and technologies and have been inspired by the biological world, mainly by the biosonar of dolphins and bats. Our research moves in this context, which is dedicated to investigating the feasibility of developing a piezopolymer sensor capable of covering the wide frequency range of a bat's biosonar. We propose an ultrasonic sensor manufactured using a sheet of polyvinylidene fluoride curved according to a logarithmic spiral geometry as it is present in biological models of the cochlea. Experiments were carried out both in transmission and reception, and demonstrated that a spiral-shaped transducer can transmit and receive ultrasonic signals similar to the specific vocalizations of most of the bats in the range between 20 and 80 kHz. The resonant frequencies of the transducer were evaluated through a finite element analysis, in agreement with experimental data covering the entire broadband. During transmission, the sound pressure level showed a maximum value of 90 dB, while during reception, the sensitivity spanned from t103.8 up to t89.1 dB. Directivity measurements demonstrated omnidirectional properties both on horizontal and vertical planes, representing a breakthrough in the field of broadband ultrasonic sensors.

中文翻译：

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螺旋形生物启发超声波传感器。

迄今为止，低频超声换能器已经使用不同的材料和技术制造，并且受到生物界的启发，主要是受到海豚和蝙蝠的生物声纳的启发。我们的研究就是在这种背景下进行的，致力于研究开发一种能够覆盖蝙蝠生物声纳的宽频率范围的压电聚合物传感器的可行性。我们提出了一种超声传感器，该超声传感器使用根据对数螺旋几何形状弯曲的聚偏二氟乙烯薄片制成，因为它存在于耳蜗的生物学模型中。在发送和接收方面都进行了实验，结果表明螺旋形换能器可以发送和接收类似于大多数蝙蝠在20至80 kHz范围内的特定发声的超声波信号。通过有限元分析对换能器的谐振频率进行了评估，并与覆盖整个宽带的实验数据相一致。在发送过程中，声压级的最大值为90 dB，而在接收过程中，灵敏度的范围为t103.8至t89.1 dB。方向性测量在水平和垂直平面上均表现出全向特性，代表了宽带超声传感器领域的一项突破。