The ultrasonic sensor is mainly composed of piezoelectric wafers, which can emit and receive ultrasonic waves. Low-power ultrasound probes are mostly used for detection. It has many different structures. It can be divided into straight probe (longitudinal wave), oblique probe (shear wave), surface wave probe (surface wave), Lamb wave probe (Lamb wave), double probe (reflection of one probe, reception of one probe) and so on.
The core of the ultrasonic sensor is a piezoelectric chip in its plastic or metal coat. There are many kinds of materials that make up wafers. The wafer size, such as diameter and thickness, is also different, so the performance of each sensor is different. We must know its performance in advance before using it.