PVDF corrugated transducer for ultrasonic ranging sensor

This paper describes a method to design and build ultrasonic transceivers using low-cost polyvinylidene fluoride (PVDF) corrugated film. The corrugated transducer features multiple curved sections, which provide a higher acoustic output compared to traditional ultrasonic transducer design using a single curved PVDF film section. We have built and demonstrated a prototype 200 kHz transducer and found it to be practical for applications requiring short-range distance measurement (20–300 mm) with SNR of 20 dB for 200 mm target. The prototype uses a single transducer that operated as both an ultrasonic transmitter and a receiver and provides a beam directivity of ±7° at −6 dB point using a 160 Vpp drive pulse. The transmitter output is 6.6 Pa (rms) at 30 cm with relative bandwidth of 33% and the receiver sensitivity is 0.55 mV/Pa. A microprocessor provides the timing signals, measures the time of flight from the transmitted pulse to the received echo, and calculates the distance.