Optimization of Piezoelectric Flexible Ultrasonic Sensors Based on Backing Layer Matching
Even with the advantages of small size,light weight,and easy matrixing,flexible ultrasonic sensors based on polyvinylidene fluoride (PVDF) piezoelectric film are susceptible to back clutter and impedance mismatc-hing,resulting in a complex frequency component of the return signal and a low signal-to-noise ratio. In order to effectively absorb the stray waves at the back of the sensor and improve the ability of unidirectional radiation of ultrasonic tungsten powder and silica gel were used to design the backing layer for flexible ultrasonic sensors,which could increase the signal voltage amplitude of the sensor by 200％ while maintaining the overall flexibility of the transducer. Secondly,according to the electrical characteristics of the flexible ultrasonic sensor,an impedance matching method for flexible ultrasonic sensors was proposed,and the best matching parameters were obtained through experiments,so that the signal-to-noise ratio of the sensor was increased from 2 dB to 30 dB. The optimized flexible ultrasonic sensors had the excellent performance of wide bandwidth,high frequency,narrow pulse. The experimental results of the measurement of the thickness of pipe test specimens with different curvatures and wall thicknesses showed that it could reach the accuracy of 0.01 mm.
flexible ultrasonic sensorsbacking layer matchingimpedance matchingsignal-to-noise ratio
万方数据
维普
