Study On Beam Field Of Plum Blossom-shaped Ultrasound Doppler Transducer

The high rate of birth defects has severely impacted the quality of China’s population.Currently, the universal fetal monitoring method is based on the ultrasound Doppler technology,in which fetal abnormality can be detected promptly and accurately in a non-invasive way.Since the ultrasound Doppler fetal heart rate (FHR) systems detect FHR information viaultrasound probes, the quality of ultrasound probes directly affect the accuracy of the detection.The research mainly includes:(1) Structure and technical parameters of ultrasound Doppler plum probe that providetheoretical basis and technical support to the overall amelioration of the ultrasound probes andfetal monitoring devices, including operating frequency, electromechanical coupling factor,electromechanical conversion factor, quality factor, impedance, directivity and sound fieldcharacteristics, emission of sound power and efficiency, sensitivity, sound output security andacoustic matching layer.(2) Distribution simulation of sound field of ultrasound Doppler plum probes. Theultrasound attenuation model of the fetal detection system has been constructed by analyzing thecharacteristics and causes of the attenuation. Then modeling and analysis have beenaccomplished of the sound fields of single-chip and array, in which the single chip is the unit ofthe array. After the modeling and analysis, the sound field distribution of the whole chip-arraycan be obtained with interference and interpolation principle. We studied the impact on the soundfield from the aspects of chip spatial distribution, chip number, size and the emitting frequency.A design proposal of a novel probe has been put forward based on the above results and wasapplied in the FHR detection system to improve the performance of the FHR monitoring system.(3) Method of Experimental measurement of the sound field of the ultrasound Dopplerplum probes. Field sound distributions and sound output parameters of different levels vertical tothe sound wave’s radiation direction have been obtained by the needle-type hydrophonemeasurement system in dehydrated free field.Through the study on the field distribution of the ultrasound Doppler plum probes, we haveimproved the sound field coverage and detection performance of the FHR detection system thathas made the probes more stable and sensitive to improve the accuracy of the monitoring resultsof the ultrasound Doppler fetal monitoring device.