A mixed frequency ultrasonic phased array (MPA) was developed to improve the focus, in which the element excitation frequencies are not all the same as in a normal constant frequency phased array. A theoretical mode...A mixed frequency ultrasonic phased array (MPA) was developed to improve the focus, in which the element excitation frequencies are not all the same as in a normal constant frequency phased array. A theoretical model of the mixed frequency phased array based on the interference principle was used to simulate the array’s sound distribution. The pressure intensity in the array focal area was enhanced and the scanning area having effective contrast resolution was enlarged. The system is especially useful for high in- tensity focused ultrasound (HIFU) with more powerful energy and ultrasound imaging diagnostics with im- proved signal to noise ratios, improved beam forming and more uniform imaging quality.展开更多
The model of time-frequency mixed processing and the towing experimental results airs discussed in the paper for the fractional beamforming of a dense spacing array. The results show that the theoretical model is in a...The model of time-frequency mixed processing and the towing experimental results airs discussed in the paper for the fractional beamforming of a dense spacing array. The results show that the theoretical model is in agreement with the experimental results and it can.be realized easily in the engineering mode. The Performance Figure of the experimental subarray system is increased about 17 dB in comparison with that of traditional array with halfwavelength spacing between elements under the same conditions, when the flow noise is a dominant component in the background noise received by a sub-array.展开更多
基金Supported by the Major Research Project of the "985" Fund of Tsinghua University (No. 012-081100501)
文摘A mixed frequency ultrasonic phased array (MPA) was developed to improve the focus, in which the element excitation frequencies are not all the same as in a normal constant frequency phased array. A theoretical model of the mixed frequency phased array based on the interference principle was used to simulate the array’s sound distribution. The pressure intensity in the array focal area was enhanced and the scanning area having effective contrast resolution was enlarged. The system is especially useful for high in- tensity focused ultrasound (HIFU) with more powerful energy and ultrasound imaging diagnostics with im- proved signal to noise ratios, improved beam forming and more uniform imaging quality.
文摘The model of time-frequency mixed processing and the towing experimental results airs discussed in the paper for the fractional beamforming of a dense spacing array. The results show that the theoretical model is in agreement with the experimental results and it can.be realized easily in the engineering mode. The Performance Figure of the experimental subarray system is increased about 17 dB in comparison with that of traditional array with halfwavelength spacing between elements under the same conditions, when the flow noise is a dominant component in the background noise received by a sub-array.
