An experimental study of the reflection from spherical and flat ended cylindrical targets suitable for fetal Doppler performance assessment
An experimental study of the reflection from spherical and flat ended cylindrical targets suitable for fetal Doppler performance assessment
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DOI：
10.1016/s0301-5629(96)00168-8
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发表时间：
1997-01-01
影响因子：
2.9
通讯作者：
Bond, AD
中科院分区：
文献类型：
--
作者：
Preston, RC;Bond, AD
对适合用作测试多普勒胎儿心跳检测器灵敏度的振荡目标的小直径目标的性能进行了系统研究。实验结果给出了 1.6-3.0 MHz 频率范围内总共 16 个目标的平面波反射损耗：不锈钢制成的球体； PTFE 制成的半球形端杆；以及由不锈钢、PTFE、聚碳酸酯和碳化钨制成的平头棒。结果表明，反射损耗随频率的精细结构变化在球形目标中最大，而在平端目标中最小。事实证明，只要在制造过程中小心谨慎，就可以使用基于平面圆盘反射器的简单理论来预测平端目标的反射损耗。碳化钨靶材由直径为 1.6 毫米的长棒逐渐变细为直径为 0.4、0.5 和 0.6 毫米的圆柱形平端，经证明可提供 60 至 40 dB 的反射损耗，并且反射损耗随频率变化平滑。它们的制造形式也不会受到支撑结构的显着干扰，因此是满足国际电工委员会 1266:1995 要求的理想目标。皇冠版权所有 1997。经 HMSO 控制者许可复制。
The performance of small-diameter targets suitable for use as oscillating targets for testing the sensitivity of Doppler fetal heartbeat detectors has been systematically studied. Experimental results are presented in the 1.6-3.0 MHz frequency range for the plane-wave reflection loss for a total of 16 targets: spherical balls made of stainless steel; hemispherical-ended rods made of PTFE; and flat-ended rods made of stainless steel, PTFE, polycarbonate, and tungsten carbide. Results show that the fine-structure variation of reflection loss with frequency is greatest in the case of spherical ball targets and least for flat-ended targets. It has been shown that, providing care is taken during manufacture, the reflection loss from a flat-ended target can be predicted using a simple theory based on a plane disc reflector. Tungsten carbide targets consisting of a long rod with a diameter of 1.6 mm tapered down to a cylindrical flat end with a diameter of 0.4, 0.5, and 0.6 mm have been shown to provide reflection losses of between 60 and 40 dB, and to have a smooth variation of reflection loss with frequency. They can also be manufactured in a form that allows no significant interference from the supporting structure and, therefore, are ideal targets to meet the requirements of International Electrotechnical Commission 1266:1995. Crown Copyright 1997. Reproduced by permission of the Controller of HMSO.