现有的接近传感器倾向于依靠磁性感应，不情愿或HALL效应设备来表现其性能特性，在诸如汽车点火传感器之类的应用中，它们会导致运行性能差。现在，牛津的研究人员大学's Physics Department have developed an extraordinarily versatile proximity sensor that uses RF signals to detect the motion of a多种金属和非 -金属，从汽车悬架，变速箱和发动机管理系统中的位置或速度传感器进行大量潜在应用，以检测不均匀液体流动的变化，例如血液/saline, water-in-oil or oil-in-water mixtures. RF传感器如何与更常规的传感器不同’用于汽车行业中位置传感的大多数类型的接近传感器使用光学或磁场进行操作，’ISIS Innova物理科学项目经理Robert Adams博士解释亚博老虎机网登录说牛津大学技术转移公司Tion Limited。’Over time wear products such as dust, grease or dirt can cover the sensor, degrading its performance. If wear products cover part of our sensor they should not degrade its performance as they will produce a static background signal, which willbe ignored by the electronics -it is only changing parameters那引起信号。’ Components of the RF SensorRF位置传感器包括三个主要零件封装陷入一个紧凑的单元 -线圈形射频天线，驱动天线的RF振荡器电路和监测电路，该电路确定了耦合天线和振荡器的行为中是否发生了变化。传感器的原型如图1所示。虽然传感器不需要使用任何特殊材料进行初始专利应用，但亚当斯指出，如果纯用于测量区域中的磁场强度，则亚博网站下载一块磁性材料需要be placed adjacent to the coil. ‘The only other instance in which special materials may be required is if the sensor is used to measure motion in extremely hot environments, i.e. 1,000°C, in which case the RF antenna coil is mounted remotely to the electronics and the coil is made of some high- 温度耐受金属，’he says.
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图1。Close up of the RF sensor being used to detect a metal toothed wheel. |
How the RF Sensors Work
The sensor functions by detecting a change in the electromagnetic proper构成其“敏感区域”的卷的关系它位于线圈口外面，形成一个近似立方体，其侧面的直径与天线线圈相似。穿过敏感区域的物体，或者存在不同材料的存在会导致这种变化。’Because the sensor uses an electromagnetic field rather thaneither a purely magnetic or electric field,’explains Adams,’它对同时侵入敏感体积的材料的磁性和电性能敏感，例如，旋转的金属齿轮穿过敏感区域的牙齿。亚博网站下载’Other examples include homogeneous liquid flowing within a pipe located in the sensitive region, which contains small bubbles or pieces of solid debris carried along in the flow. As the liquid passes through the sensor a signal is produced that is proportional to the size or mass of the debris and for which the signal type is characteristic of that particular material. RF传感器在材料回收中的应用亚博网站下载The characteristics of the electronic signal output from the sensor can be used to discriminate between different types of materials depending on their magnetic orelectricpermittivity characteristics. ‘我n plastics recycling, for example, the sensor could be used to discriminate between different types of plastics from their electrical properties,’says Adams.’Similar things可以为金属做。’ Advantages of the RF SensorThe sensor has advantages over competing devices in that: •我t requires no additional components such as magnets, coils or magnetic circuits •我t can be very small and the electronics may be accommodated on 100μm square of silicon wafer •我t has a high signal-to-噪声比，can be maximised by optimising the sensor design for a particular application •与众不同感应传感器，其输出是独立的。 概括原型已经been tested as an ignition-timing sensor on an internal combustion engine, and Isis Innovation has been approached by a couple of general bearings manufacturers, an aerospace maintenance equipment company and a couple of car component manufacturers with a view to evaluating the technology.’To date, no licences have由我们的讨论产生的says Adams.’但是，我们目前正在生产一些演示设备来展示该技术的功能o these potential licensees.’ |