一种新型声表面波无线测量系统

根据声表面波（SAW）器件的P矩阵模型，叉指反射栅外接负载阻抗不同导致声反射系数的变化。根据此原理，普通SAW器件的反射栅外接阻抗变化的常规传感器可方便地实现无线测量。通过制作相应的SAW器件并利用网络分析仪对此进行了实验验证。推导了无线测量系统的接收机信噪比与检测错误概率以及幅度分辩率的关系。发现了幅度测量存在的问题，提出采用相位法改进信号处理方法。

A Novel Wireless Measurement System Based on Surface-Acoustic-Wave Devices

According to the P matrix model of surface acoustic wave (SAW) devices, the magnitude and phase of the reflectivity of an interdigital transducer is a function of impedance at its electrical port. Thus, the conventional sensors varying in impedance can be easily read out wirelessly. Some experiments by using the vector network analyzer verified the above theory. Some disadvantages were found by experiments that the magnitude of echo signal varies with the environment temperature. The relationship between the probability of error, the signal to noise ratio of detector and the resolution of amplitude was deduced. This novel wireless measurement system was applied in the weight measurement with capacitive sensor.