Polh A
Appl. Electron. Lab., Tech. Univ. Wien.
IEEE Trans Ultrason Ferroelectr Freq Control. 2000;47(2):317-32. doi: 10.1109/58.827416.
Wireless measurement systems with passive surface acoustic wave (SAW) sensors offer new and exciting perspectives for remote monitoring and control of moving parts, even in harsh environments. This review paper gives a comprehensive survey of the present state of the measurement systems and should help a designer to find the parameters required to achieve a specified accuracy or uncertainty of measurement. Delay lines and resonators have been used, and two principles have been employed: SAW one-port devices that are directly affected by the measurand and SAW two-port devices that are electrically loaded by a conventional sensor and, therefore, indirectly affected by the measurand. For radio frequency (RF) interrogation, time domain sampling (TDS) and frequency domain sampling (FDS) have been investigated theoretically and experimentally; the methods of measurement are described. For an evaluation of the effects caused by the radio interrogation, we discuss the errors caused by noise, interference, bandwidth, manufacturing, and hardware tuning. The system parameters, distance range, and measurement uncertainty are given numerically for actual applications. Combinations of SAW sensors and special signal processing techniques to enhance accuracy, dynamic range, read out distance, and measurement repetition rate (measurement bandwidth) are presented. In conclusion, an overview of SAW sensor applications is given.
带有无源表面声波（SAW）传感器的无线测量系统为移动部件的远程监测与控制提供了全新且令人兴奋的前景，即便在恶劣环境中亦是如此。这篇综述文章全面审视了测量系统的当前状态，应能帮助设计者找到实现特定测量精度或不确定度所需的参数。延迟线和谐振器均已被采用，且运用了两种原理：直接受被测量影响的SAW单端口器件，以及由传统传感器进行电加载从而间接受被测量影响的SAW双端口器件。对于射频（RF）询问，已在理论和实验上研究了时域采样（TDS）和频域采样（FDS）；描述了测量方法。为评估无线电询问所造成的影响，我们讨论了由噪声、干扰、带宽、制造及硬件调谐所导致的误差。针对实际应用，以数值形式给出了系统参数、距离范围及测量不确定度。介绍了SAW传感器与特殊信号处理技术的组合，以提高精度、动态范围、读出距离及测量重复率（测量带宽）。最后，给出了SAW传感器应用的概述。
