PROBLEM TO BE SOLVED: To provide a surface acoustic wave element, a surface acoustic wave sensor, a sensing system, and a stress measurement method, in which when detecting a state of a measurement target based on a reflection power change, the measurement sensitivity of the detection can be increased.;SOLUTION: A reflector 9 has characteristics that a reflection coefficient is changed in accordance with stress applied to the reflector 9 itself, and the center frequencies of interdigital electrodes 5, 9 for generating surface acoustic waves are set to a predetermined frequency area including an attenuation pole in a frequency characteristic of the reflection coefficient of the reflector 9 and the vicinity of the attenuation pole. Thereby when stress is applied to the reflector 9, the reflection coefficient of the reflector 9 is sharply changed, so that energy of a reflected wave reflected by the reflector 9 is also sharply changed. When the reflected wave is converted into a response signal by the interdigital electrodes 5, 7, power of the response signal is also sharply changed. Thus, a stress change can be easily detected by detecting a change in the response signal by a transmitter-receiver 37.;COPYRIGHT: (C)2012,JPO&INPIT
展开▼
