a surface - launched acoustic wave sensor tag system for remotely sensing and / or providing identification information using sets of surface acoustic wave sensor tag devices is characterized by acoustic wave device embodiments that include coding and other diversity techniques to produce groups of sensors that interact minimally , reducing or alleviating code collision problems typical of prior art coded saw sensors and tags , and specific device embodiments of said coded saw sensor tags and systems . these sensor / tag devices operate in a system which consists of one or more uniquely identifiable sensor / tag devices and a wireless interrogator . the sensor device incorporates an antenna for receiving incident rf energy and re - radiating the tag identification information and the sensor measured parameter . since there is no power source in or connected to the sensor , it is a passive sensor . the device is wirelessly interrogated by the interrogator .