Surface acoustic wave devices for sensor applications

Identification and sensor systems based on surface acoustic waves exhibit i ntriguing properties which have hitherto remained unexploited by semiconduc tor-based systems. They offer a long readout distance of up to more than 20 m with purely passive surface acoustic wave (SAW) devices SAW devices oper ate with no battery or wiring, withstand extreme temperatures and work reli ably and maintenance-free over many decades even in harsh industrial enviro nments. Because they operate at frequencies in the GHz range, SAW identific ation and sensor systems are well protected from the electromagnetic interf erence that often occurs in the vicinity of industrial equipment such as mo tors and high-voltage lines, The fundamentals and design rules of numerous passive wireless SAW sensor and identification systems for industrial and d omestic applications as well as relevant practical work will be presented.