Multitransducer SAW Device Architecture for Passive Wireless Sensor Tags

A new architecture of surface acoustic wave (SAW) sensor tags with lower insertion loss and enhanced sensitivity is investigated. It efficiently employs two transducer arrays at the input and output of the acoustic channel, respectively. The improved sensitivity is attained due to a higher number of stronger constituent signals contributing constructively to the device response. An efficient matrix modeling approach is generalized to permit fast design and synthesis of the multitransducer sensor tags with arbitrary topologies. The modeling approach consistency is validated by energy balance. Several simulation examples of new 6-GHz SAW sensor tags, implemented on 128°YX-LiNbO3 substrate, are presented and compared against a conventional reflective delay line device. The effects of finite electrode resistivity and SAW beam diffraction are evaluated numerically, and the SAW sensor-tag design tradeoffs and principles are established.