In so rapidly growing sensing technology, Autonomous Surface Acoustic Waves (SAW) based sensors, offer high
flexibility for modern identification/sensing systems, and represent a new perspective for remote monitoring and
control. This paper gives a presentation of operating principles of wireless SAW sensors with separation in
frequency (frequency domain division-FDD) and separation in time (time domain division-TDD). The design of
interdigitated transducers (IDT), and reflectors on the different types of substrate materials as piezo crystals LiNbO3,
LiTaO3 or quartz in connection with application domains is presented. A comparison between Time Domain
Sampling-TDS and Frequency Domain Sampling-FDS principles of transmitter and receiver, gives evidence of their
advantages and disadvantages. A part of the paper dealt with the measurement results.
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