A wireless interrogation system exploiting narrowband acoustic resonator for remote physical quantity measurement

Area of Science:

• Physics
• Electrical Engineering
• Materials Science

Background:

• Acoustic wave devices, particularly Surface Acoustic Wave (SAW) resonators, are sensitive to physical perturbations like temperature, stress, and pressure.
• The resonance frequency of SAW devices changes with these perturbations, affecting wave characteristics.
• The radio frequency (RF) nature of SAW devices enables wireless sensing applications through antenna reciprocity and piezoelectric effects.

Purpose of the Study:

• To present a wireless Surface Acoustic Wave (SAW) sensor interrogation unit.
• To operate within the 434 MHz Industrial, Scientific, and Medical (ISM) band.
• To address challenges in meeting ISM standards for wireless sensor interrogation, especially mode switching.

Main Methods:

• Development of a wireless SAW sensor interrogation unit based on frequency sweep network analyzer principles.
• Implementation of a fully digital RF synthesis chain for advanced interrogation strategies.
• Focus on achieving compliance with ISM standards, including managing emission and reception modes.

Main Results:

• Successful demonstration of a wireless SAW sensor interrogation unit operating in the 434 MHz ISM band.
• Development of digital RF synthesis techniques to overcome ISM compliance challenges.
• Assessment of the interrogation range, accuracy, and dynamics of the developed reader.

Conclusions:

• The proposed digital RF synthesis chain enables robust wireless interrogation of SAW sensors.
• The system effectively complies with ISM standards, facilitating reliable wireless sensing.
• The developed wireless SAW sensor interrogation unit shows promising performance in terms of range, accuracy, and dynamics.