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Wireless sensing using oscillator circuits locked to remote high-Q SAW resonators
A Pohl1, G Ostermayer, F Seifert
1Appl. Electron. Lab., Tech. Univ. Wien, Vienna, Austria. pohl@ps1.iaee.tuwien.ac.at
Summary
This study presents a low-cost wireless method for reading surface acoustic wave (SAW) resonator sensors using a gated phase locked loop (GPLL). This technique simplifies sensor interrogation for applications like temperature and force measurement.
Area of Science:
- Electrical Engineering
- Sensor Technology
- Physics
Background:
- Surface Acoustic Wave (SAW) resonators are sensitive to environmental changes.
- Traditional interrogation methods for SAW sensors can be complex and expensive.
- Wireless readout is desirable for remote and embedded sensing applications.
Purpose of the Study:
- To introduce a novel, low-cost wireless readout method for high Q SAW resonator sensors.
- To develop an alternative to expensive signal processing interrogators.
- To demonstrate the feasibility of the proposed system for various measurements.
Main Methods:
- Excitation of SAW resonators with short radio frequency (RF) pulses.
- Utilizing a gated phase locked loop (GPLL) to lock onto the resonator's frequency.
- Synchronizing the GPLL oscillator to the sensor's resonance for easy frequency measurement.
Main Results:
- Successful wireless readout of SAW resonator sensors was achieved.
- The GPLL system effectively locked to the resonance frequency.
- Demonstrated feasibility for temperature measurements using quartz resonators.
Conclusions:
- The proposed GPLL-based wireless readout offers a cost-effective solution for SAW sensors.
- This method provides an alternative to complex and expensive interrogation systems.
- The system shows potential for various sensing applications including temperature, force, and torque.
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