A Phase Variation Passive Sensor Node for Metallic Structural Health Monitoring

What is it about?

In this work, a passive microwave sensor node, named Phavar CraSen, is proposed for metallic structural health monitoring (SHM). The working principle is based on zero-power harmonic generation to insulate the sensor node signal at 2.45 GHz from the interrogation signal’s channel at 1.225 GHz. In order to modulate sensing data with the carrier signal, a sixport modulator is integrated with four capacitive comb-like sensing structures, “CombS.”

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Why is it important?

Different characteristics of the metal surface cracks make the sensors as variable impedance loads for the modulator. The CraSen sensor offers robustness and higher sensitivity, due to its phase sensing parameter, compared to the frequency or magnitude variation sensors for damage detections. The main features of CraSen offer advantages in terms of simplicity, low cost, easy fabrication, and measurement. Applying this sensing method provides strong potential in developing smart structures for eliminating in-person inspection and maintenance as well as preventing serious structural failures.