Wireless Urine Monitoring for Diapers With Passive Antenna using Split Ring Metamaterial

In this study, we proposed an in-diaper sensor probe for babies using metamaterials, and confirmed that moisture in the diaper can be detected while the baby is wearing a diaper with built-in metamaterials. Metamaterials were designed and fabricated using splitring resonators, which have the property of reducing the transmitted waves of radio waves of a specific frequency. A decrease in transmitted waves and a shift in resonance frequency due to water absorption were observed at specific frequencies with the metamaterial alone and with the diaper worn on a PVC phantom. We will improve the degree of freedom of measurement by using reflected waves.