UHF-RFID enabled wearable flexible printed sensor with antenna performance

Many different parameters affect the antenna performance of the wearable sensors. In this study, antenna performances of textile based sensors which have different pass numbers from 1 to 5 printed using conductive ink with pad printing method were investigated. Moreover, the effect of sintering process after printing on the RF antenna performances of wearable sensors was examined. For this, antenna impedances, and reflection coefficients of the sintered, and non-sintered printed sensors were measured using a vector network analyzer. While the frequency at the collapse point of the reflection coefficient graph of the sensors without sintering and with different pass numbers was 254 MHz, the collapse point of the reflection coefficient graph of the sensors was 943 MHz after sintering. The measurements indicate that the sintering process has a significant effect on the antenna performances of wearable sensors, and it is concluded that the sintered printed wearable sensor samples enable data transmission wirelessly in short range. In addition, bending, and gain measurements was applied to wearable sensor which has the best performance according to the impedance measurement results. Thus, these UHF-RFID enabled wearable sensors with antenna performance might be good option to form a network of passive interactive sensor architecture for RFID and wearable technologies. In addition, considering the designed wearable sensor structure, it is foreseen that the potential usage areas of this structure may be moisture sensitive areas (such as supply chains and transportation of moisture-sensitive products).