Evaluation of conductive threads for optimizing performance of embroidered RFID antennas

Radio frequency identification (RFID) refers to a technology that utilizes radio signals for identifying objects automatically. This technology consists of a reader that detects the objects and a transponder that gets attached to the object and it is called tag. The tag is an enclosure that houses the antenna and an IC that stores the necessary information on that object. This thesis focuses tag antennas made for embroidered RFID. Embroidered antennas are made by sewing antenna using conductive thread onto a fabric using a computerized sewing machine. This enables us to extend the field of RFID technologies to textiles. Conventional RFID systems that use metal conductors are easy to model but the same cannot be said for embroidered RFID. The reason being conductive threads and embroidered antennas don’t have definite conductivity. The conductivity of an embroidered antenna depends multiple factors like thread conductivity, thread density, stitch density, sewing pattern etc. The target of this thesis is experimenting with conductive threads physically and for their conductivity followed by eval-uating them for the use of embroidered RFID antenna fabrication for optimizing the perfor-mance. In this thesis, using same antenna pattern and technique, tags were fabricated from 6 differ-ent conductive threads onto the same cotton fabric. The conductive threads were investigated for their conductivity, thread thickness and their strength. The antennas were tested for their read range and the effect of different threads on the antenna were analysed. The threads with the highest conductive nature gave the highest read range of 6.2 meters. The threads were also evaluated for their usability for embroidery. Some threads were too thick, some had exposed structures leading to malfunction in the sewing machine and others were too thin and ripped easily during sewing. The selected thread should not only have great performance, but also it needs to be practical. It is seen that the conductivity of antenna and hence the performance is easily improved with using high conductive thread. After taking all the factors into account, finally a thread was selected that can be used to make high performance embroidered RFID antennas and also highly suitable for embroidery process. In the future, the same work can be revisited or extended to other more versatile and higher conductivity threads. Also, the advancement is embroidery techniques will allow for more con-ductive threads to be compatible for embroidery opening more options for optimization

Evaluation of conductive threads for optimizing performance of embroidered RFID antennas

Radio frequency identification (RFID) refers to a technology that utilizes radio signals for identifying objects automatically. This technology consists of a reader that detects the objects and a transponder that gets attached to the object and it is called tag. The tag is an enclosure that houses the antenna and an IC that stores the necessary information on that object. This thesis focuses tag antennas made for embroidered RFID. Embroidered antennas are made by sewing antenna using conductive thread onto a fabric using a computerized sewing machine. This enables us to extend the field of RFID technologies to textiles. Conventional RFID systems that use metal conductors are easy to model but the same cannot be said for embroidered RFID. The reason being conductive threads and embroidered antennas don’t have definite conductivity. The conductivity of an embroidered antenna depends multiple factors like thread conductivity, thread density, stitch density, sewing pattern etc. The target of this thesis is experimenting with conductive threads physically and for their conductivity followed by eval-uating them for the use of embroidered RFID antenna fabrication for optimizing the perfor-mance. In this thesis, using same antenna pattern and technique, tags were fabricated from 6 differ-ent conductive threads onto the same cotton fabric. The conductive threads were investigated for their conductivity, thread thickness and their strength. The antennas were tested for their read range and the effect of different threads on the antenna were analysed. The threads with the highest conductive nature gave the highest read range of 6.2 meters. The threads were also evaluated for their usability for embroidery. Some threads were too thick, some had exposed structures leading to malfunction in the sewing machine and others were too thin and ripped easily during sewing. The selected thread should not only have great performance, but also it needs to be practical. It is seen that the conductivity of antenna and hence the performance is easily improved with using high conductive thread. After taking all the factors into account, finally a thread was selected that can be used to make high performance embroidered RFID antennas and also highly suitable for embroidery process. In the future, the same work can be revisited or extended to other more versatile and higher conductivity threads. Also, the advancement is embroidery techniques will allow for more con-ductive threads to be compatible for embroidery opening more options for optimization