Embroidered textile connectors for wearable systems

This thesis presents a novel textile microwave interconnect that can be easily attached and removed from textile devices. Interconnects perform a vital role in carrying RF signals between an amplifier and an antenna or other devices. Conventional interconnects used for interconnecting non-flexible circuits perform this function with very low losses, however the same is not true for transmission lines made on fabrics using conductive threads or inks. This scenario of using interconnects on fabric systems is challenging. Due to the necessity of washing fabrics, permanent attachments on the fabric have disadvantages. Theconnectionpresentedinthisthesisisdonewithoutanymetalor rigid parts on the textile devices side. The connector is held in place by magnets which are shown to have no negative impact on the microwave connection. Two models are then explored, a microstrip connector and a grounded coplanar waveguide (CPW) connector. A detailed study of the models was done and it was found that both models have reasonable results up to2GHz. The interconnects are fully characterized by de-embedding the connection part. This can be used to predict the effect the interconnect will have when used to connect a microwave equipment. The microstrip version of the interconnect is attached to an antenna and the results presented. The interconnect has no negative effect on the reflection coefficient measurement of the antenna. Repeatability tests were also performed with this model, with no visible change in the connection quality between measurements. Different embroidery patterns and stitching designs were also investigated. These are used to reduce the amount of conductive thread used up to 59% reduction in thread ammount. A wearable antenna was fully converted from rigid copper sheet to a full textile design.