Flexible Ink-Based Interconnects for Textile-Integrated RF Components

We present methods to improve the flexibility of fabric integrated RF structures by modifying solder contacts to epoxy based interconnects. Specifically, we assess the loss exhibited by two textile-based transmission lines (TLs) using interconnects made of CM-127-48 epoxy ink and solder. The TLs were fabricated with conductive surfaces embroidered onto fabric. The measurements revealed that TLs made of ink-based interconnects exhibited a loss of up to 0.2 dB/cm for frequencies from DC to 5 GHz. This represents 50% of improvement over their solder-based counterparts. For validation, a 7-element Yagi-Uda antenna was fabricated by embroidering onto denim fabric to operate at 2.45 GHz. The RF performance of the textile antenna with ink-based interconnects performed better than its solder-based counterpart. This result can be used as a guideline to integrate the textile RF modules into clothing.