Supplementary information files for "Passive chips-in-yarn integration for on-fabric batteryless identification and sensing"

These components reduce flexibility, comfort, washability, and long-term usability. Here, we report a passive chips-in-yarn strategy for creating battery-free electronic yarns that can be integrated directly into fabrics.

In this approach, radio frequency identification (RFID) chips are embedded inside yarn structures, allowing the yarns to be wirelessly powered and read by an external RFID reader without onboard batteries. The RFID chip is connected to conductive filaments that act as yarn-shaped antennas, while local encapsulation and a braided sheath protect the chip–filament junction during textile manufacturing and use. By engineering different antenna geometries, RFID yarns enable multiple functions: ID-only yarns for garment life-cycle identification, deformation-sensitive yarns for passive movement monitoring through wireless signal changes, and temperature-sensing yarns for distributed on-body thermal mapping.