Carbon Black‐Incorporated Carbon Nanofiber for Flexible and Washable Monopole Antenna

Antennas are a basic requirement for wireless technology, and generally metal conductors are being used for developing antennas. Metal‐based antennas have several limitations, such as lack of flexibility and washability and low resistance to oxidation. Here, a washable semitransparent flexible monopole antenna fabricated utilizing carbon black (CB)‐incorporated carbonized electrospun polyacrylonitrile fiber (CB‐CNF) on a polydimethylsiloxane (PDMS) substrate making it flexible and hydrophobic is reported. CB‐CNFs are prepared using electrospinning followed by a carbonization process. The incorporation of CB with CNF results in the formation of a strong 3D electrically conductive network with electrical conductivity of 1.2 S cm ⁻¹ . The PDMS substrate provides mechanical flexibility and transparency to the antenna. The CB‐CNF antenna is designed to operate in the gigahertz (GHz) frequency range from 3.6 to 8.2 GHz with an omnidirectional radiation pattern with 4.8 dBi of measured peak gain. The antenna design with CB‐CNF over a PDMS substrate has great potential to be deployed in wearable medical devices, enabling continuous health monitoring and data transmission in a wide frequency range while maintaining user comfort and hygiene.