Dielectric Characterization of Flexible Biofibers as a Potential Antenna Substrate for Wearable Antenna Application

This paper presented the dielectric characterization of flexible biofibers, including pineapple leaves fiber, bamboo fiber, and jute fiber, as potential antenna substrates for wearable applications. The open-ended coaxial probe method was utilized with a vector network analyzer to measure the permittivity of the biofibers at 2.45 GHz. Microstrip patch antennas were then designed and fabricated using the biofibers as substrates and compared to a conventional Flame Retardant 4 (FR4) substrate. The results showed the biofibers have lower permittivity and loss tangent than FR4, leading to larger antenna sizes but lower radiation efficiency. Computer Simulation Technology (CST) microwave software simulated the antenna parameters like S11 and radiation pattern. The measured S11 results for the fabricated antennas showed they operate as single band antennas, dipping slightly below 2.45GHz. The biofiber antennas has also demonstrated good bending and conformability important for wearable uses. In conclusion, the biofibers are promising low-cost, eco-friendly, flexible substrate materials for wearable antennas, although further work is needed to optimize their properties. Their characterization provides valuable insights into developing future wearable antennas using sustainable natural fibers.