Omni-Directional Circularly Polarized Button Antenna for 5 GHz WBAN Applications

An omni-directional circularly polarized wearable antenna for 5 GHz applications is proposed. The antenna is constructed on a button-like setup, using the concept of a magnetic dipole combined with a flexible patch located on a textile substrate to optimize the antenna performance. With the proposed topology, an omni-directional pattern involving a robust circular polarization (CP) for on-body communication is reached. The -10 dB impedance bandwidth ranges from 5.68 to 5.91 GHz. The 3 dB axial ratio bandwidth ranges from 5.72 to 5.9 GHz. The omni-directional pattern is ideal for indoors and the CP is able to cope with any possible polarization mismatch caused by human body motions. Comparing with literature, this antenna takes the special case of wearable applications into account, which makes it the first practical wearable button antenna that features an omni-directional radiation pattern featuring CP.