Conformal Circularly-Polarized Shoe-Integrated Antenna based on Leather Substrate and Conductive Fabric for Bluetooth Low Energy Body-Centric Links

In this work a compact 2.4 GHz wearable antenna for BLE applications, specifically designed to be fully integrated in a leather-made shoe, is designed and simulated. A slotted microstrip layout has been chosen and optimized under both electromagnetic and manufacturing point of view to be fully integrated with the shoe and to guarantee a robust wireless link with the smartphone receiver, typically placed on the upper part of the body. For these reasons the same leather has been selected as antenna substrate material, and conductive fabric to design the radiating parts and the substrate. Both antenna directivity and circular polarization have been optimized to guarantee a robust communication while saving power. The antenna shows a very satisfying performance, with a -10 dB input matching frequency bandwidth equal to 10%, and an Axial-Ratio 3 dB bandwidth of 3%.