Experimental investigation of a circularly polarised flexible polymer/composite microstrip antenna for wearable applications

A novel highly flexible, lightweight square ring circularly polarised microstrip antenna composed of SrTiO₃/polyolefin elastomer (POE) composite as substrate material and polypyrrole conductive polymer as radiating patch and ground plane is proposed, designed and fabricated for the first time. Circular polarisation is achieved by truncating the corners of square ring patch. The effect of composite substrate thickness is experimentally studied and antenna parameters are compared with a reference copper antenna. The antenna performance is experimentally studied when it is flexed under different curvature radii. Also its actual performance is investigated when mounted on human body. High frequency structure simulator (HFSS) simulation and measurement results show good performance of the proposed antennas. The polymer/composite antenna is very flexible and lightweight and can be used for flexible/wearable antenna applications.