The effect of fabric conductors on the microstrip antennas with textile patches

In wearable electronics, the antenna plays an important role in transmitting and receiving electromagnetic signals. Different from materials used in traditional rigid antennas, textile materials are inhomogeneous and their yarn options, weaving patterns and weaving parameters often influence the final radiation performance of the textile antennas. In this study, effects of different types of fabric conductors on antenna performance were investigated based on a coaxial probe fed 2.45 GHz rectangular microstrip antenna. Three types of fabrics which were plain weave fabric made of silver plated yarns, plain weave fabric made of conductive thread blended yarns and twill weave fabricate made of conductive thread blended yarns were used as the radiation patches of the antennas. The electromagnetic performance of the microstrip antennas with textile-based radiation patches were measured and compared. The measured return loss and radiation pattern showed that the antenna fabricated with silver plated yarns exhibited better antenna performance than antenna fabricated with conductive thread blended yarns. Moreover, it also implied that choosing fabrics with high conducting material content was important to get desirable antenna performance. In addition, the efficiencies of the antennas were measured, and the equivalent alternating current conductivities of the textile radiation patches were calculated and compared with their direct current conductivities.