Radiation Characteristics of Woven Patch Antennas Composed of Conductive Threads

The radiation characteristics of wearable antennas composed of conductive threads are investigated in this work. Various rectangular patch antennas with different thread diameters and intervals are modeled in a full-wave electromagnetic simulation tool by weaving thin conductors emulating conductive threads, and their resonance frequencies, radiation efficiencies, and radiation patterns are then observed. Interestingly, the radiation efficiency increases with a wider interval between the threads when a thicker conductive thread is used. This contrasts with the common assumption that radiation efficiency increases as more conductive materials are included. These results are also validated by experiments on woven patch antennas fabricated with silver-coated threads.