Textile patch antennas using double layer fabrics for wrist-wearable applications

This article introduces a performance investigation of textile patch antennas using double layer fabrics for wrist-wearable applications. Two fabric substrates [top layer: conducting part (CP), bottom layer: fabric part (FP)] are used for an antenna design, and these are assembled using an adhesive. We chose polyester (PES) as the top fabric layer (CP) because the PES is a cloth of fine texture, which is useful for the steady screen printing of the antenna geometry. Four fabric samples (Fabric 1-4) were selected from actual clothes (i.e., pants and shirts), and these were used for the bottom fabric layer (FP). The textile antennas were simulated and measured to verify their performance and to compare this with that of the common microwave substrate. Moreover, a textile antenna was tested under various bent conditions as well as regarding its specific absorption rate for on-body environments, such as the wrist and ankle. Based on the measurement results, it was confirmed that the textile antennas with double layer fabrics have good electrical performance, even in bent conditions, and can be used in wearable-fabric applications, including body centric communications.