Miniaturized wearable watch antenna for wristband applications

In this paper, a novel watch antenna for wearable application is proposed. During simulation, the human wrist is modeled by a simplified cylindrical bone tissue with a radius of 26 mm and a length of 70 mm. Different from other wearable antennas, it takes full advantage of the watch appearance and maximizes the radiation aperture. The antenna is composed of a conformal rectangular copper sheet and a copper annular ring loaded with rectangular patches inside. The former is used as watch strap while the latter is used as dial for watch applications. Inside the copper ring, rectangular patches are adopted to lower the resonant frequency as well as improve the impedance matching of the proposed antenna. The designed antenna has a simulated frequency bandwidth from 850 to 950 MHz, and a measured bandwidth from 830 to 930 MHz, both covering the 915 MHz industrial, scientific and medical (ISM) band, making it suitable for wearable applications.