Polymer-based Ultra-wideband Antenna for Wearable Application

Flexible antennas are promoting technology modernization in terms of viability. One such example is a wearable antenna, which is worn on the body and allows for flexibility, bending, and twisting. An ultra-wideband antenna (UWB) is well-suited for enabling wireless applications in the industrial, scientific, medical, and military domains, as a wider bandwidth is required to support these applications. It should be acknowledged that environmental factors must be taken into account when considering the durability of wearable devices. To withstand challenging climate conditions, it is preferable to use substrate materials that have low water absorbance and are resistant to dirt. Teflon is a particularly advantageous material for wearable antennas due to its low-loss tangent, which leads to increased radiation and minimal signal loss, even at high frequencies. The paper presents a low-cost and versatile UWB antenna design, which employs a polymer-based substrate to operate in the frequency range of 2.58-13.89 GHz. The antenna is constructed on a Teflon substrate and features a corner-truncated radiating element and partial ground plane, with overall dimensions of $50\times 40$ mm. The performance of the antenna is impacted by the movement of the human body when it is worn on body parts. Therefore, to evaluate its performance, the antenna was tested under both flat and bent conditions, with a bending analysis conducted on it. Exposure to electromagnetic (EM) radiation can pose health hazards to the human body. Therefore, the absorption of EM waves by the human body is analyzed using SAR (Specific Absorption Rate). To protect human tissue from EM radiation, the SAR value for 1 gram of tissue should be limited to 1.6 watt/kg according to International Commission on Non-Ionizing Radiation Protection (ICNIRP) guidelines. Using Ansys Electronics, SAR was simulated on the wrist and determined to be within an acceptable range.