A Five‐Notch Ultra‐Wideband Flexible Antenna for Wearable Applications

ABSTRACT

In this paper, an ultra‐wideband (UWB) notch antenna for wearable applications is proposed, and the operating frequency of the antenna is 3.04 to 14.4 GHz. On the basis of the monopole UWB antenna, five notch bands from 3.87 to 4.27 GHz, 5.23 to 6.26 GHz, 8.4 to 8.56 GHz, 9.48 to 11 GHz, and 11.45 to 12.69 GHz are realized. The antenna uses Rogers 5880 material as the dielectric substrate and is only 0.45 mm thick. Due to the use of flexible materials and the low‐profile nature of the antenna, the antenna can be slightly curved, which allows it to be applied in the wearable field. Five‐notch bands are achieved by adding a notched structure on both sides of the microstrip line, inside the rectangular patch, and at the bottom of the substrate. By adding a metal through hole inside the substrate, an electric current is introduced into the notch structure at the bottom of the substrate to achieve a better notch effect. The overall antenna size is 30 × 25 × 0.45 mm ³ , which meets the design requirements of miniaturized antennas. By simulating the S ₁₁ curved antenna and the Specific Absorption Rate (SAR) value of the human hand, the antenna is suitable for wearable applications.