Watchstrap integrated wideband circularly polarized antenna design for smartwatch applications

Abstract

Abstract A circularly polarized antenna suitable for integration into the framework of smartwatches is reported in this manuscript. The proposed antenna operates in the industrial, scientific and medical band of 5.8 GHz with a footprint of about 45 × 15 × 1.6 mm3 (0.8 λ × 0.2 λ × 0.03 λ) and is excited by a coplanar waveguide line loaded with an L‐shaped radiator patch. The antenna prototype was studied in free space and then adapted to on‐body scenarios using computer hand models. The performance of the antenna was validated in measurement in a realistic human hand, and the antenna achieves satisfactory on‐body performance; measured and simulated results are in good agreement. Furthermore, for health risk concerns related to exposure to electromagnetic radiation, the specific absorption rate (SAR) analysis for the smartwatch on wrist‐worn has also been presented which is far below the normal SAR criteria according to IEEE C95.1 guidelines. The simple structure of the proposed antenna and its high performance make it an ideal candidate for smartwatch applications in health care monitoring purpose.

Keywords

• circular polarization (CP)
• CPW feed antenna
• smartwatch application
• specific absorption rate (SAR)
• wearable antenna