ABSTRACT This paper presents a tri‐band antenna designed for integration into smartwatches, covering GPS, Wi‐Fi, and LTE frequency bands while minimizing effects of wrist interaction. The antenna addresses key design challenges such as compactness, detuning due to human body proximity, and maintaining high efficiency across multiple bands within the limited form factor of wearable devices. It has a single layer structure, comprising a patch and a ground plane, using an FR‐4 substrate with permittivity () and loss tangent () of 4.3 and 0.025, respectively. Copper is used as the conductive material for the patch and ground. The dimensions of the antenna are . It achieves a total efficiency of 81% with a peak gain of 1.99 dBi in the GPS band. For the Wi‐Fi band, the gain is 2 dBi with a total efficiency of 79.7% at 2.4 GHz. In the LTE band, the antenna exhibits a total efficiency of 81% and a gain of 4.11 dBi at 3.5 GHz. The antenna also demonstrates 6‐dB bandwidths of 165, 260, and 739 MHz for the GPS, Wi‐Fi, and LTE bands, respectively. In addition, it shows stable performance when worn on the human wrist, with minimal impact, ensuring specific absorption rate (SAR) compliance with the regulatory safety standards. These characteristics make the tri‐band antenna well suited for smartwatch applications.
Khan et al. (2026) studied this question.