Design and Validation of a Compact Dual-Band Bluetooth Antenna for Smartwatch Applications

This paper presents the compact dual-band non-planar, miniature Bluetooth antenna design for smartwatches targeting 2.45/5.8 GHz operation. The antenna features a straightforward structure that enhances bandwidth and efficiency without external matching circuits, addressing challenges like miniaturization using inductive meander lines, performance degradation due to human-body proximity, radiation obstruction from metal bezels, and strict size constraints, all while maintaining dual-band operation. The combination of an I-shaped monopole and an inverted U-shaped stripline demonstrates dual-resonance behavior, and simulations closely align with experimental measurements conducted at the microwave lab and StarLAB facility. The gain analysis demonstrates the antenna's ability to provide a Bluetooth range of 30 meters at 2.45 GHz and 10 meters at 5.8 GHz, supporting next-generation smartwatch integration with reliable connectivity.