High Gain Metal-Bezel Circular Polarization Smartwatch Antenna

A high gain metal-bezel smartwatch GPS L1 band (1575.42 ± 1.023 MHz) circular polarization (CP) antenna is proposed. The antenna is mainly composed of a metal bezel with four 0.5mm slits, four capacitors and a dual-arrow coupling feedline. Firstly, a pair of orthogonal modes are found by using characteristic mode analysis (CMA). By loading capacitors between the metal bezel and the system ground, and constructing slits in the metal bezel, the orthogonal modes are tuned so that the pair of orthogonal modes meet CP conditions. Then dual-arrow coupling feedline are used to excite the orthogonal modes respectively to achieve GPS L1 band CP. Finally, the proposed antenna achieves a high CP gain of 3.08 dBi in the +z-direction (main radiation direction), which can be used for high-precision positioning and navigation of smartwatches. The model is also fabricated and measured, and both simulated and measured results are discussed.