GPS, Bluetooth and Wi-Fi tri-band antenna on metal frame of smartwatch

A design concept of the loop antenna on the metal frame of a smartwatch device for GPS, Bluetooth and Wi-Fi 5 GHz is introduced. The antenna was designed with a 1.5 mm thick, circular metal frame with a diameter of 55 mm. The system ground of a smartwatch is encircled by the metal frame. The open stub and coupling gap inserted into metal frame were set to provide multi-band operation. With the signal feeding and the 1st shorting pin in a proper location, the antenna cover the GPS band. The antenna covers the Bluetooth band with the current loop for GPS and the coupling between stubs. As well as, the antenna covers the Wi-Fi 5 GHz band by shorting the loop with 2nd shorting pin. The design and the results thereof are described and discussed in this paper.