Multiband antennas for GPS/GSM1800/Bluetooth/Wi-Fi smart watch applications

The paper proposes multiband antennas for the smart watch applications. The size of the smart watch is 49 mm × 35 mm × 5 mm. These antennas are placed in the top side and bottom side of the smart watch and printed on a 0.4-mm thick FR-4 substrate. The sizes of these antennas in the top side and bottom side are the same 2 mm × 35 mm × 5 mm, and these two antennas are Invert-F antenna (IFA) type structure. The measured impedance bandwidths of these antennas are 1555-1680 MHz, 1705-1892 MHz and 2395-2485 MHz. The maximum of isolation of the measurement are -14.5 dB in GPS band, -12.2 dB in GSM1800 band and -18.1 dB in Wi-Fi band.