Multiband antennas for GSM/GPS/LTE/WLAN smart watch applications

In this paper, four antennas (planar inverted-F type, PIFA) are separately incorporated into a square-shaped smart watch for GSM/GPS/LTE/WLAN applications. The overall dimensions of the proposed design are 40.8 mm × 40.8 mm × 5.4 mm, in which all the four antennas are printed on the four side walls of the smart watch. Here, the PIFA used for GSM band has occupied two side walls (right and back sides), while the PIFA for GPS band has used only one of the side wall (front side), and the two PIFAs for LTE and WLAN band are printed on the same side wall (left side). The simulated and measured results have shown that all desired operating bands are well below the 6-dB return loss threshold, and the isolations between antennas are also well below 10-dB.