Low-profile full-metal-rimmed antenna with less nonground portion for smartphones

Abstract

In this article, a low-profile full-metal-rimmed antenna with less nonground portion for smartphones is presented. The proposed antenna with full-metal rim is designed on FR4 substrate within the volume of 115 x 60 x 5 mm(3). Metal rim is made up of FR4 substrate with interconnected conducting vias which surrounds inner system circuit board. The gap between metal rim and system ground plane is 1.5mm and they are connected by a single ground patch. Moreover, folded monopole branches are implemented on circuit board to obtain wide bandwidth and improve impedance matching at higher bands. Therefore, proposed antenna contains a system circuit board with monopole branches and a full metal rim which serves GSM (850), DCS (1800), PCS (1900), UMTS (2100), LTE (2300/2500), WiBro (2350), ISM (2400), SDM-B (2650), and W-LAN system operating bands. The proposed antenna also has an attractive feature of utilizing very less portion of ground clearance about 4 x 38 mm(2) for placing monopole antenna and still covering a wide range of operating bands. This biggest merit makes it a potential candidate for metal rimmed smartphone applications with lesser nonground portion. A sample proposed structure has been realized on FR4 substrate to prove the design concept.