Wideband balanced folded dipole antenna with a dual-arm monopole structure for mobile handsets

In this study, a balanced antenna for mobile handset applications with enhanced bandwidth performance, covering the bands from 1.8 to 2.45 GHz, is investigated. The antenna is a slot planar dipole with folded structure and a dual-arm on each half. The antenna impedance was investigated using a two-port S-parameter method. For the purpose of antenna power gain measurement, a wide bandwidth planar balun was employed to support a balanced feed from an unbalanced source. For validation, a prototype of the proposed antenna was fabricated and tested. The performance of the antenna was then verified in terms of return loss, radiation patterns and power gain. The calculated and measured results show good agreement and the results also confirm good wideband characteristics with low induced current in the ground plane, thus minimising performance variations and SAR.