Multi-band weakly ground-coupled balanced antenna design for portable devices

A balanced antenna for wireless portable devices applications with multiple band operational performance is investigated and discussed. The designed antenna is weakly ground-couple, although can be considered as an energy-efficient radiator. The antenna structure is a thin-strip planar dipole with a dual-folded structure on each arm. The performance of the proposed antenna is analysed and optimised for WLAN and WiMAX applications over the relevant frequency bands, including the 2.4 and 5.2 GHz WLAN bands and the 2.5 and 3.5 WiMAX bands. For validation, the antenna prototype was fabricated and tested. The performance of this balanced antenna was verified and characterised in terms of the return loss, radiation pattern and power gain. The predicted and measured results show acceptable agreement and the results also confirm good impedance bandwidth characteristics with excellent dual-band operation.