Compact multiband planar monopole antennas for smart phone applications

A compact multiband planar monopole antenna is discussed. Tuning techniques, including offset feed, etching meandered slot and cutting tuning inset, are applied to the radiator in order to maximise the operating frequency range of the antenna. Experimental results demonstrate that the proposed design covers the operating bands of seven wireless services including the DCS/PCS/W-CDMA/2.4-/5-GHz WLANs/Bluetooth and the WiMAX in United States. The design concept, step-by-step guidelines, radiation mechanism and the simulated and experimental results are carefully investigated. The finite-size ground plane effect is taken into account as well. This antenna features multiband operations, almost omnidirectional radiation patterns in one of the principal cuts, and a compact size of 22.75 times 20 mm². It is especially suitable for smart phone applications which are involving in integrating multiple wireless services into a single hand-held unit.