Multiband printed monopole antenna with defected ground plane for GPS/WLAN/WiMAX applications

This work presents a small size multiband antenna suitable for GPS, WLAN and WiMAX Applications. The antenna has three branches that the modified branches consist of the straight branch that a bent stub has been added to the end of it. Also new design for defected ground structure is used to improve the impedance matching of the antenna. The omnidirectional radiation pattern and good gain with impedance matching below -10 dB over all frequency bands have been achieved. It was found that the results of simulations and measurements agree well over each separated frequency bands.