Research of Planar Printed Antennas for Wlan and Uwbcommunication Systems

This book presents the research of planar printed antennas for WLAN andUWB communication systems. At firsta 2.4-GHz horizontally polarized omnidirectional planar printedantenna adopts the printedAlford-loop-type structure for WLAN applications is presented. The study of the antenna printed on a simulated PCMCIAcard and that inserted inside a laptop PC are also conducted. Secondly, a planar triangular monopole antenna (PTMA) ispresented for UWB communication. The measured voltage standing wave ratio is lessthan 3 from 4 to 10 GHz. Then, a novel technique to enhance the bandwidth of theconventional PTMA is presented. With two symmetrical corrugations extended fromthe flat ground plane, a significant improvement on the impedance bandwidth up toabout 4:1 can be achieved. Measured VSWR of the printed PTMA with the ridgedground plane is less than 2 from 3 to 12 GHz. The measured antenna patterns alsoshow the monopole-type omni-directional radiation patterns from 3 to about 10 GHz.