A Wideband Dual-Sleeve Monopole Antenna for Indoor Base Station Application

The design and enhanced bandwidth performance of a dual-sleeve monopole antenna for indoor base station application is presented. By a top-loading circular patch shorted to the ground plane through four shorting probes, the size reduction is achieved. The dual-sleeve structure is successfully employed to improve the impedance bandwidths through achieving another two resonant modes. A measured impedance bandwidth for VSWR ≤ 2 of about 137% ranging from 730 to 3880 MHz is achieved. It is very suitable for GSM900, DCS1800, PCS1900, UMTS, IMT2000, WiBro, WiMAX2350/3500, and wireless LAN (IEEE 802.11b).