%0 Journal Article %T Ultra-Wideband Cavity-Backed Bowtie Antenna for Pattern Improvement %A Zhi-Ya Zhang %A Shaoli Zuo %A Xiaolu Zhang %A Guang Fu %J PIER Letters %D 2013 %I EMW Publishing %R 10.2528/PIERL12110909 %X The design and ultra-wideband performance of a cavity-backed bowtie antenna with the parasitic dipole and parasitic circular ring is presented. Besides the elliptical bowtie dipole and the taper feeding microstrip for obtaining ultra-wideband impedance characteristics, the parasitic dipole and parasitic circular ring to effectively improve the radiation pattern can be used for obtaining the stable broadside unidirectional radiation patterns. An ultra-wideband impedance characteristic of about 118.2% for VSWR ¡Ü 2 ranging from 2.75-10.7 GHz is achieved. A unidirectional radiation pattern, a stable peak gain of around 7.4-10.8 dBi and low cross polarization over the whole operating band are also produced. A prototype has been fabricated and tested, and the experimental results validate the design procedure. %U http://www.jpier.org/pierl/pier.php?paper=12110909