ULTRA-WIDEBAND CAVITY-BACKED BOWTIE AN- TENNA FOR PATTERN IMPROVEMENT

Abstract—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 ≤ 2 ranging from 2.75–10.7GHz 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. 1