Super-wideband fractal antenna of two-arm structure with broadband balun

Abstract

A balanced two-arm antenna has been proposed for super-wideband (SWB) operation to work efficiently over the frequency range (2.95−34GHz). The antenna proposed for SWB operation can be considered as composed of two main parts. The first part is the radiating surface of the antenna and is composed of two-arms leading to a balanced antenna structure. For wideband operation, each arm has a double-fractal (angular/radial) structure. The second part of the antenna structure is the wideband feeding balun that is responsible for realising maximum power transfer and impedance matching while feeding the balanced radiating two-arm structure from the conventional unbalanced coaxial line. A prototype has been fabricated for experimental characterisation of the proposed antenna. Both the simulation results and the experimental measurements come in good agreement with each other showing that the proposed antenna can be good candidate for many super-wideband applications of future generations of mobile communications. The proposed antenna has overall dimensions of 40.0mm×21.0mm×1.5mm. It is shown by simulation and measurement that the proposed antenna has %BW of 168%, RBW of 11.5:1, and BDR of 2015. The maximum gain ranges between 2.3 and 6.2 dBi. The radiation efficiency is greater than 98% over the frequency range (2−24GHz) and is greater than 85% over the frequency range (24−34GHz).