A Study of Miniaturized Wide-Band Antenna Design

In this paper, an antenna with a miniature structure and wide-band is presented. We designed a two-arm conical spiral antenna according to the structure features of the Archimedes spiral and the conical helical antenna, and proposed an exponential asymptote balun to match the impedance. Unlike traditional antenna designs which optimize antenna and matching module separately, we adopted the differential evolution (DE) algorithm to optimize both the antenna and balun simultaneously. In addition, the peak radiation direction of the antenna was added as a constraint when evolving the antenna, which is usually ignored in normal evolutionary antenna designs. Simulation results indicate that the evolved antenna can basically fulfills the requirements. And the evolved antenna with the additional constraint has smaller deviation angle between the peak radiation direction and the antenna’s axis than that without the constraint.