Characterization of Series Iteration Log-periodic Fractal Koch Printed Antenna Equipped with Balun Unit

Achmad Munir¹, Dida Tuhu Putranto² & Heroe Wijanto²

¹Radio Telecommunication and Microwave Laboratory
School of Electrical Engineering and Informatics, Institut Teknologi Bandung
Jalan Ganesha No.10, Bandung 40132, Indonesia
²Department of Electrical and Communication
Faculty of Engineering, Telkom University
Jalan Telekomunikasi, Dayeuh Kolot, Bandung, 40257, Indonesia
Email: munir@ieee.org

Abstract. In this paper, characterization of log-periodic fractal Koch antenna in series iteration and equipped with balance-unbalance (balun) unit is investigated numerically and experimentally. The proposed antenna which is deployed an FR-4 Epoxy dielectric substrate using printed-antenna techniques is designed based on Koch fractal geometry in series iteration to minimize its transversal dimension. Since the proposed antenna is a balanced antenna type, then it requires a balun circuit to be available being fed from a coaxial type transmission line. Prior to realization and experimental characterization, some basic antenna parameters including VSWR, impedance characteristic, gain, and radiation pattern are investigated numerically to obtain the optimum architectural design. Moreover, the number of antenna elements as well as the effect of balun unit is also analyzed numerically. From the result, it shows that the proposed antenna has a dimension of 120mm x 150mm, working bandwidth from 0.7GHz–2.6GHz for VSWR < 2, and overall gain of more than 6dB for frequency range > 1.6GHz. 

Keywords: balun unit; characterization; fractal Koch geometry; log-periodic antenna; series iteration.