Marianela

PLANAR FIVE-ELEMENT YAGI-UDA ANTENNA
Tomáš Kořínek, Milan Polívka Dept. of Electromagnetic Field at Electrotechnical Faculty of CTU in Prague Technická 2, 166 27 Prague 6, Czech Republic e-mail:korinet@fel.cvut.cz; polivka@fel.cvut.cz Abstract The paper describes a design of planar five-element Yagi-Uda antenna for 2,4 GHz band. The structure has been optimized for a maximum directivity andmaximum front-toback ratio by planar simulator IE3D. Special feature of the antenna are reflector formed by ground plane edge and solution of impedance symmetrization and matching. Antenna has beenrealized and measured. Comparison of simulated and measured data are also presented. Introduction The planar five-element Yagi-Uda antenna (see fig. 1) has been designed for an ISM (Industrial, Science,Medical) band with a frequency range 2.40 – 2.483 GHz. Similar threeelement antenna array has been realized in [1]. The structure of the planar antenna consists of three main parts. The first part is anantenna array itself. The second one is a planar microstrip-coplanar balun that provides symmetrization and matching of unbalanced feeding microstrip (MS) line to balanced coplanar strip (CPS) line.The third part is the symmetrical CPS line that transforms array impedance Zarr to the impedance ZCPS at the MS-CPS balun output (see reference planes in Fig. 1 a).

a)

b) Fig. 1 The structure ofthe planar Yagi-Uda antenna a) layout, b) photograph of the antenna (parameters: L6=82mm, L7=52.84mm, L8=47.8mm, L9=40.95mm, L10=36.54mm, L11=100mm, L12=165mm, W5=0.74mm, W6=1mm, W7=2.52mm, W8=4.6mm,W9=6.35mm, S1=15.1mm, S2=13.32mm, S3=32.13mm, S4=22.6mm, S5=0.61mm)

Antenna array The analysis and optimization of antenna array has been done by planar simulator IE3D that uses integralequation/method of moment (IE/MoM) analysis in frequency domain. Simulator IE3D ver. 10.23 includes the ability of the analyses with finite substrate dimensions that also has been used in simulation of...