Double orthogonal phase stubs technique for Minkowski fractal reflectarray antenna

ABSTRACT

We propose a unit cell consisting of Minkowski fractal with double stubs to attain a broad phase range for the reflectarray antenna. In this study, single stub for Minkowski fractal and double stubs with orthogonal symmetry are simulated using HFSS™ program with Floquet Port incidence. It is observed that the single stub causes higher cross polarization level compared to the double orthogonal stubs. Simulation results are supported by the experimental data obtained from the measurements using waveguide setup. As a result, a broad phase response, better reflection loss, and 10.9% shrinkage in patch size are obtained using double stubs with orthogonal symmetry. Subsequently, the proposed unit cell is used to design and fabricate a full-scale 221 element reflectarray antenna, which may be used, particularly, in aeronautical and space applications. At 10 GHz, simulation results are compared with the measured data, and good agreement is observed.

KEYWORDS:

• Minkowski fractal antennas
• reflectarrays
• cross polarization

Acknowledgements

The authors thank Prof. Özlem Aydın Çivi at Middle East Technical University for her permission to access test facilities and suggestions, and assistants Damla Alptekin, İbrahim Semih Küçük, Feza Turgay Çelik and lab technician Adem Ateş for their valuable help during the experiments

Disclosure statement

No potential conflict of interest was reported by the authors.

ORCID

Ender Öztürk http://orcid.org/0000-0002-6390-8089

Birsen Saka http://orcid.org/0000-0001-8259-0734

Additional information

Notes on contributors

Ender Öztürk

Ender Öztürk received the B.S and M.S degrees in electrical and electronics engineering from Bilkent University, Ankara, Turkey and Ph.D. degree from Hacettepe University, Ankara, Turkey, in 2005, 2008, and 2018, respectively. He is working as an ICT Expert in ICT Authority of Turkey since 2008. His research interests include electromagnetic theory, fractal antennas and reflectarray antennas.

Birsen Saka

Birsen Saka received the B.S., M.S., and Ph.D. degrees in electrical engineering from Hacettepe University, Ankara, Turkey, in 1986, 1989, and 1995, respectively. She worked as an engineer at ASELSAN Electronic Industries, Inc., Ankara, from 1986 to 1989. Since 1989, she has been a member of the Department of Electrical Engineering, Hacettepe University where currently she is a Professor. Her research interests include electromagnetic theory, reflector antennas, fractal antennas, array processing, electromagnetic compatibility, and optimization problems.