A new method for synthesis and designing transmissive linear-to-circular polarization converters based on branch line circuit model

Abstract

This paper proposes a new design method of a linear-to-circular polarization converter based on the branch line circuit model. The series branches are implemented by dielectric spacers and the shunt branches are implemented by anisotropic admittance sheets. The admittance matrix of the anisotropic admittance sheets is derived by even and odd mode analysis. A unit cell consisting of two metal layers and a dielectric spacer is then designed using an iterative algorithm for operation from 15.5 to 23 GHz. Results indicate that the axial ratio and insertion loss of the designed polarizer are better than 3 and 1.5 dB respectively, for incident angles between ±45°. To validate the simulation results, a waveguide-based test setup is designed and fabricated, with measurement results indicating good agreement with simulations. The proposed method can be potentially applied to design other anisotropic structures such as half-plate polarizers and polarization rotators.

KEYWORDS:

• Admittance matrix
• anisotropic media
• circular polarization
• linear polarization
• metasurface

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by R&D Center of Mobile Telecommunication Company of Iran (MCI) [grant number RD-51-9911-0024].

Notes on contributors

Davood Siyar

Davood Siyar received the BSC and MSC degrees from KN Toosi University of Technology, Tehran, Iran in 2016 and 2017, respectively. Now he is a PhD student and researcher at Wireless Terminal Measurement (WiTeM) Laboratory, KN Toosi University of Technology. His research interest includes phased array antennas, active and passive microwave and mm-wave component.

Hadi Aliakbarian

Hadi Aliakbarian (Senior Member, IEEE) received the B.S. and M.S. degrees in electrical and telecommunication engineering from the University of Tehran, Tehran, Iran, in 2002 and 2005, respectively, and the Ph.D. degree in electrical engineering from Katholieke Universiteit Leuven (KU Leuven), Leuven, Belgium, in 2013. He has been an Assistant Professor with the K. N. Toosi University of Technology, Tehran, since 2013. He currently leads the Wireless Terminal Measurements Laboratory (WiTeM), K. N. Toosi University of Technology. His research interests include different aspects of antennas, propagation, and electromagnetic compatibility and electromagnetics in health and agriculture.

Ping Jack Soh

Ping Jack Soh (Senior Member, IEEE) received the B.Eng and M.Eng degrees in Electrical Engineering (Telecommunications) from Universiti Teknologi Malaysia, and the Ph.D. degree in Electrical Engineering from KU Leuven, Belgium. He is an Associate Professor at the Centre for Wireless Communications (CWC), University of Oulu, Finland. His research interests include antennas and their applications in wearables/body area communication, metasurfaces and reflectors, 5G/6G communications, compact satellites, EM safety and absorption, and wireless techniques for healthcare.