Single screen cross slot polarization convertors with enhanced bandwidth and frequency selective filtering performance

ABSTRACT

This paper describes a new design strategy which is used to obtain a fivefold increase in the 3 dB axial ratio bandwidth of linear to circular polarization convertors based on anisotropic frequency selective surfaces composed of single screens of cross slots. The performance improvement is obtained by employing stratified dielectric media to carefully tailor the shape of the TE and TM spectral transmission responses. We demonstrate that a bandwidth of 24.5% can be achieved at a center operating frequency of 10.6 GHz using an array of unequal length cross-slots embedded centrally between two 2.25 mm thick dielectric slabs (ε_r = 9.0). Moreover it is shown that the inherent self-filtering behavior of the structure provides greater rejection of unwanted signals than designs embedded in lower permittivity material. Computed and experimental axial ratio results are compared to verify the new design methodology.

KEYWORDS:

• Frequency selective surfaces
• circular polarization
• linear to circular polarization convertors
• periodic structures

Acknowledgements

The first author is supported by a PhD scholarship funded by the Department for the Economy (DfE) Northern Ireland. The authors would also like to thank Mr. Hong Ma, Mr. Georg Grainger and Dr. Sandeep Kumar for their assistance in manufacturing the structure.

Disclosure statement

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

Additional information

Funding

This was the funding information provided by the university and has been used for previous publications. The first author has her PhD funded by the Department for the Economy for Northern Ireland (NI).

Notes on contributors

Sarah Clendinning

S. Clendinning received her MSci degree in Physics from Queen’s University Belfast in 2017. She is currently a PhD student in electronic engineering at the Center for Wireless Innovation (CWI) at Queen’s University Belfast. Her research interests include polarization conversion using resonant frequency selective surfaces.

R. Cahill

R. Cahill received a BSc degree in Physics from the University of Aston in Birmingham 1979 and a PhD degree in microwave electronics from the University of Kent 1982. He is currently a reader in microwave engineering at Queen’s University Belfast in the UK. His research interests include the development of space qualified Frequency Selective Surfaces (FSS), ultra-thin resistively loaded FSS based microwave absorbers, linear to circular FSS based polarizers, and electronically controlled liquid crystal antennas. He has authored over 210 publications and holds 5 global patents.

D. Zelenchuk

D. Zelenchuk, PhD, Senior Member of the IEEE, is a Lecturer with the Centre for Wireless Innovations, ECIT, Queen's University Belfast, UK. His research interests include antennas and frequency selective surfaces, mobile, automotive and space applications, electromagnetic field theory, material characterization, millimeter-wave circuits, and advanced packaging, propagation in complex environments, and various physical phenomena. He has authored over a 100 publications.

V. Fusco

V. Fusco FREng, FIEEE, FIET, FIAE, MRIA. In 2012 he was awarded the IET senior achievement award, the Mountbatten Medal for seminal contributions in the field of microwave electronics. His fundamental work on active antenna front-end techniques and artificial electromagnetic materials has provided generic advances in low cost phased and self-tracking antenna array architectures. He has written over 550 papers and two books and holds 12 antenna related patents. He co-founded a major research Electronics, Communications and Information technology Research Institute at Queens University Belfast which now employs over 200 people.