On bandwidth maximization of fixed-geometry arrays through convex programming

ABSTRACT

We propose a new approach to solve the problem of optimal power synthesis of array antennas, so that maximum possible bandwidth can be granted to fixed sidelobe-level performances. The proposed approach can be applied to any kind of fixed-geometry array that radiates pencil beams and to linear equispaced arrays that generate shaped patterns. The designing problem is cast as a sequence of Convex Programming optimizations. Numerous numerical experiments, including full-wave synthesis of realistic antennas, were carried out and their results discussed here to assess the array antennas’ capability of achieving ultra-wideband performances.

KEYWORDS:

• Array optimization
• power synthesis
• UWB antennas

Acknowledgements

The authors thank Prof. G. Sorbello (University of Catania, Italy) for providing the data required for CST™ full-wave simulations.

Disclosure statement

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

ORCID

T. Isernia http://orcid.org/0000-0003-3830-9540

P. Rocca http://orcid.org/0000-0003-4522-6903

A. F. Morabito http://orcid.org/0000-0001-7502-6238

Notes

1 Pencil beams’ synthesis is referred to as “optimal” as long as it provides, for fixed antenna resources and a given null-to-null beamwidth, the best possible SLL performance. Once the array geometry, Ω, and θ₀ are fixed, such a goal can be pursued by minimizing (2).

2 Note that, in (6), all AEPs are supposed to be “phase-adjusted”, i.e. computed by placing the coordinate origin at each element center (and then identifying the corresponding location-related phase term) [23,28].

3 The approach would also work in case of compensation effects from different elements of the array (so that, if one element exhibits some variation from f, the latter is compensated by an opposite variation of another element).

4 The layout’s symmetry and constant spacing led in all the performed synthesis experiments (but for the ones pertaining to a non-broadside target direction) to purely real excitations. This finding agrees with the theory developed in [15] and updated in [29], and it does not affect the actual maximum radiation performances of the synthesized systems.

Additional information

Notes on contributors

L. T. P. Bui

L. T. P. Bui received the Bachelor's degree from the Ho Chi Minh University of Technology, in 2014, and the Master's degree in Telecommunications Engineering from the University of Trento in 2017. He currently is a Ph.D. student at the ICT International Doctoral School, University of Trento, Trento, Italy. His research interests include antenna design and optimal synthesis (with application ranging from wideband systems to radar telecommunications), array signal processing, numerical optimization technicques in computational electromagnetics.

N. Anselmi

N. Anselmi received the master’s degree in telecommunication engineering from the University of Trento, Trento, Italy, in 2012, and the Ph.D. degree from the International Doctoral School, Information and Communication Technology, Trento, in 2018. Since 2012, he has been a member of the ELEDIA Research Center, Trento. His current research interests include synthesis methods for unconventional antenna array architectures, tolerance analysis of antenna systems, and electromagnetic inverse scattering techniques, with interest on compressive sensing methodologies for microwave imaging applications. Dr. Anselmi was a recipient of the “Giorgio Barzilai” Award for Young Researchers by the Italian Electromagnetic Society, in 2016.

T. Isernia

T. Isernia received the Laurea (summa cum laude) and Ph.D. degrees from the University of Naples Federico II, Naples, Italy. He is currently a Full Professor in Electromagnetic Fields with the Università Mediterranea of Reggio Calabria, Reggio Calabria, Italy, where he serves as the Supervisor of the LEMMA Research Group and the Director of the Information Engineering Department. He currently is also with the Consorzio Nazionale Italiano per le Telecomunicazioni Consortium, Parma, Italy, where he serves as a Member of the Board of Administrators. His current research interests include field synthesis problems for biomedical imaging and therapeutic applications, inverse problems in electromagnetics, with particular emphasis on phase retrieval, inverse scattering, and antenna synthesis problems. Dr. Isernia was a recipient of the G. Barzilai Award from the Italian Electromagnetics Society in 1994.

P. Rocca

P. Rocca received the M.S. degree (summa cum laude) in telecommunications engineering and the Ph.D. degree in information and communication technologies from the University of Trento, Trento, Italy, in 2005 and 2008, respectively. He is currently an Associate Professor with the Department of Information Engineering and Computer Science, University of Trento, and a member of the ELEDIA Research Center, Trento. He was an Invited Professor with the University of Paris Sud, Orsay, France, in 2015, and the University of Rennes 1, Rennes, France, in 2017. He has authored or coauthored over 300 peer-reviewed papers on international journals and conferences. His current research interests include the framework of artificial intelligence (optimization and machine learning) techniques as applied to electromagnetics, antenna array synthesis and design, and electromagnetic inverse scattering. Prof. Rocca was a recipient of the National Scientific Qualification for the position of Full Professor in 2017, the IEEE Geoscience and Remote Sensing Society, and the Italy Section with the Best Ph.D. Thesis Award IEEEGRS Central Italy Chapter.

A. F. Morabito

A. F. Morabito has received the Laurea degree in Telecommunications Engineering (summa cum laude) and the Ph.D. degree in Computer, Biomedical, and Telecommunications Engineering from the University of Reggio Calabria, Italy, wherein he has been an Assistant Professor in Electromagnetic Fields since 2010. His research work is mainly focused on models and effective strategies for electromagnetic forward and inverse scattering problems, antenna theory, design, optimal synthesis, and therapeutic applications, with applications ranging from biomedical imaging to radar and satellite telecommunications. Dr. Morabito is a member of the IEEE AP/ED/MTT North Italy Chapter, the European Association on Antennas and Propagation, and the Italian Electromagnetics Society. He has authored or coauthored about 100 papers published on peer-reviewed scientific journals or international conference proceedings, and has been awarded by the Italian Electromagnetics Society with both the Barzilai Prize and the Latmiral Prize. Prof. Morabito was a recipient of the National Scientific Qualification for the position of Associate Professor in 2017.