Gain and Bandwidth Enhancement Using NZRI – Metasurface

Abstract

This paper focuses on enhancing the bandwidth and gain of a coaxially fed microstrip patch antenna using Near Zero Refractive Index (NZRI) Metasurface. A metasurface comprising closely spaced 4 × 4 concentric circular rings is proposed to generate a wideband NZRI surface. The proposed metasurface provides µ_eff = 0.0018 and ϵ_eff = 4.4, making its refractive index near zero (i.e. – η_eff = 0.09) at 2.4 GHz. It is a wideband structure with an effective refractive index of less than 0.14 in 1–3 GHz. The metasurface is arranged over a coaxially fed microstrip square patch antenna to enhance its gain and bandwidth. The antenna and metasurface are printed on FR4 substrate of thickness 1.6 mm and dielectric constant 4.4 to verify its performance. A patch antenna is designed to operate near 2.4 GHz. A prototype of size (0.72λ × 0.72λ × 0.048λ) is fabricated and tested. The metasurface can improve the gain of the developed patch antenna by 4.3 dB and bandwidth by 11.5% (i.e. 45 to 320 MHz) at 2.4 GHz. 1 dB gain bandwidth is the same as that of impedance bandwidth.

KEYWORDS:

• Bandwidth enhancement
• Compact
• Gain enhancement
• Metasurface
• NZRI
• Wideband

ACKNOWLEDGEMENTS

The authors thank Shri. N. M. Desai, Director, SAC, for his enormous support while doing this work. The authors also thank Latheef A Shalik, IIST, for his help in Antenna fabrication and engineers of the Antenna Measurement facility of SAC for their assistance in pattern measurement.

DISCLOSURE STATEMENT

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

Additional information

Notes on contributors

Gaurav Kumar

Gaurav Kumar received the BTech degree in avionics from IIST, Valiyamala, India, in 2017. He worked as a research fellow for 3 months at the University of Manitoba, Canada, under the MITACS Internship 2016. Since 2017, he has been working as a scientist in the Antenna Systems Group, Space Applications Centre, Ahmedabad, Microwave Sensors Antenna Division (MSAD) and involved in the design and demonstration of various state-of-the-art antenna systems related to microwave remote sensing and interplanetary experiments. His research interests include metamaterial and metasurfaces, miniaturized antennas, single-layer multiband antenna, UWB antennas for rover and orbiter-based GPR applications.

Basudeb Ghosh

Basudeb Ghosh obtained a bachelor's degree in electronic sciences and a master's degree in electronics from the University of Calcutta in 1999 and 2001, respectively, and a PhD degree with a specialization in microwave engineering from the Indian Institute of Technology (IIT) Roorkee in 2009. He served Durgapur Institute of Advanced Technology and Management, Durgapur, India as an assistant professor in the Department of Electronics and Communication Engineering during 2009–2010. At present, he is working as an associate professor in Dept. of Avionics, Indian Institute of Space Science and Technology (IIST). Before joining IIST, he worked in Chang Gung University, Taiwan as a post-doctoral research associate. His main area of research work includes computational electromagnetic techniques, passive microwave devices, metasurface antennas, and wireless power transfer. Email:[email protected]

Soumyabrata Chakrbarty

S B Chakrabarty obtained BE (Hons) degree from NIT Silchar (previously REC) in 1988, ME from Jadavpur University in 1992 both in electronics and telecommunication engineering and a PhD degree in microwave engineering from the Indian Institute of Technology, Kharagpur in 1996. He served NIT, Silchar (previously REC) as a lecturer in the Department of Electronics and Telecommunication Engineering during 1995–1996. He is currently working in Antenna Systems Group, Space Applications Centre, Ahmedabad as Head, Microwave Sensors Antenna Division and is involved in the development of a variety of state-of-the-art antenna systems related to microwave remote sensing. He served the German Aerospace Centre (DLR) during 1999–2000 as a guest scientist deputed from ISRO. His area of research is computational electromagnetics, microwave and millimeterwave/submillimeterwave antennas. He has authored and co-authored over 80 papers published in IEEE Transactions on EMC, MTT and IET Journals, International Journal of Electronics, Journal of Electromagnetics, Journal of Electrostatics, Microwave and Optical Technology Letters, etc. in addition to several technical reports at the Space Applications Centre/ISRO. He has also presented many papers at international conferences. He received INSA visiting fellowship 1996 and was shortlisted for INSA young Scientist award 1997, and received ISRO excellence team awards two times for his contribution in Radar Imaging Satellite (RISAT) and Scatterometer of Oceansat-II. Email:[email protected]

Milind B. Mahajan

Milind Mahajan obtained BE (Electronics) degree in 1991 from Marathwada University, Aurangabad, and MTech degree in microwave engineering from IIT, BHU, Varanasi in 1993. He received the PhD degree from D D University, Nadiad in 2015. He started his career in Spacecraft Payload Group of Space Applications Centre, Ahmedabad in 1993. He is currently working as group director, Antenna Systems Group. He worked as a guest scientist at German Aerospace Centre (DLR) in 2001. He was the designer of shaped reflectors and dual gridded reflector antennas, high-power helix antenna, multiple beam antennas for the various INSAT and GSAT programs. His current interests are contoured beam reflector antennas and digital beam forming-based antennas. He held many responsibilities as deputy project director, Comm. Payload Antenna Systems of INSAT-4A/4B/4C, GSAT 7/7A and Advanced Communications Satellite , GSAT-11 projects. He has led the team to develop the antenna systems for navigation satellites, radar imaging satellites and Chandrayaan-2 missions. He was the recipient of the Space Gold Medal of the Astronautical Society of India in 2005, ISRO’s team excellence awards in 2007, 2008, 2015, and 2017. He has over 50 publications in national/international journals and conferences and 3 national /international patents to his credit. Email:[email protected]