This article presents a high gain patch antenna with negative refractive index (NRI) superstrate for the application of Radio frequency energy harvesting system. Triangular split ring resonators (TSRR)-strip line are used as a NRI superstrate to enhance the gain of the patch antenna. It is demonstrated that the proposed triangular split ring resonator (TSRR) structure metamaterial yields negative value of an effective refractive index that over the frequency range of 774 MHz to 974 MHz. The negative refractive index structure is applied as a superstrate to a microstrip patch antenna. The simulation results show that the gain is effectively improved by 2.326 dB (85.96 %) after the incorporation of negative refractive index metamaterial superstrate on to the conventional patch antenna. The results illustrated that the gain of the proposed antenna is enhanced over the desired frequency band 935 MHz to 960 MHz. The air gap between the antenna and superstrate was also studied by applying the theory of Fabry-Perot (F-P) resonant cavity to obtain the optimum air gap of 55 mm to achieve the maximum gain. The proposed antenna is also fabricated and tested, the measured results shown that have good agreement with the simulated results in term of S -parameters and radiation characteristics.
This Research work is funded by Ministry of Higher Education Malaysia Grant No. is FRGS/2/2013/ ST02INTI/ 02/01.
K.A. Devi: INTI International University Nilai, Malaysia, firstname.lastname@example.org
Ng Chun Hau: INTI International University Nilai, Malaysia email@example.com
C. K. Chakrabarty: Universiti Tenaga Nasional, Kajang, Malaysia, firstname.lastname@example.org
Norashidah Md. Din: Universiti Tenaga Nasional, Kajang, Malaysia, norashidah @uniten.edu.my
K.A. Devi Ng Chun Hau C. K. Chakrabarty Norashidah Md. Din
D. H. Schaubert, D. M. Pozar, and A. Adrian, “Effect of microstrip antenna substrate thickness and permittivity: comparison of theories with experiment,” IEEE Trans. Antennas Propag., vol. 37, no. 6, pp. 677–682, 1989.
 J. A. Ansari and R. B. Ram, “Broadband Stacked U-slot microstrip patch antenna”, Progress In Electromagnetics Research Letters,A. Ansari and R. B. Ram,” vol. 4, pp. 17–24, 2008.
 T. A. RAHMAN, “Reconfigurable Ultra Wideband Antenna Design and Development for Wireless Communication,” Universiti Teknologi Malaysia, 2008.
 V. G. Veselago, “The Electrodynamics of Substances With Simultaneously Negative Values of ? and ?,” Sov. Phys. Uspekhi, vol. 509, no. 4, pp. 509–514, 1968.
 S. Enoch, G. Tayeb, P. Sabouroux, N. Guérin, and P. Vincent, “A metamaterial for directive emission.,” Phys. Rev. Lett., vol. 89, no. 21, p. 213902, 2002.
 B.-I. Wu, W. Wang, J. Pacheco, X. Chen, T. M. Grzegorczyk, and J. A.Kong, “A Study of Using Metamaterials As Antenna Substrate To Enhance Gain,” Prog. Electromagn. Res., vol. 51, pp. 295–328, 2005.
 P. Ding, E. J. Liang, W. Q. Hu, L. Zhang, Q. Zhou, and Q. Z. Xue, “Numerical simulations of terahertz double-negative metamaterial with isotropic-like fishnet structure,” Photonics Nanostructures - Fundam. Appl., vol. 7, no. 2, pp. 92–100, 2009.
 P. Dawar and A. De, “Bandwidth Enhancement of RMPA using ENG metamaterials at THz,” Mater. Sci. Appl., vol. 4, pp. 579–588, 2013.
 H. a. Majid, M. K. a. Rahim, and T. Masri, “Microstrip Antenna’S Gain Enhancement Using Left-Handed Metamaterial Structure,” Prog. Electromagn. Res. M, vol. 8, pp. 235–247, 2009.
 C. Sabah, “Progress In Electromagnetics Research B, Vol. 22, 341–357, 2010,” Prog. Electromagn. Res. B, vol. 22, pp. 341–357, 2010.
 K. Inamdar, Y. P. Kosta, and S. Patnaik, “Proposing a Criss-Cross Metamaterial Structure for Improvement of Performance Parameters of Microstrip Antennas,” Prog. Electromagn. Res. C, vol. 52, no. August, pp. 145–152, 2014.
 M. Ullah, M. Islam, and M. Faruque, “A Near-Zero Refractive Index Meta-Surface Structure for Antenna Performance Improvement,” Materials (Basel)., vol. 6, no. 11, pp. 5058–5068, 2013.
 J. Wang, L. Gong, Y. Sun, Z. Zhu, and Y. Zhang, “High-gain composite microstrip patch antenna with the near-zero-refractive-index metamaterial,” Opt. - Int. J. Light Electron Opt., vol. 125, no. 21, pp. 6491–6495, 2014.
 H. Zhou, Z. Pei, S. Qu, S. Zhang, J. Wang, Z. Duan, H. Ma, and Z. Xu, “A novel high-directivity microstrip patch antenna based on zero-index metamaterial,” IEEE Antennas Wirel. Propag. Lett., vol. 8, pp. 538–541, 2009.
 Xiaolong Huang, Yong Liu, Xiaohong Tang, Zhongxun Zhang, “Novel Nested SplitRring-Resonator SRRr) for CompactFfilter Application,” Prog. Electromagn. Res., vol. 136, pp. 765–773, 2013.
 C. A. Balanis, Antenna Theory Analysis and Design, Third Edit., no. 3. 2005.
 D. R. Smith, D. C. Vier, T. Koschny, and C. M. Soukoulis, “Electromagnetic parameter retrieval from inhomogeneous metamaterials,” Phys. Rev. E, vol. 71, no. 3, p. 036617, 2005.