In this work, an anisotropic zero index material is designed for use in Vivaldi antennas. The metasurface structures are placed within the aperture of a Vivaldi antenna to improve the directivity and gain of the emitted radiation. The range of operation is in the ultrahigh frequency (UHF) range, between 300 MHz and 3 GHz. Two approaches are presented: a type of resonant metallic metamaterial that belongs to the larger class of anisotropic zero index metamaterials and a non-resonant material. A technique for lowering the dimensions of the resonant metamaterial unit cell is presented and applied. The work presented consists of simulation results obtained with HFSS modelling software from ANSYS.
2. Alu, A., M. G. Silveirinha, A. Salandrino, and N. Engheta, "Epsilon-near-zero metamaterials and electromagnetic sources: Tailoring the radiation phase pattern," Phys. Rev. B, Vol. 75, 155410, Arpil 2007.
3. Yang, Y., Y. Wang, and A. E. Fathy, "Design of compact Vivaldi antenna arrays for UWB see through wall applications," Progress In Electromagnetics Research, Vol. 82, 401-418, 2008.
4. Gibson, P. J., "The Vivaldi aerial," 9th European Microwave Conference, IEEE, 1979, DOI: 10.1109/EUMA.1979.332681.
5. Ambhore, V. B. and A. P. Dhande, "An overview on properties, parameter consideration and design of meandering antenna," International Journal of Smart Sensors and Ad Hoc Networks, Vol. 1, No. 4, 2012, ISSN No. 22248-9738.
6. Das, A., S. Dhar, and B. Gupta, "Lumped circuit model analysis of meander line antennas," 11th Mediterranean Microwave Symposium (MMS), 2011.
7. Warnagiris, T. J. and T. J. Minardo, "Performance of a meandered line as an electrically small transmitting antenna," IEEE Transactions on Antennas and Propagation, Vol. 46, No. 12, December 1998.
8. Popescu, A.-S., T. Rexhepi, I. Bendoym, A. Golovin, and D. T. Crouse, "UHf metamaterial enhanced antenna," META’15, the 6th International Conference on Metamaterials, Photonic Crystals and Plasmonics, New York, N.Y., 2015.
9. Chen, X., T. M. Grzegorczyk, B.-I. Wu, J. Pacheco, Jr., and J. A. Kong, "Robust method to retrieve the constitutive effective parameters of metamaterials," Phys. Rev. E, Vol. 70, 016608, July 26, 2004.
10. Nevrly, J., "Design of Vivaldi antenna,", Diploma Thesis, Czech Technical University, Czech Republic, 2007.
11. Zinieris, M. M., R. Sloan, and L. E. Davis, "A broadband microstrip-to-slot-line transition," Microwave and Optical Technology Letters, Vol. 18, No. 5, August 1998.
12. Schuppert, B., "Microstrip/slotline transitions: Modeling and experimental investigation," IEEE Transcations on Microwave Theory and Techniques, Vol. 36, No. 8, August 1988.
13. Zhou, B., H. Li, X. Zou, and T.-J. Cui, "Broadband and high-gain planar Vivaldi antennas based on inhomogeneous anisotropic zero-index metamaterials," Progress In Electromagnetics Research, Vol. 120, 235-247, 2011.
14. Bhaskar, M., E. Johari, Z. Akhter, and M. J. Akhta, "Gain enhancement of the Vivaldi antenna with band notch characteristics using zero-index metamaterial," Microwave and Optical Technology Letters, Vol. 58, No. 1, 233-238, January 2016.