The influence of semi-planar chiral metamaterial (CMM) structures on the important characteristics of circularly polarized (CP) antennas is investigated in this paper. Based on this idea, CP planar two-arm Archimedean spiral (ARSPL) antenna and helical antenna are designed and the effects of chiral covers on their gain (or directivity), axial-ratio (AR), and return loss are considered. The results demonstrate that this method is greatly effective and the addition of a semi-planar CMM cover at an optimized distance over the CP antenna, significantly improves its gain and axial ratio.
2. Singh, G., "Double negative left-handed metamaterials for miniaturization of rectangular microstrip antenna," Journal of Electromagnetic Analysis & Applications, Vol. 2, 347-351, 2010.
3. Lee, J. and Y. Hao, "Characterization of microstrip patch antennas on metamaterial substrates loaded with complementary split-ring resonators," Microwave Opt. Tech. Lett., Vol. 50, No. 8, Aug. 2008.
4. Alu, J., F. Bilotti, N. Engheta, and L. Vegni, "Subwavelength compact, resonant patch antenna loaded with metamaterials," IEEE Trans. Antennas Propag., Vol. 55, No. 1, Jan. 2007.
5. Li, L.-W., Y.-N. T. S. Yeo, J. R. Mosig, and O. J. F. Martin, "A broadband and high-gain metamaterial microstrip antenna," Appl. Phys. Lett., Vol. 96, 164101, 2010.
6. Chaimool, S., K. L. Chung, and P. Akkaraekthalin, "Simultaneous gain and bandwidths enhancement of a single-feed circularly polarized microstrip patch antenna using a metamaterial reflective surface," Progress In Electromagnetics Research B, Vol. 22, 23-37, 2010.
7. Griguer, H., E. Marzolf, H. Lalj, F. Riouch, and M. Drissi, "Patch antenna bandwidth enhancement through the use of metamaterials," International Conference on Telecommunications, 2009, ICT'09, 2009.
8. Enoch, S., G. Tayeb, P. Sabouroux, N. Guerin, and P. Vincent, "A metamaterial for directive emission," Phys. Rev. Lett., Vol. 89, 2002.
9. Hu, J., et al., "A new patch antenna with metamaterial cover," Zhejiang University SCIENCE A, Vol. 7, 89-94, 2006.
10. Attia, H., L. Yousefi, M. S. Boybay, and O. M. Ramahi, "Enhanced-gain microstrip antenna using engineered magnetic superstrates," IEEE Antennas Propag. Lett., Vol. 8, 2009.
11. Wu, B.-I., W. Wang, J. Pacheco, X. Chen, T. Grzegorczyk, and J. A. Kong, "A study of using metamaterials as antenna substrate to enhance gain," Progress In Electromagnetics Research, Vol. 51, 295-328, 2005.
12. Attia, H., L. Yousefi, and O. M. Ramahi, "Analytical model for calculating the radiation field of microstrip antennas with artificial magnetic superstrates theory and experiment," IEEE Trans. Antennas Propag., Vol. 59, No. 5, May 2011.
13. Chen, K.-S., K.-H. Lin, and H.-L. Su, "Microstrip antenna gain enhancement by metamaterial radome with more subwavelength holes," Asia Pacific Microwave Conference, 2009, APMC 2009, 2009.
14. Xiao, X. and H. Xu, "Low refractive metamaterials for gain enhancement of horn antenna," Journal of Infrared Milli Terahz Waves, Vol. 30, 225-232, 2009.
15. Tretyakov, S., I. Nefedov, A. Sihvola, S. Maslovski, and C. Simovski, "Waves and energy in chiral nihility," Journal of Electromagnetic Waves and Applications, Vol. 17, No. 5, 695-706, 2003.
16. Dong, J., "Exotic characteristics of power propagation in the chiral nihility fiber," Progress In Electromagnetics Research, Vol. 99, 163-178, 2009.
17. Dong, J., J. Li, and F.-Q. Yang, "Guided modes in the four-layer slab waveguide containing chiral nihility core," Progress In Electromagnetics Research, Vol. 112, 241-255, 2011.
18. Naqvi, A., A. Hussain, and Q. A. Naqvi, "Waves in fractional dual planar waveguides containing chiral nihility metamaterial," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 11--12, 1575-1586, 2010.
19. Dong, J. F. and C. Xu, "Surface polaritons in planar chiral nihility metamaterial waveguides," Opt. Commun., Vol. 282, 3899-3904, 2009.
20. Tuz, V. R. and C.-W. Qiu, "Semi-infinite chiral nihility photonics: Parametric dependence, wave tunneling and rejection," Progress In Electromagnetics Research, Vol. 103, 139-152, 2010.
21. Naqvi, Q. A., "Fractional dual solutions in grounded chiral nihility slab and their effect on outside field," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 5--6, 773-784, 2009.
22. Qamar, S. R., A. Naqvi, A. A. Syed, and Q. A. Naqvi, "Radiation characteristics of elementary sources located in unbounded chiral nihility metamaterial," Journal of Electromagnetic Waves and Applications, Vol. 25, No. 5--6, 713-722, 2011.
23. Ahmad, S. and Q. A. Naqvi, "Directive EM radiation of a line source in the presence of a coated nihility cylinder," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 5--6, 761-771, 2009.
24. Pendry, J. B., "A chiral route to negative refraction," Science, Vol. 306, 1353-1354, 2004.
25. Mackay, T. G., "Plane waves with negative phase velocity in isotropic chiral mediums," Microwave Opt. Tech. Lett., Vol. 45, No. 2, 120-121, 2005.
26. Zhao, R., T. Koschny, E. N. Economou, and C. M. Soukoulis, "Comparison of chiral metamaterial designs for repulsive Casimir force," Phys. Rev. B, Vol. 81, 235126, 2010.
27. Plum, E., J. Zhou, J. Dong, V. A. Fedotov, T. Koschny, C. M. Soukoulis, and N. I. Zheludev, "Metamaterial with negative index due to chirality," Phys. Rev. B, Vol. 79, 035407, 2009.
28. Zhou, J., J. Dong, B. Wang, T. Koschny, M. Kafesaki, and C. M. Soukoulis, "Negative refractive index due to chirality," Phys. Rev. B, Vol. 79, 121104, 2009.
29. Li, Z., R. Zhao, T. Koschny, M. Kafesaki, and C. M. Soukoulis, "Chiral metamaterials with negative refractive index based on four ``U'' split ring resonators," Appl. Phys. Lett., Vol. 97, 081901, 2010.
30. Wu, Z., B. Q. Zhang, and S. Zhong, "A double-layer chiral metamaterial with negative index," Journal of Electromagnetic Waves and Applications, Vol. 24, No. 7, 983-992, 2010.
31. Zhao, R., L. Zhang, J. Zhou, T. Koschny, and C. M. Soukoulis, "Conjugated gammadion chiral metamaterial with uniaxial optical activity and negative refractive index," Phys. Rev. B, Vol. 83, 035105, 2011.
32. Li, Z., K. B. Alici, E. Colak, and E. Ozbay, "Complementary chiral metamaterials with giant optical activity and negative refractive index," Appl. Phys. Lett., Vol. 98, 161907, 2011.
33. Li, Z., F.-Q. Yang, and J. Dong, "Design and simulation of L-shaped chiral negative refractive index structure," Progress In Electromagnetics Research, Vol. 116, 395-408, 2011.
34. Ye, Y. and S. He, "90° polarization rotator using a bilayered chiral metamaterial with giant optical activity," Appl. Phys. Lett., Vol. 96, 203501, 2010.
35. Ye, Y., X. Li, F. Zhuang, and S.-W. Chang, "Homogeneous circular polarizers using a bilayered chiral metamaterial," Appl. Phys. Lett., Vol. 99, 031111, 2011.
36. Illahi, A. and Q. A. Naqvi, "Study of focusing of electromagnetic waves reflected by a PEMC backed chiral nihility reflector using Maslov's method," Journal of Electromagnetic Waves and Applications, Vol. 23, No. 7, 863-873, 2009.
37. Jin, Y. and S. He, "Focusing by a slab of chiral medium," Optics Express, Vol. 13, No. 13, 4974-4979, 2005.
38. Monzon, C. and D. W. Forester, "Negative refraction and focusing of circularly polarized waves in optically active media," Phys. Rev. Lett., Vol. 95, 123904, 2005.
39. Wang, B., T. Koschny, and C. M. Soukoulis, "Wide-angle and polarization-independent chiral metamaterial absorber," Phys. Rev. B, Vol. 80, 033108, 2009.
40. Cheng, Q., W. X. Jiang, and T. J. Cui, "Investigations of the electromagnetic properties of three-dimensional arbitrarily-shaped cloaks," Progress In Electromagnetics Research, Vol. 94, 105-117, 2009.
41. Luo, Y., J. Zhang, H. Chen, B.-I. Wu, and L.-X. Ran, "Wave and ray analysis of a type of cloak exhibiting magnified and shifted scattering effect," Progress In Electromagnetics Research, Vol. 95, 167-178, 2009.
42. Lindell, I. V., A. H. Sihvola, S. A. Tretyakov, and A. J. Viitanen, Electromagnetic Waves in Chiral and Bi-isotropic Media, Artech House, Boston, 1994.
43. Serdyukov, A., I. Semchenko, S. Tretyakov, and A. Sihvola, Electromagnetics of Bi-anisotropic Materials Theory and Applications, Gordon and Breach Science Publishers, 2001.
44. Zhao, R., T. Koschny, and C. M. Soukoulis, "Chiral metamaterials: Retrieval of the effective parameters with and without substrate," Optics Express, Vol. 18, No. 14, Jul. 2010.
45. Balanis, C. A., Modern Antenna Handbook, John Wiley & Sons, 2008.
46. Kraus, J. D. and R. J. Marhefka, Antennas: For All Applications, 3rd Ed., McGraw Hill, New York, 2001.