A microstrip patch antenna is designed that have metallic ring coplanar to radiation patch for gain enhancement is proposed. The design forces conversion of the surface wave energy into the space wave energy by the scattering of surface waves from metallic ring. The metallic ring is placed around the metal patch at a distance of d1 from the edges of the metal patch and width of metallic ring is d2. Using CST Microwave studio, the results of the patch antenna without metallic ring and patch surrounded by metallic ring are simulated and compared. The proposed microstrip patch antenna operates at the 10. 5 GHz frequency. By this proposed antenna design there is enhancement in the gain of microstrip patch antenna about 185% as compared to conventional one (without metallic ring).

1. Waterhouse, R. B. and Kluwer, MA. 2003 ch. 4. Microstrip Patch Antennas—A Designer's Guide. Boston, Academic Publishers
2. Sievenpiper, D. , Zhang, L. , Jimenez Broas, R. F. , Alexopoulos, N. G. and Yablonovitch, E. 1999 High-impedance electromagnetic surfaces with a forbidden frequency band. IEEE Trans. Microwave Theory Techn.
3. Boutayeb, H. , Denidni, T. A. , Mahdjoubi, K. , Tarot, A. -C. , Sebak, A. -R. , and Talbi, L. 2006 Analysis and design of a cylindrical EBG-based directive antenna. IEEE Trans. Antennas Propag.
4. Gonzola and De Maagt and sorola 1999 Enhanced patch-antenna performance by suppressing surface waves using photonic-bandgap substrates. IEEE Trans. Microwave Theory Techn.
5. Ali, M. T, Jaafar, H. , Subahir, S. , and Yusof, A. L. 2012 Gain Enhancement of Air Substrates at 5. 8GHz for Microstrip Antenna Array. IEEE
6. Hussein Attia and Leila Yousefi 2011 High-Gain Patch Antennas Loaded With High Characteristic Impedance Superstrates. IEEE Antennas And Wireless Propagation Letters.
7. Rivera-Albino, A. and Balanis, C. A. 2013 Gain Enhancement in Microstrip Patch Antennas Using Hybrid Substrates. IEEE Antennas and Wireless Propagation Letters.
8. Kumar, P. , Batra, D. , and Shrivastav, A. K. 2010 High gain microstrip antenna capacitive coupled to a square ring with surface mounted conical horn. Int. J. Electron. Commun. Technol.
9. Yong H. Cho. , Cheolsig Pyo and Jaeick Choi 2003 Gain Enhancement of Microstrip Patch Antenna Using Parasitic Metallic Bar. IEEE AP-S.
10. Lee, C. S. and Nalbandian, V. and Schwcring, F. 1994 Gain enhancement of a thick microstrip antenna by suppressing surface waves. IEEE AP-S.
11. Balanis, C. 2012 Advanced Engineering Electromagnetics.
12. Dalin Jin, Bing Li, Jingsong Hong 2012 Gain Improvement of a Microstrip Patch Antenna Using Metamaterial Superstrate with the Zero Refractive Index. IEEE
13. CST. Computer simulation technology microwave studio 2011. [Online]. Available: http://www. cst. com.

Gain Microstrip Patch Antennas Return Loss Surface Waves