Improvement of Antenna Radiation Efficiency by the Suppression of Surface Waves

Homayoon Oraizi, Bahram Rezaei

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DOI: 10.4236/jemaa.2011.33013                

Abstract

The characteristics of coplanar waveguide (CPW) fed ring antennas (such as gain, efficiency and polarization purity) are degraded by the dielectric losses and excitation of surface waves on the substrates. To counteract such effects, we propose to remove some portions of the substrate in the vicinity of the metallic patches, which effectively eliminates the conditions for the generation of surface waves. The proposed technique is applied to a CPW-fed ring antenna and a prototype model is fabricated. The measurement data and the computer simulation results agree well and indicate the efficacy of the technique for the improvement of antenna gain and efficiency.

Keywords

CPW-fed Ring Antenna, Surface Waves, Radiation Efficiency

Conflicts of Interest

The authors declare no conflicts of interest.

References

[1]	K. Fujimoto, A. Henderson, K. Hirasawa and J. R. James, “Small Antennas,” John Wiley and Sons, Research Studies Press, New York, 1987.
[2]	K. Fujimoto and J. R. James, “Mobile Antenna Systems Handbook,” Artech House, Norwood, 1994.
[3]	J. James and P. Hall, “Handbook of Microstrip Antennas,” Peter Peregrinus Ltd., London, 1989.
[4]	J. Liang, C. C. Chiau, X. Chen and C. G. Parini, “Printed Circular Disc Monopole Antenna for Ultra Wideband Ap- plications,” Electronics Letters, Vol. 40, No. 20, September 2004, pp. 1246-1248.
[5]	W. Wang, S. S. Zhong and S.-B. Chen, “A Novel Wideband Coplanar-Fed Monopole Antenna,” Microwave and Optical Technology Letters, Vol. 43, No. 1, October 2004, pp. 50-52. doi:10.1002/mop.20372
[6]	S.-Y. Suh, W. Shutzman, W. Davis, A. Waltho and J. Schiffer, “A Novel CPW-Fed Disc Antenna,” IEEE Antennas and Propagation Society Symposium, Monterey, Vol. 3, 20-25 June 2004, pp. 2919-2922.
[7]	D. M. Pozar, “Microwave Engineering,” John Wiley, Hoboken, 2007.
[8]	Y. Qian, W. R. Deal, N. Kaneda and T. Itoh, “A Uniplanar Quasi-Yagi Antenna with Wide Bandwidth and Low Mutual Coupling Characteristics,” IEEE AP-S International Symposium, Orlando, July 1999, pp. 924-927.