We propose a circularly polarized microstrip patch antenna using artificial magneto-dielectric (AMD) substrate. The proposed antenna has a square patch with dual feeding point using Wilkinson power divider in order to achieve circularly polarized radiation pattern. The AMD substrate is constructed by single sprit ring resonators, which are arrayed in both x and y directions. The designed antenna has the characteristics of the axial ratio less than 1.7 dB, the peak gain of 0.55 dBic, and the right handed circular polarized radiation pattern at Korea UHF RFID service band. The sizes of the antenna and radiating patch are 100 mm×100 mm×5.2 mm and 65 mm×65 mm (0.199λ0×0.199 λ0), respectively.
2. Marrocco, G., "Gain-optimized self-resonant meander line antenna for RFID applications," IEEE Antennas and Wireless Propagation Letters, Vol. 2, 302-305, 2003.
3. Hansen, R. C. and M. Burke, "Antennas with magneto-dielectrics," Microwave and Optical Technology Letters, Vol. 26, No. 2, 75-78, July 20, 2000.
4. Mosallaei, H. and K. Sarabandi, "Magneto-dielectrics in electromagnetic: Concept and applications," IEEE Transactions on Antennas and Propagation, Vol. 52, No. 6, 1558-1567, June 2004.
5. Callister, W. D., Materials Science and Engineering, an Introduction, Wiley, New York, 2000.
6. Yousefi, L., H. Attia, and O. M. Ramahi, "Broadband experimental characterization of artificial magnetic materials based on a microstrip line method," Progress In Electromagnetics Research, Vol. 90, 1-13, 2009.
7. Ikonen, P. M. T., S. I. Maslovski, C. R. Simovski, and S. A. Tretyakov, "On artificial magneto-dielectric loading for improving the impedance bandwidth properties of microstrip antennas," IEEE Transactions on Antennas and Propagation, Vol. 54, No. 6, 1654-1662, June 2006.
8. Karakkain, M. and P. Ikonen, "Patch antenna with stacked split-ring resonators as an artificial magneto-dielectric substrate," Microwave and Optical Technology Letters, Vol. 46, No. 6, 554-556, September 20, 2005.
9. Ansoft High Frequency Structures Simulator (HFSS) Version 11.0, Ansoft Corporation, , 2008.
10. Lee, D., P. Park, J. Kim, and J. Choi, "Aperture-coupled UHF RFID reader antenna for a handheld application," Microwave and Optical Technology Letters, Vol. 50, No. 5, 1261-1263, May 2008.
11. Chen, Z. N., Chen, Z. N., X. Qing, and H. L. Chung, "A universal UHF RFID reader antenna," IEEE Transactions on Microwave Theory and Techniques, Vol. 57, No. 5, May 2009.