A novel fractal structure using Koch and Sierpinski fractal-shapes is proposed. By inserting the Sierpinski carpets into the single patch and etching the inner and outer patch edges according to Koch curves, the resonant frequency of the patch antenna can be lowered significantly. And the higher of the iteration order of the fractal shapes, the lower the resonant frequency becomes. In this paper, a novel small-size single patch microstrip antenna based on the proposed fractal-shapes is designed, fabricated and measured. It is experimentally found that the size reduction can reach 80.3%. Compared to the conventional square single patch antenna, the proposed antenna maintains comparable radiation patterns. Therefore, the small-size single patch microstrip antenna considered here can be applied to portable wireless communication systems requiring small devices.
2. Reed, S., L. Desclos, C. Terret, and S. Toutain, "Patch antenna size reduction by means of inductive loads," Microwave and Optical Technology Letters, Vol. 29, No. 2, 79-81, 2001.
3. Lin, Y. D. and T. Itoh, "Frequency-scanning antenna using the crosstieoverlay slow-wave structures as transmission line," IEEE Trans. on Antennas Propagation, Vol. 39, 377-380, 1991.
4. Kim, J.-H., I.-K. Kim, J.-G. Yook, and H.-K. Park, "A slow-wave structure with Koch fractal slot loops," Microwave and Optical Technology Letters, Vol. 34, No. 2, 87-88, 2002.
5. Wong, K.-L., Compact and Broadband Microstrip Antennas, Wiley, New York, 2002.
6. Desclos, L., Y. Mahe, S. Reed, G. Poilasne, and S. Toutain, "Patch antenna size reduction by combining inductive loading and short-points technique," Microwave and Optical Technology Letters, Vol. 30, No. 6, 385-386, 2001.
7. Chen, W.-L. and G.-M. Wang, "Small size edge-fed sierpinski carpet microstrip patch antennas," Progress In Electromagnetics Research C, Vol. 3, 195-202, 2008.
8. Kim, I.-K., J.-G. Yook, and H.-K. Park, "Fractal-shape small size microstrip antenna," Microwave and Optical Technology Letters, Vol. 34, No. 1, 15-17, 2002.
9. Anguera, J., C. Puente, C. Borja, R. Montero, and J. Solder, "Small and high-directivity bow-tie patch antenna based on the Sierpinski fractal," Microwave and Optical Technology Letters, Vol. 31, No. 3, 239-241, 2001.
10. Chen, W. L., G. M. Wang, and C. X. Zhang, "Small-size microstrip patch antennas combining koch and sierpinski fractal-shapes," IEEE Antennas Wireless Propagation Letters, Vol. 7, 738-741, 2008.
11. Tsachtsiris, G., C. Soras, M. Karaboikis, and V. Makios, "A reduced size fractal rectangular curve patch antenna," IEEE Electromagnetic Compatibility International Symposium, 2003.
12. Hoefer, W. J. R., "Equivalent series inductivity of a narrow transverse slit in microstrip," IEEE Trans. Microwave Theory Tech., Vol. 25, 822-824, 1977.