Application of Z-type and Hilbert fractal structures for Multiband and circularly polarized microstrip antennas

In this paper, a microstrip monopole antenna is introduced based on the series connection of Z-type and Hilbert fractal configurations. Specifically, the series connection of five fractals in zig-zag formation is studied in detail. It is shown that the proposed structures have multiband and wideband radiation characteristics, and may provide circular polarization. Effective miniaturization of antennas may be realized by decreasing the low frequency limit and generating higher frequencies for broadbanding. Furthermore, defected ground patterns may also lead to the increase of frequency bandwidths.