Small-Size Microstrip Patch Antennas Combining Koch and Sierpinski Fractal-Shapes

A novel technique to reduce the size of microstrip patch antennas is proposed. By etching the patch edges according to Koch curves as inductive loading, and inserting the Sierpinski carpets into the patch as slot loading, it is experimentally found that the resonant frequency of the patch can be greatly lowered, and the higher the iteration order of the fractal shapes, the lower the resonant frequency becomes. And this property can be utilized to reduce the size of the microstrip patch antennas. It is also found that, the radiation patterns of the proposed fractal-shaped antennas maintained because of the self-similarity and centro-symmetry of the fractal shapes. The patches derived from this technique can find applications in integrated low-profile wireless communication systems.