Design, simulation, fabrication and measurement of a multiband fractal Yagi antenna

A multiband element has been designed based on the Sierpinski sieve fractal which operates over two frequency bands. This stems from the self-similarity of the fractal. However, due to the leakage of current from one scale of the geometry to other scales, the radiation pattern can become distorted for different operating bands. A filtering element can be placed inside the Sierpinski element to achieve similar radiation patterns over various operating bands. This multiband element which achieves a spectrally stable radiation pattern in its multiple radiating bands is incorporated into the design of a Yagi antenna to achieve directive patterns over two frequency bands.