#### Sierpinski gasket antenna

Image of the Sierpinski gasket antenna. |

The *Sierpinski* gasket is a simple fractal geometry that provides multi-band performance in antenna
applications. This antenna's bands are typically spaced factor 2 apart (as shown in a typical s11 vs
frequency plot below - the first 3 operating bands are shown here). By adjusting the fractal geometry, other
band spacings are can be achieved.

Typical reflection coefficient vs frequency (normalised by the first iteration
fractal operation band frequency f1) with reference impedance of 100 Ohm. |

The *Sierpinski* gasket is a simple fractal geometry that provides multi-band performance in antenna
applications. This antenna's bands are
typically spaced factor 2 apart (as shown in a typical s11 vs frequency plot below - the first 3 operating
bands are
shown here). By adjusting the fractal geometry, other band spacings are can be achieved.

The antenna's pattern and impedance performance in each band are identical, up to the point where truncation and substrate effects come into play. This makes the Sierpinksi bowtie suitable for applications where matched multi-band performance is important.

Physically the *Sierpinski* bowtie is quite similar to the standard bowtie and similar construction
techniques may be used.
Although the *Sierpinski* bow tie is more complex to manufacture when compared to a standard bowtie
antenna, its impedance and 3D pattern are
much more stable across band. The images below compare typical gain performance between the
*Sierpinski* gasket and a standard bow tie with the
same outer dimensions at various frequencies. The last image shows comparison of typical boresight gain
(theta=0, phi=90) vs frequency for both these antennas.

Comparison of typical normalised gain (phi=90) in dB vs. Angle for Sierpinski and
standard bow-tie with the same outer dimensions at 1x, 2x, 3.9x and 7.8x f1. |