# Why is it that fractal antennas can filter out so many frequencies?

As known, fractal antennas are used for example in cell phones. But why is it that so many different kinds of frequencies can be filtered out of the forest of radio waves surrounding us? Is it because of the self-similarity, when you look at different scales of the antenna pattern?

• Sounds like a question for electronics.stackexchange.com – user56903 May 12 '16 at 10:51
• Very interesting subject. As an aside, may I ask if anyone know for any similar treatments in biology-biophysics? Thanks. – Constantine Black May 12 '16 at 16:17
• What do you mean by treatments? – descheleschilder May 12 '16 at 16:57
• I know that fractal antennas can be used for the generation of energy. A very broad spectrum of mainly radio frequencies can be converted to energy. Same principle. But what is the principle? – descheleschilder May 12 '16 at 18:12
• You seem to know a lot of things that are just not so... like that one can generate energy with antennas. :-) – CuriousOne May 12 '16 at 21:54

Yes, it's because of self-similarity, although self-similarity alone doesn't guarantee$^1$ good performance. I believe you can understand a fractal antenna as a collection of many antennas of different size/scales put together in a very compact way.
$^1$The full-text of the paper is available here.