What are Fractal Antennas?

 Fractal antenna was initially presented by W1YW at the ARRL convention in October 1994. Fractal antenna uses a self similar design to maximize the effective length of the material used to receive or transmit electromagnetic radiation within a given total surface area or volume. Self similar design can be better understood by having a look at the public domain image from Wikipedia by Nathan Cohen (W1YW) which is shown below:


The specialty of design is that fractal antennas are very compact and capable of multiband operations. Hence fractal antennas are useful in cellular telephony and microwave communications. Another advantage is that size is smaller without the use of additional component like a loading coil, which is often used to electrically shorten antennas. 


Loading coils though they make antenna size more convenient for mounting, causes loss of RF energy in the resistance of the coils which is not zero! In a way the design can be considered similar to the linear loaded dipole antennas, in which instead of loading coils, the excess length is folded back, with separators. 


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