In this paper explain the fractal theory and antennas that made by fractals theory. Then a fractal antenna has been designed and simulated. This fractal is sierpinski gasket. The height of this antenna is less than wave length. In addition to, this antenna has high radiation resistance and little imaginary resistance comparison to monopole antenna. This antenna also is a multi band antenna, this means that antenna working in several frequency band, and this is suitable for an antenna, because we can chose the best frequency band. The radiation pattern of this antenna is omni directional like a simple monopole antenna. Also the antenna dimension gets better for having a high efficiency and the most bandwidth in 266 MHz to 274 MHz frequencies. For simulating this antenna used the S-NEC software that is one of a specific for antenna design and simulation.