New bi-band fractal antennas

In this paper Koch fractal antennas for bi-band operations at UHF frequencies (868MHz and 2.45GHz) are analyzed. In particular, two modified models of Koch fractal dipoles are compared to the standard bi-band Koch fractal dipole antenna. The goal is to reduce the size of the fractal antenna while still providing good gain and allow operation at multi-frequencies. A size reduction of 8% with respect to the standard Koch antenna is obtained, by using a new set of fractal antenna. The standard and the modified fractal Koch antennas are printed on glass-epoxy FR-4 substrate having a thickness of 1.6 mm and a relative permittivity of 4.4. The return loss parameter and radiation properties of the fabricated antennas are measured and compared with simulation results.