Study And Application Of Fractal Antennas In The Multi-frequency Wireless Communication

For the properties of self-similarity and space-filling, fractal antenna, since it's born, has made breakthrough in realizing multi-frequency and miniaturization. This paper puts the emphasis on the application of the fractal antenna techniques to multi-frequency wireless communication.Theory analysis includes three parts. First, the instruction of fractal antenna and iterative function system (IFS); next, an over view of fractal antenna engineering both in element and array, pointing out the suitability of each fractal antenna; finally, a systematical study of Sierpinski Carpet antenna is undertaken with the aim of gaining an insight into its multi-frequency property, and the traditional opinion is modified, the guidelines for the multi-frequency design of Sierpinski antenna are given.With the fractal antenna techniques applying to the area of wireless communication, two antennas are designed based on the knowledge gained and practical needs. One works in four communication bands of DCS+PCS+UMTS+WLAN2, and can be used as a handset antenna, in which Koch curve is used as the edge of microstrip patch, PIFA and U Slot are introduced in the structure; another one is designed for PCMCIA Card and works in dual-band of WLAN in 2.4GHz and 5.8GHz, that is a modification of the traditional Sierpinski triangular antenna. The results of experiment and measurement are in good agreement.