Multi-band bowtie antenna based on fractal geometry

The expansion of the wireless communication market is driving the increasing demand for low-profile multi-band antennas for a large variety of applications in personal and satellite communication systems. Most of the existing printed antennas designs operate at one or double frequencies, while the demand is for versatile multi-frequency antennas operational in GSM, GPS, UMTS and Bluetooth applications. The nature of the fractal geometry applied in antenna designs offer two major advantages: design of operational small scaled antennas and multi-frequency operation. As such it is appealing to use fractal geometries in multi-frequency applications. The major drawback in a straight-forward application of fractal geometry in antenna design is the lack of flexibility in the control of the operational frequencies. Usually, the operational frequencies are determined by the type of fractal used in the design. In this paper, we present a novel algorithm based on fractal geometry flexible enough to control the location of the required operational frequencies. The algorithm is applied to the design of a bowtie antenna to operate in four arbitrary frequencies. The simulations are performed with the Antenna Designer commercial software from HFSS. Results of the antenna radiation characteristics are presented.