Summary
International Symposium on Antennas and Propagation
2008
Session Number:3C22
Session:
Number:3C22-2
Broadband Fractal Antennas
David C. Ni, Chou Hsin Chin,
pp.-
Publication Date:2008/10/27
Online ISSN:2188-5079
Summary:
Design of fractal antennas is currently targeted for highly desirable characteristics such as compact size, low profile, conformal, multi-band and broadband, as described in [1], [2], and [3]. Most of the designers adopt operations such as translation, rotation, iterations, etc. on the fractal generator motifs, such as Koch, Minkoski, Cantor, Torn Square, Mandelbrot, Caley Tree, Monkey’s Swing, Sierpinski Gasket, Julia etc. for the creation of the self-similar shapes. To further improve the frequency responses, they applied modifications on the created shapes, such as in [4]. Recently, new approaches, such as Generic Algorithm, are studied for handling antenna optimization on multi-dimensional parameters [5]. For commercial use, the fractal antennas need to comply with engineering requirements, such as antenna efficiency, directivity, gain, radiation pattern etc. in addition to the aforementioned desirable characteristics. These requirements are critical to the signal integrity, such as specified in UWB standard. However, most of broadband antennas are not capable of maintaining conformal characteristics due to different radiating areas, generation of harmonics etc. which alter antenna characteristics, such as radiation pattern, drastically and subsequently limit the bandwidth that the antennas can perform. Recently, we have developed a new approach to design fractal antennas based on Herman Rings [6,7 and 8]. Herman Rings are characterized by fractal internal and external contours. This approach is based on the methodologies used in the area of dynamic systems in conjunction with fractal geometry as described in [9], [10], and [11]. In this paper, we further explore this new approach and examine antenna efficiency, directivity, gain, radiation pattern of such antennas. We study the features based on the comparison of antennas at different order of iterations.