Fractal design of multiband and low side-lobe arrays

Abstract

Abstract-Most array factor design techniques are highly dependent on the operating wavelength. In this paper, a novel technique based on fractal structures is described for multiband operation. The analysis is focused in two different approaches: the fractal spatial arrangement of array elements and the fractal design of array factors. Although the patterns of fractal arrays show some interesting similarity properties at several bands, the directivity is not held constant through the bands. Nevertheless, such structures have been shown to be useful for designing low side-lobe arrays with equally weighted current elements. On the other hand, the fractal array factors presented do keep the same shape at several bands because they are designed as selfsimilar curves. The arrays that would synthesize such patterns present a characteristic power-law current distribution analogous to the spectral distribution of the bandlimited fractal Weierstrass function.

Enabling and Exploiting Self-Similar Central Symmetry Formations

“…The key point in the exploitation of formation flying techniques for the deployment of an antenna array is that the performance of a homogeneous pattern of array elements can be matched or surpassed by fractal geometries as per [15] and [16]. Fractal geometries as defined by [15] can be considered self-similar structures propagated from a core initiator through a number of stages of growth by an identical generator.…”

“…From the array point of view, self-similarity and sparseness lead to a number of benefits -similar performance in operation across a number of frequencies becomes possible due to the repetitive nature of the array pattern as per [15] and [16], array performance degrades gracefully with element failure and finally equivalent performance can be achieved for a fraction of the number of elements used in square lattice arranged arrays [20].…”

Analysis of Novel Fractal Optical Antenna Arrays - A Conceptual Approach

“…FRACTAL THEORY is a relatively emerging field of mathematics that has changed the way scientists view of looking at a natural occurring phenomena in this world [1][2][3][4][5][6][7][8][9]. This paper makes an attempt of extending the concept of fractal antenna array to the optical regime for the design of fractal optical antenna arrays.…”

Scattering Behaviour of Fractal Based Metallo-Dielectric Structures

“…Some of the other areas of study include frequency selective surfaces, diffraction by band limited fractal screens, the reflection and transmission properties of fractal multilayers, the side lobe computation of fractal arrays, the scattering of electromagnetic wave from corrugated random surfaces with fractal slopes etc. [6][7][8][9][10].…”