S.V. Krupenin, V.V. Kolesov, A.A. Potapov, E.N. Matveev
Two types of fractal antennas (regular and irregular) are studied by means of numerical analysis. A novel deterministic irregular fractal structures for antenna design are introduced. Deterministic fractal clusters for antenna design were built within modified numerical aggregation models of two types. The first model was introduced by Thouy and Jullien and represents cluster-cluster aggregation. The second one, also known as DLA model, was introduced by Witten and Sander and represents particle-cluster aggregation. Both aggregation models were modified to obtain reproducible aggregates of the same fractal structure. Such modification implies utilization of chaotic integer algorithm with delay for pseudorandom sequence generation. 2D pseudorandom fractal clusters were built within both modified aggregation models. 3D cluster was built within modified Witten-Sander model. Microstrip and monopole antennas are based on 2D and 3D geometries, respectively. The multifrequency and wideband behavior of irregular fractal antennas is described. The behavior of the microstrip irregular fractal antennas is studied under excitation point displacement. Such reconfiguration is shown to control spatial-frequency antenna characteristics. Excitation point displacements allow to allocate frequency bands and/or vary radiation pattern of the irregular fractal antennas.
The multiband behavior of regular fractal antennas based on Sierpinski gasket and Cayley tree is described. Resonant features of Sierpinski monopole antenna are studied under variations of the flare angle of Sierpinski gasket.
Keywords: antennas, fractal antennas, fractal clusters, multifrequency antennas, wideband antennas, reconfigurable antennas.