Зуб, С.В.

Телешун, Д.Ю.

Слюсарь, І.І.

Variants of models of quasi-fractal ring structures are considered in the work. For their synthesis a vector description of the fractal transformation of individual segments of the initial geometric shape is proposed. The combination of the decomposition of the geometric shape and multidimensional fractal approach allows to simplify the synthesis of fractal 3D structures and/or to use several types of fractals, including with a different number of iterations. This approach allows achieving broadband and multi-band antenna systems. The influence of the segmentation level and the power scheme on the spatial-frequency characteristics of the antenna was investigated. Due to the complexity of describing the interaction radio waves with antennas of non-Euclidean geometry for their synthesis and analysis taken methods of numerical simulation. A number of assumptions are introduced. Evaluation and comparison of antennas held by the following spatial and frequency characteristics: amplitude-frequency response, beam pattern and voltage standing wave ratio (VSWR). To estimate the bandwidth was used the definition of the band by the criterion of return loss less than -10 dB and (VSWR) ≤ 2. The «fractional bandwidth» parameter was used to compare antennas with different bandwidth limits. The search for the optimal power supply scheme was carried out on the basis of the choice of the port location of the antenna power supply circuit, as well as the aperture of the «opening» of the outer ring. The most successful arrangements are based on an even number of segments, for example, 24 segments with an angular size of 15 deg. In addition, the paper considers several variants of the model of 2-rings quasi-fractal vibrators. One group is synthesized by fractal transformation of the tangential component of the outer perimeter of the quasi-fractal ring in a checkerboard pattern, and the other, respectively, by the inner perimeter of the outer ring. To maximize the potential of the synthesized configurations of the antenna components, options based on the implementation of the «monolithic» structure of the inner ring are proposed. In general, the transition from single-ring to 2-rings vibrator geometry has significantly reduced the lower bandwidth bound. The most successful models provide broadband at the level of δf = 0.9 and the minimum return loss at the level of -40 dB. The obtained estimates of fractional bandwidth indicate the prospects of the proposed approach for the implementation of antenna systems with a high level of broadband.

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