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A general approach for the synthesis of the optimal sequential network for use in sequentially rotated antenna (SRA) arrays with an arbitrary number of elements is presented. The performance of this class of antennas are strictly bound to the capacity of the feeding network to produce the nominal power distribution and phase progression. Despite the very high interest in the scientific community on SRA architectures, very few papers have addressed the problem of synthesizing a generic network, with an arbitrary number of outputs. In this paper we propose a novel approach based on closed formulas which solves the synthesis problem exactly, for a given frequency. The proposed approach is then validated with a set of simulations and with the fabrication and measurement of a prototype. Both the simulations and the experimental validation confirms the effectiveness of the proposed method. [ABSTRACT FROM AUTHOR]

ABSTRACT A pentagonal circular polarized subarray composed of five elements is proposed for operation at 2.45 GHz. The array is based on the sequential rotation architecture (SRA), implemented with a sequential phase distribution network. Despite a more complex design in comparison to the canonical 4-elements SRA, a pentagonal subarray is more suited to be packed in a Bucky-ball or icosahedral arrangement, ideal for smart antennas with wide angle spatial coverage. A single-layer via-less prototype is fabricated on a common FR4 substrate. Measurements show a realized gain of 6.15 dBi with a polarization purity exceeding 20 dB at 2.45 GHz. © 2017 Wiley Periodicals, Inc. Microwave Opt Technol Lett 59:1077-1081, 2017 [ABSTRACT FROM AUTHOR]

Taguchi's method is a quality design technique whose applications in numerical single-objective optimization have been recently exploited. In this article, a novel multi-objective (MO) algorithm based on Taguchi's technique is illustrated and its performances assessed. Validation is performed through a comparison between the presented algorithm and a MO genetic algorithm (GA) based optimization, first on different sets of test functions and then on a practical antenna array synthesis problem. Results indicate a generally better behavior of the proposed algorithm in terms of convergence and spreading over the Pareto front with respect to the GA benchmark. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2013. [ABSTRACT FROM AUTHOR]

In this paper an antenna array operating in circular polarization in the C-band is presented. The array is based on the sequential rotation architecture, applied to six elements, and arranged in hexagonal shape. Thanks to its geometry, the array is suitable for tiling of surfaces as well as for regular solid arrangement. Satisfying experimental validation of a prototype based on the proposed design is observed, with a peak gain of 10.4 dB at 5.8 GHz maintained within 3 dB over a 500 MHz band, a 10 dB return loss bandwidth of 500 MHz, and a 3dB axial ratio bandwidth of almost 400 MHz, meaning 6.5% of fractional bandwidth. [ABSTRACT FROM AUTHOR]

A multisegment artificial neural network (ANN) is proposed as an interpolation technique for the evaluation of the electromagnetic field diffracted at the edge of anisotropic impedance wedges under plane wave illumination at oblique incidence. Multisegmentation is needed as the high-frequency wedge diffracted field is characterized by a number of discontinuities at the shadow boundaries of the geometrical optics and surface wave fields. The proposed approach is applied, as a test case, to the problem of an anisotropic impedance right-angled wedge illuminated by a skewly incident plane wave. Some exact analytical solutions valid for specific surface impedance tensors are used to obtain numerical data for the ANN training phase as well as to show the interpolation capabilities of the implemented ANN. Nevertheless, the proposed ANN structure is general and can be trained with data obtained from other available solutions (analytical, perturbative, numerical) valid for more general wedge configurations, eventually leading to a single software tool encompassing all of them and providing accurate approximations of the wedge diffracted field in a relatively short time, comparable to that of a closed form analytical solution. [ABSTRACT FROM AUTHOR]

This paper deals with many different neural network architectures that have been introduced to simulate the electromagnetic behavior of complex microwave devices and antennas. Many issues linked to the peculiarities of such devices are addressed. Furthermore, the inverse problem of designing a microwave device, once the required characteristics are given, is also developed by using a neural network approach. © 2002 John Wiley & Sons, Inc. Int J RF and Microwave CAE 12: 90–97, 2002. [ABSTRACT FROM AUTHOR]

This paper describes a new method to analyze elliptical horns. The method is based on a coordinate transformation, which maps the elliptical shape to a circular shape, allowing to use the 2.5-D body-of-revolution finite-element method formulation with a greatly improved efficiency over 3-D methods. Applications are shown to the analysis and design of shaped arbitrary axial ratio horns. [ABSTRACT FROM AUTHOR]

High efficiency, compactness, light weight and low return loss are of high importance in antennas, especially in space applications. In this contribution a modified nondominated sorting genetic algorithm (NSGA-II) is applied to the design of Horn antennas for discrete lens applications to achieve a Pareto-optimal solution. Horn design is aimed not only towards higher possible efficiency but also towards large band and compactness. © 2011 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2011. [ABSTRACT FROM AUTHOR]