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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]

A single-layer via-less rectangular patch antenna for automotive applications in C-band is proposed. To match the needs of a vehicular dedicated short range communication protocol, the resonant edge of the antenna is enlarged to narrow the beamwidth in the H-plane, while at the same time a pair of thin slots serve as inhibitors for the higher modes, permitting adequate matching and polarization purity. The proposed single patch antenna presents a realized gain about 6.85 dB, H-plane beamwidth narrower than ±32°, E-plane beamwidth larger than ±45.5°, and return loss exceeding 20 dB with a 3 dB bandwidth of 500 MHz, with a minimum at 5810 MHz, hence suitable for coexistence of different communication standard in the C-band. Furthermore, its compact dimension permits the direct integration within a radio front-end. [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]

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]

This paper describes the design and experimental characterization of a circular polarized printed antenna for dual-band WiFi operation at 2.45 GHz and 5.10 GHz. The patch design is based on a combination of slits loading and gap-coupling applied to a disc patch in order to enhance the radiation performances in terms of polarization purity and bandwidth at the two operation frequencies. Experimental validations confirm a maximum gain around 6.0 dB for both 2.45and 5.10 GHz, as well as an axial ratio as low as 0.5 dB and a return loss exceeding 15 dB on the operating frequencies. These characteristics are suitable for operationing in IEEE802.11x networks. [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]

This short contribution presents a selected, annotated bibliography in asbtract form, limited to books, book chapters, and special issues of international journals, devoted to high-frequency techniques for antenna and scattering problems as well as to related topics such as integral evaluation, advanced boundary conditions, and so on. This bibliography - which, of course, is our personal selection - may be of use for the interested reader who wishes to go into details in the high-frequency electromagnetics field beyond the contents of this special section which, albeit of very high quality, is nevertheless limited due to the Magazine's page constraints. Most of the reference given are in English, and most were published in Europe or America, so they should be easily accessible to readers of this Magazine. The list cannot of course cover the whole spectrum of books and journals devoted to high-frequency techniques, but surely encompasses the most relevant references. [ABSTRACT FROM AUTHOR]

State-of-the-art radomes exploit frequency selective media so as to be transparent for the frequencies of the antenna protected by them and opaque to other frequencies. This feature helps in reducing the radar cross section of the antenna and in protecting it from interference. The study of a frequency selective radome is a daunting task, since the radome is usually large in terms of wavelengths, hence full wave analyses are prohibitive. In this paper an approximate technique, based on the physical optics concept, is proposed to attain an estimation of the behavior of a radome shielded antenna in a short time with a commonly available computer. Results are validated against a full wave technique over a relatively small radome. [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]

Efficient and accurate modeling of electromagnetic structures is valuable in antenna analysis and design, and time domain solutions are at a premium over frequency domain in the case of ultra wide band signals or transients. Among the full wave electromagnetic methods in time domain the method of moments in time domain (MoM-TD) is very interesting. Such a method can be implemented, as for frequency domain, either resorting to a thin wire approximation or to a surface patch model. Depending on the structure to be analyzed one or the other is most convenient. For heterogeneous structures both implementations might be needed, and the problem of the attachment between a perfectly conducting thin wire and a perfectly conducting surface is hence relevant. In this paper, attachment modes are introduced in MoM-TD. The solution is validated on a test case and against another numerical technique. [ABSTRACT FROM AUTHOR]

Three ground-backed compact strip-and slot-sinuous antennas are analyzed. Proposed configuration allows for a single lobe, polarization-versatile, high efficiency, and ultrawide band antenna not needing a cumbersome lossy back cavity typical of conventional single-lobe sinuous antennas. Simulations show attained performances as well as tuning possibilities. [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]

A slot-coupled rectangular dielectric resonator antenna (DRA) operating in the 14-14.5GHz frequency band is investigated as a possible radiating element for an active integrated antenna of a transmitting phased array. The effectiveness of the resonator shape factor on achieving harmonic tuning is addressed. Simulation results show that the DRA shape factor can be used to provide a fine tuning of the DRA input impedance both at the fundamental frequency and its first harmonics, so synthesizing the proper load for the optimization of the microwave amplifier power-added efficiency (PAE). [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 is the second part of a special section of the IEEE Antennas and Propagation Magazine that - as stated in the title - was conceived to celebrate 50 years since the publications of two fundamental scientific works: the paper by J. B. Keller, ?Geometrical Theory of Diffraction,? Journal of the Optical Society of America, 52, 1962, pp. 116?130; and the book by P. Ya. Ufimtsev, Method of Edge Waves in the Physical Theory of Diffraction, Moscow, Soviet Radio, 1962 (in Russian). [ABSTRACT FROM AUTHOR]

In two recent issues of the Antennas and Propagation Magazine (specifically, Volume 55, No. 3, June 2013, and Volume 55, No. 4, August 2013), the history of diffraction and the associated chief contributors/scholars to same were impeccably presented. [ABSTRACT FROM AUTHOR]

A foreword to the Historical Corner of "IEEE Antennas and Propagation Magazine" is presented.

This issue of the historical corner hosts a paper by Carl-Henrik Walde, Secretary of the Swedish URSI Committee. It describes a special session about ?The History of Antennas in Sweden,? which took place on April 11, 2013, within the EuCAP conference in G?teborg, Sweden (Figure 1). EuCAP is the European Conference on Antennas and Propagation, created and organized yearly by EurAAP (European Association on Antennas and Propagation). It was held for the fi rst time in November 2006 in Nice by regrouping the former JINA (Journ?es Internationales de Nice surles Antennes) and ICAP (International Conference on Antennas and Propagation) conferences, two European Space Agency (ESA) Workshops on Satellite Antennas and Propagation, and the final Workshop of the EC-COST Action 284 on Antennas, in the spirit of AP2000. [ABSTRACT FROM AUTHOR]

A foreword from the associate director of "IEEE Antennas & Propagation Magazine" for the journal's October 2011 issue is presented.