Circularly Polarized Arrays of Sequentially Crossed Dipoles

[Abstract] Usual configurations of dipoles that radiate circularly polarized fields consist of elements arranged in crossed pairs, with one component of each pair in top of the other component. As an alternative to this, in a previous work it was presented an array composed of 4 separate and sequentially rotated dipoles, with uniform and out-of-phase feeding distribution. Here we generalize the concept and analyze the behavior of analogous setups composed of up to 20 elements, showing the variation of copolar/crosspolar gains, and axial ratio, in terms of the array elements number

Variation in Bandwidths Among Solutions to Shaped Beam Synthesis Problems Concerning Linear Arrays of Parallel Dipoles

The problem of synthesizing a linear array generating a shaped beam pattern with M filled s has 2M alternative solutions. In this study we examined their bandwidths as regards compliance with pattern quality or input impedance requirements in the presence and absence of a backing ground plane. Placing a ground plane behind the antenna almost doubles sidelobe level bandwidth

Analysis, Synthesis, and Diagnostics of Antenna Arrays through Complex-Valued Neural Networks

This is the peer reviewed version of the following article: Julio C. Brégains; Francisco Ares "Analysis, synthesis, and diagnostics of antenna arrays through complex-valued neural networks", Microwave and Optical Technology Letters, 1512 - 1515 Volume: 48, Issue: 8, Aug. 2006, which has been published in final form at DOI: 10.1002/mop.21706. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving[Abstract] It is shown in this paper that when artificial neural networks are extended to be complex valued, they can be incorporated as a very powerful and effective tool in the analysis, synthesis, and diagnostics of antenna arrays

A WiMAX Conformal Broad-Beam Antenna

[Abstract] The numerical model of a very simple conformal antenna, prepared to work in the 3.4 to 3.6 GHz WiMAX range, is presented. The pattern radiated by the proposed antenna displays high gain and excellent linear polarization within the broad coverage zone.Xunta de Galicia; 09TIC008105PRXunta de Galicia; 07TIC002206PRMinisterio de Ciencia e Innovación; TEC2007-68020-C04-01Ministerio de Ciencia e Innovación; TEC2008-04485Ministerio de Ciencia e Innovación; CSD2008-00010

Perturbation of the Phases of Taylor Field Samples in the Synthesis of Linear and Circular Array Antennas

[Abstract] Antenna design specifications do not usually restrict the phase of the radiated field. Antenna synthesis techniques generally exploit this freedom only indirectly, but direct phase perturbation can be fruitful

Variation in The Bandwidths of Pattern-Quality Parameters and Maximum Embedded Impedance among the Solutions to Shaped-Beam Synthesis Problems for Collinear Dipole Arrays

[Abstract] We investigated variation in the bandwidths of ripple, sidelobe level, -3 dB beamwidth, and maximum element embedded (active) impedance (|Z/sup e/|/sub max/) among multiple collinear dipole arrays radiating a given flat-topped beam pattern. The main finding was that ripple and sidelobe level bandwidths are much greater than when the dipoles are parallel

Synthesis of Multi-Radial Line Antenna for HIPERLAN

This paper is a postprint of a paper submitted to and accepted for publication in journal Electronics Letters and is subject to Institution of Engineering and Technology Copyright. The copy of record is available at IET Digital Library"[Abstract] We present a new antenna concept - the multi-radial travelling wave line antenna - that achieves a broadband conical radiation pattern suitable for use in multiple C-band wireless computer networks

Visualizing the 3D Polar Power Patterns and Excitations of Planar Arrays with Matlab

[Abstrac] This paper discusses the use of Matlab to create three-dimensional polar plots of the power patterns of planar arrays together with 3D plots of the amplitudes and phases of their excitations. A few lines of Matlab M-code suffice to create complex plots

Effects of Measurement Distance on Measurements of Symmetrically Shaped Patterns Generated by Line Sources

[Abstract] Symmetrically shaped patterns, generated by real continuous linear apertures derived from Taylor distributions, resemble Taylor sum patterns in regard to the distance-dependence of their sidelobe heights. Their ripple shows negligible near-field degradation. If the aperture distribution is complex, however, the ripple and sidelobe levels show previously unreported degradation behavior, including a lowering of the first sidelobe level

On the Feasibility of Time-Modulated Arrays for Digital Linear Modulations: a Theoretical Analysis

[Abstract] Wireless communications are widely based on linear digital modulation methods, which introduce the digital baseband information in the amplitude and/or in the phase of a carrier sinusoid. Time-modulated arrays, on the other hand, constitute an interesting technique capable of adapting the power radiation pattern of an antenna array. In this work, we study from a theoretical point of view the impact of time-modulated arrays on the transmission of linearly modulated digital communication signals. The work focuses on the requirements to safeguard the integrity of the signal and on the quantification of the useful power radiated within the desired band