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

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 Multiple-Pattern Planar Antenna Arrays with Single Prefixed or Jointly Optimized Amplitude Distributions

This is the peer reviewed version of the following article:Brégains, J. C.; Trastoy, A.; Ares Pena, F. J.; Moreno Piquero, E. "Synthesis of multiple-pattern planar antenna arrays with single prefixed or jointly optimized amplitude distributions", Microwave and Optical Technology Letters, 74 - 78 Volume: 32, Issue: 1 , 5 Jan. 2002, which has been published in final form at DOI: 10.1002/mop.10094. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."[Abstract] Previous work on the generation of multiple radiation patterns by a single linear array antenna with an unchanging excitation amplitude distribution is generalized to planar arrays. The amplitude distribution common to all of the excitation distributions can be prefixed or optimized jointly with the phase distributions

Application of Time Modulation in the Synthesis of Sum and Difference Patterns by Using Linear Arrays

"This is the peer reviewed version of the following article: Fondevila, J.; Brégains, Julio Claudio; Ares Pena, F. J.; Moreno Piquero, E. "Application of time modulation in the synthesis of sum and difference patterns by using linear arrays", Microwave and Optical Technology Letters, 829–832 Volume: 48, Issue: 5, May. 2006, which has been published in final form at DOI 10.1002/mop.21489. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."[Abstract] In this paper, time modulation is applied to a small number of elements of a linear array that radiates either sum or difference patterns, in order to take control over their sidelobe levels. The simulated annealing (SA) technique helps to obtain the optimum time pulses applied to such elements in terms of sideband minimization

Geoquímica del W en el área circundante al yacimiento de cheelita de Barruecopardo (Salamanca)

La microclinización, proceso ácido débil, implica una corrosión de plagioclasas y una transformación biotita-clorita, con paso del W de dicha biotita a la fase volátil, bajo forma compleja. El descenso de presión en las fisuras (filones) hace precipitar a los wolframatos. Este mecanismo explica el empobrecimiento en W en las inmediaciones del yacimiento, y justifica una explicación geoquímica y mineralógica expuesta precedentemente

Optimizing Uniformly Excited Linear Arrays through Time Modulation

[Abstract] The letter shows that, by the proper use of time modulation in equispaced linear arrays with uniform excitation distribution, it is possible to maintain the sidelobe zone of the radiated power below a certain - previously stipulated - level, whereas the undesired harmonics are minimized. In addition to that, the further extension of the technique to non-equispaced arrays permits a broadband response to be obtained, by simply searching the positions of the elements that reach the desired power pattern behavior within the required bandwidth

On the Multiplicity of Solutions of Taylor Linear Sources Generating Symmetrical Power Patterns with Filled Nulls

[Abstract] As expressed in earlier works, if filled nulls are required in a power pattern generated by a Taylor line source, their corresponding roots must be complex. This leads to a multiplicity of solutions emerged from the fact that the power pattern keeps unaltered if the signs of the imaginary part of the roots are changed. In view of this attribute, the selection of the most favorable roots set, in terms of variability of amplitude excitation distribution, for example, is allowed. It is shown in this paper that, if the pattern is symmetric, a further consideration, never reported so far, can increase the number of available solutions

Optimal Synthesis Of Circular Apertures Based On Ludwig Distributions

This is an Accepted Manuscript of an article published by Taylor & Francis in Electromagnetics on January of 2003, available online: http://www.tandfonline.com/10.1080/02726340390159414[Abstract] Ludwig distributions are a generalization of circular Taylor distributions that generate radiation patterns with wide-angle side lobe levels decaying faster than for Taylor patterns. In this paper we show that by means of an appropriate optimization technique the zeros of Ludwig patterns can be perturbed so as to improve or modify pattern and/or aperture distribution characteristics without altering the wide-angle decay behavior. The examples presented include footprint patterns, pencil beam patterns with individually controlled side lobe heights, footprint beams generated by real excitations, and pencil beam patterns with aperture distributions that are smoother than the original Ludwig distribution

Calculating Directivities with the 2D Simpson's Rule

[Abstract] C++ routines implementing the simple generalization of Simpson's rule to two dimensions for calculating antenna directivities compare well with methods currently available in common symbolic and numerical calculation packages