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

Método para determinação de resíduos de clorpirifos em alface por cromatografia a líquido de alta eficiência.

Este trabalho propõe método de análise de resíduos de Clorpirifós em amostras de alface por cromatografia a líquido de alta eficiência (CLAE). A análise foi realizada em cromatógrafo Shimadzu, com detector de ultravioleta ajustado em 229 nm, Coluna C-18, modelo Zorbax ODS (4,6 mm x 25 cm, 5 um), fluxo de 1 mL/min e temperatura de 35°C. Usou-se Metanol:Água (82: 18) como fase móvel e volume injetado de 50 UL. Amostras de alface (20 g) foram trituradas e homogeneizadas na presença de 50 mL de Diclorometano (DCM). O material foi filtrado a vácuo e evaporado a temperatura de 50°C. O resíduo foi retomado com fase móvel, agitado, desgaseificado, filtrado em membrana 0,22 Um e injetado no cromatógrafo (injetor automático). Os resultados do teste de repetitividade mostraram recuperação média de 101,91 %. O método proposto é simples e rápido para determinação de resíduos de Clorpirifós em amostras de alface

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

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