Browsing GI-GTEC - Artigos by Issue Date
Now showing items 1-20 of 117
-
Optimal Synthesis of Line Source Antennas Based On Rhodes Distributions
(Taylor & Francis, 2002)[Abstract] In this paper we show that by means of an appropriate optimization technique the zeros of Rhodes radiation patterns can be perturbed so as to improve or modify pattern and/or the aperture distribution characteristics ... -
Synthesis of Multiple-Pattern Planar Antenna Arrays with Single Prefixed or Jointly Optimized Amplitude Distributions
(John Wiley & Sons, Inc., 2002-01-05)[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 ... -
Near-Field Quasi-Null Control with Far-Field Sidelobe Level Maintenance in Line Source Distributions
(The Institution of Engineering and Technology, 2002-06-06)[Abstract] An improving method, based on the Taylor line source, that allocates a quasi-null in a specified angular position of near-field pattern, and simultaneously controls the general topography of the far-field sidelobe ... -
Avoiding Interference in Planar Arrays through the Use of Artificial Neural Networks
(Institute of Electrical and Electronics Engineers, 2002-08)[Abstract] This article implements an artificial neural network to find, through computer simulation, the excitations of a square planar array. The array is composed of 52 uniformly spaced subarrays, and has a quasi- in ... -
Variation in The Bandwidths of Pattern-Quality Parameters and Maximum Embedded Impedance among the Solutions to Shaped-Beam Synthesis Problems for Collinear Dipole Arrays
(Institute of Electrical and Electronics Engineers, 2003)[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 ... -
Near Field Quasi-Null Control with Far Field Sidelobe Level Maintenance in Line Source Difference Patterns
(Taylor & Francis, 2003)[Abstract] A previously developed method to place a quasi-null in a specified angular position of the near-field line source in sum patterns while, simultaneously, the far-field sidelobe level is maintained under a desired ... -
Optimal Synthesis Of Circular Apertures Based On Ludwig Distributions
(Taylor & Francis, 2003-01)[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 ... -
Effects of Measurement Distance on Measurements of Symmetrically Shaped Patterns Generated by Line Sources
(Institute of Electrical and Electronics Engineers, 2003-02)[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 ... -
Synthesis of Multi-Radial Line Antenna for HIPERLAN
(The Institution of Engineering and Technology, 2003-08)[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. -
Measurement Effects on Ø-Symmetric Shaped Patterns Generated by Circular Continuous Apertures
(Institute of Electrical and Electronics Engineers, 2003-10)[Abstract] Sidelobe-level and ripple behaviors of Ø-symmetric shaped patterns, generated by circular, real and complex, continuous Taylor distributions, is analyzed as a function of measurement distances. This paper reveals ... -
Visualizing the 3D Polar Power Patterns and Excitations of Planar Arrays with Matlab
(Institute of Electrical and Electronics Engineers, 2004-04)[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 ... -
Calculating Directivities with the Two-Dimensional Simpson's Rule
(Institute of Electrical and Electronics Engineers, 2004-08)[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 ... -
Optimizing Uniformly Excited Linear Arrays through Time Modulation
(Institute of Electrical and Electronics Engineers, 2004-12)[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 - ... -
Perturbation of the Phases of Taylor Field Samples in the Synthesis of Linear and Circular Array Antennas
(Institute of Electrical and Electronics Engineers, 2004-12)[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. -
On the Multiplicity of Solutions of Taylor Linear Sources Generating Symmetrical Power Patterns with Filled Nulls
(Institute of Electrical and Electronics Engineers, 2004-12)[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 ... -
Variation in Bandwidths Among Solutions to Shaped Beam Synthesis Problems Concerning Linear Arrays of Parallel Dipoles
(Institute of Electrical and Electronics Engineers, 2005-01)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 ... -
Matrix Pseudo-Inversion Technique for Diagnostics of Planar Arrays
(The Institution of Engineering and Technology, 2005-01-06)[Abstract] It is shown, by means of numerical simulation, that the Moore-Penrose pseudoinverse of a matrix taken from an overdetermined system can be applied to retrieve the excitation distribution of a planar array of ... -
A Comparison of Optimization Techniques for Power Patterns with Low Sidelobes Generated by Linear Arrays with Efficient Excitation Distributions
(John Wiley & Sons, Inc., 2005-04-05)[Abstract] Equispaced linear arrays that have uniformly excited central elements and monotonically decreasing flanking segments have been shown to yield low-sidelobe patterns with specified constraints on the effective ... -
Utilization of Blind Source Separation Algorithms for MIMO Linear Precoding
(Springer, 2006)[Abstract] In this paper we investigate the application of Blind Source Separation (BSS) algorithms for the decoding of linearly precoded MIMO communication systems and for the design of limited feedback channels that send ... -
Beam Reconfiguration of Linear Arrays Using Parasitic Elements
(The Institution of Engineering and Technology, 2006-02-13)[Abstrac] An innovative method for linear arrays beam reconfiguration is presented. This pattern reconfigurability is achieved by a mechanical displacement of a parasitic array located in front of an active one. Two worked ...
