ACES Software Section



Interactive Visualization of Two and Three Dimensional Antenna Patterns Using Personal Computers

Atef Z. Elsherbeni, Clayborne D. Taylor Jr.

An interactive antenna pattern visualization package "APV" is developed to generate and display the far field patterns of different antennas and antenna arrays. The patterns are displayed in two or three dimensions depending on the antenna type or geometry. The three dimensional representation is based on the spherical coordinate system, where the radial coordinate (which is proportional to the amplitude of the pattern) is plotted as a function of the two angular coordinates. The two dimensional representation allows linear and polar formats with linear or dB scales. In the three dimensional representation, the user can view the entire radiation pattern (or array factor pattern) or one of the x-y, x-z, or y-z plane cuts one at a time. Changing the viewing angle is also allowed for a complete visualization. The user selects the antenna type and parameters through a user-friendly interface. Default values are initially presented to help the user decide on different antenna parameters. This version of the software provides visual analysis for the radiation fields from thin wire dipole antennas, circular loops, and infinite and finite corner reflector antennas. In addition to standard antenna geometries, the software permits one to visualize in an interactive procedure, the array factors of different types of antenna arrays. Among those arrays are the linear uniform and non-uniform arrays, Binomial arrays, Dolph-Tschebyscheff linear arrays, rectangular and circular two dimensional arrays, and cubic and spherical three dimensional arrays.

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Analysis of Antenna Arrays Using Personal Computers

Atef Z. Elsherbeni, Patrick H. Ginn

An antenna array is a group of antennas arranged in such a way to produce a radiated field with specific radiation characteristics that cannot be achieved by a single antenna. There are several configurations used for grouping individual antennas into arrays. The most common array configurations are linear (uniform, nonuniform, binomial, etc.), two-dimensional (circular, rectangular, etc.), and three-dimensional (cubic, spherical, etc.). Different aspects of the analysis of antenna arrays have been dealt with in several text books. Computer aided instructions are also available for selected types of arrays. The objective of this software package is to provide a comprehensive coverage for the analysis of antenna arrays that can be used for undergraduate education. The "ARRAYS" (version 2) software package is designed to help students understand, in an interactive and visual procedure, the analysis of many types of antenna arrays using the principle of pattern multiplication. Furthermore, this software provides a visual response, almost immediately, of the effects of changing any of the antenna parameters on its radiation pattern. This feature is important in familiarizing students with the elementary patterns of different types of antennas before using them in an array. Version 2 of "ARRAYS" is developed as an upgrade of the first version of "ARRAYS". The most important features of this upgrade are: menu windows that can be controlled with a mouse or keyboard cursor keys; multiple planes for calculating and observing the radiation patterns (the user can now choose three planes of observation which can be toggled during the viewing screens); single item editing, (the user can edit a single piece of data instead of re-inputting the entire list of data); the ability to save the computed radiation patterns for future display and analysis, user-defined data for element patterns and pattern scanning for specific levels by two distinct pointers.

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Electromagnetic Fields Inside Waveguides And Cavities

Atef Z. Elsherbeni, Clayborne D. Taylor Jr.

The waveguide and cavity program WGC has been developed to provide interactive procedure for visualizing the electromagnetic fields inside cylindrical waveguides and cavities using a personal computer. It is an upgrade of the software WGVMAP which computes and displays the field lines inside waveguides in a plane transverse to the propagating wave. In WGC, both transverse and longitudinal field components are presented graphically, using colors and vectors instead of field lines. The field vector representation is based on the technique presented in [2]. With WGC the user can observe the effect of changing any of the physical or electrical parameters on the resulting electric and magnetic field distribution in any specified plane cut. Additionally, WGC can be used to create movie segments or animation of the field patterns inside cavities and waveguides using an appropriate sequencing of computed field values. The mathematical expressions of the field components are derived from the classical solution of the wave equation using the separation of variables technique. The executable code of the software is available for the IBM-PC computer family, or compatible. A VGA monitor, mouse, and postscript printer are required. The waveguide and cavity program WGC has been developed to provide interactive procedure for visualizing the electromagnetic fields inside cylindrical waveguides and cavities using a personal computer. It is an upgrade of the software WGVMAP which computes and displays the field lines inside waveguides in a plane transverse to the propagating wave. In WGC, both transverse and longitudinal field components are presented graphically, using colors and vectors instead of field lines. The field vector representation is based on the technique presented in [2]. With WGC the user can observe the effect of changing any of the physical or electrical parameters on the resulting electric and magnetic field distribution in any specified plane cut. Additionally, WGC can be used to create movie segments or animation of the field patterns inside cavities and waveguides using an appropriate sequencing of computed field values. The mathematical expressions of the field components are derived from the classical solution of the wave equation using the separation of variables technique. The executable code of the software is available for the IBM-PC computer family, or compatible. A VGA monitor, mouse, and postscript printer are required.

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PSvec - A utility program to generate a postscript file showing vector fields.

Alon S. Barlevy, Atef Z. Elsherbeni, and Yahya Rahmat-Samii

Description: This utility is developed to create postscript files showing vector field distributions in any desired plane cut (x-y, y-z, or x-z plane cuts) in a finite difference time domain (FDTD) algorithm. This utility is not a stand alone program, but a collection of subroutines developed using FORTRAN 77. The output of these subroutines is a postscript file. The postscript files can be viewed using Ghostview or printed to a postscript printer. This routine was tested on IBM RISC 6000 workstations and on PC's running Windows 95 operating system. The user defines the dimensions for the plot, and the program automatically scales the plot to the defined dimensions. The program also automatically chooses a scale for the vectors, such that the largest arrow size does not touch the next vector (provided that two consecutive vectors do not point in opposite directions). The length of the vector is proportional to the amplitude of the field value. By calling this routine repeatedly, different plots can be put on the same page, or on different pages. When there are different plots (in the same postscript file) an option is given whether to rescale the vector plots to one uniform scale, or have a different scale for each plot. The advantage of having different scales is to allow one to see features that might not otherwise be observable. Limitations and approximations: There are no approximation in this code, since this code is only designed to display data, not calculate data. One major limitation is that the vector field is only plotted for the components of the vector in the plane of the cut. For example, if the desired plane cut is a x-y cut, then the output will only show the x and y components of the chosen electric (magnetic) vector field for a desired value of z and time. The z-component of the vector field will not be displayed.

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2D Finite Difference Time Domain Visualization

Allen W. Glisson, Atef Z. Elsherbeni

The 2D Finite Difference Time Domain code "tmpml" animates time domain scattering by a material geometry excited by a z-directed electric current line source. A fairly general scattering geometry can be described by defining various regios with difference isotropic constitutive parameters. The program cannot model anisotropic materials in its current form. The perfectly matched layer (PML) absorbing boundry condition is applied at the computational boundaries.

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1D Matlab Finite Difference Time Domain Code

Allen W. Glisson, Atef Z. Elsherbeni

The 1D Matlab Finite Difference Time Domain code animates time domain reflection and transmission of a plane wave through one or two homogeneous material slabs.

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Q Factor Measurement with Network Analyzer

Darko Kajfez

QDEMOW is a limited version of the program Qzero for Windows. The program is a tool to assist an experimentalist in the reflection-type measurement of the unloaded Q factor of a microwave or rf resonator. The input data file should contain the S11 values in the vicinity of the resonant frequency, preferably written in Touchstone S-parameter format.

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POFACETS: Matlab Physical Optics RCS Prediction Code (GUI Based)

Elmo E. Garrido, Jr. and David C. Jenn

POFACETS is an implementation of the physical optics approximation for predicting the radar cross section (RCS) of complex objects. It provides a convenient tool for a "first cut" at the RCS of complex shapes by representing its constituent parts by triangular facets. The software calculates the monostatic or bistatic RCS of the object for the parameters specified by the user and displays plots for the model geometry and its RCS.

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POFACETS: Matlab Physical Optics RCS Prediction Code (Non GUI Based)

Elmo E. Garrido, Jr. and David C. Jenn

POFACETS is an implementation of the physical optics approximation for predicting the radar cross section (RCS) of complex objects. It provides a convenient tool for a "first cut" at the RCS of complex shapes by representing its constituent parts by triangular facets. The software calculates the monostatic or bistatic RCS of the object for the parameters specified by the user and displays plots for the model geometry and its RCS.

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Propagation of an Elliptically Polarized Wave

Mark D. Tew

A graphical interface to visualize the propagation of a general elliptically polarized plane wave.

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A Graphical User Interface (GUI) for Plane Wave Scattering from a Conducting, Dielectric or a Chiral Sphere

Veysel Demir, Atef Elsherbeni, Denchai Worasawate and Ercument Arvas

A software package is developed and presented to calculate plane wave scattering from a chiral sphere. The package involves a user-friendly GUI, which enables the user to enter the scattering parameters and observe the results, in near real time, and save the calculated data and displayed figures. As will be discussed in the following sections, due to the nature of the chiral constitutive relations, the developed program can be used to calculate scattering from a dielectric or a perfectly conducting sphere as well.

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A Graphical User Interface for Calculation of Reflection and Transmission Coefficients of a Layered Medium

Veysel Demir and Atef Z. Elsherbeni

A graphical user interface (GUI) is developed using Matlab and Fortran in order to calculate reflection and transmission coefficients of a layered medium, and optimize reflection and transmission in given ranges of parameters. Reflection and transmission of electromagnetic waves by a layered medium is in the scope of undergraduate/introductory graduate level electromagnetics courses and has well-known straightforward solutions. The main emphasis of this package is to let students learn how the optimization for a problem, commonly taught at the undergraduate level, can lead to useful applications and that various applications can also be attempted and fostered using the knowledge they gained through their education. A graphical interface is then necessary to allow ease of use for applications without a need for re-programming or teaching optimization at this early stage of teaching. The developed program provides an easy to use interface to define and visualize the geometry of the problem, and display the solutions for reflection and transmission coefficients, as well as the field distributions in the medium. Furthermore, another module of the program helps the user define parameters to sweep and optimizes reflection or transmission for a given target value within the given ranges of sweeping parameters. In this contribution, algorithms to calculate fields in a layered medium due to normally incident plane waves have been described and a software package that is developed based on these algorithms has been demonstrated.

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Pic2Mag Ace Version - You draw virtual magnets and Pic2Mag draws the fields! (tm)

Michael Snyder

Pic2Mag Ace version is a small lightweight application that allows you to analyze interactions between multiple magnetic fields using a 640x640 PNG image file that depicts their layout. Designed to be used as a preliminary program that your students can use to test hundreds of permanent magnet ideas, and see their what if scenarios; before using a professional program like Comsol(tm) or Ansys(tm) for a detailed analysis. The program uses colors in a graphics file to represent magnetic materials with different magnetic moments.(tm) The program looks for certain RGB pixel values in the png file and when it finds an exact match the program plots that magnetic pixel as a 1mm x 1mm x 1mm permanent magnet with a defined magnetic moment angle. The special Pic2Mag Ace version has all the features of the paid Pic2Mag Pro version with the resolution of the Pic2Mag freeware version. This hybridization makes the Pic2Mag Ace version the fastest Pic2Mag program written to date, and most images take less than 30 seconds to process.

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