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CELIA is an acronym of Computational ELectromagnetic Interaction Analysis software. Celia is an integrated EM analysis package based on the Yee finite difference time domain (FDTD) method.
The FDTD method has achieved unrivalled popularity amongst conventional computational electromagnetic techniques as a result of its ability deal with the complexities of practical electromagnetic engineering problems. A wealth of background knowledge and methods has been developed over the last two decades on the use and extension of the basic Yee numerical scheme to tackle a wide diversity of applications.
The benefit of the method is its simplicity. FDTD is a spatial discretisation method that solves Maxwell's equations in the local volume of the discrete elements. In this way complex material characteristics such as anisotropy, non-linearity and frequency dependence, for example, can be considered simply by incorporating the properties at the microscopic level. Macroscopic considerations such as geometric complexity and material heterogeneity are then dealt with trivially by ensuring sufficient resolution within the domain of interest.
A further advantage of the method is that it is a time domain technique as opposed to a frequency domain technique. In many applications this is advantageous as modern systems generally utilise wide bandwidth waveforms that are more efficiently computed in time.
Celia comprises a fully integrated environment for defining, solving and post-processing electromagnetic analysis problems. The package is presented within a Microsoft Windows graphical user interface or GUI. The GUI is written in Microsoft Visual C++ and will run on all 32-bit Windows operating systems (95,98,NT and 2000). The solver is written in ANSI standard Fortran 90 and is portable to any platform with a FORTRAN compiler.
The software is built in modular fashion for ease of use and provides five tools within the GUI to enable the specification and solution of an extensive range of electromagnetic problems. (see applications page for examples)
The Celia GUI is a Microsoft Windows platform graphical user interface to the Celia FDTD solver. It will run on all 32-bit Windows operating systems (95,98,NT and 2000). The GUI provides five tools, as follows:
Each tool is used from a top-level project management environment that allows control of each modelling job through an Explorer style interface.
project management
interface Project files are maintained in separate project directories, the interface providing access to a single project at any one time. The screen layout contains drop down menus, toolbars and three windows. Provided in the interface are a project file browser and a text file edit/display window for managing, viewing and editing project files directly. The toolbar/menu provides access to the each of the tools used to specify the necessary elements of the model.
The material manager is a database management tool that allows the specification of materials and their properties. This database is global and all materials within the database are available from the geometry editor for constructing solids.
The solver input dialog is a tabbed style dialog that guides the user in the input of all necessary data such as mesh size, boundary conditions, source function etc. A text input file is the single repository of all solver data. This data can be accessed through the dialog, or via text editor for proficient users.
The geometry editor is a CAD style tool for specifying the problem geometry and meshing this prior to solution.
geometry edit
sessionThe solver is self-explanatory. This will cause the solver to execute using the model specified. Solver capabilities are covered on a separate sheet.
The post-processor provides graph plotting and data visualisation facilities to examine the output from the model. Provided are graph plot, contour and carpet plot and 3D iso-surface plotting facilities.
post-processor
session