Table of Contents
D. Muller, L. Nicolas
Centre de Genie Electrique de Lyon
Ecole Centrale de Lyon
Other applications or tools from this site:
mField,
Edgar
To the list of Colos applications
mWave is a package solving in real time the analytical field equations to show the electric or the magnetic field -- for either TE or TM modes -- inside an infinitely long wave-guide of circular or rectangular cross-section.
- The user interface as well as the solver have been designed to conform to following specifications. One may study either TE or TM guided propagating modes.
- Any component x, y or z, or the magnitude of the electric or magnetic field may be shown.
- One may interactively modify the a/b ratio of the rectangular waveguide -- or the radius of the circular guide -- as well as the physical parameters mu and epsilon.
- The user has to be able to interactively modify the frequency of the source to show how a given mode may travel inside the waveguide at different frequencies.
At a high enough frequency, more than one mode can propagate. mWave is able to show the fields resulting from the superposition of two or more waves propagating in the waveguide at a given frequency
.
mWave showing the amplitude of Electric field
for mode TE11 propagating in a waveguide of
5cmx5cm cross-section
Since one of the main goals of the mWave package is to display results as quickly as possible, one obviously could not use advanced numerical methods like finite elements or boundary integral equations. To gain speed, mWave uses analytical field equations with the hypothesis of an infinitely long wave-guide of circular or rectangular cross-section, which are solved in real time for any pixel of the displayed window.
The field values are represented using colour scales rather than the well-known field lines, to support the notion that the field is present everywhere. Otherwise students easily could believe that things only happen where lines are drawn.
In a second step, field lines may be drawn in addition to the coloured zones, showing for example that the field is not constant when moving along a field line. The field lines are animated to show the field direction.
The highly interactive implementation allows for easy tryout of any configuration. By giving immediate feedback, it supports comprehension of dynamic phenomena, making this package into a powerful tool for the intuitive understanding of the field behaviour inside a waveguide. The way, the cutoff frequencies of the various propagating modes order themselves along the frequency axis, described by a quite complicated formula, is an example of what may be intuitively understood using mWave without knowing the underlying mathematical aspects.
This package is written in C and the user interface conforms to industrial standards X-Window (X11R5) and Motif (1.2) which guarantees easy porting to most Unix platforms.
All highly interactive actions may be taken using activators (buttons, scrollbars) on the front panel, whereas less frequent actions like configuration modifications or file access are done using the menu tree accessible from a standard menubar.
The mWave package also implements a BMS (Broadcast Message Server) interface which allows to do any actions accessible from the user interface by sending messages to the application. This mechanism may be used for example to produce automatic demo runs or to generate long animation sequences which would be too long to be produced directly by a user manipulating the package.
BMS is implemented on HP stations and is available on DEC and IBM systems. It is possible to compile mWave without using the BMS features for systems where such a server is not available.
This package is intended to be used by high-school or PhD students aiming at a better and more intuitive understanding of waveguides.
This software is currently evaluated by research staff members at ECL (Ecole Centrale de Lyon - France), Universite de Limoges - France, and RPI (Rensselaer Polytechnic Institute, Troy - NY).