readme.txt

This software gave volume MoM solution by the CG-FFT method

Welcome the user oriented version of CG-FFT.

I first would like to thank Prof. Catedra from Spain, for his software, which was published in the IEEE
 book of RCS of complex objects.

This software gave volume MoM solution by the CG-FFT method. The original software dealt only 
with few canonical bodies, and limited polarizations and aspect angles.  This version gives you the 
possibility to calculate the RCS of arbitrary dielectric/metallic bodies and gives you a user oriented 
graphical user interface (in MATLAB 5.2) with which you can easily enter complex objects.
After you have (hopefully) unzipped the zip filer provided, you should have 3 directories, namely 
CG_Files, mfile and ffiles. The CG_files directory contains the geometry data files. The mfiles
 contains the MATLAB pre-post processing routines and the ffiles contains the Fortran files which 
actually calculate the RCS.
In order to start the program you must have MATLAB vs. 5 and up.  In the MATLAB command 
prompt you should "cd c:\cg_fft\mfiles" (if you put the program in drive C).  and then press "cg_fft". 
This will open the main command window.  
In order to define the object geometry, you must first choose from the configuration menu the global 
and cell size item.  Then you can enter the number of hexagons in each canonical direction (which 
should be 2^n, like 8, 16 etc..) and also enter the hexagon size (it can be different for each canonical 
direction).  It should be noted that the cell size should be not more than 1/10 wavelength of the 
problem. Problem size can vary from 8*8*8 which will be solved very fast to about 128*128*128 
which will take a lot of time and requires PC with a lot of RAM. Of course Nx Ny and Nz does not 
have to equal to each other, just obey 2^n. 
After we have defined the problem size we can enter the geometry. This is done in the insert/edit 
geometry menu. An important note is that the geometry is defined only of the positive quadrate of the 
XYZ volume.
Here you can choose to enter arbitrary boxes, ellipsoids, truncated cones and truncated triangular 
cylinders.  When entering the permittivity, the imaginary part should be positive for normal lossy 
materials.  The ellipsoids can be formed as partial by defining the initial theta and phi angles which 
they cover. The same goes for the truncated cones.
After you have entered a new geometry item you can not erase it but you can edit it and put the 
permittivity to 0 if you wand to ignore it. Because in the final girding process, all the permittivities are 
summed up, you can create shell (for instance hollow dielectric sphere) by fist entering a normal 
dielectric sphere and then entering a smaller sphere with the same permittivity as the previous sphere 
but with negative signs.
After entering the geometry it is time to save it, use the save command in the file menu.

Before performing the RCS calculation we must first grid the volume , by using the command "View 
geometry, Girded data'".  This might take some time for large geometry. 
After girding the geometry, we can calculate the RCS and then view the results when the program 
stops. 
Don't forget that you have to have a Fortran compiler in order to run the RCS computation.
Also remember to close all windows after you view them.

Important Note:

This software is provided freely in the internet, however if  you appreciate my efforts and want to ask 
for some changes/support, I require that you send me 50$ for supporting this effort, so I can register 
you as a certified (valuable...:)  ) users.
Thanks

Aharon Blank     [e-mail]