3D MoM-MATLAB CODE-irregular terrain modelling

irregular terrain model matlab

I am a newbie in EM methods and i am working on my thesis concerning propagation modeling.
First, i want to simulate with MATLAB the EM scattering over PEC sphere. I read "Antenna and EM modeling" book by Prof Makarov. Has someone MATLAB code for 3D MOM using RWG basis functions??
could someone explain how should i define the vertices and edges of each RWG triangle and how will i make the integration within each triangular patch?
Moreover, is someone familiar with MoM applied for irregular terrain modeling?
i am supposed to use a topographic database from a suburban area (mountains and hills) and i have to apply MoM for computing the E-field. How can integrate the MoM equations in a whole area?
Thanks in advance and sorry for the "big" questions!!
Aris

mom matlab .m

alright, let's divide your big questions into a number of smaller ones

1. The MoM code using RWG basis functions is in the accompanying CD-ROM of the book, and you may also download the updated version from the book website.

2. I don't know what do you mean by defining the triangles, yu should have a number of points that define the surface of your structure and then use delauny triangulation to obtain the triangulation, the matlab function delauny defines the vertices of each triangle. You should then convert these into + and - triangles as written in the book.

3. I have used MoM to model small structures (10 lambda or so), I am not sure if it can be used for larger areas (unless you are talking about low frequency, and in such case yu will face the problem of singular matrices)

4. I don't know what do you mean by integrating MoM on the whole area, you integrate over each triangle.

regards,
Adel

makarov mom matlab

Thanks Adal....
Concerning irregular terrains, i will load a topographic database in MATLAB. Then i am supposed to use MoM-integral equations for the intermediate obstacles. So, i think that i have to approximate the obstacles (mountains) with pec spheres or cylinders and hence to implement MoM over each structure..All this process seems quite complex to me!!! To be more specific, the database includes x-y-z coordinates that consitute a map. So, i will assume a transmitter and receiver at 2 certain locations and i will take into account the obstacles that obstruct the wave propagation.
A simple approach that crossed my mind is that since i have the MoM code for a 3D sphere, i must find a way, if possible, to use this for multiple pec structures.
Sorry if i confused you and thanks again.
Aris

in matlab there is limitation on total no of RWG fns that can be used ..can you tell me some way to overcome that limitation or share some code in FORTRAn

Are you talking about MATLAB license issues (limit on maximum matrix size for some versions) ? You might want to use the 64bit version of MATLAB in this case your maximum matrix size is not limited to 2GB.

Another trick is to use single precision matrices (half the memory), you have to make sure that the functions that you are using support them though.

Adel

some methods such as MLFMA (by Rokhlin and Chew) , AIM and PFFT presented to extent the MoM for complex large structures. you can find more information about them in the literature.

If you are interested in modeling propagation you might be interested in TIREM:

**broken link removed**

could you tell me how to split an object in RWG function? Is an object splited into N or 2N triangulars?