Export radiation pattern to stl

Hey there,

I try to export a radiation pattern (3D) in the .stl format. That's my code:

fc = 62e9;
pm = design(patchMicrostrip, fc);
pattern(pm, fc);

Now it would be great to export this pattern as .stl or something similar. I'll be greatful for every idea or hint.

Thanks in advance!

[Anne]

I thought about (and tried them):

> stlwrite (part of the antenna package), which needs a triangulation object as input, but i couldn't find a way to convert the 3D-pattern to a triangulation object

> surf2stl (https://uk.mathworks.com/matlabcentral/fileexchange/4512-surf2stl), which needs a Surface as input.

h = gcf;
get(h)
children = h.Children
axChild = children(6).Children

This shows me that "Axes" has a Child of type Surface. I can export this to an stl without problems, but it's just a sphere. So there has to be some information missing.

Thanks in advance for any helpfull idea!

Answer 1

[Sai Kiran]

Hi,

Please follow the steps below to export the 3D radiation pattern to .stl format.

[D,A,E]=pattern(pm,fc)

where D is the Directivity, A is an array of azimuth angle and E is an array of elevation angle.

[A,E]=meshgrid(A,E);

Download the surf2stl function from the below link.

surf2stl - File Exchange - MATLAB Central (mathworks.com)

surf2stl('filename.stl',D,A,E);

The resultant stl file contains the 3D radiation pattern.

I hope it resolves your query.

Answer 2

[DGM]

Let's go the rest of the way.

% let's say we have the pattern data
l = linearArray;
[D A E] = pattern(l,70e6);

% yeah, we're gonna need to expand
[A E] = meshgrid(A,E);

% but we also need to change to cartesian
% note the change of units and the shift on D
[X Y Z] = sph2cart(deg2rad(A),deg2rad(E),D - min(D(:)));

% now the data is in a form that can be accepted by surf() or surf2stl()
hs = surf(X,Y,Z); axis equal

% but we really don't need to use surf2stl() if we don't want to
[F,V] = surf2patch(hs,'triangles'); % the 'triangles' option is needed
T = triangulation(F,V); % now we can just write it like any STL
stlwrite(T,'test.stl')

% for show and tell, let's just read it back and show it
T = stlread('test.stl');
figure
trisurf(T,'facecolor',[1 1 1]*0.8,'edgecolor','none')
view(3); view(-40,33); camlight; 
axis equal; grid on

As an aside, trying to learn toolboxes I don't even have, while in the confines of the forum editor is really a cumbersome feeling.

See also:

https://www.mathworks.com/matlabcentral/answers/501620-how-to-save-the-result-of-stlwrite-to-a-specific-directory-chosen-by-the-user#comment_3341828