Plotting antenna field patterns in spherical coordinates

Hi, I have a 2D array which of the form A(theta, phi) and I want to plot A as a 3D surface. I have read advice which suggests to use the sph2cart function to convert to Cartesian coordinates, then use surf or mesh, but as size(A) = 46 90, i.e. it is not a square 2D array, it will not work. Any suggestions? Thanks

Answer 1

[Kelly Kearney]

Why do you think your array needs to be square? Mesh, surf, etc. will accept any gridded data. Assuming your A values represent the radius at any given theta and phi:

 theta = linspace(0, pi, 90);
 phi = linspace(0, 2*pi, 46);
 [theta, phi] = meshgrid(theta, phi);
 A = ones(size(theta));
 [x,y,z] = sph2cart(theta, phi, A);
 mesh(x,y,z)

Is this what you're after?

[Rhiannon]

Exactly what I was after. I was getting error messages when I was using sph2cart, and I assumed it was because I didnt have a square array, but it must have been something else.

Thank you

Answer 2

[Ebrahim Forati]

Just added a couple of fixes to Kelley's answer:

theta = linspace(-pi/2, pi/2, 90); % theta is w.r.t. xy plane

phi = linspace(0, 2*pi, 46);

[theta, phi] = meshgrid(theta, phi);

A = ones(size(theta));

[x,y,z] = sph2cart(phi, theta, A); % fixed this line too

mesh(x,y,z)

Answer 3

[Vishwanath Iyer]

Consider the following function in Antenna Toolbox for plotting radiation patern data:

https://www.mathworks.com/help/antenna/ref/patterncustom.html