# MATLAB Radiation Questions

1. Sep 12, 2006

### golfingboy07

Questions:

1. A short dipole pz is oscillating with angular frequency omega. Draw contours of equal intensity of the radiation from this dipole in the x,z plane

2. A linear centre fed antenna is oriented along the z axis. Draw contours of equal intensity of the radiation from this dipole, in the x,z plane, for a half wave antenna and for a full wave antenna. Compare these cases , and also compare with the case of the short dipole

Thanks

2. Sep 13, 2006

### J77

Any ideas?

3. Sep 13, 2006

### chroot

Staff Emeritus
We're not going to do your homework for you. Do you have any idea how to approach this problem? If you can tell us where you're stuck, we can help.

- Warren

4. Sep 13, 2006

### golfingboy07

Sorry. I realise that.
Not sure where to start- maybe with <S> = (p^2 * omega^4* sin^2theta)/ (32*pi*epsilion_zero*c^3*r^2) for the short dipole case
And then use the 'contour' command in MATLAB. Have a range of theta values for a particular r and then change r to get multiple contours. Not really sure on this though. Any ideas to get me started?

Thanks

GM

5. Sep 13, 2006

### golfingboy07

Or better yet maybe use the 'polar' plotting function in MATLAB...

6. Sep 14, 2006

### J77

In Matlab you need to set up a grid.

In cartesian form, easiest if square:

x=[-10:0.1:10] y=[-10:0.1:10]

Then you evaluate your function z at all these points.

ie. size(z)=[length(x),length(y)]

You can then use contour(x,y,z) to plot it.