circularly polarised antenna

hi all
can anybody tell me how to simulate the circularly polarised fm antenna and some design tips which s/w for the simulation

thanks in advance

What about the antenna do you want to simulate? Most circular polarizations are made with a horizontal and a vertical antenna fed 90 degrees apart. If this is your case you can take advantage of orthogonality and simulate each antenna separately and add the electric fields at any azimuth, elevation, and range. Or you can do the whole works at once.

SuperNEC is good but it requires matLAB.
There are several free NEC programs here http://www.qsl.net/wb6tpu/swindex.html

Hi Flatulent,

using your method of 2 orthogonally feed antenna to obtain circular polarisation, how do I obtain cicular polarisation radiation plot? Can this be done automatically in SuperNEC or do I need to phyically extract the data files and then add them?

Many thanks in advace 4 ur help :)

Cheers,
Element7k

If you do the whole thing at one time the results are correct.

If you do each half separately, you will have to add them by the square root of the sum of the squares method.

This latter is very inconvenient if you want numeric values. If you just want to look at the two plots and add them in your imagination it is usable.

I do not know enough about each simulator to know how the outputs can be combined.

The advantage of doing them separately and combining them in your imagination is that you can tell the amount of circular polarization. When the two fields are equal it is circular. When they are slightly different it is elliptic, and when one is much larger than the other it is linear with the polarization of the larger field's antenna.