How to polarize a signal before sending it to the antennae
So I'm not sure what your working on (context helps!), but here's some general advice:

A signal is generally polarized by the orientation of the antenna you are outputting from.  A vertically oriented antenna will output waves which will be more easily picked up by another vertically oriented antenna.  A horizontally oriented antenna will output waves which will be more easily picked up by a horizontally oriented antenna.

Vertical polarization has the benefit of being omni-directional (when using a whip or dipole antenna).  Horizontal polarization has the benefit of bouncing off the surface of the earth (or ocean) with less loss, thus generally traveling further with the same power.  The downside to horizontal polarization is that you generate a directional wave so it needs to be aimed at the target.

You can get a varying polarization by having two antennas orthogonally oriented and then varying the strength of the signal in the antennas.

I hope that helps!