polarizer ku antenna
Now I am working in a SATCOM terminal for ku band. We need (in transmiter) a waveguide polarizator. We have design one corrugated waveguide but we are studing different possibilites. I have seen one polarizer which consists on a waveguide with an internal dielectric plate, but we need to rorate this dielectric plate to obtain different linear polarisations and we don not know how we can make it possible. Can anyone help me please? I have been loking for information but I have not found none. Besides I have seen another magnetic ferrite polarizers. Does anybody know if this devices are adapted for this application.
Thaks to all.
you might consider meanderline polarizers or a screen consistion of parallel wires and then rotate the screen as needed. Place the screen at the aperture of your horn.
I have seen the wire screens work from 500 MHz to 200 GHz (not the same screen of course).
Thank you so much.
But Can I put this parallel wire screen into the waveguide ?
In that case, I do not undestand how I can make the mechanical rotation of the screen into the waveguide.
Thank you so much.
What you shold do is that you print some meander lines or slant lines on a board and then you cut the board so the lines pose at the angle you want relative to waveguide (bu default 45 degree)
Yes it is perfect. But this terminal has polarization tracking. Depending on antenna location we need different linear polarization (different polarization angle) so we need modify the output polarization angle with this waveguide polarizer so I think that is necessary modify the lines orientation in the screen, is is ok?
Article attached explains a method of modeling meanderline polarizers
You can find another type of polarizer, the transpolarising surface made of square patches and diagonal slots. Other twist polarizers are made of meander lines or simply strip lines.
The principle of operation is primarily due the 45o tilt in the incident electric field with respest to the direction of the meander or strip lines. Then, a 90o rotated electric field is reflected. For the case of the square patches with diagonal slots, the incident electric field should be aligned with the patches (45o with respect to the slots).
You can find more information by searching on twist polarizers, cross-polarising or transpolarising surfaces. Good luck,
Pere