Transformation polization

[hannguyen]

polization

I am designing a horn antenna. In order to receive every type of polization my horn need to build a transformation polization but I do not how to calculate its. Please help me how to do. My horn frequency range: 8 GHz-12 GHz I am using CST softwave and Magus antenna. Thank you for your help.

 

[sonofsky]

design double ridged horn antenna

Hi,you can use double ridged horn antenna, then, different feed arrangement can produce different polarization. same technique can refer to four-arm-sinuous-antenna……

Regards!

 

[Azulykit]

waveguide to coax transition with step transform

no matter what you do there will always be a polarization you will not receive.

 

[biff44]

how to convert a circular lnb to linear

A double ridge waveguide horn will normally only receive one polarization, the one where the Efield is developed across the two ridges. If you had a 4 ridge horn--two ridges in the horizontal, and two ridges in the vertical plane, that can be a different. story.

If you want to get fancy with mode converters, you can do more, but with only a combined output:
**broken link removed**

A circular horn will be able to circular polarization. You will need a way to convert the circular polarization into a single output. If you get fancy, you can get two outputs--one for RH and one for LH polarization. Satellite TV LNB receivers do this, for example.

A square horn will be able to receive two linear polarizations if designed properly.

One of the best investments of $20 you can ever make is to buy a cheap LNB dual polarization satellite converter antenna heads, take it apart, and see how it works. Fascinating stuff.

 

[hannguyen]

Re: Transformation polarization

Thank you for your help.
I am really confused about how to do this antenna because the signal we need to receive we do not know about the polarization. It could be linear or circular...So my antenna have to receive every type of polarized. I had seen an antenna which was fabricated by Russia engineer but it is different frequency range. They built a transition waveguide to coax, a transformation polarization and horn antenna I think that this antenna can receive any polarized because this antenna convert polarized step by step from aperture to waveguide. But I do not know how to calculate and design the transformation polarized. I had done waveguide to coax, horn antenna by CST and Magus software. Please help me.

 

[Azulykit]

The background idea here is that the various polarizations can be considered to be made up of orthogonal components. Any antenna will capture some of the radiated energy from any other (except one that is perfectly cross polarized).

The issue here may be one of polarization mis-match. For example a linear antenna will receive any circular polarized signal with -3 dB of loss relative to the appropriate circular antenna. A slant 45 degree linear antenna behaves similarly relative to vertical or horizontal linear.

A linear vertical antenna will not receive from a linear horizontal as they are "cross" polarized. Any circular will be able to receive from either, with a -3 dB polarization loss.