How to test BSA pattern with +45/-45deg X-POL dipoles

guys,

I want test the Horizontal and Vertical 3dB beamwidth of a BSA with +45/-45deg X-POL. There are 2 ways: 1)DUT is rotated 45deg 2)source antenna is rotated 45deg.Which is right? I hope get your suggestion.

Thanks!
XuQing

I think the source antenna should be rotated to +/45 degree.
In my case, my source antenna is a standard gain horn.

In my case, my source antenna is a yagi, which is rotated to +/45 degrees to do the test.

Hi, there's no difference between rotating the DUT and rotating the source antenna, in fact you could use the DUT as the source and measure at the Rx antenna........ The only thing you have to make sure is that both antennas have the same polarization.

So in your case you should rotate the antenna that makes the meassurement process easier for you.......

There is a question.
If source antenna rotated +/-45deg to suit BSA which placed vertically and test horizontal pattern. Then the POL direction will cross with source antenna when BSA rotate 180deg in horizontal plane.
So the right way must be rotating BSA +/-45deg, and the source antenna keep vertical POL, when test horizontal pattern.

Thanks a lot!
XuQing

But will u rotate the BSA +/-45 degrees in practical use?

Of course No, I only want to get a correct pattern testing method for that kind of antenna.

Thanks!
XuQing

Hi XuQing

If you rotate the DUT antenna in 45° you get different cut of
the pattern. the beamwidth in 45°pol of the DUT it's between
the Horizontal beamwidth and Vertical beamwidth
So you have to do it in the source antenna to get the write
beamwidth
.

Yes, rotating DUT antenna in 45° will get +/-45deg cut pattern. But that's a real case. Because the Tx and Rx signal is +/-45deg POL in practical use. So the useful Tx and Rx EM field transmission should be in +/-45deg cut pattern.

Thanks !
XuQing