omnidirectional dual polarization antenna?

[biff44]

Is there any design for a omnidirectional antenna that receives both horizontal and vertical polarizations without incuring a 3 dB hit in gain for the dual polarization feature? I think the answer is no, since you are in essence passively combining two different antennas, but I would be interested if there was a way to do it without additional loss.

 

[Malek Lamari]

A topic of great interest !
ok, i am excited to know more; lets discuss the origin of the loss.
is it due the mutual coupling effect of two near antennas ?

 

[biff44]

I am very interested in picking up 3 dB whenever possible! I did an antenna once where I combined a vertical polarized whip with a horizontal polarized loop, and it did give me omnidirectional dual polarization pickup. They were both "small" antennas, and I did not have precise measuring equipment, so I never empirically answered the question of if I took a 3 dB hit on each polarization. I combined them 90 degrees out of phase, as that seemed to work better than 0 degree in-phase combining.

Rich