dual circularly polarized antenna with branch line coupler feed

[povilas555]

Hi all, I'm some what confused about dual polarized antennas. In some cases it is concurrent dual polarization, while in others it is switchable between the two polarizations.

Take this example with branch coupler feeding each antenna and four antennas arranged in sequential rotation feed:

can feed like this achieve simultaneous dual circular polarization? Or is it switchable dual polarization where each port, RH and LH, are excited one at a time?

 

[PlanarMetamaterials]

Superposition applies in this passive circuit, so it can do both/either. We assume the power dividers appropriately decouple the LH and RH ports.

 

[povilas555]

Superposition applies in this passive circuit, so it can do both/either. We assume the power dividers appropriately decouple the LH and RH ports.

just to make sure I get this right. If there is sufficient isolation between LH and RH ports, then you can transmit/receive two independent beams in LHCP and RHCP at the same frequency?

 

[PlanarMetamaterials]

"Independent" is a complicated word here - I'm not sure if the LH and RH channels would have zero correlation, I could see it depending on things such a modulation scheme, etc. You could perform a simulation using one of these units as the transmitter, and another as the receiver, to find out!

 

[povilas555]

"Independent" is a complicated word here - I'm not sure if the LH and RH channels would have zero correlation, I could see it depending on things such a modulation scheme, etc. You could perform a simulation using one of these units as the transmitter, and another as the receiver, to find out!

I think if cross-polarization levels are good, then beams should be more or less independent.