winglj
Full Member level 4
Hi, everyone.
I have a question about to design a four-port devices, as shown in the attached picture. The Ant 1 and Ant 2, as well as Tx and Rx ports are isolated at both Tx and Rx bands.
For Tx band at (a), the signal paths should be from Tx port to Ant 1 and Ant 2, equal amplitude but with 90 degree phase difference.
For Rx band at (b), the signal paths from Ant 1 and Ant 2 to Rx port, also with 90 degree phase difference.
The ideal I come up with is shown in (c), with one branch-line coupler cascaded with Tx and Rx filters at its own port. However, by a simple simulation, I found that the impedance matching at Ant 1 and Ant 2 ports are pretty bad.
I am wondering are there any good architecture that can finish the functionality?
Thanks.
I have a question about to design a four-port devices, as shown in the attached picture. The Ant 1 and Ant 2, as well as Tx and Rx ports are isolated at both Tx and Rx bands.
For Tx band at (a), the signal paths should be from Tx port to Ant 1 and Ant 2, equal amplitude but with 90 degree phase difference.
For Rx band at (b), the signal paths from Ant 1 and Ant 2 to Rx port, also with 90 degree phase difference.
The ideal I come up with is shown in (c), with one branch-line coupler cascaded with Tx and Rx filters at its own port. However, by a simple simulation, I found that the impedance matching at Ant 1 and Ant 2 ports are pretty bad.
I am wondering are there any good architecture that can finish the functionality?
Thanks.