[SOLVED] (ADS) issue at designing a yagi antenna with rat-race coupler feeding

[th3jabi]

I am designing a yagi antenna at 9GHz and I want to implement a rat-race coupler to unbalance the signal and broaden bandwidth. The thing is that even though the coupler and the antenna work as intended when simulated on their own, every configuration i've tried with both of them in the same layout results in all the power getting reflected (not all but most of it) with almost no radiation at 9GHz. I'd say the layout has all the impedances properly matched: Z0=50ohm at the input and output paths of the rat-race, sqrt(2)*Z0=70.7ohm at the ring, and an odd impedance Zo=50ohm at the coupled lines feeding the antenna. Does anyone know what may be happening here? or at least something i can do to keep checking my design. Thank you.

I attached images of my actual layout and the s11 curve i currently have for the design.

 

[BigBoss]

If I were you, I'd separate these structures and check them individually.
Pay attention to Phase Relationships too because this is the key factor.

 

[th3jabi]

If I were you, I'd separate these structures and check them individually.
Pay attention to Phase Relationships too because this is the key factor.

hello and thank you for replying! when you say phase relationships, do you mean that the coupled lines feeding the antenna are operating with a phase difference of 180º respect to each other? if that is the case, it should be like that given that when i simulated the rat-race individually it worked as intended, delivering the port 1 signal to the output ports (the ones feeding the antenna) at -3dB and with a phase difference of 180º and the length and shape of the antenna feeding lines are the same for both.

I have also tried simulating the antenna individually adding a balun at the feeding and it also worked properly, showing almost -20dB at the operating frequency.

 

[BigBoss]

I have just seen now two errors on your layout. Two microstrip lines are not connected properly. You can see these point as turquoise color instead of blue.
Check again your layouts' connections. They don't touch properly to each other.

 

[th3jabi]

I have just seen now two errors on your layout. Two microstrip lines are not connected properly. You can see these point as turquoise color instead of blue.
Check again your layouts' connections. They don't touch properly to each other.

Ooh! thank you so much. i didn't know that marker meant the terminals were not connected (i should have suspected something was wrong as they were different from the rest)