Simulation of LCX in CST

Hello!
I am trying to simulate an Leaky Coaxial Cable (LCX) on CST. I used the coaxial connector template. I am exciting the cable at one port with a waveguide port. I've changed the boundary conditions to open (add space), except on the waveguide (it is only open).
The problem is that the results that I have for S11 are not the expected. The LCX that I am trying to simulate is described in a paper and the paper has S11 results obtained on a network analyser.
Can anyone tell me what I maybe doing wrong? Should I use another template or excitation port?
By the way, how can I terminate the cable with a certain impedance?

Can you link reference paper here?

you solve your problem?