CST MWS excitation source

Hello
I want to model wall and see the Electric field as EM wave travels through wall into free space. I created the model (attached). But I am unable to decide how to give an excitation source at a point marked. I tried discrete port as shown but E field doesn't appear to decay at the source location accordingly. I am looking at magnitude of E vector as function of time. How can I provide the value of E field say gaussian pulse at point 1 traveling straight towards the wall.
Thanks

Hi, do you know how to set the point dipole source?