Schematic-to-layout power splitter

I am currently trying to simulate an array of Vivaldi antennas. I work with ADS Momentum. I have finished the elementary antenna design, but I am having problems with the 2-way Wilkinson power splitter. I designed and optimized it using Schematic, but when I create the layout and try to simulate it, some of the results are good (S11, S21), but some are wrong (S22, S23). I am using only one layer (resistors are Lumped with artwork).

I read that I could create a handmade resistors instead, on a different layer and connected using via to each section of the power splitter. Sadly, I don't know exactly how to obtain the needed resistance by means of dimensions and resistivity.

I also know that I could use EMDS co-simulation to skip the layout, but I have no experience with it.

have you used isolation resistor? i mean you need to use finally sch simulation for the layout component and place isolator resistor.

if your S11 and S21 are good result , but S22 and S33 are worng
you must to check the isolation resistor(100 ohm), it placement between port2 and port3
about layer problem , you should chose the resistor size (0402,0805,1210...etc.)and measurment Port2 and Port3 distance
and simulation of HFSS,IE3D....etc. to check result.

You can also put a match stub on port 2 and port 3 to adjust VSWR of S22 and S33.

---------- Post added at 22:47 ---------- Previous post was at 22:46 ----------

Or a impedance transformation microstrip at port 2 and port3.