ads limitations

hi all
any one know real limitations for ADS momentum , I'm simulating very narrow slotline at high frequency with very thin film
here the parameters :
substrate1: 500um
substrate2(thin film): 1.5 um
slotwidth :10um
slot length : 5 mm
frequency 30GHz

i have completely wrong results , i don't know what is wrong is that because of ADS momentum limitations ???? and if yes please suggest to me how i can simulate this slotline
thanks
Amr

Please share the design with us to find the wrong

From the given parameters, I can't see much oddity. Yet I'm also new to ADS. All I know is that I have simulated structures with 3um minimum dimension and 1mm maximum dimension, 20nm minimum dielectric layer, and 0.2um metal thickness, and the result seems to be correct.