filter optimization!

i need help to optimize this dbr filter!

i sythetize my DBR filter with ADS with ideal line and i post here the sheme!
after that
I transcribed the lresults by using line calc and then on new window ADS I simulated my circuit with the acquired length, and as you can see it, results don't corresponds in no way to those acquired in ideal lines because i do not take into account models of incoherence of end of lines and junctions

so, my question what is the procedure of optimization to find the new length of microstrip lines to find which gets closer most ideal case?

THANX

ok,i finnaly got it!
if someone is interested by the results i post them below!

my error in the design i posted above is that i don't take in acount from the effective permittivity!