correct way to optimize

I'm optimizing my transmission line schematic by automatic optimization tools for 60GHz LNA. If I constrain the value within 10~20% range to what I calculated and relax other less important parameters, the results are not very ideal. However, if I fix the width, let it run from a wider range of length, the results are surprisingly better but with very long length. Which is the correct way to optimize?

Thanks,

It seems that there is a problem in your calculations.Did u simulate your tlines before optimization?The width of the tline defines its characteristics impedance the length of tline combined with characteristic impedance determines its input impedance.Did you use your tlines for impedance matching? If so , try to simulate your impedance matching matching networks individually.


Regards,
ALP

As long as the selected variable is with in the limits of design /fab rules it is OK.
Optimization methods are many.
Do not worry about it