Simulation with transmission lines

[eee100]

Hello all,

I have designed a circuit in ADS which includes amplifiers and a bandpass filter. Filter is composed of lumped smt components. I have optimized the circuit for better S11 and S21 curves. Everything was fine up to this point. Then I started to design the layout and added transmission lines using MLINs and defined MSub. After this I went back to schematic to re-simulate. Now all my curves are messed up... I tried to optimize TL lengths and lumped element values but no luck. How can I obtain better results? I am using values for FR4 substrate. I didn't know that TLs would have a big impact on the circuit like this

 

[BigBoss]

Have you tried to simulate your filter by using Momentum EM simulator ?? If you already have done it, it should normally work well..


Then, you should simulate them in co-simulation environment.I mean, your layout and your discrete components should be simulated simultaneously.

 

[HouJun]

simulate them separately to see which one has problem

 

[sajan09]

Try adjusting T-Line widths rather than lengths. And yes do try to simulate them in parts