LNA Layout Design in AWR Microwave office software

I am doing project on design of LNA (12 GHz). I am using NE3210S01 transistor manufactured by Renesas corp. (formerly NEC corp.). I using the non linear model of the transistor in AWR Microwave office environment. I have completed the input matching and output matching circuits using lumped element for gain=12 dB and NF=0.7 dB. After that i want to generate Layout of the LNA. But i am facing many problems in this step.
I followed the example given in AWR Microsoft office 2011 "10GHz LNA design". In that design i saw the final input and output matching circuit(lumped+distributed) and got confused.
Why one should use Microstrip line/transmission line in between lumped elements of matching circuit? and How to calculate the length and width?
Also when i saw the final layout of stable amplifier that was completely different. Some additional distributed elements added in that final circuit.
Kindly help me.

If you post your layout, we can say something..

In order to optimize s-parameters on filters used in front-end input and output, impedance transformer line matching is necessary. Many resources exist on strip design.

winersonly said:

Why one should use Microstrip line/transmission line in between lumped elements of matching circuit?

Click to expand...

In many cases, the lines are only used to connect the SMD, and have no explicit "transmission line" functionality. They are just modelled with microstrip elements in schematic because this includes the electrical effect of that layout path, and also enables automatic layout generation.

If you would draw the connection between the SMD with wires in layout (no microstrip elements) the only way to include their electrical effect is EM simulation.