23cm Amplifier Development using RFSim99 - Part 2

Following on from Part 1, here is how I plan to replace the matching netowrks with microstrip.

Step 1 : Input network

1. Remove the LC components on the input network.
2. Press Simulate and read off input impedance of 4.96R+j3.93R
   
   
3. We know that one full revolution of the Smith Chart is 23cm/2. By inspection we can see that we need a transmission line around 62 degrees (135 degrees/2)
   
   
    
4. Insert a 4cm transmission line (62degrees electrical length at 1296MHz) and press Simulate
   
5. Not quite long enough. Trial and error guesswork gives us 4.4cm. The alternative to this inspection approach is to use a program like Iowa Hills Smith Chart which I prefer. But I'll stay on-topic.
6.  Now we need to move along the arc towards the origin with a series capacitor. I started with 6pF, since it was there on the output network. There was little movement so I halved it each iteration. I found 0.82pF was the closest standard value. You can buy these!
   
   
   

Step 2 : Output network.

1.  Repeat along the lines in Step 1. It is a nice coincidence that the output transmission line is the same length as the input line. Since we hit the arc running towards the origin a littel closer to the origin than the input network did, we can use less reactacne. I guessed 1pf. Turns out 1.2pF is better.

Results

We still have stability and good matching. Gain is  unchanged at 18dB. But now we have two standard value capacitors and some PCB drafting to do.

I'll post about the artwork next.