one sided matching network question for power amplifier

[yefj]

Hello,As you can see in the photos bellow i only matched the input of the Power amplifier and got my desired 15dB gain.
Why its working? i am supposed to match the output too.
In what cases we can match the input only?
Thanks.

 

[vfone]

In a single stage Power Amplifier, input match will affect the Gain , when the output match will affect the Output Power, the Linearity, and the Efficiency of the PA.
For the latest three characteristics, the output match should give a compromise getting decent values for all of them.

 

[BigBoss]

There are many errors in your simulation set-up bud .. You didn't use a coupling capacitor,( Id(M1)=6.88mA, Id(M0)=443uA !!)
You circuit may not be stable..
You should use an Input Stage Matching for Highest Gain then you have to work on Output Stage Matching Circuit to achieve Max. Pload OR max. Efficieny with a appropriate Gain.
So, iteration will be necessary because they are not obtained generally simultaneously..

 

[yefj]

Hello Big Boss, the problem is as you can see in my circles plot,when i select a dot inside this circle it gives me only the Zd parameter which is the input impedance needed to be on that dot,cadence is not giving the output impedance needed to be in that dot inside the circle.
So i assumed that we dont need output matching for getting 15dB power gain.

You said (beyong Coupling capacitor for current balancing)
We need to do circles again but from the other way around to achieve max. Efficieny with a appropriate Gain?
so i Switch the ports to match for the output?
Thnaks.