Rf power amplifier output power

[Irfan110]

The S-parameter analysis (S21=18dB, S11=-23dB) of the power amplifier is perfectly matched but output power is extremely low. How can I improve the output power?

 

[FvM]

Misses any relevant informations about the amplifier design.

You apparently keep your habbit of making stepped simulations with too few points.

 

[vfone]

If you get S21=18dB, and you get -0.7dBm output power for -10dBm input power, means that your PA is already in compression at -0.7dBm input power.

 

[Irfan110]

I need to design a 2.45GHz Digital Power Amplifier with 20MHz bandwidth and output power should be greater than 20dBm.

 

[BigBoss]

Output Power Level of an Amplifier depends on few factors more not only matching.
-Operating Point and Biasing Current
-Available Power from the Amplifier by Load Pull Measurements ( Optimum Load for max. Output Power )
-Input Matching that ensures the available power from the source is delivered to Amplifier
20dBm is not a high Power Level. Even medium power transistors ( FET or BJT ) may provide this level.

As I understand from your curve, the amplifier is wrong biased because the Transfer function is not regular. Check you biasing conditions

 

[amihomo]

Hi
Make sure you carefully follow the design procedure:
1) Refer to transistor's datasheet and invoke the source and load impedances to be matched with transistor in the frequency of interest (Zs, ZL)
2)perform source/load pull simulation in ADS to find the best Zs and ZL to meet the delivered power and power added efficiency (PAE) requirements of your design.
2) Design the input and output matching networks to match 50 ohm line to Zs and ZL
3)perform load pull simulation again in presence of matching networks again and modify the designed matching networks to get the best result.

BR