Hello,

I have set up a simple circuit. Port with 50 Ohm internal resistance and 100 Ohm load resistor. I would like to deliver fixed power to this resistor. Therefore, I set up 1dBm power property on PORT. With reflection coefficient of 0.333(3) (for voltage) or 0.111(1) (for power) I expect that the forward power increase factor is 1/(1-0.333^2)=1.125. This means the power delivered from PORT is 1.125dBm, reflected power is 1.125dBm * 0.111(1)=0.125dBm and the power delivered to load is 1.125dBm - 0.125dBm=1dBm.
When I run pss analysis and check Results -> Direct plot -> Main form -> Power and click on the terminal of the 100Ohm load resistor I get 0.4885dBm.
Can anyone explain this number?

Thank you.

See http://www.designers-guide.org/Forum/YaBB.pl?num=1235497885/1#1

tempora123 wrote on Feb 25^th, 2009, 1:43am:
Pinc=Pdis/(1-abs(Gamma)**2)
But power value set in port is Pinc not Pdis.
This is your misunderstanding.

tempora123 wrote on Feb 25^th, 2009, 1:43am:
This 0.4885dBm is Pdis for Pinc=1dBm at Gamma=1/3.