I've got a coupler in my receiver chain that I want to model with the 3 port S parameters that I've measured but I need to include the effect of the coupler on the noise figure of tthe system. If it were a 2 port passive loss I'd just use |s21| for the noise figure and append it to the end of the s2p file like you're supposed to. But you cant include noise data in s3p files. So how do I model the noise of a passive lossy 3 port device like a coupler?
You shouldn't have to append your *.s2p file with noise figure values at all - Genesys knows that this is a passive device and will use this to calculate the effect on noise figure accordingly. You should only need to add in noise data for active components such as amplifiers.
The attached s2p file has an example of the noise figure data at the bottom of the file below the *! NOISE PARAMETERS* line.
To convince yourself this is true run a simple system simulation with a just a 30dB amplifier and measure the noise figure. Then insert your coupler before the amplifier. The noise figure should have increased by the amount of loss is has. See attached Genesys file with this all set up to go.
regards
Dan
Edited by: dan.peabody on Jun 30, 2014 2:24 AM