Biasing of ads model microwave transistors

[dineshmoorthy]

DEAR SIR

i have a basic doubt in biasing of S parameter model OF microwave transistor provided in ADS. i have observed without biasing of transistor , with a matched termination i able to get the S parameter values provided in the datasheet with s parameter simulation. do i need to bias the model while using in circuit design in ADS?

THANK YOU

 

[RealAEL]

S-parameter data is measured using a device already biased at a specific bias point of interest. It contains only that data at that bias point and not anything to specify how the device will operate at other bias points. When you re-use that s-parameter data in a circuit simulation the assumption is that you will be simulating the circuit with the device biased at the same level as that for which the measurements were taken. You do not actually need to bais the device to get the appropriate simulation data. If any bias network was connected to the device it would have no effect, it would not matter if the bias was 1V or 100V the results would be the same.