I have a question about MESFET operation. When Vgs=O V and Vds=O V, why I do not observe capacitance at the output ?

 

Because you have no method for observing capacitance? Because all 3 pins are tied together?

 

Output compared to where? With which mesfet? In what kind of circuit? With what measuring device?

 

Hey Guys. Actually I have used VNA for S-Parameter measurements. In S22 I do not observe curve tracing in capacitance region of Smith chart when Vgs=O V and Vds=O V. But The curve traces the capacitive region of Smith chart when Vgs=O V and Vds=2 V.
The measurement are made by connecting MESFET as a 2-port network and common source configuration. Gate is input port and Drain is output port.