My microwave circuits class is currently covering 2 port network. It has covered z, y, a, b, g, h, and ABCD parmeters but has not got to S-parameters...

My microwave circuits class is currently covering 2 port network. It has covered z, y, a, b, g, h, and ABCD parmeters but has not got to S-parameters section. Given that, students were given these critical thinking questions.

1. Generally, circuits and components are divided into passive and active circuits.  Is there a way to know if a black-box sub-circuit is passive or active by looking at its 2-port parameters?  If yes, how?  If no, why not?
2. Suppose we have the 2-port measurement of a simple network that is made up of 2 components (L, C, or R) that are connected in series or parallel or a combination of series/parallel. Is there a way of knowing what the two component types are and what their values are? Can you give an example?
3. Suppose in the above case, one of the two components is a transmission line. Can we tell that there is a TL? If yes, how? If no, why not?